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    Epidemiological Investigation of Respiratory Pathogens in Deceased Fattening Pigs in Major Pig Farming Area of Middle and Eastern China and Characterization of Pasteurella multocida
    LUO SuXian, ZHOU Hong, LIN HuiXing, FAN HongJie
    Scientia Agricultura Sinica    2024, 57 (11): 2254-2264.   DOI: 10.3864/j.issn.0578-1752.2024.11.016
    Abstract628)   HTML13)    PDF (1165KB)(141)       Save

    【Objective】This study aims to isolate and identify prominent bacterial respiratory pathogens from samples collected from fattening pigs that have died from respiratory diseases in major domestic pig farming area of middle and eastern China. And identifying these bacterial pathogens will offer valuable evidence for preventing and controlling the significantly prevalent respiratory diseases in recent years. Moreover, the characteristics of Pm were identified, providing reference for the development of Pm vaccines.【Method】The lungs of pigs died from respiratory disease were collected from large-scale farms in major pig farming area of middle and eastern China from 2021 to 2023. Blood agar and TSA were employed for the isolation of pathogens, which were then identified through microbiological and molecular biology methods. Additionally, MLST typing and virulence testing in mice were conducted on Pm isolates. The primers for PCR against seven housekeeping genes of adk, est, gdh, mdh, pgi, pmi and zwf of Pm were designed. Then the productions of amplicons were sequenced and submitted to perform MLST typing. The capsule and lipopolysaccharide typing were detected by PCR. The virulence factor genes were detected by PCR. Single isolates of A type and selected D and F types of Pm were evaluated for virulence in ICR mice. LD50 of JS-65, JS-51 and JS-34 were detected in ICR mice.【Result】A total of 73 Pm isolates were obtained, with an isolation rate of 15.53%. Additionally, 71 SS isolates, 29 APP isolates, and 10 GPS isolates were obtained, with isolation rates of 15.11%, 6.17%, and 2.13% respectively. The typing results indicated that the prevailing subtype among Pm isolates was A:L3, accounting for 55%. Among SS isolates, subtype 9 was the prevailing type, accounting for 38.03%. Among APP isolates, subtype 15 was the prevailing type, accounting for 51.72%. Among GPS isolates, subtype 5/12 was the prevailing type, accounting for 60.00%. Co-infection included Pm+SS, Pm+APP, SS+APP and Pm+APP+GPS, accounting for 16.67% of the total pig population. Three capsule types were isolated: A (67%), D (30%), and F (3%). Two lipopolysaccharide types were found: L3 (56%) and L6 (44%). Nine ST genotypes were identified: ST79, ST50, ST7, ST74, ST13, ST27, ST9, ST287, and ST370, with proportions of 33%, 26%, 16%, 10%, 4%, 4%, 3%, 3%, and 1%, respectively. The results of virulence gene detection showed that the positivity rates of ptfA, fimA, hsf-2, exbB, exbD, tonB, fur, nanH, sodA, and sodC genes were greater than 95%. The positivity rates of hsf-1, pfhA, tadD, hgbA, hgbB, pmHAS, ompA, ompH, oma87, and plpB genes ranged from 40% to 90%. The positivity rates of tbpA and nanB genes were between 10% and 30%; the toxA gene was not detected. The virulence test results indicated that all mice died when exposed to less than 102 CFU of strain A, the mortality rate of mice was between 60% and 100% when exposed to 103 CFU of strain D, and the mortality rate of mice was 60% when exposed to 5×103 CFU of strain F. LD50 of JS-65, JS-51, and JS-34 were detected in ICR mice, and the results showed that JS-65 LD50<10 CFU, and JS-51 LD50=6.3 × 102 CFU, JS-34 LD50=3.98 × 103 CFU.【Conclusion】Based on the bacterial pathogen isolates from 2021 to 2023, the primary pathogen bacterium of the respiratory tract in dead fattening pigs were Pm, SS, APP, and GPS. Pm had the highest number of isolates and isolation rate from lung tissue. The RIRDC identified a Pm strain of ST370 and extended MLST typing data in pigs. PCR typing results showed that the dominant serotype of Pm was A:L3:ST79, which exhibited the highest virulence in ICR mice with a minimum lethal dose of less than 10 CFU. These results serve as the foundation for the development of an inactivated Pm vaccine.

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    QTN Mining and Candidate Gene Screening of Upland Cotton (Gossypium hirsutum L.) Seed-Related Traits
    BAI BingNan, QIAO Dan, GE Qun, LUAN YuJuan, LIU XiaoFang, LU QuanWei, NIU Hao, GONG JuWu, GONG WanKui, ELAMEER ELSAMMAN, YAN HaoLiang, LI JunWen, LIU AiYing, SHI YuZhen, WANG HaiZe, YUAN YouLu
    Scientia Agricultura Sinica    2024, 57 (15): 2901-2913.   DOI: 10.3864/j.issn.0578-1752.2024.15.001
    Abstract596)   HTML119)    PDF (3621KB)(564)       Save

    Objective】Exploring the genetic loci and related genes that control cottonseed size traits to lay a foundation for subsequent study on the molecular mechanism cottonseed size formation. 【Method】The upland cotton recombinant inbred line (RIL) population composed of 300 lines was used as the research material. Seven phenotypic traits including cottonseed index (SI), seed length-cutting acreage (SLA), seed length-cutting perimeter (SLP), seed length (SL), seed width (SW), length-width ratio (LWR) and seed roundness (SR) were evaluated in four environments. The RIL population was genotyped by liquid phase chip strategy. The high-quality single nucleotide polymorphism (SNP) markers and phenotypic data were subjected to perform genome-wide association study (GWAS), and quantitative trait nucleotides (QTNs) associated with cottonseed size-related traits were mined. The genetic effects of QTNs were analyzed to identify candidate genes. 【Result】Seven cottonseed size-related traits showed a continuous normal distribution in four environments, which expressed a sizable phenotypic variation. The coefficient of variation ranged from 1.82% to 10.70%. The influencing effect on trait formation were basically as genotype>environment>genotype × environment, indicating suitability for GWAS analysis of these results. Correlation analysis showed that the seed index was significantly correlated with SLA, SLP, SL and SW, and LWR was significantly correlated with SR, indicating the possible existence of pleiotropic loci. GWAS was performed using the 3VmrMLM model, and a total of 47 QTNs were associated with these seven traits. A total of 11 QTNs were associated on chromosome A07, of which three physical loci in the region of 71.99-72.87 Mb, A07:71993462, A07:72067994 and A07:72198802 were very close and simultaneously associated with SI, SLA, SLP, SL and SW in four environments. The average value of R2 between markers was>0.8 (P<0.001), showing a large linkage disequilibrium. Genetic effect analysis showed that there were two haplotypes in this region. Among these cottonseed size relating traits, haplotype Ⅱ and haplotype I were significantly different, indicating that these loci directly affected cottonseed size traits and could be used for molecular marker-assisted selection. The expression patterns of the genes in the interval were analyzed using TM-1 transcriptome data. The results revealed that Gh_A07G1767 was preferentially expressed and Gh_A07G1766 specifically expressed at the stage of cottonseed development. These results speculated that these genes may play an important role in the growth and development of cottonseed.【Conclusion】47 QTNs were identified, and two candidate genes related to cottonseed development were screened.

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    Effects of Sowing Date Adjustment on Yield and Quality of Winter Wheat and Summer Maize in Northern Area of North China
    ZHAO HuaRong, ZHOU GuangSheng, QI Yue, GENG JinJian, TIAN XiaoLi
    Scientia Agricultura Sinica    2024, 57 (15): 2964-2985.   DOI: 10.3864/j.issn.0578-1752.2024.15.005
    Abstract569)   HTML38)    PDF (698KB)(1957)       Save

    Objective】Based on the field staging experiments, this study revealed the different responses of winter wheat and summer maize sowing date adjustments in growth and development, photosynthetic physiological characteristics, grain filling, yield formation and quality to climate warming in northern area of North China, providing scientific basis for agricultural production measures to cope with climate change in North China Plain.【Method】Different sowing date experiments of winter wheat and summer maize have been conducted at Hebei Gucheng Agricultural Meteorology National Observation and Research Station in northern area of North China from 2017 to 2023, which were set up in four sowing dates, including 10 d early sowing, 10 d late sowing, 20 d late sowing, and control. The growth process, above-ground dry matter accumulation and distribution, photosynthetic characteristics of leaves, grain filling rate, yield agronomic traits, and grain nutrients of winter wheat and summer maize were observed. 【Result】 The whole growth period of winter wheat was shortened with the delay of sowing date, mainly because of the shortening of seedling stage before winter. There was a parabolic relationship between the whole growth period and sowing date of summer maize. The seedling stage was shortened by 1.3 d, and the flowering stage and grain formation-filling stage were extended by 1.5 d and 1.6 d for every 10 d delay of sowing date. The grain filling characteristics of winter wheat and summer maize were not sensitive to sowing date adjustments, and the grain filling rate of summer maize was little different during different sowing dates, but the grain formation period, the filling end date and the peak date were successively delayed due to the delay of sowing date, and the duration of filling days was shortened by 4.0 d for every 10 d delay of sowing date. Under the background of warm autumn and winter in northern wheat region, the sowing duration of winter wheat was extended, while its influence on the yield was obviously weakened. The delay of sowing date with the increase of sowing seed amount would result in yield increase slightly. The yield of summer maize decreased significantly with the delay of sowing date, and the decline rate of theoretical yield was 1 381.50 kg·hm-2 for every 10 d delay of sowing date, but the yield of winter wheat and summer maize showed a jumping decease for 20 d late sowing. The grain distribution rate increased by 1.67% for winter wheat, decreased by 1.57% for summer maize with every 10 d delay of sowing date. As a result, the harvest index increased by 0.017 for winter wheat, and decreased by 0.016 for summer maize with every 10 d delay of sowing date. The leaf photosynthetic rates (Pn) of winter wheat and summer maize were also different in response to sowing date, they were similar for winter wheat during different sowing dates, while decreased by 1.21 μmol·m-2·s-1 for summer maize for every 10 d delay after sowing date. Sowing date adjustments had no significant effects on grain quality of winter wheat and summer maize in northern area of North China. 【Conclusion】Extending suitable sowing date range and sowing date delay of winter wheat in North China Plain were positive and effective measures to adapt to climate warming. The early sowing of summer maize in North China Plain might avoid the negative effects of high temperature and heat damage, and would promote the increase of yield.

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    China Urgently Needs to Transform from Mainland Agriculture to Cross-Sea Agriculture
    REN JiZhou, JIAO Hong, YANG RuiXue, XU Gang, ZHAO An
    Scientia Agricultura Sinica    2024, 57 (13): 2698-2702.   DOI: 10.3864/j.issn.0578-1752.2024.13.016
    Abstract528)   HTML78)    PDF (407KB)(389)       Save

    Relying on its special geographical advantages, China has established a continental agricultural country. Chinese land area was nearly 10 million square kilometers, while its population had never exceeded 80 million from the Qin and Han Dynasties to the Ming Dynasty, so known as “a vast territory with abundant resources”. However, during the Qianlong period in the 19th century, its population suddenly increased to 400 million, and the land area was already insufficient. In the early days of the founding of the People’s Republic of China, the population reached 650 million, and further reached 1.41 billion in 2020 based on The Seventh Census. The per capita water and soil resources are only about 1/3 to 1/4 of the world level, which making it a resource-poor country. It is not easy to obtain enough food and even more difficult to achieve a moderately prosperous lifestyle relying solely on domestic resources. The shortage of water and soil resources is an urgent problem despite the huge potential for technological innovation. In nearly a century and a half, the historical tragedy of the collision between China’s agricultural civilization and the world’s industrial civilization has reminded us to break through the mentality of “domestic is the world” fostered by land-based agriculture and to set sail to the sea. China needs to transform from “self-sufficient” mainland agriculture to “shared supply and common sustenance” cross-sea agriculture, establishing itself as the main base, utilizing the world’s agricultural resources, and building world agriculture. It is an urgent need to set up a long-term national policy in order to transform mainland agriculture into cross-sea agriculture, to build a global agricultural database in order to respond to the demand of the international food market, to adjust accurately and timely the domestic agricultural structure in order to reduce international trade risks, and to make a global strategic deployment as soon as possible for China’s agriculture.

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    Application Status and Development Suggestion of Direct-Seeding Rice Cultivation in China
    LIAO Ping, WENG WenAn, GAO Hui, ZHANG HongCheng
    Scientia Agricultura Sinica    2024, 57 (24): 4854-4870.   DOI: 10.3864/j.issn.0578-1752.2024.24.003
    Abstract513)   HTML43)    PDF (728KB)(335)       Save

    With the continuous improvement in rice cultivation techniques, China has maintained a high rice production level of about 210 million tons over the past decade. Direct-seeding rice cultivation technology, recognized for its efficiency and simplicity, has been favored by Chinese farmers. However, controversies persist regarding direct-seeding rice compared to transplanted rice in national-scale production. Thus, this study employed meta-analysis techniques to quantify disparities in grain yield, economic benefit, rice quality, lodging characteristic, and greenhouse gas emissions between direct-seeding rice and transplanted rice. Our results indicated that direct-seeding rice significantly reduced grain yield by an average of 6.3% relative to transplanted rice, which was main due to the reduced total spikelet (-3.8%) and filled-grain percentage (-1.8%). In different planting systems in China, the yield of direct-seeding rice had significantly decreased compared to transplanted rice, and the direct-seeding rice-induced reductions in yield of single rice (-10.9%) and late rice (-13.1%) were higher than those of middle rice (-4.8%) and early rice (-4.4%). The grain yield reductions for direct-seeding rice were from 10% to 20% in Jilin, Liaoning, Xinjiang, Ningxia, Shandong, Jiangsu, and Zhejiang provinces, meanwhile Heilongjiang and Jiangxi provinces saw reductions of 5% to 10%, but it had no significant effect in other provinces. Direct-seeding rice resulted in comparable net economic return relative to transplanted rice (p> 0.05). Direct-seeding rice reduced milled rice rate (-3.1%) and gel consistency (-3.5%), improved appearance quality (chalkiness percentage and chalkiness degree, which decreased by 25.3% and 22.5%, respectively), whereas no significant effects were observed on nutrition quality and taste value. Direct-seeding rice increased lodging index at base of the first (+12.4%) and third (+10.3%) internodes, but not at the second internode, indicating an increase in risk of lodging relative to transplanted rice. In terms of greenhouse gas emissions, direct-seeding rice fields showed reductions in methane emissions (-42.8%), global warming potential (-36.2%), and greenhouse gas intensity (-41.1%) compared to transplanted rice fields, while promoting nitrous oxide emissions (+29.1%). In addition, a review was recounted on nitrogen utilization and its loss, water and energy use efficiency, and weed incidence. Finally, the recommendations for the future advancement of direct-seeding rice were proposed, main focusing on rice variety breeding, rice cultivation technique optimization, rice planting area layout, as well as policies and services with the goal of technological innovation and regionalized application of direct-seeding rice cultivation technology in China.

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    Research Progress of Southern Corn Rust and Resistance Breeding
    WANG Shuai, ZHANG RuYang, WANG RongHuan, SONG Wei, ZHAO JiuRan
    Scientia Agricultura Sinica    2024, 57 (14): 2732-2743.   DOI: 10.3864/j.issn.0578-1752.2024.14.003
    Abstract497)   HTML34)    PDF (1827KB)(1592)       Save

    Maize is the most widely cultivated, used and highest yield crop in the world and China. Southern corn rust (SCR) is an air borne disease caused by Puccinia polysora Underw., which mainly occurs in tropical and subtropical maize growing areas. In recent years, SCR has become one of the major diseases in the Huang-Huai-hai maize production region due to the climate change, which directly leads to compromised grain quality and poor yields in maize and significantly jeopardizes maize production in China. At present, SCR usually spreads in a large area within a short period of time once occurred because most maize varieties promoted in China are susceptible, and conventional chemical measures is usually in vain. Therefore, cultivating resistant cultivars by exploiting resistance genes in maize germplasm resources is the most effective and economical strategy for controlling SCR. The highly resistant germplasm is scarce in maize resources, mainly from tropical and subtropical regions, and barely no temperate germplasm can be directly used in breeding practice. Compared with foreign maize germplasm, the highly resistant maize germplasms of China were much less, mainly from local landraces or P group materials containing tropical origins with relatively limited genetic variation. The identification and cloning of SCR resistance genes in maize is essential for promoting molecular marker-assisted breeding, as well as accelerating the breeding process of new varieties with desired resistance. At present, several SCR resistance genes have been identified and cloned, laying a foundation for molecular marker-assisted selection. Over the years, Chinese breeders have developed a number of elite maize inbred lines resistant to SCR with limited resistance germplasm resources, and successfully created disease-resistant hybrids. Recent studies on the genome of SCR pathogens revealed that pathogens have differentiated into highly toxic lineages in China, thus escaping the recognition of resistance genes. Therefore, the exploration and utilization of extensive genetic resources in resistant germplasm still need to be further strengthened. In this paper, we outlined the biological characteristics and hazards of SCR, systematically summarized the research progresses in the identification and utilization of maize germplasm resources resistant to SCR, the mapping and cloning of SCR resistant genes and the breeding of resistant varieties, and prospect the future research direction of SCR. This review will provide references for the prevention and control of SCR, as well as the breeding of resistant maize varieties.

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    Analysis of Maize Phenylalanine Ammonia-Lyase (PAL) Family Genes and Functional Study of ZmPAL5
    CAO LiRu, YE FeiYu, KU LiXia, MA ChenChen, PANG YunYun, LIANG XiaoHan, ZHANG Xin, LU XiaoMin
    Scientia Agricultura Sinica    2024, 57 (12): 2265-2281.   DOI: 10.3864/j.issn.0578-1752.2024.12.001
    Abstract465)   HTML62)    PDF (6268KB)(304)       Save

    【Objective】 Mining the key drought-resistant genes of maize, revealing its drought-resistant molecular mechanism, and providing genetic resources and theoretical guidance for the cultivation of new drought-resistant maize varieties.【Method】Transcriptome data combined with weighted gene co-expression network (WGCNA) and screening methods for physiological and biochemical indicators of drought resistance were used to identify ZmPAL genes associated with drought resistance and rewatering. Genome-wide analysis of the genes encoding PAL was performed using bioinformatics methods. Quantitative real-time fluorescence PCR (qRT-PCR) was used to detect the expression of ZmPAL genes under drought treatment conditions, as well as the expression characteristics of ZmPAL5 among different inbred lines and the expression patterns in different tissues. Finally, genetic transformation was used to analyze the drought resistance function of ZmPAL5 in maize, and the deletion-type Arabidopsis mutant was analyzed for drought resistance with the help of CRISPR/Cas9 technology for the PAL5 homologous gene.【Result】Nineteen maize ZmPAL genes were identified, six of which were clustered on chromosome 5 and encoded proteins that were mostly hydrophilic acidic proteins and relatively evolutionarily conserved in the PAL family of genes. The promoter region of ZmPAL genes contained a large number of cis-acting elements associated with hormonal and abiotic stress responses. Six core genes were identified, four of which were significantly up-regulated for expression after drought treatment. In particular, ZmPAL5 showed an 8.57-fold increase in expression after drought stress. The expression level of ZmPAL5 was found to be significantly higher in the drought-resistant inbred line Zheng 8713 than in the drought-sensitive inbred line B73 under both drought stress and rewatering treatments. Meanwhile, ZmPAL5, a constitutively expressed gene, showed a high level of expression in young stems. Overexpressed ZmPAL5 maize grew well under drought stress, and its relative water content, lignin, chlorophyll, soluble protein, proline content, and activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase were 1.52, 1.49, 1.47, 1.43, 1.44, 1.41, 1.53, 1.41, and 1.35 times, but the malondialdehyde content was 0.65 times that of the wild type. The PAL5-deficient Arabidopsis mutant was sensitive to drought. Under drought stress, its physiological and biochemical indexes showed the opposite trend to those of overexpression of ZmPAL5 maize. 【Conclusion】 Six core genes (ZmPAL3, ZmPAL5, ZmPAL6, ZmPAL8, ZmPAL11, and ZmPAL13) were screened in response to drought stress, in which the expression of ZmPAL5 was positively correlated with drought resistance. ZmPAL5 positively regulated the drought resistance and resilience of the plant by influencing the content of osmotically regulated substances and antioxidant enzyme activities.

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    Construction of ms1 Basic Recurrent Populations Adapted to Different Ecological Regions Using Maturity Genes E1 and E2 in Soybean
    HU XueJie, LIU LuPing, WANG FengMin, HAN YuHua, SUN BinCheng, MA QiBin, HUANG ZhiPing, FENG Yan, CHEN Qiang, YANG ChunYan, ZHANG MengChen, ZHANG Kai, QIN Jun
    Scientia Agricultura Sinica    2024, 57 (17): 3305-3317.   DOI: 10.3864/j.issn.0578-1752.2024.17.001
    Abstract457)   HTML47)    PDF (1730KB)(361)       Save

    【Objective】Soybean is a short day crop that is sensitive to photoperiod, and it maybe lead to premature or late flowering when it is planted in different ecological areas. Therefore, in the application of ms1 (male sterility 1) basic population for recurrent selection in different ecological regions, there are problems such as the flowering time unsynchronization between local donor parents and acceptor sterile plants and low introduction rate. The purpose of this study is to construct ms1 basic recurrent population adapted to three ecological regions for improving the probability of flowering time synchronization between donor parents and acceptor sterile plants and reveal the changes of maturity genes E1 and E2 genotypes and phenotype of each population after two rounds of cross-fertilize for providing evidence for improvement of the flowering and maturity time of soybeans.【Method】We used 528 donor parents from different ecological regions and the ms1 basic population as materials. The donor parents were genotyping with the KASP markers of maturity genes E1 and E2 reported by previous research. The donor parents were classified according to E1 and E2 genotypes and mixed with seeds of ms1 basic population respectively, and these populations were planted in different ecological areas according to the suitable genotypes of each region for two rounds of cross-fertilize in two years. Northeast ecological region population was planted in Hulunbuir, Inner Mongolia and Chengde, Hebei, respectively. Huang-Huai-Hai ecological region population was planted in Shijiazhuang, Hebei and Xuchang, Henan. South ecological region population was planted in Guangzhou, Guangdong. Seeds harvested from different ms1 populations were planted in Sanya, Hainan every winter. The flowering and maturity time of donor parents and ms1 basic population were investigated, and the proportions of E1 and E2 genotypes in populations of different region were calculated.【Result】According to genotypes of maturity genes E1 and E2, the donor parents were divided into four groups E1E1/E2E2, E1E1/e2e2, e1e1/E2E2 and e1e1/e2e2 with ratios of 12.1%, 65.0%, 19.3%, and 3.6%, respectively. In the ms1 basic population, the late flowering genotype E1E1/E2E2 had the highest proportion (48.6%), and the flowering time of the population was late, mainly concentrated in 45-51 days. After two rounds of import by cross-fertilize, the percentage of target genotype e1e1/e2e2 increased from 33.0% to 51.6% in Hulunbuir of Northeast China, and the percentage of the e1e1/e2e2 genotype increased from 1.6% to 8% in Chengde. The percentage of target genotype e1e1/E2E2 increased from 18% to 23.1% in Shijiazhuang of Huang-Huai-Hai ecological area, and the percentage of E1E1/e2e2 increased from 12.5% to 30% in Xuchang, respectively. The percentage of E1E1/E2E2 remains above 80% in Guangzhou of South ecological region. The proportion of heterozygous genotypes of target imported genotypes was also increasing in the population. After two rounds of cross-fertilize, there were significant differences in flowering time among ms1 populations of different ecological regions, indicating that phenotypes of different populations also changed with the change of genotype of flowering genes.【Conclusion】Importing genotype of donor parents into the ms1 population based on their genotypes of flowering genes can increase the frequency of suitable genotypes in each ecological region, construct ms1 basic recurrent populations adapted to different ecological regions, increase the probability of flower time synchronization of local donor parents and acceptor ms1 sterile plants, achieve open pollination, gene aggregation and accumulation in soybean, and enrich the genetic diversity of the population, further improve breeding efficiency.

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    Effects of Soil Film Tillage on Soil and Crop in Farmland
    YANG ShiQi, YAN Xin, HAN Yu
    Scientia Agricultura Sinica    2024, 57 (15): 3010-3022.   DOI: 10.3864/j.issn.0578-1752.2024.15.008
    Abstract451)   HTML47)    PDF (1317KB)(222)       Save

    Objective】To make clear the agricultural productive value of soil film tillage, the effects of soil film tillage on soil moisture, temperature and nutrient changes in farmland were explored, and the effects of soil film on crop root growth and yield were revealed too, so as to provide the theoretical basis and technical methods for the application of soil film.【Method】Soil film was induced by spraying a 1.0% concentration of carboxymethyl cellulose ammonium (CMC-NH4) aqueous solution, and the field experiment was conducted with five treatments, including 0 (CK), 50.0 (T1), 100.0 (T2), 200.0 (T3), and 300.0 kg·hm-2 (T4). The effects of CMC-NH4 application rate on soil moisture, temperature, nutrients, microorganisms, crop roots and yield in multiple cropping of spring wheat and summer maize were studied.【Result】Soil film treatment of spring wheat and summer maize could increase average daily soil moisture content by 3.3%-7.0% (P<0.05, the same as below) and 1.9%-6.1%, average daily temperature by 7.9%-12.6% and 5.6%-11.7%, contribution of soil accumulated temperature of growth period by 88.98-141.94 ℃ and 60.25-136.65 ℃, root length of 0-30 cm soil layer by 37.5%-17.1% and 11.2%-1.7%, root surface area of 0-30 cm soil layer by 15.3%-4.5% and 12.5%-9.2%, respectively, and root biomass (dry weight) in 0-30 cm soil layer were enhanced by 17.0%-41.5% and 30.9%-36.7%, respectively. Finally, the grain yield of spring wheat per unit area was increased by 7.3%-18.8% and above-ground dry weight of summer maize per unit area was increased by 33.6%-49.0%. and the soil nitrogen, phosphorus and potassium content as well as soil microbial diversity were improved too. 【Conclusion】As a novel type of soil tillage, soil film had the function of farmland coverage, which greatly contributed to improve soil hydrothermal environment, and promote nutrient absorption and utilization, root growth and crop yield. At the same time, soil film produced the important technique and method to make the better plough layer structure that is “compact surface, loose top and tight bottom of plough layer”, which would support the improvement of crop productivity, farmland soil amendment and agricultural high-quality development. In this study, the recommended application rate was 100.0 kg·hm-2 in Ningxia Yellow River irrigation area.

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    A Retrieval System for Great Soil Groups from China’s Provisional Soil Classification System for the 3rd National Soil Census
    LONG HuaiYu, LU ChangAi, JI HongJie, ZHANG RenLian
    Scientia Agricultura Sinica    2024, 57 (21): 4264-4275.   DOI: 10.3864/j.issn.0578-1752.2024.21.008
    Abstract409)   HTML40)    PDF (482KB)(606)       Save

    【Objective】The State Council’s Office of the Leading Group for the 3rd National Soil Census released China’s Provisional Soil Classification System for the 3rd National Soil Census (Trial), abbreviated as 3PSC-T, in 2023, without retrieval system, which is unable to address long-standing questions such as “one soil having multiple names” and “different soils sharing the same name”. Therefore, the retrieval system for great soil groups need be built. 【Method】The retrieval indicators for each great soil group were extracted from the soil classification basis in 3PSC-T by using multiple methods, such as referring to existing diagnostic horizons and characteristics, refining existing diagnostic horizons and characteristics, simplifying descriptive statements, and inducting characteristic soil layers. Four principles for retrieval order were set up, which included prioritizing the importance of agriculture, prioritizing ease over difficulty in identification, narrowing down meaning, clustering similar types, and reflecting the spatial evolution and development patterns of soil. 【Result】Consequently, the retrieval system for 62 great soil groups in 3PSC-T was established, and the retrieval order was: 1 Artificial soils, 2 Paddy soils, 3 Vegetable cultivated soils, 4 Irrigation silting soils, 5 Irrigated desert soils, 6 Solonetzs, 7 Frigid plateau solonchaks, 8 Desert solonchaks, 9 Acid sulphate soils, 10 Coastal solonchaks, 11 Meadow solonchaks, 12 Volcanic soils, 13 Frigid frozen soils, 14 Purplish soils, 15 Phospho-calcic soils, 16 Lithosols, 17 Skeletal soils, 18 Takyr, 19 Neo-alluvial soils, 20 Aeolian soils, 21 Loessial soils, 22 Red primitive soils, 23 Limestone soils, 24 Bleached baijiang soils, 25 Podzolic soils, 26 Brown coniferous forest soils, 27 Dark-brown earths, 28 Brown earths, 29 Yellow-brown earths, 30 Yellow-cinnamon soils, 31 Gray forest soils, 32 Black soils, 33 Gray-cinnamon soils, 34 Cinnamon soils, 35 Torrid red soils, 36 Chernozems, 37 Castanozems, 38 Castano-cinnamon soils, 39 Black loessial soils, 40 Brown calcic soils, 41 Sierozems, 42 Gray desert soils, 43 Gray-brown desert soils, 44 Brown desert soils, 45 Mountain meadow soils, 46 Shrubby meadow soils, 47 Shajiang black soils, 48 Meadow soils, 49 Fluvo-aquic soils, 50 Bog soils, 51 Peat soils, 52 Latosols, 53 Latosolic red earths, 54 Red earths, 55 Yellow earths, 56 Dark felty soils, 57 Felty soils, 58 Frigid calcic soils, 59 Cold calcic soils, 60 Cold brown calcic soils, 61 Frigid desert soils, 62 Cold desert soils, and 63 Cambosol. 【Conclusion】It was found that some soil groups in 3PSC-T had overlapping or inclusive associations with one another. This necessitates the creation of a retrieval system to effectively address the issue of “one soil having multiple names” and “different soils sharing the same name”. In general, the majority of the soil groups in 3PSC-T had the ability to provide retrieval indicators through the examination of profile morphology as well as physical and chemical properties of the soil. Nevertheless, the soil groups within the alpine soil order deviated from the classification principles of the overall classification system. This deviation posed challenges in differentiating them based on profile morphology and soil physicochemical properties. Instead, distinguishing these soil groups required consideration of non-soil properties, such as distribution area and altitude. Further efforts were required to enhance the categorization of soil types in 3PSC-T. It is suggested to incorporate specific groups and to establish a new group called Cambosol.

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    Identification and Gene Mapping of Hard Seededness Mutant Mzp661 in Soybean
    MIAO Long, SHU Kuo, HU YanJiao, HUANG Ru, HE GenHua, ZHANG WenMing, WANG XiaoBo, QIU LiJuan
    Scientia Agricultura Sinica    2024, 57 (11): 2065-2078.   DOI: 10.3864/j.issn.0578-1752.2024.11.002
    Abstract400)   HTML32)    PDF (6352KB)(222)       Save

    【Objective】Hardness, a structural feature of seed physical dormancy, is an important trait in soybean domestication. Although hardness is beneficial for seeds to survive in unfavorable environments, it will seriously reduce the emergence rate of soybean in the field, and detrimental to yield and processing quality. Analyzing the QTL and candidate genes using bulked segregant analysis sequencing (BSA-Seq), can provide a theoretical reference for understanding the molecular mechanism of hard seededness in soybean.【Method】The hard seed mutant Mzp661 was obtained from the seeds of Zhongpin 661 induced by ethyl methane sulfonate (EMS), and was crossed with cultivated soybean Zhonghuang 13 (male parent) to construct recombinant inbred line (RIL) population. The progeny lines were investigated for seed hardness, water absorption capacity and anatomical structure of seed coats. Two types of extreme lines in the RIL population, with hard seeds or with imbibed seeds, were selected to construct DNA mixed pools respectively, and then BSA-Seq technology was used to detect genotype differences in extreme-mixed pools and parents. Euclidean distance (ED), delta SNP-index, and delta InDel-index methods were applied to associate hard seed genetic loci of soybean. Combining with bioinformatics analysis, transcriptome data of different soybean tissues and gene annotation information, candidate genes within significant association regions were predicted.【Result】In the progenies of Mzp661, all areas of imbibitive seeds had the penetration ability, and the seed volume increased continuously with the soaking time. However, no changes were observed for hard seeds over 36 hours. With the prolonged of soaking time, the seed coat of hard seeds began to shrink locally and gradually spread to other parts, and finally cotyledons recovered their imbibition ability. The hard seed not only has smooth and compact seed coat, but also has regular network structure of cuticle and thicker palisade layer, while numbers of stomata and loose structures, tiny cracks and thinner palisade layer were existed in the imbibed seeds. These results suggest that the seed hardness of Mzp661 may be caused by the impermeability of the seed coat. ED, delta SNP-index and delta InDel-index association analysis methods not only identified the reported seed physical dormancy locus qHS1, but also simultaneously detected the candidate region Chr.06: 45897227-47746047, which contains a total of 189 genes. Further, transcriptome data and gene annotation predicted that Glyma.06G275300, which is specifically and highly expressed in seeds, might be the candidate gene for this associated region to regulate soybean seed hardness.【Conclusion】Seed hardness of soybean mutant Mzp661 was caused by the impermeability of the seed coat, and Glyma.06G275300 was predicted as a candidate gene affecting the structure of seed coat using BSA-Seq.

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    Effects of Long-Term Fertilization on Soil Aggregate Stability and Its Driving Factors in Black Soil and Brown Soil
    LI TianJiao, ZHANG NaiYu, SHEN WenYan, SONG TianHao, LIU HongFang, LIU XiaoYan, ZHANG XiuZhi, PENG Chang, YANG JinFeng, ZHANG ShuXiang
    Scientia Agricultura Sinica    2024, 57 (19): 3835-3847.   DOI: 10.3864/j.issn.0578-1752.2024.19.010
    Abstract390)   HTML20)    PDF (1387KB)(173)       Save

    【Objective】 The effects of long-term different fertilization practices on aggregate distribution and stability of two typical soils (black soil and brown soil) in the black soil area were compared, and the key factors affecting aggregate stability were explored to provide the theoretical support for alleviating soil structural degradation. 【Method】 Based on a 34-year long-term positioning experiment in black soil and a 45-year long-term positioning experiment in brown soil, soil samples of 0-20 cm were collected by selecting the common fertilization treatments: no fertilization (CK), chemical fertilizer (NPK), and chemical fertilizer combined with organic fertilizer (NPKM), as well as the special treatments of chemical fertilizer plus straw (NPKS) in black soil and manure (M) in brown soil. Soil chemical properties were determined and soil aggregates were sieved by wet-sieving procedure. 【Result】 Compared with CK, the proportion of microaggregates (>0.25 mm) under the NPK treatment in black soil and brown soil was significantly reduced by 8.6% and 11.3%, respectively, and the mean weight diameter (MWD) of aggregates was significantly reduced by 18.6% and 10.7%, respectively, indicating that the stability of aggregates in black soil and brown soil was significantly reduced by chemical fertilizer alone. The MWD under the NPKM and M treatments in brown soil increased significantly by 44.2% and 17.9%, respectively, whereas that had not noticeably changed under the NPKM treatment and significantly increased by 11.8% under the NPKS treatment in black soil, indicating that the application of pig manure in brown soil and straw return in black soil were important measures to improve aggregate stability. The stability of soil aggregates was mainly affected by soil chemical properties. NPK resulted in the decrease of pH and exchangeable Ca and Mg ions in black soil and brown soil, which hindered the formation and stability of microaggregates. The application of organic fertilizers (M, NPKM, NPKS) inhibited the decrease of soil pH, increased the content of particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), and promoted the association of organic carbon with Fe/Al oxides and Ca/Mg ions, which accelerated the aggregation process of soil particles, maintaining and improving the stability of aggregates. The comprehensive analysis showed that the factors affecting the stability of black soil aggregates were chelated Al (Alp), Ca2+, POC, pH and MAOC in order from the largest to the smallest, among which the stability of black soil aggregates was significantly negatively correlated with Alp and positively correlated with other factors. The key factors affecting the stability of brown soil aggregates were POC, chelated Fe (Fep), pH, Mg2+, Ca2+, amorphous Al (Alo), Alp and amorphous Fe (Feo) in order from the largest to the smallest, among which the stability of brown soil aggregates was significantly negatively correlated with Alo and Feo and positively correlated with other factors. 【Conclusion】 The application of organic fertilizers (pig manure, straw return) could mainly increase the contents of soil POC and Ca2+, inhibit soil acidification, and improve the stability of aggregates in black soil and brown soil, which were important fertilization practices to delay the degradation of soil structure in black soil areas.

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    Evaluation of Drought Resistance in Soybean Germplasm and Identification of Candidate Drought-Resistant Genes
    LI ShengYou, WANG ChangLing, YAN ChunJuan, ZHANG LiJun, SUN XuGang, CAO YongQiang, WANG WenBin, SONG ShuHong
    Scientia Agricultura Sinica    2024, 57 (10): 1857-1869.   DOI: 10.3864/j.issn.0578-1752.2024.10.002
    Abstract381)   HTML41)    PDF (4749KB)(748)       Save

    【Objective】 In order to provide theoretical basis for molecular breeding of soybean drought resistance, the different evaluation indexes of drought resistance were comprehensively used to screen soybean germplasm with drought-resistance, and the candidate drought-tolerant genes were identified. 【Method】 In 2018, 2019, 2020 and 2021, a total of 188 soybean germplasm were used to determine pod number per plant, biomass per plant and yield per plant under well-watered and drought stressed conditions. Drought resistance index (DI), improved drought resistance index (IDI), weighted drought resistance coefficient (WDC) and weighted drought resistance index (WDI) were used to identify drought resistance of soybean germplasm. The single nucleotide polymorphisms (SNP) loci significantly associated with these parameters were detected by genome-wide association study (GWAS), and the candidate genes for drought resistance were screened by RNA-seq and qRT-PCR analysis of soybean seedling leaves under drought stress. 【Result】 The DI, IDI, WDC and WDI of 188 soybean germplasm varied widely, and five classification criteria for each drought resistance parameter were determined by hierarchical classification method. Among them, Liaodou 15, Liaodou 69, Liaodou 14, Jinzhangzi Huangdou, Zhonghuang 606, Kexin 3 and Koreane 4 were identified as first-grade drought resistant by all evaluation methods. By using GWAS for DI, IDI, WDC and WDI, a total of 15 significantly SNP loci were detected under multiple environments, and the contribution rate of these loci to phenotypic variation ranged from 12.46% to 25.60%. There are 226 annotated genes within 200 kb intervals of upstream and downstream for the significant SNP loci. According to RNA-seq and qRT-PCR analysis of drought-resistant cultivar Liaodou 14 and drought-sensitive cultivar Liaodou 21 under drought stress, a total of 32 annotated genes were significantly differentially expressed by drought stress. Among them, eight genes including Glyma.02G182900, Glyma.04G012400, Glyma.06G258900, Glyma.15G100900, Glyma.01G172600, Glyma.04G012300, Glyma.01G172200 and Glyma.04G010300, encodes calcium-dependent protein kinase, universal stress protein A-like protein, G-type lectin S-receptor-like serine/threonine-protein kinase, protein phosphatase 2C, isoflavone reductase, isoflavone reductase homolog, auxin-like protein, and bZIP transcription factor, respectively. 【Conclusion】 Seven germplasm were identified from 188 soybean germplasm by comprehensive application of different drought tolerance parameters. A total of 15 SNP loci significantly associated with drought tolerance parameters were identified by GWAS, and eight candidate genes were identified.

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    Transcriptome Analysis for Screening Key Genes Related to Regulating Branching Ability in Apple
    ZHANG HaiQing, ZHANG HengTao, GAO QiMing, YAO JiaLong, WANG YaRong, LIU ZhenZhen, MENG XiangPeng, ZHOU Zhe, YAN ZhenLi
    Scientia Agricultura Sinica    2024, 57 (10): 1995-2009.   DOI: 10.3864/j.issn.0578-1752.2024.10.011
    Abstract381)   HTML44)    PDF (5633KB)(1675)       Save

    【Background】 The number of branches on an apple tree plays a pivotal role in its environmental adaptability, growth, survival, and resource competition. In production practice, the apple cultivars with more branches can better meet the needs of pruning and shaping, not only do they facilitate timely adjustments to the tree's structure based on local conditions, but also they ensure a uniform distribution of fruit-bearing branches, thereby guaranteeing both fruit quantity and quality. 【Objective】 In this study, by using the top buds and lateral buds of more-branched cultivar Huaxing and fewer-branched cultivar Huashuo at the same developmental stage, the transcriptome sequencing was carried out to identify key genes regulating the ability of branching, as well as to elucidate the potential mechanism underlying branching phenotype, and finally to provide the theoretical basis for improving the branching ability and yield of apple. 【Method】 The lateral and terminal buds of Huashuo and Huaxing were sampled for RNA-seq. By differential expressed gene (DEG) and analysis and weighted gene co-expression network (WGCNA) analysis, the core candidate genes that were responsible for branch number difference were identified and further demonstrated their function by Arabidopsis transformation.【Result】 A total of 2 920 DEGs were identified from the comparison between the terminal buds, while 5 127 DEGs were screened out from the comparison between the lateral buds. DEGs were mainly enriched in phytohormone signaling pathway. Notably, the auxin signaling pathway, and strigolactone signaling pathway seemed to have the closest connection with the branching ability of apple with the related genes encoding MdIAA3, MAX2, TCP, and JAZ, which showed significant differences between lateral buds. Furthermore, DEGs annotated to cell cycle and cell wall modification families, such as CYC (Cyclins), CDK (Cyclin-dependent kinase), and EXPA (Expansin), also demonstrated a positive correlation with apple branching ability. In addition, those candidate genes obtained from WGCNA analysis also showed high possibility of getting involved in branch number regulation. Heterologous transformation of Arabidopsis with MdIAA3 could significantly enhance the overall growth, increased pod number and branching number of Arabidopsis. 【Conclusion】 Through comprehensive research, 13 candidate regulatory genes were identified that potentially played a crucial role in transcriptional regulation for branch number. MdIAA3 was ectopically expressed in Arabidopsis, which significantly promoted plant growth and branching ability. It was plausible that these genes regulated branching through processes, such as cell differentiation and development, cell wall modification, auxin, and strigolactone signaling pathway.

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    Effects of Layered Fertilization Under Different Irrigation Conditions on Vertical Distribution of Soil Nutrients and Root Growth and Function of Wheat
    BU MingNa, YANG XiWen, TENG ZhengKai, HU NaiYue, ZHANG Shuo, WANG ChunYan, YANG Jian, LIANG WenXian, MA WenQi, HE DeXian, ZHOU SuMei
    Scientia Agricultura Sinica    2024, 57 (11): 2125-2142.   DOI: 10.3864/j.issn.0578-1752.2024.11.007
    Abstract380)   HTML38)    PDF (1309KB)(640)       Save

    【Objective】In order to explore the effects of fertilization on soil nutrients and wheat (Triticum aestivum L.) root growth, and to shape a good root architecture, so as to provide a theoretical basis for scientific fertilization and high-yield and high-efficiency production of wheat field.【Method】The experiment was conducted in Yuanyang Scientific and Educational Park of Henan Agricultural University from 2021 to 2023. The pool planting positioning experiment is adopted. And three fertilization treatments (F0: no fertilization; F1: shallow application of N, P, K fertilizer; F2: 1/3 shallow application plus 2/3 deep application of N, P, K fertilizer) and three irrigation treatments (W1: prior to sowing irrigation; W2: prior to sowing irrigation plus irrigation at jointing stage; W3: prior to sowing irrigation plus irrigations both at jointing and anthesis). A total of 9 treatment combinations were used to determine concentration dynamics of soil nutrients and root morphological and physiological traits at different soil layers within 0-100 cm.【Result】Under different irrigation frequencies, the concentrations of available N, P, K nutrients were relatively high in top soil layer and decreased with the soil depth. In the soil layer of 0-60 cm, the trend of concentrations of available N, P, K nutrients under different treatments was as F2>F1>F0. Especially, the nutrient concentrations were significantly increased in 20-40 cm soil layer in layered application treatment (F2). Compared with those in shallow application (F1), the concentrations of nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium increased by 16.03%, 7.67%, 8.82%, and 6.32% under F2 under different irrigation frequencies from anthesis to maturity, respectively. Also, under F2 treatments, the concentrations of both nitrate nitrogen and total nitrogen increased in 80-100 cm soil layer, and irrigation enhanced the treating effects. The distribution of available potassium concentration in 0-100 cm soil layer exhibited an S-shaped curve, and K concentration increased at maturity stage suggesting the phenomenon of potassium excretion. The wheat roots were mainly located in the 0-40 cm soil layer. Morphological & quantitative traits and physiological function of roots were significantly improved under F2 in the 20-40 cm soil layer: compared with those under F1, the root length density, root surface area density, root volume ratio, root dry weight density, root vigor, and root physiological potential were increased by 38.42%, 16.93%, 25.65%, 43.07%, 33.12%, and 31.10%, respectively. The correlation analysis showed that concentrations of available N, P, K nutrients in 0-20 cm soil layer were significantly positively correlated with root morphological & quantitative traits (P<0.01). Root physiological potential in 0-60 cm soil layer was significantly positively correlated with soil nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium, respectively.【Conclusion】The layered N, P, K fertilization combined with key irrigations at three stages achieved a high degree of coordination between root configuration, growth, physiological functions, and appropriate distribution of available N, P, K nutrients, and enhanced the root biomass in 20-40 cm soil layer, indicating more absorptions of nitrogen, phosphorus, and potassium from the soil and a higher grain yield.

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    Analysis of Heterosis and Combining Ability of Lodging Resistance Traits of Spring Wheat Varieties (Lines) in the Ningxia Yellow River Irrigation Area
    SUN WeiHao, LIU Ting, SANG YiNan, YANG ZhengWei, ZHANG GaiSheng, SONG YuLong, ZHANG ShuangXi
    Scientia Agricultura Sinica    2024, 57 (13): 2497-2508.   DOI: 10.3864/j.issn.0578-1752.2024.13.001
    Abstract368)   HTML46)    PDF (689KB)(192)       Save

    【Objective】 The essence of conventional wheat breeding involves the continuous multi-generation selection and maintenance of hybrid F1 trait heterosis. Exploring the heterosis and combining ability of lodging-related traits among spring wheat varieties (lines) in the Yellow River irrigation area of Ningxia, and clarifying significantly agronomic indexes related to anti-lodging traits in wheat that can provide a certain theoretical basis for utilizing heterosis in lodging traits of spring wheat, and for the screening and maintenance of its descendants in Ningxia.【Method】 This study utilized 14 spring wheat varieties (lines) from Ningxia Yellow River Irrigation Area as parent materials. According to NCⅡ incomplete diallel crossbreeding design, forty-five combinations were produced. Meanwhile, heterosis, combining ability, and correlation analyses were performed on 13 traits related to lodging resistance, such as plant height and culm type index, in their parents and their F1 generation.【Result】 Significant differences in lodging resistance trait were observed among different spring wheat varieties (lines). Meanwhile, there is a certain level of heterosis in lodging resistance traits was evident in the F1 generation. The main stem thrust resistance of NZ42, M6445, and M8887 showed high general combining ability (GCA) values of 11.68, 8.00, and 10.67 respectively. Significant combinations for main stem thrust resistance included M6445×M8887, M6445×MJ48, NZ42×N2038, NZ42×M7723, NZ42×NZ39, and H3015×Ningchun50. Correlation analysis revealed that plant height was significantly positively correlated with the first internode length and second internode weight, and highly significantly positively correlated with the second and fourth internode lengths. Besides, the main stem thrust resistance was highly significantly positively correlated with fresh weight of the main stem, stem diameter, bending moment and culm type index, but significantly negatively correlated with the fourth internode length. However, it was not significantly correlated with the second internode weight and fullness.【Conclusion】 The excellent parent varieties identified were NZ42, M6445, and M8887. Meanwhile, the excellent combinations of NZ42 × NZ39, M6445 × MJ48, and M6445 × M8887 were also observed in this study. In addition, Heterosis was present among most lodging resistance traits in different combinations, but the heterobeltiosis was less pronounced. The resistance to lodging was influenced by both additive and non-additive effects of parental genes, with a greater influence from the maternal genetic background. Furthermore, the plant height and main stem thrust resistance are significantly correlated with the fourth internode length, bending moment, and culm type index, serving as important references for selection of lodging-resistant generations.

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    Research Progress on Seed Shattering of Rice
    LÜ ShuWei, TANG Xuan, LI Chen
    Scientia Agricultura Sinica    2025, 58 (1): 1-9.   DOI: 10.3864/j.issn.0578-1752.2025.01.001
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    Seed shattering is a major factor limiting rice production, and breeding new rice varieties with moderate seed shattering is a key challenge faced by rice breeders worldwide. Rice is the most important cereal crop in China, plays a vital role for national food security. Seed shattering is one of the most important traits during rice domestication, and the abscission zone is the important region to control seed shattering. Compared with wild rice, cultivar has eliminated the seed shattering with partially developed abscission layer. Seed shattering not only has a direct impact on the yield, but also affects the way of its mechanical harvest. In order to breed rice varieties with moderate seed shattering in agricultural production, it is necessary to mine and utilize important seed shattering genes and introduce them into excellent rice varieties for genetic improvement, so as to breed new rice varieties suitable for mechanical harvesting with moderate seed shattering. Several seed shattering genes had been identified by map-based cloning, such as SH4/SHA1, qSH1, OsSh1/ObSH3, and their functional mechanisms had been analyzed. At the same time, new rice materials with moderate seed shattering have been successfully developed through CRISPR/Cas9 gene editing technology, gamma ray mutagenesis technology and gene introduction methods. Seed shattering has an important effect on grain yield and rice harvesting methods, in this paper, we reviewed the methods, physiologic basis, the identification of seed shattering genes and genetic mechanism of seed shattering in rice. At the same time, it is proposed that by using the important genes in excellent rice germplasm resources, could provide reference for exploring the mechanism of rice seed shattering, and breed new rice varieties suitable for mechanical harvesting with moderate seed shattering.

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    Identification of Resistant Germplasms and Mining of Candidate Genes Associated with Resistance to Stalk Rot Caused by Synergistic Infection with Fusarium spp. in Maize
    GUI CuiLin, MA Liang, WANG YinYing, XIE FuGui, ZHAO CaiHong, WANG WenMiao, LI Xin, WANG Qing, GAO XiQuan
    Scientia Agricultura Sinica    2024, 57 (13): 2509-2524.   DOI: 10.3864/j.issn.0578-1752.2024.13.002
    Abstract359)   HTML36)    PDF (5108KB)(2072)       Save

    【Objective】 Maize stalk rot is one of the common and most devastating diseases in major maize production areas in China. Under natural conditions, maize stalk rot is mostly caused by the synergistic infection of various pathogens. The purpose of this study was to screen elite maize germplasms resistant to the synergistic infection with F. graminearum and F. verticillioides. Meanwhile, QTN associated with resistance to the infection by synergistic infection of two Fusarium species and the candidate resistance genes were identified, which will provide gene resources and theoretical reference for molecular breeding of maize variety resistant to synergistic infection of different pathogens.【Method】 Using a maize natural population as experimental materials, the maize stalk rot phenotypes were investigated upon simultaneous infection with F. graminearum and F. verticillioides. Furthermore, GWAS analysis was conducted to identify significant resistance SNP and to predict candidate genes for stalk rot resistance.【Result】 Through the phenotypic analysis of stalk rot caused by synergistic infection under both field and laboratory conditions, it was found that inbred lines from different sources and subgroups showed significant phenotypic variation. More specifically, the field assay results showed that the inbred lines collected from China were more resistant and that from USA were more susceptible to synergistic infection. Moreover, the inbred lines of tropical and subtropical subgroup were more resistant, whereas the inbred lines of Mixed subgroup more susceptible. The seedling assay results under laboratory condition showed that the lines collected from USA were more resistant, whereas that from CIMMYT were more susceptible. The lines of SS subgroup were more resistant, and that of Mixed subgroup were more susceptible. By integrating field and laboratory phenotypic data, 29 and 16 lines with higher levels of resistance to synergistic infection were screened out respectively, and 6 resistant lines were identified under both conditions. Moreover, based on the field phenotype GWAS, 18 QTNs associated with the resistance were identified, and 93 candidate genes associated with stalk rot resistance to synergistic infection were mined. Among these candidate genes, four genes showed haplotype variation, whose expression levels were up-regulated in disease-resistant lines.【Conclusion】 Using the natural population of maize with great diversity in genetic background, 6 resistant lines to the synergistic infection with Fusarium spp. were identified under two conditions, which can be used as potential germplasm resources for maize stalk rot resistance in the future. Four candidate genes that might be involved in the resistance to synergistic infection were identified by GWAS, which will provide genetic resources for the breeding maize varieties with enhanced resistance to stalk rot caused by F. graminearum and F. verticillioides.

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    QTL Mapping and Candidate Gene Screening for Nitrogen Use Efficiency in Maize
    HAN XuDong, YANG ChuanQi, ZHANG Qing, LI YaWei, YANG XiaXia, HE JiaTian, XUE JiQuan, ZHANG XingHua, XU ShuTu, LIU JianChao
    Scientia Agricultura Sinica    2024, 57 (21): 4175-4191.   DOI: 10.3864/j.issn.0578-1752.2024.21.002
    Abstract352)   HTML30)    PDF (7416KB)(251)       Save

    【Objective】Genetic improvement for efficient utilization of maize nutrients represents a crucial method to ensure national food security. Exploring quantitative trait locus (QTL) and related candidate genes of nitrogen use efficiency can provide a theoretical basis for improving the efficiency of nitrogen fertilizer in maize and cultivating high-yield and high-efficiency maize varieties. 【Method】In this study, QTL mapping analysis in one recombinant inbred line (RIL) population constructed by KA105 and KB024 was performed for grain yield under two different nitrogen treatments, including the derived traits partial factor productivity from applied nitrogen (PFPN), low nitrogen tolerance coefficient (LNTC) and nitrogen agronomic efficiency (NAE). Concurrently, integrating the seedling transcriptome data of the parent KA105 under nitrogen treatment, differentially expressed genes were identified, and candidate genes associated with maize nitrogen use efficiency were mined through co-expression analysis. Subsequently, the selected candidate genes were validated using qRT-PCR. 【Result】Through mapping analysis, a total of 36 QTLs distributed across different chromosomes were detected, explaining 1.63% to 17.26% of the phenotypic variation. Among these, eight major QTLs with a phenotypic variation explanation rate exceeding 10% were identified, along with seven genetically stable QTLs commonly identified across different traits or environments. Notably, qNNGYP1 located on chromosome 1 has been repeatedly detected in previous studies, with a phenotypic explanation rate of up to 11.73%. Additionally, other QTLs (qNNGYP1, qPFPN1) co-located in this interval across different environments, suggesting it as a focal region for further investigation. Combining transcriptome data of seedlings under low nitrogen stress, 39 differentially expressed genes within these QTL intervals were identified, and 6 key genes were identified through co-expression network prediction. The result of qRT-PCR indicated that the expression trends of the candidate genes under both nitrogen treatments were consistent with the transcriptome data. Specifically, GRMZM2G366873 was involved in the regulation of auxin homeostasis and may participate in maize responses to low nitrogen stress, drought stress, and boron stress through auxin signal transduction, also regulating ear length. GRMZM2G414192 was involved in the response of the photosynthetic system to low nitrogen stress and was regulated by brassinosteroids. GRMZM2G414043 was associated with maize grain length and biomass, while GRMZM2G040642 may be involved in the long-distance signal transduction of nitrogen. 【Conclusion】In summary, a total of 36 QTLs were identified, distributed across chromosomes 1, 4, 5, 7, 8, and 9, including eight major QTLs (PVE>10%). The candidate genes GRMZM2G366873, GRMZM2G414192, GRMZM2G414043, and GRMZM2G040642 were identified as potential genes for maize nitrogen efficiency.

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    Identification and Evaluation of Phenotypic Characters and Genetic Diversity Analysis of 169 Tomato Germplasm Resources
    LI YuShan, XIAO Jing, MA Yue, TIAN Chao, ZHAO LianJia, WANG Fan, SONG Yu, JIANG ChengYao
    Scientia Agricultura Sinica    2024, 57 (18): 3671-3683.   DOI: 10.3864/j.issn.0578-1752.2024.18.012
    Abstract349)   HTML15)    PDF (3378KB)(152)       Save

    【Objective】 The phenotypic genetic diversity and taste performance of cultivated and wild tomato germplasm resources from around the world was analyzed, in order to screen specific and high-quality tomato resources, so as to provide the germplasm and theoretical support for the exploration of excellent tomato genes and tomato breeding. 【Method】 A total of 169 tomato resources collected domestically and internationally were used as the research object, and 38 phenotypic traits of them were measured throughout the entire growth period. The genetic diversity analysis, cluster analysis, and comprehensive evaluation of tomato germplasm phenotypes were conducted through multiple statistical analysis methods, such as genetic diversity index, principal component analysis, weight, systematic clustering, and membership function. 【Result】 The variation coefficient of phenotypic traits in 169 tomato samples ranged from 18% to 368%, and the genetic diversity index ranged from 0.036 to 2.302. There were 26 traits with a genetic diversity index >1, among which the genetic diversity index for mature fruit color was the highest (2.302), indicating that the 169 tomato samples in this study were diverse in type and rich in genetic diversity. Correlation analysis showed that tomatoes with the higher plant height, the more flowers per inflorescence, and the smaller fruits had a higher sugar-to-acid ratio. Principal component analysis showed that 16 phenotypic traits (single fruit weight, number of ventricles, fruit shoulder shape, fruit shoulder furrows, longitudinal and transverse diameters of fruits, ratio of sugar to acid, soluble solids, cork size, growth habits, plant height, second inflorescence node position, inflorescence type, mature fruit color, number of inflorescence flowers, and plant type) had a relatively large contribution rate to resource variation, and could be used as the main indicator for cluster analysis. The clustering analysis results showed that 169 tomato resources were divided into 10 major groups at a Euclidean distance of 5.0. The first and second groups were Solanum cheesmanii, the third and tenth groups were upright tomatoes with different fruit sizes, the fourth and fifth groups were ordinary large fruit tomatoes with unlimited growth, the sixth group was large fruit tomatoes in the upright type, the seventh and eighth groups were mostly cherry tomatoes and a small number of Solanum Pimpinellifolium, and the ninth group was limited growth large fruit tomatoes. Using the membership function method and weight analysis, a comprehensive evaluation was conducted on the taste and flavor of tomato fruits. Based on the D-value ranking of the comprehensive evaluation, 10 sweet and sour-tasting Solanum Pimpinellifolium and cherry tomatoes with good taste were selected, and 5 sweet, fleshy, and sandy-soft-tasting large fruit tomato resources were selected. 【Conclusion】 The research results clarified the phenotypic specificity and rich genetic diversity of 169 tomato germplasm resources. Cluster analysis screened out tomato resources specific to each group and used fruit taste-related indicators to screen cherry tomatoes and ordinary large fruit tomato resources for better performance. This study could serve as the theoretical and material basis for the genetic improvement of excellent tomato resources and new variety breeding.

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    An EIN3/EIL Family Gene, ZmEIL9 Regulates Grain Development in Maize
    ZHU JunJie, ZHANG XinYue, PAN MengYing, ZHANG JingWen, ZHENG Qi, LI YuLing, DONG YongBin
    Scientia Agricultura Sinica    2024, 57 (18): 3522-3532.   DOI: 10.3864/j.issn.0578-1752.2024.18.002
    Abstract346)   HTML28)    PDF (5579KB)(169)       Save

    【Objective】 Grain size and weight are the important factors affecting the yield of maize. The EIN3/EIL gene family is a sort of key transcription factors in the ethylene signaling transduction pathway, and the functions and regulatory mechanisms of the EIN3/EIL gene ZmEIL9 were analyzed in maize kernel development to elucidate its molecular mechanisms.【Method】 The expression patterns of ZmEIL9 in maize kernel at different developmental stages were analyzed by bioinformatics and RT-qPCR. The multiple sequence alignment of ZmEIL9 and its homologs from different species was performed, and the phylogenetic trees was constructed based on the neighbor-joining method. The sequence characteristics of ZmEIL9 protein were analyzed, and subcellular localization of ZmEIL9 was performed. The insertion mutants of Mu transposon and CRISPR/Cas9 knockout mutants of ZmEIL9 were screened, and the agronomic traits including grain filling rate, storage substances such as starch granule and protein content were analyzed. 【Result】 According to the members of EIN3/EIL family in maize, phylogenetic trees showed that ZmEIL9 was closely related to ZmEIL1 and SbEIL1. In the transcriptomic database of maize inbred line B73, the expression levels of ZmEIL9 were higher in the grain at early and late developmental stages. However, the expression levels were higher in inbred line N04 at the middle and late developmental stages. ZmEIL9 encoded 644 amino acids in the inbred lines Dan232 and N04, while its homolog in inbred line B73 has 642 amino acids. Subcellular localization analysis indicated that ZmEIL9 was localized in nucleus. The ZmEIL9 mutants with different Mu transposon insertion sites and CRISPR/Cas9 knockout mutants with amino acid frameshift mutations were obtained, respectively. The plant height, grain length, and 100-grain weight of Mu mutants and knockout mutants were significantly lower than those of its wild counterpart. The grain dry weights at different developmental stages were also analyzed, and the grain filling rates of Zmeil9 mutant were lower than those of the wild type. The starch granules of Zmeil9 mutant were significantly smaller and had an irregular shape based on scanning electron microscopy (SEM) observations. The contents of total starch and the concentration of zein protein in the Zmeil9 mutant were significantly lower than those in the control. 【Conclusion】ZmEIL9 plays an important regulatory role in the kernel development of maize.

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    Identification of Molecular Markers Associated with Body Size Traits Through Genome-Wide Association Analysis in Wenchang Chickens
    LUO Na, AN BingXing, WEI LiMin, WEN Jie, ZHAO GuiPing
    Scientia Agricultura Sinica    2024, 57 (10): 2046-2060.   DOI: 10.3864/j.issn.0578-1752.2024.10.015
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    【Objective】 Body size traits are the primary indicators for evaluating avian growth characteristics. By selecting molecular markers and candidate genes related to body size traits in Wenchang chickens, this study could provide the theoretical support for deciphering the genetic mechanisms and molecular breeding of body size traits. 【Method】 Three generations of Wenchang chicken lines in Hainan Province (n=2 024) were used in this study. Five body size traits were measured on each chicken at market age, including shank length, shank girth, body slope length, keel length, and chest width. Blood samples were collected for DNA extraction, followed by sequencing and genotyping using the "Jingxin No.1" 55 K chip. Genome-wide association analysis was conducted using GEMMA and PLINK software to identify SNP loci and important candidate genes associated with body size traits. LD analysis was performed to identify haplotypes significantly associated with body size traits. 【Result】 Phenotypic data showed that, at 113 days of age, Wenchang cockerels had average shank length of 8.64 cm, shank girth of 0.46 cm, body slope length of 19.73 cm, keel length of 12.32 cm, and chest width of 6.81 cm. Wenchang hens had average shank length of 6.98 cm, shank girth of 0.40 cm, body slope length of 17.79 cm, keel length of 10.45 cm, and chest width of 6.24 cm. After quality control, 42 206 SNPs and 2 024 individuals were retained for further analysis. PCA analysis using PLINK software revealed some dispersion among the three generations, prompting the inclusion of the top three principal components as covariates in the GWAS analysis to correct for population structure effects. The GWAS results identified 19 SNPs significantly or suggestively associated with shank length (P value=2.17789E-06/4.35578E-05), 23 SNPs associated with shank girth, 7 SNPs associated with body slope length, and 2 SNPs associated with keel length. No SNPs significantly associated with chest width were identified. Annotation of significant loci identified 16 candidate genes related to body size traits, including LDB2, NCAPG, FAM184B, and KCNIP4. LD haplotype analysis revealed 3 significant haplotypes in GGA4, with candidate genes LDB2 and NCAPG annotated in significant block loci. Regarding the shank length trait, two loci, including rs316943436 and rs313978573, were situated within the haplotype block. For shank girth, five loci, namely rs313196946AA, rs316242963, rs315796839, rs313978573, and rs734365522, were located within the haplotype block. In the case of body slope length, only one locus (rs313978573) resides within the haplotype block. 【Conclusion】 Through the GWAS method, those potential candidate genes for shank length, including SEPSECS, LGI2, DHX15, KCNIP4, NCAPG, FAM184B, LDB2, and CC2D2A, were identified. For shank girth, potential candidate genes encompassed FH, TBC1D1, DTHD1, SEPSECS, LGI2, SOD3, PPARGC1A, KCNIP4, NCAPG, FAM184B, CLRN2, LDB2, TAPT1, and CC2D2A. KCNIP4, LDB2, TAPT1, and NRXN3 were identified as potential candidate genes for body slope length, while FAM184B emerged as a potential candidate gene for keel length. In summary, this study established LDB2, NCAPG, and FAM184B as potential functional genes associated with various body size traits, providing the theoretical support for molecular marker-assisted selection in enhancing body performance in Wenchang chickens.

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    Genetic Composition Analysis of a New High Quality and High Yield Wheat Cultivar Taikemai33
    QI XiaoLei, WANG Jun, LÜ GuangDe, MU QiuHuan, MI Yong, SUN YingYing, YIN XunDong, QIAN ZhaoGuo, WANG RuiXia, WU Ke
    Scientia Agricultura Sinica    2024, 57 (22): 4391-4401.   DOI: 10.3864/j.issn.0578-1752.2024.22.001
    Abstract343)   HTML60)    PDF (1486KB)(211)       Save

    【Objective】Taikemai33, derived from a cross between Zhengmai366 and Huaiyin9908, is a new released wheat cultivar with high quality, high yield, and excellent disease resistance, which has a broad genetic base, and a high potential for application in wheat production. The objective of this study is to dissect the genetic composition of Taikemai33 to provide information for parental selection to use this cultivar to develop more new wheat cultivars. 【Method】Taikemai33 and its pedigree parents including Zhengmai366, Huaiyin9908, Yumai47, PH82-2-2, Yumai13, Yumai 2 hao, Bainong3217, Yanda24, Xiannong39, Fengchan 3 hao and Funo were screened using the 55K wheat SNP chip to dissect the genomic composition of Taikemai33 to evaluate the genetic contributions of each parental line to Taikemai33. 【Result】The similarity coefficient between Taikemai33 and its pedigree parents ranged from 0.72 to 0.93, and the genetic composition of Taikemai33 was highly similar to Zhengmai366, the pedigree mother parent, with a genetic similarity coefficient of 0.93. SNP marker analysis showed that the pedigree parents contributed different proportion to the genome of Taikemai33, with the pedigree mother contributed 66.57%, whereas the pedigree father contributed 33.43%, indicating that Taikemai 33 inherits more genetic materials from the maternal lineage. Furthermore, the pedigree mother contributed 71.0%, 85.0% and 49.4% to subgenome A, B and D of Taikeimai33, whereas those were 29.0%, 15.0% and 50.6% contributed by the pedigree father. For each chromosome, the pedigree mother contributed more on chromosome 1A, 2A, 3A, 4A, 7A, 1B to 7B, 1D and 2D, whereas the pedigree father contributed more on chromosome 5A, 4D, 6D and 7D. The contributions of the pedigree parents on 6A, 3D and 5D were equal. Taikemai33 genotype map showed that the contribution loci of the pedigree mother were distributed in clusters on chromosome 1A, 5A, 7A, 2B, 7B, 2D, with those from the pedigree father were on chromosome 4A, 5A, 6D, 7D. Interestingly, among the polymorphic SNP loci, between Zhenmai366 and Huaiyin9908, Taikemai33 showed 109 loci that were absent in both parents, distributing on 19 chromosomes except 1A and 6A. Chromosome 4A, 2B, 6B and 7D of Taikemai33 confer most of the polymorphic SNPs in clusters with cluster number of 10, 9, 11, and 9. 【Conclusion】We constructed the genotype map and dissected the genetic composition of Taikemai33, determined the loci contributed by the pedigree parents and identified that Taikemai33 inherited more genetic materials from the pedigree mother and conferring some specific loci different with the pedigree parents.

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    Yield Gain Analysis of Wheat Varieties in Sichuan from 2000 to 2020
    LUO JiangTao, ZHENG JianMin, DENG QingYan, LIU PeiXun, PU ZongJun
    Scientia Agricultura Sinica    2024, 57 (20): 3945-3956.   DOI: 10.3864/j.issn.0578-1752.2024.20.001
    Abstract334)   HTML50)    PDF (672KB)(238)       Save

    【Objective】Analyzing the yield and yield related traits of Sichuan wheat varieties from 2000 to 2020, providing reference for genetic improvement of yield in Sichuan wheat varieties. 【Method】From 2019 to 2022, a community trial design was used to measure the yield and related traits of 145 wheat varieties in Sichuan Province since 2001 to 2016, as well as 60 high-yield wheat varieties (Varieties with top yields in regional trials in Sichuan Province over the years) since 2000 to 2020. This data was used to analyze the trend of yield and yield related trait changes in Sichuan wheat cultivars cultivated from 2000 to 2020. 【Result】145 Sichuan wheat varieties from 2001 to 2016 have an average annual genetic gain of 37.20 kg·hm-2 or 0.66% in yield. Grain number per spike and effective spike number per unit area showed an increasing trend, while thousand grain weight and plant height showed a decreasing trend. Correlation analysis showed that effective spike number per unit area was positively correlated with yield. Path analysis showed that the continuous increase of effective spike number per unit area (annual increase 0.42×104/hm2 or 0.13%) was the main factor for the increase of yield potential of high-yielding varieties. The average annual yield genetic gain of 60 high-yield wheat varieties from 2000 to 2020 was 61.10 kg·hm-2 or 0.89%, the effective spike number per unit area showed an increasing trend, the plant height showed a decreasing trend, and the grain number per spike and thousand grain weight had almost no change. Correlation analysis shows that there was a significant positive correlation between yield and the number of effective ears per unit area. Path analysis showed that the continuous increase in effective spike number per unit area (with an average annual increase of 1.80×104/hm2 or 0.51%) was also a major factor in improving the yield potential of 60 high-yield wheat varieties in Sichuan from 2000 to 2020. 【Conclusion】The improvement and breeding of wheat yield heritage in Sichuan Province has made some progress, especially the improvement effect of high yield breeding is remarkable, and the yield level of wheat varieties in Sichuan Province is gradually increasing. The continuous increase in effective ears per unit area was the main factor for improving the yield potential of Sichuan wheat varieties. High grain number per spike and thousand grain weight are important foundations for high yield in Sichuan wheat, but their genetic improvement is in a bottleneck period. Increasing the effective spike number per unit area is the key to furtherly improve the yield of wheat in Sichuan.

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    Targeted Metabolomics-Based Analysis of Peel Color Differences Between Yellow and Red Hawthorn
    GUO RongKun, DONG NingGuang, NONG HuiLan, WANG Han, TENG WeiChao, MENG JiaXin
    Scientia Agricultura Sinica    2024, 57 (12): 2439-2453.   DOI: 10.3864/j.issn.0578-1752.2024.12.013
    Abstract334)   HTML10)    PDF (3121KB)(327)       Save

    【Objective】 The aim of this study was to explore the accumulation pattern of flavonoids and carotenoids of yellow and red hawthorn peel during the fruit ripening process, as well as to deepen the understanding of the coloration mechanism of hawthorn peel, so as to provide the guidance for peel color-directed genetic breeding. 【Method】The fruit peel of yellow hawthorn (Crataegus pinnatifida Jinruyi) and red hawthorn (Crataegus pinnatifida Ruanzi) was used as test materials. The components and content of flavonoid and carotenoid in the peel of the two cultivars during different growth stages were examined qualitatively and quantitatively based on targeted metabolomics analysis. The differential accumulation of flavonoids and carotenoid metabolites between the two cultivars was analyzed by the orthogonal partial least squares discriminant analysis (OPLS-DA). 【Result】A total of 130 kinds of flavonoids and 49 kinds of carotenoids were detected in the peel of the two hawthorn cultivars, and the components and content of these metabolites were significantly different between the two cultivars during different growth stages. The anthocyanin content of the Ruanzi peel was 400 times higher than that of the Jinruyi peel, which in the Ruanzi peel and Jinruyi peel at the mature period (S5) was 930.04 and 2.32 µg·g-1, respectively. The major anthocyanin species was cyanidin-3-O-galactoside, which accounted for more than 95% of total anthocyanins. The carotenoid metabolism analysis showed that there was no significant difference in total carotenoid content between Ruanzi and Jinruyi during the S1-S3 period, and lutein was the predominant accumulated carotenoid. The content of β-carotene, β-cryptoxanthin, neoxanthin, α-carotene, and zeaxanthin in the Jinruyi peel were significantly higher than that in the Ruanzi peel during the S4-S5 period. The massive accumulation of these carotenoid metabolites in the Jinruyi peel led to the difference in carotenoid content in the two hawthorn cultivars during the S4-S5 period. 【Conclusion】 In the hawthorn fruit mature period, the accumulation of anthocyanin in the Ruanzi peel led to the appearance of red, and the accumulation of carotenoid in the Jinruyi peel led to the appearance of yellow. The differential accumulation of anthocyanins and carotenoids played an important role in the hawthorn peel different coloration.

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    Effects of Unmanned Dry Direct-Seeded Mode on Yield, Grain Quality of Rice and Its Economic Benefits
    WENG WenAn, XING ZhiPeng, HU Qun, WEI HaiYan, SHI YangJie, XI XiaoBo, LI XiuLi, LIU GuiYun, CHEN Juan, YUAN FengPing, MENG Yi, LIAO Ping, GAO Hui, ZHANG HongCheng
    Scientia Agricultura Sinica    2024, 57 (17): 3350-3365.   DOI: 10.3864/j.issn.0578-1752.2024.17.004
    Abstract329)   HTML19)    PDF (595KB)(196)       Save

    【Objective】This study aimed to provide the theoretical and technical support for the innovation of green, high-yield, high-quality and high-efficiency unmanned dry direct-seeded (UDDS) cultivation technology of rice.【Method】Medium-maturing medium japonica rice (Nanjing 5718) was selected as the experimental material, with unmanned carpet seedling mechanical transplantated (UCSMT), and conventional carpet seedling mechanical transplantated (CSMT) serving as control methods. A three-year field experiment was conducted to assess the impact of UDDS on growth, yield formation, quality characteristics of rice, and its economic benefits.【Result】(1) Although UDDS was carried out with 2-3 days earlier than the control, it exhibited a full growth cycle that was 12-13 days shorter than those of UCSMT and CSMT, primarily due to the shortened period from sowing to jointing stage. (2) The average yield under UDDS from 2020 to 2022 was 10.5 t·hm-2, representing a 3.0% increase than that of CSMT, although this difference was not statistically significant. In comparison with UCSMT, UDDS exhibited a significant yield reduction of 5.4%, and this decrease could be attributed to a reduction in the spikelet number per panicle, resulting in fewer total spikelet numbers and a decrease in dry matter accumulation and transport capacity from heading to maturity. (3) Compared with CSMT, UDDS exhibited slightly reduced processing quality, amylose, and protein contents, with no significant differences were observed. However, the significant reductions in chalkiness percentage and degree were noted, while the taste value increased, though not significantly. Compared with UCSMT, UDDS demonstrated a significant decrease in head milled rice rate, chalkiness percentage, degree, and amylose content, and protein content also decreased, though not significantly. Additionally, UDDS exhibited higher RVA peak viscosity and a significant improvement in taste value. (4) Under the UDDS mode, the cost of rice planting decreased, and the net income increased by 1.15 × 103 yuan·hm-2 and 0.93 × 103 yuan·hm-2, than that under UCSMT and CSMT, respectively.【Conclusion】In the rice-wheat rotation system, UDDS realized the synergy of high yield and income increase, and improved the appearance quality and cooking and eating quality of rice, the UDDS cultivation technology should be optimized in terms of improving the total spikelet number, accumulation and translocation of dry matter during filling stage, thereby getting the goals of high rice yield, great quality, and efficient synergy, simultaneously.

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    Breeding of the Fusarium Head Blight (FHB)-Resistant Wheat Cultivar Lunxuan 20 Using the Dwarf-Male Sterile Wheat Molecular Strategy in the Yellow and Huai River Valley Winter Wheat Region
    MAI ChunYan, LIU YiKe, LIU HongWei, LI HongJie, YANG Li, WU PeiPei, ZHOU Yang, ZHANG HongJun
    Scientia Agricultura Sinica    2024, 57 (19): 3719-3729.   DOI: 10.3864/j.issn.0578-1752.2024.19.001
    Abstract329)   HTML29)    PDF (5763KB)(206)       Save

    【Objective】To develop high-yielding and FHB-resistant wheat cultivars in the Yellow and Huai River Valley Winter Wheat Zone (YHWZ), simultaneously improving of yield and resistance was conducted in this study.【Method】Using the elite parent dwarf male sterile (DMS) wheat combined with double haploid (DH) technology and molecular marker assisted selection (MAS) of Fhb1 (DMS wheat molecular breeding strategy), DH lines were developed using Sumai 3 as a donor (FHB- resistant parent) and Zhoumai 16’s DMS wheat, Zhoumai 16, Lunxuan 136 and Lunxuan 6 as recipient parents. The agronomic traits (plant height, heading date, yield, etc.) and FHB resistance were evaluated for these DH lines.【Result】A total of 51 Fhb1-DH lines characterized by facultative growth habit, semi-dwarf and white grains were selected using this strategy. The average number of infected spikelets of 51 lines were 5.7 and 7.3 at the 2020Henan and 2020Beijing sites, respectively, and average disease severities were 27.7% and 35.2%, which is not different from moderately susceptible control Huaimai 20. There was no significant difference in grain yield per hm2 between the mean performance of the 51 lines and the control Zhoumai 18. DH116 (Lunxuan 20), a promising line from the 51 lines, was further evaluated for FHB resistance and agronomic traits in multiple environments. The resistance of Lunxuan 20 to FHB was significantly improved, and no significant difference was found in the number of infected spikelets or disease severity between Lunxuan 20 and moderately or highly resistant controls at four sites. Lunxuan 20 showed slightly greater grain yield per hm2, and significantly higher number of spikelets per spike and thousand grain weight (P<0.05), earlier heading date and shorter plant height (P<0.05) than the control Zhoumai 18 in two environments. The grain yield per hm2 of Lunxuan 20 was 4.6% and 1.7% higher than the control cultivar Bainong 207 in the two list trials of Henan Province, and 3.5% higher than Bainong 207 in the demonstration trial. Resistance of Lunxuan 20 to FHB ranged from moderate susceptibility to moderate resistance in two-year list tests using the single-floret injection and spray inoculation methods. Lunxuan 20 carries the semi-dwarfing gene Rht-D1b at the Rht-D1 locus, and the recessive alleles vrn-A1, vrn-B1 and vrn-D1 associated with the winter growth habit at the Vrn-A1, Vrn-B1 and Vrn-D1 loci. Based on the wheat 660K single nucleotide polymorphisms (SNPs), 64.7% of the SNPs were shared by Lunxuan 20 and its parents, and the direct genetic contributions of Zhoumai 16, Lunxuan 136, Lunxuan 6 and Sumai 3 to Lunxuan 20 were 69.8%, 12.6%, 6.1% and 11.5%, respectively.【Conclusion】A high-yielding and FHB-resistant wheat cultivar Lunxuan 20 was bred using the DMS wheat molecular breeding strategy.

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    Preliminary Study on Appearance Quality Evaluation of Semi-Waxy Rice in Yangtze River Delta Region
    FAN Peng, YANG TianLe, ZHU ShaoLong, WANG ZhiJie, ZHANG MingYue, WEI HaiYan, LIU GuoDong
    Scientia Agricultura Sinica    2024, 57 (16): 3105-3115.   DOI: 10.3864/j.issn.0578-1752.2024.16.001
    Abstract311)   HTML25)    PDF (1344KB)(355)       Save

    【Objective】Due to the cloudy and translucent appearance characteristics of semi-waxy rice, there is a lack of effective evaluation methods in the industry at present. It is necessary to construct an evaluation method for the appearance quality of semi-waxy, and classify the appearance quality of semi-waxy rice, so as to provide technical support for the standardization and development of semi-waxy rice industry. 【Method】In this study, according to GB/T 15682-2008 "Grain and Oil Inspection of rice, Rice cooking and edible quality sensory evaluation method", the appearance quality score of semi-waxy rice was obtained by artificial evaluation method, and various appearance indexes of semi-waxy rice were measured, including chalkiness, transparency, grain type and color space related indexes. Pearson correlation coefficient, max-relevance and min-redundancy, competitive adaptive reweighted sampling and intersection feature selection methods were used to analyze the relationship between chalkiness, transparency, grain shape and color space related indicators and the appearance sensory score of semi-waxy rice, and select the core indicators that can determine the appearance quality of semi-waxy rice for constructing and verification of semi-waxy rice appearance evaluation model. Finally, the model was used to estimate the overall appearance quality of semi-waxy rice in the Yangtze River Delta region and graded according to the estimated score. 【Result】Through comparing the estimation accuracy and stability of four models, this study found that the semi-waxy rice appearance evaluation model, represented by the equation Y=5.68+0.17X4+0.19X6-0.03X9-0.12X10, demonstrated the highest accuracy and stability. This model was constructed using chalk rice transparency (X4), overall transparency (X6), chalkiness (X9), and L*(X10), which were selected by the intersection feature selection method. Notably, this model incorporates the fewest number of indicators, with a coefficient of determination (R2) of 0.86 during model validation and a simulated root mean square error (RMSE) of 0.32. After using this model to estimate the appearance of most of the semi-waxy rice in the three rice-growing areas of the Yangtze River Delta, It was found that the appearance scores of the first 20%, 20%-50%, 50%-90% and last 10% of semi-waxy rice materials in the Yangtze River Delta region in this study were greater than 0.23, -0.48-0.23, -1.68--0.48 and less than -1.68, respectively, which can represent four levels of appearance quality of semi-waxy rice in practical applications: Level 1, Level 2, Level 3, Out of level. At the same time, it was found that there were significant gradient differences in grain type, chalkiness, transparency and color space among different appearance grades of semi-waxy rice, but there were different degrees of crossover between their value ranges.【Conclusion】Using chalk rice transparency (X4), overall transparency (X6), chalkiness (X9), and L*(X10), an effective estimation model of semi-waxy rice appearance could be established: Y=5.68+0.17X4+0.19X6-0.03X9-0.12X10. With reference to the scoring range of each appearance grade of semi-waxy rice in Yangtze River Delta region, the appearance of a single semi-waxy rice material can be quickly determined by the appearance estimation score. The evaluation of semi-waxy rice by appearance estimation model is beneficial to take into account the different appearance phenotypes of semi-waxy rice, and can accurately reflect the actual situation of semi-waxy rice appearance.

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    Research Progress of ApiAP2 Transcription Factors in Regulating the Growth and Development of Toxoplasma gondii
    HU DanDan, LUO RunQi, LIANG RuiYing, WANG Lei, LIANG Lin, SI HongBin, DING JiaBo, TANG XinMing
    Scientia Agricultura Sinica    2024, 57 (13): 2687-2697.   DOI: 10.3864/j.issn.0578-1752.2024.13.015
    Abstract309)   HTML13)    PDF (869KB)(478)       Save

    Toxoplasmosis is one of the most serious zoonotic parasitic diseases in the world. WHO data show that the positive rate of Toxoplasma gondii antibody in the global population is 25%-50%. The vertical transmission caused by T. gondii infection in pregnant women seriously endangers the health of fetuses and infants, and T. gondii infection is also the main cause of death in immunocompromised patients. In livestock production, toxoplasmosis causes abortion and stillbirth in pregnant animals, which is seriously harmful. T. gondii is an obligate intracellular protozoan parasite that belongs to the apicomplexan protozoa, and its life cycle is complex, including asexual reproduction in intermediate hosts (humans and other warm-blooded animals) and sexual reproduction in terminal hosts (cats). In order to complete the complex life cycle of T. gondii in the intermediate and terminal hosts, its transformation and growth at different developmental stages require strict and accurate gene regulation. Therefore, revealing the regulatory mechanism of T. gondii growth and development is of great significance for the development of therapeutic drugs and vaccines. ApiAP2 transcription factor is a kind of protein family with AP2 domain and strong regulatory function, which plays a core regulatory role in the growth and development of parasites such as Plasmodium and T. gondii. It is a breakthrough to elucidate the regulation mechanism of development and transformation of T. gondii at different life cycle stages. As a model organism for the study of apicomplexan, 67 transcription factors containing AP2 domain have been annotated in T. gondii genome. Some of these transcription factors play crucial regulatory roles in the growth, development, and transformation processes of T. gondii throughout its life cycle. However, the biological functions of most AP2 transcription factors are unknown, especially the research on the development and regulation of sexual reproduction stage is relatively scarce. In this paper, the research methods, biological functions, regulatory interaction genes and networks of AP2 transcription factors of T. gondii have been systematically reviewed. The aim was to explore the genes or molecules that play a core regulatory role in the important nodes of T. gondii growth and development. The regulatory mechanism of different growth and development stages of T. gondii complex life cycle was preliminarily outlined at the micro molecular level, and its role and potential in the development of new drugs and vaccines were prospected. To provide new ideas and entry points for the prevention and control of animal toxoplasmosis and block the source of human toxoplasmosis infection, we should practice the concept of “disease prevention in animals and front-line defense” and strive to achieve “one world, one health” for everyone’s well-being.

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    The Efficiency of Haplotype-Based Genomic Selection Using Genotyping by Target Sequencing in Pigs
    LIU YanLing, QIU Ao, ZHANG ZiPeng, WANG Xue, DU HeHe, LUO WenXue, WANG GuiJiang, WEI Xia, SHI WenYing, DING XiangDong
    Scientia Agricultura Sinica    2024, 57 (11): 2243-2253.   DOI: 10.3864/j.issn.0578-1752.2024.11.015
    Abstract307)   HTML12)    PDF (1051KB)(132)       Save

    【Objective】This study explored the efficiency of haplotype-based genomic selection using genotyping by target sequencing technology in order to provide the useful experience for molecular breeding of pigs in China.【Method】The growth traits records of 1 267 Large White pigs and the reproduction trait records of 800 Large White pigs were collected and genotyped by using the porcine 50K liquid-phase SNP panel (liquid-phase 50K) based on the Genotyping by Target Sequencing (GBTS) as well as its target resequencing data. Three strategies for haplotype block partition, including fixed SNP number, fixed length, and target block, were proposed to construct haplotypes, and the corresponding haplotype-based genomic prediction were compared with single SNP genomic prediction. The target block partition strategy was mainly based on target resequencing data obtained by the GBTS, and one haplotype block contained one target site in liquid-phase 50K and its upstream and downstream SNPs (mSNP) within 400 bp from target resequencing data. In this study, after phasing haplotype using Beagle 5.1 within each haplotype block, the different haplotypes were recoded as haplotype alleles, and then haplotype allele matrix was constructed using haplotype dosage model. A single-step GBLUP model (ssGBLUP) was then used to estimate genomic breeding values for three traits of days at 100 kg body weight (AGE), backfat thickness at 100 kg (BF), and total number of born (TNB). A two-trait animal model was implemented for two growth traits of AGE and BF, and repeatability model for TNB. Younger validation population and five-fold cross validation were carried out to assess the efficiency of genomic prediction. The correlation coefficients between estimated breeding values and genomic estimated breeding values were measured as the accuracy of genomic prediction, and the regression coefficients of genomic estimated breeding values on estimated breeding values were measured unbiasedness, respectively.【Result】The results from the younger validation population showed that the target resequencing data yielded lower accuracies of genomic selection on three traits than liquid-phase 50K SNP, even its number of SNP after genotype quality control was increased from 42 302 in liquid phase 50K to 88 105. The haplotype blocks partitioned by target block strategy contained 2.08 SNPs and 5.67 haplotype alleles on average. The accuracies of haplotype-based genomic selection based on all three haplotype block partition strategies were improved, and the target block gained the largest improvement, yielding 4.80%, 1.98% and 6.04% higher accuracies on AGE, BF and TNB than liquid- phase 50K, respectively. In addition, the target block strategy generated the lowest bias in most scenarios as well. The five-fold cross-validation obtained similar results as younger validation population did, target block gained advantages over both single SNP and other haplotype block partition methods. The fixed length of 400 bp block partition strategy performed comparable with target block, while it was time demanding. Although fixed 2 and 5 SNP haplotype block partition methods performed better than single SNP method, they were worse than target block.【Conclusion】Due to the short length, the linkage disequilibrium between most of the target sites in liquid-phase 50K SNPs and their mSNPs in same blocks are strong, resulting in target block strategy obtained higher accuracy in haplotype-based genomic selection than single SNP and other haplotype block partition strategies, which could make use of the technique advantage of GBTS, and further broaden the application of liquid-phase chip.

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    Progress on Detection Methods for Gene-Edited Organisms
    WU YuHua, ZHAI ShanShan, PU HaoZhen, GAO HongFei, ZHANG Hua, LI Jun, LI YunJing, XIAO Fang, WU Gang, XU LiQun
    Scientia Agricultura Sinica    2024, 57 (17): 3318-3334.   DOI: 10.3864/j.issn.0578-1752.2024.17.002
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    Gene editing techniques have made gene edited (GE) organisms enter commercial applications from laboratories. In 2022, the Ministry of Agriculture and Rural Affairs specifically issued the “Guidelines for Safety Evaluation of Genetically Edited Plants for Agricultural Use (Trial)” for the safety evaluation of GE plants without introducing exogenous genes. In 2023, China granted the first biosafety certificate for GE soybean AE15-18-1, marking the official start of the commercialization process of GE crops in China. GE organisms are different from traditional genetically modified organisms (GMOs) containing exogenous DNA sequences, making common GM detection strategies inapplicable to the detection of GE organisms. As the industrialization of GE crops progresses positively, how to efficiently and accurately detect whether a product is gene-edited and its editing characteristics is an important basis for the commercial use and intellectual property protection of GE products. There is an urgent need to develop detection technologies suitable for GE products. With the goal of detecting whether the target sequence has been edited, many detection technologies have been developed based on PCR, sequencing, and other technologies, and are widely used in the screening of GE products in the research and development process. After industrialization, safety supervision and intellectual property protection require not only the detection of whether the sample has been edited but also the rapid identification of the nucleotide sequence characteristics of the sample to determine its origin and identity. Subsequently, precise quantification of the GE components is necessary to determine whether quantitative labeling is required. Currently, it is difficult to quickly identify the identity of GE products with only a few base insertions, deletions, and single nucleotide variations (SNV) using conventional PCR or sequencing technologies. It is even more challenging to accurately quantify the content of GE components. Aiming at the rapid identification of the DNA sequence characteristics after editing and precise quantification, based on the molecular characteristics of GE products, this paper reviews the application of the gel electrophoresis-based PCR method, the sequencing-based method, the real-time PCR-based method, the digital PCR-based method, the editing enzyme-based method, and the instrument-based method in detection of GE organisms, and expounds the advantages and disadvantages of each method during detection. This review initially explores the detection and quantification strategies suitable for GE organisms and provides a reference for subsequent development of detection methods for GE organisms.

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    Interactive Effects of Planting Density and Nitrogen Application Rate on Plant Grain Yield and Water Use Efficiency of Two Maize Cultivars
    TIAN LongBing, SHEN ZhaoYin, ZHAO XiaoTian, ZHANG Fang, HOU WenFeng, GAO Qiang, WANG Yin
    Scientia Agricultura Sinica    2024, 57 (21): 4221-4237.   DOI: 10.3864/j.issn.0578-1752.2024.21.005
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    【Objective】Reasonably increasing planting density combined with appropriate nitrogen (N) application rate is an important technical approach for increasing maize yield and resource use efficiency. Understanding the interactive effects of planting density and N rate on maize growth, evapotranspiration (ET) and water use efficiency (WUE) during the growing season, could provide a basis for improving its use efficiency when increasing planting density and controlling N input in maize production. 【Method】Field experiments were conducted during 2022 to 2023 in Jilin Province. Two maize cultivars, Liangyu 99 (LY99) and Demeiya 3 (DMY3), were used in this study. Three planting densities of 50 000, 70 000 and 90 000 plants/hm2 and four N application rates of 0, 100, 200 and 300 kg N·hm-2 were designed to investigate the effects of planting density and N application rate on grain yield and water productivity of different maize cultivars, as well as the dry matter (DM), soil water content, ET and WUE at various growth stages. 【Result】Planting density significantly affected DM and grain yield of maize, but the response trends varied between cultivars. Grain yields of LY99 with 70 000 plants/hm2 was 11.1% and 18.3% higher than that with 50 000 and 90 000 plants/hm2, respectively. The average yield of DMY3 planted with 70 000 plants/hm2 and 90 000 plants/hm2 was 10.5% and 9.3% higher than that of 50 000 plants/hm2, respectively. Nitrogen fertilization significantly increased DM and grain yield of maize, and also showed significant interactive effects with cultivar or planting density. Compared with N0, grain yields of LY99 were increased by 38.0% to 60.7% under N1, and the yield increases for DMY3 were 24.4% to 38.2%. Notably, the yield responses to N rates were more pronounced for LY99 compared with DMY3. For both cultivars, the yield differences between low N rate and high N rate enlarged with increasing planting density, with LY99 showing a more distinct performance. The water consumption and utilization of maize plants were also significantly affected by planting density, N rate and their interaction. During the growing season, the total ET of DMY3 continually increased with increasing density, while that of LY99 showed the highest values with 70 000 plants/hm2 among different densities. In each density condition, the ET of both cultivars increased with increasing N application rates. The WUE of maize plants showed complex responses to planting density and N rate at different growth stages, due to the varied annual precipitation and distribution patterns. The average increase of water productivity of LY99 under planting 50 000 and 70 000 plants/hm2 was 8.6% and 10.4% compared with 90 000 plants/hm2 respectively. DMY3 had the highest water productivity when planting 70 000 plants/hm2, which increased by 5.8% and 5.3% compared with 50 000 and 90 000 plants/hm2, respectively. The water productivity showed different responses to N rate among the three densities. In general, the difference of nitrogen application under low density was small, but it increased significantly under medium and high density. Compared wtih DMY3, LY99 showed higher increases for water productivity when N fertilizer was applied under medium and high density conditions. The correlation analysis showed that interactive effects of planting density and N rate significantly affected maize yield and water productivity by influencing the water utilization at various growth stages. 【Conclusion】Planting density and N rate had significant interactive effects on maize yield and water utilization in the rain-fed region of Northeast China. The two maize cultivars used in this study could obtain high grain yield and water productivity under a moderately higher density of 70 000 plants/hm2 combined with 200 kg N·hm-2 rate.

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    Genome-Wide Identification of Soybean LOX Gene Family and the Effect of GmLOX15A1 Gene Allele on 100-Seed Weight
    WANG Wei, WU ChuanLei, HU XiaoYu, LI JiaJia, BAI PengYu, WANG GuoJi, MIAO Long, WANG XiaoBo
    Scientia Agricultura Sinica    2025, 58 (1): 10-29.   DOI: 10.3864/j.issn.0578-1752.2025.01.002
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    【Objective】Based on whole genome identification and analysis of soybean LOX gene family members, to understand the taxonomic evolutionary relationships of each member, to study the expression specificity of each gene member in different tissues and their response to abiotic stress, which provided a theoretical basis for further research on the molecular characteristics, evolutionary process, and function of the LOX gene family. 【Method】Based on the LOX protein sequences of rice and Arabidopsis species in Ensembl database, BLASTP alignment of homologous LOX protein sequences in soybean whole genome database was performed, and MEGA X software was used to construct a phylogenetic tree; Using website MEME for protein conserved motif analysis; Using online software GSDS 2.0 to analyze gene structure; Using TBtools for chromosome localization drawing; Analyze soybean LOX family replication genes using McscanX; Using the PlantCARE website to predict the promoter elements of soybean LOX gene family; Draw gene expression heatmaps of soybean under different tissues and abiotic stress using TBtools, and develop molecular markers for the excellent allele variant GmLOX15A1-G/A significantly correlated with 100-seed weight.【Result】A total of 43 LOX genes were identified in soybean, unevenly distributed on 13 chromosomes. Collinearity analysis indicates that the GmLOX gene has undergone extensive replication during the evolutionary process. Meanwhile, 39 different types of cis regulatory elements were detected in the LOX gene promoter, indicating that they may be involved in different pathways such as growth and development, light response, stress response, and hormone induction. Expression pattern analysis revealed that the LOX gene has different levels of expression in different tissues of soybean, indicating that members of this family have tissue and spatiotemporal expression specificity. Under drought stress conditions, the GmLOX gene was significantly differentially expressed in soybean roots and leaves (P<0.05). Among them, GmLOX3A3, GmLOX7A1, GmLOX20B1, GmLOX13A1, and GmLOX20A2 were significantly upregulated or downregulated in roots and leaves, suggesting that the GmLOX gene may play an important role in response to stress. At the same time, it was found that GmLOX15A1 is highly expressed in grain tissue and there is an excellent G/A allele variation in the seventh exon of the gene coding region. Molecular markers were developed for this variant site, and the correlation between different haplotypes of GmLOX15A1 and 100-seed weight was analyzed using 1 200 soybean germplasm resources from different ecological regions over a period of 2 years. The results showed that compared to the GmLOX15A1-A genotype, the average 100-seed weight of soybean germplasm carrying the GmLOX15A1-G allele gene increased by 2.33 g (P<0.001). 【Conclusion】A total of 43 members of the LOX family were identified in soybeans, which can be divided into 3 subfamilies. The promoter region of the GmLOX gene contains a large number of cis acting elements that respond to hormones and stress, playing different roles in drought stress response. Among them, GmLOX15A1 is highly expressed in grain tissue and there is an excellent G/A allele variation in the seventh exon of the coding region of this gene. Compared with the GmLOX15A1-A genotype, the average 100-seed weight of soybean germplasm carrying the GmLOX15A1-G allele gene is significantly increased by 2.33 g. This locus can be used as an excellent haplotype for genetic improvement of soybean grain size.

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    Genetic Diversity Analysis of Winter Wheat Germplasm Resources in Shanxi Province Based on 55K SNP Array
    LEI MengLin, LIU Xia, WANG YanZhen, CUI GuoQing, MU ZhiXin, LIU LongLong, LI Xin, LU LaHu, LI XiaoLi, ZHANG XiaoJun
    Scientia Agricultura Sinica    2024, 57 (10): 1845-1856.   DOI: 10.3864/j.issn.0578-1752.2024.10.001
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    【Objective】 Analyzing the evolutionary patterns of genetic diversity of wheat germplasm resources, providing richer and more diverse original parental materials for parental selection and variety selection in wheat breeding in Shanxi Province.【Method】 Using 323 landraces and 105 cultivated varieties as natural populations, a 55K SNP chip was used to perform whole genome scanning on 428 natural populations, analyzing genetic diversity, genetic structure, principal components, genetic clustering, and phylogenetic relationships among varieties. 【Result】 The distribution of SNP loci on 21 chromosomes ranged from 329 to 1 639, with an average of 1 152. The distribution range of 7 partially homologous groups is 2 154-3 852, with an average of approximately 3 456. The distribution pattern of the genome is: B genome>A genome>D genome. Genomic annotation polymorphism markers have the highest distribution among gene regions, accounting for about 50%. Analysis shows that SNP loci cover 21 chromosomes, 7 homologous groups and 3 genomes, but their distribution varies, with a polymorphism rate of 45.60%. The average observed heterozygosity of the entire population (0.0185) was lower than the expected heterozygosity (0.4992). The changes in the average shannon wiener index and polymorphism information content of the entire natural population were not significant. Comparing the diversity parameters of natural populations, it was found that the genetic diversity of the population is not high, the genetic diversity of cultivated varieties is slightly higher than that landraces. The population structure analysis of natural populations divides the population into two major groups. Group I has 307 materials, mainly landraces. Group Ⅱ has 121 materials, mainly cultivated varieties. The natural groups were divided into five groups by both principal component and cluster analysis. The average genetic distance between the varieties in group I is 0.21831, with a range of 0.00127-0.72461. The average genetic distance between varieties in group Ⅱ is 0.14619, with a range of 0.00038-0.76489. The varieties in group Ⅲ the average genetic distance between the varieties of group Ⅳ is 0.16521, with a range of 0.00049-0.43033. The average genetic distance between varieties of group Ⅳ is 0.17643, with a range of 0.00118-0.60496. The average genetic distance between varieties of group V is 0.12039, with a range of 0.00042-0.37032. It can be seen that the variation of genetic distance between wheat varieties is large in Shanxi Province. However, the average genetic distance value is low, the clustering classification differentiation is obvious. The genetic relationship between varieties in the middle of the group is relatively close. Comparison shows that the average genetic distance of group I and group Ⅳ is higher than that of group Ⅱ, group Ⅲ and group V. The genetic distance variation of group I and group Ⅳ is higher than that of group Ⅲ and group V. It can be seen that the genetic distance of cultivated varieties is generally greater than that of landraces.【Conclusion】 The 55K SNP chip was used to analyze the genetic diversity of Shanxi winter wheat germplasm resources, clarifying the distribution characteristics of genetic diversity at the genomic level between Shanxi wheat cultivated varieties and landraces. The introduction of exogenous genes into cultivated varieties is beneficial for improving genetic diversity, while the genetic diversity of landraces is relatively low. At the same time, the genetic relationships of very few varieties are polarized, so it should be rationally used differently in subsequent utilization.

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    Differential Analysis of Aroma Substance Content and Gene Expression in the Berry Skins of Different Grape Germplasms
    XU MengYu, WANG JiaYang, WANG JiangBo, TANG Wen, CHEN YiHeng, SHANGGUAN LingFei, FANG JingGui, LU SuWen
    Scientia Agricultura Sinica    2024, 57 (13): 2635-2650.   DOI: 10.3864/j.issn.0578-1752.2024.13.011
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    【Objective】 This study aimed to explore the differences in the types, content, and related gene expression levels of volatile aroma compounds in the mature grape skins of different grape germplasms, so as to provide a reference basis for the analysis of the metabolic regulation mechanism of grape volatile aroma substances and the full utilization of aroma resources. 【Method】 In this study, GC-MS was used to identify the types and content of volatile aroma substances in the pericarp of 13 grape germplasms. The transcriptional level of the entire genome was also analyzed by using Illumina high-throughput sequencing platform.【Result】 A total of 154 volatile aroma substances were detected in the 13 grape germplasms, mainly including aldehydes, esters, terpenoids and other compounds. The germplasm with the highest content of volatile aroma substances in the skin was Kyoho, while the lowest was Cabernet Sauvignon. Esters were the most abundant volatile aroma substances in the skins of Kyoho and Petit Verdot, while aldehydes were the most abundant volatile aroma substances in the other germplasms skins. Twelve characteristic aroma substances such as hexanal, ethyl caprylate and linalool contributed more to the aroma of grape skins. The results of principal component analysis showed that there were large differences in volatile aroma substances in the skins of Kyoho, Thompson Seedless, Red Globe and other germplasm. The results of transcriptome analysis showed that the number of differentially expressed genes (DEGs) varied considerably among different germplasms. DEGs were significantly enriched in the pathways of linoleic acid metabolism, α-linolenic acid metabolism, phenylalanine metabolism, tyrosine metabolism, and monoterpene biosynthesis. The expressions of lipoxygenase (LOX), alcohol acyltransferase (AMAT), deoxyd-xylose-5-phosphate reductase (DXS), alcohol dehydrogenase (ADH) and other genes were highly correlated with the content of aroma compounds. Further analysis revealed that the transcription factors WRKY7, WRKY28, ARF4, and ARF22 were potential regulators of aroma synthesis in grapes.【Conclusion】 The content of aroma substances and the expression of related genes in the pericarp of different grape germplasm varied greatly, and the results of the joint multi-omics analysis provided a reference for further research on the synthesis mechanism of volatile aroma substances in grapes.

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    Soybean Disease Resistance, Yield and Quality Correlation
    ZHAN YuHang, WANG Jie, LI YongGuang, HAN YingPeng
    Scientia Agricultura Sinica    2024, 57 (11): 2061-2064.   DOI: 10.3864/j.issn.0578-1752.2024.11.001
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    Aroma Quality Analysis of Guangdongxiangshui Lemon Based on Molecular Sensory Technology
    ZHANG SiNing, ZHANG XingRui, WU DongXuan, KANG JingBo, CHEN XiaoLin, GENG LiJun, YIN GuangMin, CHEN JiaJing, GAO JunYan, CAI ZhongHu, LIU Yuan, XU Juan
    Scientia Agricultura Sinica    2025, 58 (1): 141-155.   DOI: 10.3864/j.issn.0578-1752.2025.01.011
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    【Objective】Tea drinks made from Guangdongxiangshui lemon is popular among consumers, but its aroma profile, main aroma-active compounds and corresponding key biosynthesis genes still need to be analyzed. In this study, integrated molecular sensory technology including metabolomics and sensory evaluation was used to explore the material basis and corresponding key genes for the aroma quality of Guangdongxiangshui lemon, aiming at laying a foundation of the citrus aroma quality. 【Method】The volatiles of Guangdongxiangshui lemon from three areas, including Weishan, Yunfu and Wuzhou, were detected via GC-MS, and the aroma quality were evaluated by sensory evaluation panels. The aroma active compounds of Guangdongxiangshui lemon were identified by GC/O-MS combined with aroma extract dilution analysis (AEDA), aroma activity value (OAV) analysis and aroma recombination experiment, and then the characteristic aroma compounds were further identified. Based on gene family analysis, the genes related to aroma formation were illustrated. 【Result】A total of 40, 21 and 33 volatiles were identified in the flavedo, pulp and slices of Guangdongxiangshui lemon, respectively. The samples with the highest volatile content in flavedo and pulp tissues were from Weishan and Yunfu, respectively. In terms of aroma attributes, the aroma intensity of Guangdongxiangshui lemon slices from Weishan and Yunfu was significantly higher than that of Wuzhou. The whole fruit aroma quality of samples from Wuzhou was better than that of samples from other origins. Solvent-assisted flavor evaporation (SAFE) and other methods were used to extract the essential oil of Guangdongxiangshui lemon in Weishan, and 25 aroma active compounds were identified. Combined with OAV analysis and aroma recombination experiments, citronellal and citral were further identified as its characteristic aroma compounds, and the aroma flavor wheel was further constructed. Based on the conserved domain and Blast comparison, 52 terpene synthase (TPS) genes were identified in Guangdongxiangshui lemon genome, which might be involved in the aroma compounds synthesis. 【Conclusion】The volatile spectrum and sensory evaluation showed that the aroma quality of Guangdongxiangshui lemon slices from Weishan were outstanding. A total of 25 aroma active compounds were identified. Among them, citronellal and citral were the characteristic aroma compounds of Guangdongxiangshui lemon, while d-limonene provided a background aroma. Combined with quantitative descriptive analysis and odor note collected via GC/O-MS, the aroma wheel of Guangdongxiangshui lemon was constructed with 15 aroma descriptors in 6 categories, including ‘fruity’ ‘woody’ ‘medicinal’ ‘spicy’ ‘floral’ and ‘grassy’. Furthermore, 52 TPS genes were mined in Guangdongxiangshui lemon genome, which might participate in the aroma compounds synthesis.

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    Development and Identification of Molecular Markers for Oil-Related Functional Genes and Polymerization Analysis of Excellent Alleles in Soybean
    WU ChuanLei, HU XiaoYu, WANG Wei, MIAO Long, BAI PengYu, WANG GuoJi, LI Na, SHU Kuo, QIU LiJuan, WANG XiaoBo
    Scientia Agricultura Sinica    2024, 57 (22): 4402-4415.   DOI: 10.3864/j.issn.0578-1752.2024.22.002
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    【Objective】Polymerizing soybean high oil genotypes aims at breeding varieties with higher oil content to improve economic efficiency and nutritional value. It is of great significance to increase agricultural output, reduce processing costs and meet global demand for vegetable oil growth.【Method】Glyma.18G027100 C2 gene family was identified by bioinformatic analysis method at the whole genome level. A total of 66 soybean C2 gene family members were identified, named GmC2-01.1-GmC2-20.2 according to chromosome position. Tissue pattern analysis revealed that 7 genes were highly expressed in grains among 66 C2 family genes (GmC2-03.6, GmC2-02.7, GmC2-07.2, GmC2-18.1, GmC2-18.4, GmC2-19.1 and GmC2-20.2). In order to analyze the effect sites of these genes on soybean oil content, SNP sites in the coding regions of these genes were obtained from SFGB database. Correlation analysis of oil content in two years showed that GmC2-18.1 has SNP loci that significantly affect oil content. The genetic diversity of GmC2-18.1 coding region was analyzed by 12 extreme materials. There was a G/A mutation at 2 038 273 bp in coding region of Wm82.a2.v1 version, which regulated seed oil content. It was preliminarily speculated that this gene played a role in seed development or nutrient accumulation. Then, SNP/InDel molecular markers were developed for GmC2-18.1-G/A gene combined with InDel natural allelic variation site 225 bp upstream of the start codon of GmSWEET39, T/C natural allelic variation site at 8 381 058 bp in coding region of GmST1, A/C natural allelic variation site at the third exon of 41 854 422 bp in coding region of GmMFT. 1 200 soybean germplasm resources from three ecological regions in China were identified by markers in 2 years.【Result】Analysis of variance showed that GmC2-18.1-G, GmSWEET39-Deletion, GmST1-T and GmMFT-A significantly increased oil content by 1.72, 1.95, 1.58 and 2.06 percentage points (P<0.01). The results showed that the average oil content of soybean seeds carrying GmC2-18.1-G, GmSWEET39-Deletion, GmST1-T and GmMFT-A high-oil allele type (PFAT-1) was 22.89%, which increased by about 4.5% compared with that carrying GmC2-18.1-A, GmSWEET39-Insertion, GmST1-C and GmMFT-C low-oil allele type (PFAT-14). 5 percentage points, the contribution rate to oil content is about 21.69%. 【Conclusion】Based on the markers developed above, 115 PFAT-1 high oil alleles were screened.

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    Analysis of Genome-Wide Methylation Differences and Associated Gene Expression of Sesame Varieties Under High Temperature Stress
    SU XiaoYu, TAN ZhengWei, LI ChunMing, LI Lei, LU DanDan, YU YongLiang, DONG Wei, AN SuFang, YANG Qing, SUN Yao, XU LanJie, YANG HongQi, LIANG HuiZhen
    Scientia Agricultura Sinica    2024, 57 (24): 4825-4838.   DOI: 10.3864/j.issn.0578-1752.2024.24.001
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    【Objective】This study aimed to explore the differences in genome-wide DNA methylation patterns and their relationships with associated gene expression in different heat-tolerant sesame varieties under high temperature stress, in order to gain a deeper understanding of the regulatory mechanisms of DNA methylation in sesame's response to high temperature stress, and to provide a theoretical basis for heat tolerance breeding in sesame. 【Method】Two sesame varieties, Zhengtaizhi 3 (heat-tolerant) and Shandong White Sesame (heat-sensitive), were selected as experimental materials and cultivated under high temperature (41 ℃) and control (30 ℃) conditions for 10 days. Nanopore sequencing technology was used to conduct methylation sequencing of the genomic DNA of these two sesame varieties, and transcriptome sequencing was performed to analyze changes in the expression of associated genes. Minimap 2 software was utilized for reference genome sequence alignment, and Tombo software was employed to detect 5mC, CpG, and 6mA methylation sites. Differentially methylated regions (DMRs) were identified based on a genome segmentation approach. Finally, functional annotation and pathway analysis of DMR-associated differentially expressed genes (DMR-DEGs) were conducted using GO, COG, and KEGG databases. 【Result】Under high temperature stress, significant changes were observed in the genome-wide DNA methylation patterns of both Zhengtaizhi 3 and Shandong White Sesame. Specifically, the m6A and cytosine methylation (mC) contents of Zhengtaizhi 3 increased, while those of Shandong White Sesame decreased. A total of 621 DMRs (Zhengtaizhi 3) and 374 DMRs (Shandong White Sesame) were identified across the entire genome, mainly distributed in promoter and intergenic regions. Further analysis revealed that these DMRs were significantly associated with 113 DMR-DEGs (Zhengtaizhi 3) and 56 DMR-DEGs (Shandong White Sesame), respectively, and that demethylated DMRs were closely related to upregulated gene expression. Functional annotation results indicated that these DMR-DEGs were primarily involved in biological processes such as carbohydrate transport and metabolism, posttranslational modification, protein turnover, signal transduction, and secondary metabolite biosynthesis. 【Conclusion】This study revealed the differences in genome-wide DNA methylation patterns and their relationships with associated gene expression in different heat-tolerant sesame varieties under high temperature stress. Zhengtaizhi 3, a heat-tolerant sesame variety, regulated the expression of related genes by increasing DNA methylation levels under high temperature stress, while Shandong White Sesame, a heat-sensitive variety, exhibited a decreasing trend in methylation levels. In particular, the dynamic changes in CpG site methylation played a crucial role in regulating sesame's response to high temperature stress. These findings provide new insights and theoretical support for understanding the mechanisms of sesame heat tolerance and for heat tolerance breeding.

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    The Differences of Plant Nitrogen Transport and Grain Nitrogen Accumulation in Different Yield Levels of Wheat Field
    ZHANG Zhen, SHI Yu, YU ZhenWen, ZHANG YongLi
    Scientia Agricultura Sinica    2024, 57 (13): 2539-2548.   DOI: 10.3864/j.issn.0578-1752.2024.13.004
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    【Objective】 Improving the nitrogen transport and accumulation of nutrient organs after wheat flowering, as well as improving the nitrogen accumulation characteristics of wheat grains, is beneficial for increasing the nitrogen accumulation and yield of wheat. This study aimed to clarify the physiological mechanisms underlying the differences in nitrogen utilization efficiency among wheat plants at different yield levels, so as to provide a theoretical basis for reducing yield differences and improving nitrogen utilization efficiency and to achieve high yield and efficient production of wheat.【Method】 The field experiments were conducted in Shiwang Village, Xiaomeng Town, Shandong Province for two consecutive years from 2020 to 2022. Using Tobacco Farmer 1212 as the planting material, three yield levels of wheat fields with a perennial winter wheat yield of around 10 500 kg·hm-2 (S), 9 000 kg·hm-2 (H), and 7 500 kg·hm-2 (M) were selected to compare and analyze the differences in plant nitrogen accumulation and transport, grain nitrogen accumulation characteristics, and grain yield in wheat fields with different yield levels.【Result】 Compared with H and M wheat fields, S wheat field significantly increased the number of spikes per unit area and thousand grain weight, with grain yield 19.64%-27.91% and 51.68%-80.87% higher than H and M wheat fields, respectively, resulting in the highest nitrogen absorption efficiency, nitrogen partial productivity and nitrogen harvest index. The nitrogen accumulation in the nutrient organs of S wheat field during the flowering period increased by 14.22-42.11 kg·hm-2 and 53.74-103.16 kg·hm-2, respectively. The nitrogen accumulation in mature nutrient organs was S, H>M. Compared with H and M wheat fields, S wheat field significantly increased the nitrogen transport of pre flowering nutrient organs and nitrogen accumulation after flowering, and increased the contribution rate of nitrogen accumulation in post flowering nutrient organs to grains, thereby achieving the highest nitrogen accumulation in mature grains. The S wheat field significantly increased the content of free amino acids and soluble proteins in flag leaves after flowering, for promoting the inter source sink transport of nitrogen. According to the logistic equation fitting, the S wheat field significantly increased the maximum and average accumulation rates of grain nitrogen, prolonged the duration of grain nitrogen accumulation, and was the main reason for obtaining the highest grain nitrogen accumulation.【Conclusion】 Suitable soil environment in S wheat field could promote the transfer of stored nitrogen from vegetative organs to grain, and increase the rate of grain nitrogen accumulation and prolong the duration of grain nitrogen accumulation, which was the main reason for the highest grain yield and nitrogen use efficiency.

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    Cloning and Heat Tolerance Function of Wheat TaGRAS34-5A Gene
    DIAO DengChao, LI YunLi, MENG XiangYu, JI SongHan, SUN YuChen, MA XueHong, LI Jie, FENG YongJia, LI ChunLian, WU JianHui, ZENG QingDong, HAN DeJun, $\boxed{\hbox{WANG ChangFa}}$, ZHENG WeiJun
    Scientia Agricultura Sinica    2025, 58 (4): 617-634.   DOI: 10.3864/j.issn.0578-1752.2025.04.001
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    【Objective】The GRAS family constitutes a unique class of plant-specific transcription factors that play a pivotal role in plant development and stress response. To elucidate the function of GRAS family genes in wheat heat tolerance,which can provide genetic resources and theoretical foundation for wheat heat-resistant breeding.【Method】A potential heat stress-responsive transcription factor gene, TaGRAS34-5A, was identified through transcriptome analysis of TAM107 and Chinese spring wheat seedlings under high-temperature conditions. Subsequently, a bioinformatics analysis was performed on TaGRAS34-5A, and a phylogenetic tree was constructed to elucidate its molecular characteristics. The expression pattern of TaGRAS34-5A under various stresses, including high temperature, abscisic acid (ABA), ethylene (ETH), and salicylic acid (SA) treatments, were examined using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) method. The subcellular localization of the TaGRAS34-5A protein was determined using wheat protoplast transient expression technique. Furthermore, the heat tolerance function of TaGRAS34-5A was validated using the heterologous expression system of Saccharomyces cerevisiae and the BSMV:VIGS (Barley stripe mosaic virus: Virus-Induced Gene Silencing) silencing technique. potential interacting proteins of TaGRAS34-5A were screened using yeast two-hybrid technology, and the heat tolerance function was verified, providing preliminary insights into its heat tolerance mechanism.【Result】TaGRAS34-5A, equipped with a characteristic GRAS domain and belongs to the GRAS transcription factor family, is localized to both the cell nucleus and cytoplasm. Bioinformatics analysis indicates that the TaGRAS34-5A promoter contains a large number of hormone response elements and light response elements, and it is most closely related to TaSCL14, OsGRAS23, and AtSCL14 in terms of phylogenetic relationships, suggesting its potential function in responding to oxidative stress. Its expression is upregulated under high-temperature, ethylene (ETH), abscisic acid (ABA), and salicylic acid (SA) treatments, peaking at 4, 6, 0.5, and 12 hours post-treatment, respectively, with the most significant induction observed under heat stress and SA. Functional assays in yeast demonstrated that heterologous expression of TaGRAS34-5A enhances the heat tolerance of the yeast. The results of BSMV:VIGS transient silencing experiment showed that after the 42 ℃ high-temperature treatment, TaGRAS34-5A silenced plants exhibited decreased chlorophyll content, reduced POD enzyme activity, increased cellular peroxidation, and decreased heat tolerance compared to the control. Preliminary studies on the heat tolerance mechanism suggest that TaGRAS34-5A exhibits strong transcriptional self-activation activity.it may modulate wheat heat tolerance by interacting with proteins such as the bZIP family transcription factor HBP-1b and the E3 ubiquitin ligase hel2, thereby regulating cellular redox homeostasis and detoxification processes, positively influencing the heat tolerance of wheat.【Conclusion】TaGRAS34-5A is induced by heat, ABA, ETH, and SA, and its encoded protein is located in the nucleus and cytoplasm. It exhibits transcriptional activation activity. Heterologous overexpression of TaGRAS34-5A enhances the heat tolerance of Saccharomyces cerevisiae. Silencing TaGRAS34-5A in wheat plants increases cellular peroxidation, decreases chlorophyll content, and reduces heat tolerance. TaGRAS34-5A may regulate the heat tolerance of wheat by modulating cellular redox state and detoxification processes.

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    Wheat Enolase Gene TaENO1-5B Involved in Regulating Plant Height and Grain Number Per Spike in Multiple Environments
    ZHANG ZiHui, ZHANG YanFei, LI Long, LI ChaoNan, WANG JingYi, YANG DeLong, MAO XinGuo, JING RuiLian
    Scientia Agricultura Sinica    2024, 57 (14): 2717-2731.   DOI: 10.3864/j.issn.0578-1752.2024.14.002
    Abstract294)   HTML28)    PDF (7663KB)(130)       Save

    【Objective】 Enolase is a key rate-limiting enzyme in the process of glycolysis, and plays a crucial role in plant growth and development, and response to abiotic stress. The function of common wheat enolase gene TaENO1-5B was revealed and molecular markers were developed to provide genetic resources for improving wheat through molecular breeding. 【Method】 TaENO1-5B was cloned from wheat variety Hanxuan 10. The domains of its encoded protein were analyzed on the SMART website. The secondary and tertiary structures of the protein were predicted by Phyre2 software. Real-time quantitative fluorescent PCR was used to analyze the expression levels of the target gene in wheat tissues at different developmental stages and its expression patterns under phytohormone treatment and abiotic stress. Thirty wheat germplasm with rich genetic diversity were used as plant materials to analyze the gene sequence polymorphisms, and develop molecular markers. The association analysis between TaENO1-5B haplotypes and phenotypic traits was carried out in a natural population consisting of 323 wheat accessions. The trend of breeding selection of superior haplotype in different wheat production zones in China was analyzed by using a landrace population and a modern variety population. 【Result】 TaENO1-5B gene consists of 17 exons and 16 introns encoding 446 amino acids and contains a conserved N-terminal domain and a C-terminal TIM (triose-phosphate isomerase) barrel domain. TaENO1-5B was expressed in all tissues of wheat at seedling, jointing, heading and flowering stages, and the expression level was higher in roots, root bases and spikes. The TaENO1-5B promoter region contains a variety of cis-acting elements, including elements responding to plant hormones, such as abscisic acid (ABA), auxin (IAA), and methyl jasmonate (MeJA), as well as elements responding to drought and low temperature. The expression of TaENO1-5B was significantly induced by phytohormones and abiotic stress in wheat. Four SNPs were detected in the promoter region and three SNPs in the gene region of the TaENO1-5B gene, which constituted three haplotypes, i.e., Hap-5B-1, Hap-5B-2, and Hap-5B-3. Among them, Hap-5B-2 was a favorable haplotype highly associated with shorter plant height, more spikelets per spike, and more grains per spike under various environments such as drought and high temperature, and had been positively selected in the breeding history of major wheat production zones in China. The KASP (kompetitive allele-specific PCR) marker developed based on the SNP (2 399 bp, G/A) of the TaENO1-5B promoter region was significantly correlated with the spikelet number per spike in multiple environments. 【Conclusion】 TaENO1-5B gene responds to phytohormones and abiotic stress, and is significantly correlated with plant height, spikelet number per spike and grain number per spike under various environments such as drought and high temperature. Hap-5B-2 is a favorable haplotype with shorter plant height and more number of spikelets and grains per spike. Molecular markers developed based on the variation sites of TaENO1-5B gene sequence can be used for genetic improvement of plant height and related yield traits in wheat.

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    Preparation of Fluopyram-Loaded Nanofiber Nematicide and Its Biological Activity Against Meloidogyne incognita
    LING WenZheng, CAO HaiChao, YU JiaMin, ZONG Hao, WANG Kai, FENG Chao, CHEN Dan
    Scientia Agricultura Sinica    2024, 57 (15): 2997-3009.   DOI: 10.3864/j.issn.0578-1752.2024.15.007
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    Objective】Root-knot nematode disease has become an important influencing factor restricting the development of protected agriculture in China, among which Meloidogyne incognita has caused the most serious yield loss. At present, there are few types of nematicides in China, the objectives of this study are to prepare the fluopyram-loaded nanofiber nematicide based on the electrospinning technique, evaluate its biological activity against M. incognita, and to enrich the types of effective nematicides for controlling root-knot nematode disease of crops and expand the application field of nanofiber agents.【Method】Two kinds of fluopyram-loaded nanofiber nematicide (Flu@NF) were prepared by coaxial electrospinning technology with different biodegradable materials as shell materials and solvated fluopyram as core materials. The morphology, structure, elemental composition, functional components and thermal stability of Flu@NF were characterized by SEM, EDS, TEM, FTIR and TGA. With 41.7% fluropyram suspension as control agent, the biological activity of Flu@NF against 2nd stage juveniles (J2) and egg mass of M. incognita was evaluated.【Result】PEG/PCL-Flu@NF and CA-Flu@NF using polyethylene glycol (PEG), polycaprolactone (PCL) and cellulose acetate (CA) as shell materials were successfully prepared under high pressure +15 kV, core-shell solution flow rate 1﹕4 and receiver side distance of 24 cm. The average diameter of two kinds of agents was 316 and 440 nm, respectively. Fibers were in accordance with the inner and outer microstructure of core-shell, and the shell thickness was separately 71.15 and 24.84 nm. The loading capacity of two kinds of fluopyram-loaded fibers was 15.32% and 20.37%, respectively. Moreover, the thermal stability of fluopyram was significantly improved after shell coating by coaxial electrospinning. Compared with fluropyram suspension, the slow-release performance of fluopyram-loaded fibers was significantly improved, and the mortality of J2 was significantly increased with the extension of treatment time at different concentrations. The lethality rate of the two fiber agents against J2 was higher than 98% after 24 h treatment at high concentration (25 mg·L-1). After treatment with low concentration (4 mg·L-1) for 24 h, the lethality rate of the two fiber agents against J2 was 91.4% and 79.6%, respectively. The two kinds of nematicides had good inhibition effects on the hatching of nematode eggs, after 3 d treatment at high concentration (25 mg·L-1), the unhatched rate of eggs was 71.8% and 89.2%, respectively, and after 3 d treatment at low concentration (4 mg·L-1), the unhatched rate of eggs was 59.4% and 76.2%, respectively.【Conclusion】Based on coaxial electrospinning technology, the nanofibers prepared with PEG/PCL and CA as shell materials have excellent coating effect on fluopyram, and the fluopyram-loaded fibers have high biological activities on M. incognita through slow-release action, which has great potential to prevent and control root-knot nematode disease through crop root protection.

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    Identification of Key Genes in the Flavonoid Synthesis Pathway of Meconopsis integrifolia Based on WGCNA
    CHEN XiaoJuan, WANG HaiJu, WANG FuMin, YONG QingQing, HUANG ShunMan, QU Yan
    Scientia Agricultura Sinica    2024, 57 (15): 3053-3070.   DOI: 10.3864/j.issn.0578-1752.2024.15.011
    Abstract291)   HTML31)    PDF (9745KB)(1805)       Save

    Objective】Flavonoids are known for their anti-inflammatory, anti-cancer, and antibacterial properties, and are one of the main medicinal components of Meconopsis integrifolia. By analyzing the spatial metabolome information and transcriptome data from various parts (roots, stems, leaves and petals) of M. integrifolia, the key genes regulating the flavonoid synthesis could be excavated. This research could provide valuable insights into the mechanism underlying flavonoids synthesis in M. integrifolia, paving the way for genetic breeding aimed at enhancing flavonoid content. 【Method】Transcriptome sequencing was conducted on the root, stem, leave and petal of M. integrifolia to analyze the distribution of flavonoids across different parts using spatial metabolomic data. The weighted gene co-expression network analysis (WGCNA) was employed to identify key modules and key genes closely related to flavonoid synthesis. To validate the reliability of the transcriptome data, 12 genes were selected for qRT-PCR analysis. 【Result】Flavonoids accumulation in M. integrifolia varied across different parts, with petals being the primary site of accumulation, where 8 main flavonoids were identified. Transcriptome sequencing revealed a total of 20 085 expressed genes, among which 286 genes expressed were exclusively expressed in flowers, showing 3.6-4.2 times more expression than that in other plant parts. Using WGCNA to categorize highly expressed differential genes, a total of 14 co-expression modules were identified, and the key modules, including MEturquoise and MEgreen, were significantly associated with 8 main flavonoids (P<0.05). KEGG analysis demonstrated that the genes within these two modules were primarily enriched in metabolism-related pathways, with some genes enriched in pathways related to flavonoid synthesis. MEturquoise and MEgreen comprised 18 and 6 genes related to flavonoid synthesis, respectively, and screened 14 core structural genes (5 CHSs, 2 HIDHs, 2 CCoAOMTs and FLS, CYP75B1, CHI, HCT, and CYP73A) and one transcription factor HB2, which were predominantly highly expressed in petals or stems. The consistent gene expression trends between qRT-PCR and transcriptome data were observed, which showed that the analysis results derived from the transcriptome data were reliable. 【Conclusion】The accumulation of flavonoids and gene expression patterns in different organs of M. integrifolia varied significantly, and 14 core structural genes and one transcription factor were screened to be closely related to the accumulation of flavonoids across different organs. These genes might play a key role in regulating the synthesis and differential accumulation of flavonoids in different organs of M. integrifolia.

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    Optimization and Application of Rapid Evaluation System for Citrus Huanglongbing Resistance Mediated by Agrobacterium rhizogenes
    CAO Peng, ZHOU JinHuan, WANG XinLiang, LI ChuXin, LI JiaXIN, JIANG Pei, LIU JinXiang, SONG Zhen
    Scientia Agricultura Sinica    2024, 57 (16): 3182-3191.   DOI: 10.3864/j.issn.0578-1752.2024.16.007
    Abstract288)   HTML17)    PDF (2987KB)(140)       Save

    【Objective】Citrus Huanglongbing (HLB) is a destructive citrus disease primarily caused by Candidatus Liberibacter asiaticus (CLas). The objective of this research is to investigate the growth pattern of CLas in citrus hairy roots at the initial stage of infection, optimize the rapid evaluation system of Agrobacterium rhizogenes-mediated HLB resistance and apply it to the resistance evaluation of antimicrobial peptides.【Method】A plant expression vector, pGNGM1300, was employed to transform different citrus varieties via the hairy root transformation system, which was mediated by A. rhizogenes K599. Subsequently, varieties with rapid induction and high transformation rate were then selected. Following inoculation with CLas, the presence of CLas in hairy roots was consistently demonstrated through the use of real-time quantitative PCR (qPCR), which allowed for the monitoring of its growth pattern. Further, the optimization of the HLB resistance evaluation system permitted the HLB resistance evaluation of antimicrobial peptides to be conducted via (RT-) qPCR analysis of CLas and related genes, quantification of callose deposition, microstructure observation, and symptom assessment.【Result】Among the 11 tested citrus varieties, citron (Citrus medica) exhibited the fastest induction of hairy roots (15 d), accompanied by the highest induction rate (73.75%) and a substantial transgene positivity rate (53.54%) in hairy roots. The results of regular qPCR monitoring indicated that CLas began to colonize roots on 20-30 days post-inoculation (dpi). At 30-50 dpi, there was a notable increase in the CLas content. The content of the CLas exhibited a slight fluctuation at a range of 60 to 120 dpi, though the discrepancy with 50 dpi was not statistically significant. The results of the antimicrobial peptide resistance evaluation, conducted on MaSAMP (stable antimicrobial peptide), HBD-4 (homo sapiens defensin beta 4), and CB (cecropin B), revealed that at 50-120 dpi, the content of CLas in both MaSAMP- and CB-expressing plants was significantly lower than that of the control. However, except that at 90 dpi, the CLas content was also significantly lower in HBD-4-expressing plants than the control. The callose content in all three plants expressing antimicrobial peptides was significantly lower than that of the control (60 dpi). There was no visible cell wall thickening in the phloem, and no significant deposition of starch grains or callus was observed. Furthermore, none of the plants exhibited signs of root death at 90 dpi.【Conclusion】This study elucidates the growth dynamics of CLas in citrus hairy roots during the early stages of infection and optimizes a rapid scoring system for A. rhizogenes-mediated HLB resistance. In addition, the results show that overexpression of MaSAMP, HBD-4 and CB effectively suppresses CLas proliferation, reduces callose deposition and alleviates HLB symptoms. These findings have the potential to be used in the prevention and control of HLB.

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    Genome Wide Association Analysis of Soluble Sugar Content in Fresh Seeds of Soybean Landraces
    ZHANG YuMei, DING WenTao, LAN XinLong, LI QingHua, HU RunFang, GUO Na, LIN GuoQiang, ZHAO JinMing
    Scientia Agricultura Sinica    2024, 57 (11): 2079-2091.   DOI: 10.3864/j.issn.0578-1752.2024.11.003
    Abstract286)   HTML16)    PDF (2025KB)(907)       Save

    【Objective】Soluble sugar content is one of the important quality traits of vegetable soybean. The genetic variation and genetic mechanism of soluble sugar content in fresh soybean seeds were studied to provide a basis for germplasm innovation and quality breeding of vegetable soybean.【Method】Using 133 soybean landraces from the Northeast region, the North region, the Huanghuaihai region and the South region, the soluble sugar content of fresh seeds was determined in the three environments of Lianjiang in spring, Fuqing in spring and autumn, in 2021. In combination with 82 187 high-quality SNP markers, the whole genome association analysis of soluble sugar content was conducted based on the mixed linear model MLM (Q+K), and the SNP loci with significantly related to soluble sugar content were identified. The candidate intervals were selected by the significant SNP loci and the extension of 119.07 kb linkage disequilibrium decay distance at both ends. The candidate genes were predicted according to the annotation and tissue expression information of the genes in the candidate intervals.【Result】The variation range of soluble sugar content in fresh seeds under three environments was 3.37-33.84 mg·g-1, the genetic variation coefficient was 24.59%-32.69%, and the heritability of soluble sugar content was 68.14%. 6, 8 and 22 SNPs were significantly associated with the soluble sugar content of fresh seeds were detected in Lianjiang in spring, Fuqing in spring and autumn, respectively, and phenotypic variation was 12.43%-29.27%. A total of 86 genes were obtained in the candidate regions of 9 significant SNP loci with higher interpretation rate of phenotypic variation, and 9 candidate genes were further screened by gene annotation and tissue expression information. These candidate genes are mainly involved in biological processes such as transcription factors, glycoprotein families and carbohydrate synthesis and transport. Among them, Glyma.01g016500, Glyma.13g042100, Glyma.16g131800 and Glyma.16g155300 were more highly expressed in soybean seeds and pods, which can be used as the most potential candidate genes for soluble sugar in fresh soybean seeds.【Conclusion】Through genome-wide association analysis, 36 SNPs significantly associated with soluble sugar content in fresh seeds were detected, and 9 candidate genes were further screened out, which may be involved in the regulation of soluble sugar content in fresh soybean seeds. Among them, Glyma.01g016500, Glyma.13g042100, Glyma.16g131800 and Glyma.16g155300 can be the key candidate genes for regulating soluble sugar content in fresh soybean seeds.

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    Soil Water Use Characteristics of Spring Wheat with Multiple- Cropping Green Manure and Nitrogen Reduction in Northwest Irrigated Areas
    ZHANG DianKai, LI Pan, FAN Hong, HE Wei, FAN ZhiLong, HU FaLong, SUN YaLi, TAN XiangNian, YIN Wen, CHEN GuiPing
    Scientia Agricultura Sinica    2024, 57 (11): 2189-2201.   DOI: 10.3864/j.issn.0578-1752.2024.11.011
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    【Objective】The aim of this study was to explore the effects of multiple-cropping green manure and reduced nitrogen (N) application on water use characteristics of spring wheat in northwest irrigated areas, so as to provide a theoretical basis for optimizing the efficient use of water resources in spring wheat production.【Method】A split-zone design was adopted, with two cropping patterns of multiple-cropping green manure (W-G) and post-wheat fallow (W) in the main zone, three N fertilizer levels in the sub-plot: conventional N fertilizer application (180 kg·hm-2, N3), N fertilizer reduction of 15% (N2, 153 kg·hm-2), and N fertilizer reduction of 30% (N1, 126 kg·hm-2). The effects of multiple-cropping of green manure and nitrogen reduction on yield, water consumption and water use efficiency of spring wheat were studied from 2020 to 2021.【Result】The multiple-cropping green manure combined with moderate reduction of nitrogen fertilizer increased the pre-sowing soil water storage of spring wheat, and W-G increased the pre-sowing soil water storage of spring wheat by 11.5% to 13.5% compared with W pattern, while the multiple-cropping green manure combined with N reduction of 15% (W-GN2) and multiple-cropping green manure combined with N fertilizer reduction of 30% (W-GN1) increased the pre-sowing soil water storage of spring wheat compared to control post-wheat fallow combined with conventional N fertilizer application (W-N3) by 12.1% to 20.2% and 15.2% to 16.6%, respectively. W-G reduced water consumption of spring wheat by 12.6% to 13.7% compared with W-GN1, and W-GN2 reduced water consumption of spring wheat by 15% compared to W-N2 and W-N3, respectively. W-G effectively harmonized the water demand characteristics of spring wheat before and after the reproductive period by reducing the evapotranspiration modulus coefficient of spring wheat at the early stage of nodulation and filling, and increasing the evapotranspiration modulus coefficient of pre-sowing to jointing and early-filling to maturity (the proportion of water consumption of the two stages to the total water consumption of the whole reproductive period was 60.5% to 64.1%). Finally, the synchronization of water supply and demand during the growth and development of spring wheat was enhanced. W-G had the advantage of yield increase, with 13.5% to 14.1% under W pattern. W-GN2 and W-N3 had yield increases of 16.7% to 18.4% and 13.6% to 14.6% under W-N2 and W-N3, respectively. Thus, W-G improved water use efficiency by 29.4% to 31.0% compared with the W pattern, and among the multiple-cropping green manure, W-GN2 improved water use efficiency by a greater extent than W-N2 and W-N3 by 44.2% to 46.8% and 39.1% to 43.5%, respectively, and W-GN1 and W-GN3 by 36.2% to 50.7% and 9.1% to 17.0%, respectively.【Conclusion】The multiple-cropping green manure combined with 15% N fertilizer reduction (i.e., 153 kg·hm-2 of N fertilizer) improved spring wheat yield and water use efficiency compared with conventional water and N fertilizer management, and could be recommended as a production technique for efficient water use in spring wheat in dry irrigated areas.

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    Isolation and Identification of Soybean Rhizosphere Growth-Promoting Bacteria and Their Salt Tolerance and Growth-Promoting Effects
    SHAO JiaZhu, LÜ Wen, LIAO XinLin, YUAN XinYu, SONG Zhen, JIANG DongHua
    Scientia Agricultura Sinica    2024, 57 (21): 4248-4263.   DOI: 10.3864/j.issn.0578-1752.2024.21.007
    Abstract282)   HTML42)    PDF (6181KB)(716)       Save

    【Objective】Plant growth-promoting rhizobacteria (PGPR) can effectively promote plant growth through long-term mutualistic symbiosis with plants. The objective of this study is to screen and identify rhizosphere growth-promoting actinomycetes from soybean rhizosphere soil and clarify their growth-promoting mechanisms, and to lay a foundation for the development and utilization of microbial agents. 【Method】Different actinomycetes were collected using soil dilution coating method and plate streak inoculation method. The growth-promoting characteristics of isolates were analyzed using phosphorus solubilization, potassium solubilization, and siderophore assay media. Through microscopic observation, physiological and biochemical experiments, and multi-gene sequence analysis, the target growth-promoting actinomycetes were identified. Different salt concentrations (0-10%) were set to determine the salt tolerance of the target isolate. The growth-promoting ability of the isolate on soybean seedlings was detected by pot experiments and whether spraying the culture medium of the isolate under salt stress conditions could improve the stress resistance of soybean plants was evaluated. 【Result】Thirteen PGPR isolates were screened and obtained. Among then, the Sg-7 isolate not only had strong abilities to dissolve phosphorus, potassium, siderophore, and IAA production, but also effectively antagonized Pseudomonas syringae pv. glycinea (Psg). Based on morphological characteristics, biochemical, and multi-gene analyses, the soybean rhizosphere growth-promoting bacterium Sg-7 was identified as Streptomyces griseocarneus. The Sg-7 strain had certain salt tolerance characteristics, with a maximum tolerance to 7% NaCl salt concentration. Pot experiments showed that the diluted culture fluid after irrigation could effectively promote the germination of soybean seeds and improve growth indicators such as root length, stem diameter, fresh weight, and leaf area. Under 150 mmol·L-1 salt stress, irrigation with a 50× dilution of the Sg-7 culture fluid could effectively enhance SOD enzyme activity of soybean leaf, which was 1.84 times that of the salt stress treatment group. The CAT enzyme activity after irrigation with 100× dilution of culture fluid was 4.33 times higher than that of the salt stress treatment group. The POD enzyme activity after irrigation with 10× dilution of culture fluid was 1.10 times that of the salt stress treatment group. The culture fluid of Sg-7 strain could also enhance the root activity of soybean plants and promote the increase of carotenoid content in leaves to resist stress, which was 3.05 and 1.12 times that of salt stress treatment group, respectively. 【Conclusion】S. griseocarneus Sg-7 strain is a potential plant rhizosphere growth-promoting bacterium with broad development potential and practical application value.

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    Research on the Production Potential of Main Sugarcane Varieties Under Different Planting Modes in Hilly and Mountainous Areas
    ZHAO Yong, AI Jing, WANG YuTong, ZHANG ZhongFu, YANG HongQi, LI JiaQun, GUO ZhaoJian, LIU HaiJun, QIN Wei, DENG Jun, ZHANG YueBin
    Scientia Agricultura Sinica    2024, 57 (19): 3743-3757.   DOI: 10.3864/j.issn.0578-1752.2024.19.003
    Abstract282)   HTML11)    PDF (3568KB)(260)       Save

    【Objective】The research focused on the production potential of sugarcane main varieties under the different planting modes in mountainous and hilly regions, in order to explore the relationship between the varieties and mechanical adaptation, screen the adaptable varieties for mechanical production, and clarify the main characteristics of the varieties, thus to provide the theory for promoting the completely mechanical production of sugarcane in mountainous and hilly regions.【Method】Two different ecological types of sugarcane production regions in mountainous regions of Yunnan were selected to study the production potential of four main planting varieties, including LC05-136, YZ05-49, YZ05-51, and YZ08-1609, under two different planting modes (the completely mechanical or manual production).【Result】The yield and sucrose content of sugarcane varied between the two factors of varieties and planting modes, and the yield was significantly affected. Under the mechanical production, the yield of YZ08-1609 was significantly higher than that with the treatment of artificial production (P<0.01), while YZ05-51 showed the opposite trend (P<0.01), under the mechanical production, the sucrose content of YZ08-1609 is slightly higher than that with the artificial production (P>0.05), while these of LC05-136 and YZ05-49 were slightly decreased (P>0.05). The planting density and the emergence rate of sugarcane varied with both varieties and production modes. The planting density under the machinery production was generally higher than that under the artificial production, while the emergence rate was generally lower than that with the treatment of the artificial production. The emergence rate of YZ05-51 under the machinery production significantly decreased (P<0.05), while the emergence rate of YZ08-1609 remained relatively stable (P>0.05). The main agronomic traits of sugarcanes varied with both varieties and the production modes. The millable stalks of YZ08-1609 under the machinery production were significantly higher than that under the artificial production (P<0.05); the industrial characteristics were mainly influenced by the variety. YZ08-1609 owned higher growth potential under the machinery production, with significantly higher yield and millable stalks compared with these under the artificial production, and slightly higher sucrose content; YZ05-51 owned higher growth potential under the artificial production with the performance of higher yield under the artificial production. 【Conclusion】Different sugarcane varieties owned the different adaptabilities to the machinery production, like some sugarcane varieties were suitable for the machinery production and some were suitable for the manual production. During pushing forward the progress of the application of mechanical production in sugarcane planting, the adaptability of varieties should be fully considered. Overall, sugarcane varieties suitable for the machinery production should own higher sugarcane yield and more millable stalks, and the sucrose content should be less affected or even slightly higher than that under the manual production.

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    Construction and Application of SSR Marker Identification System for Bitter Gourd Varieties
    SU GuoZhao, LI AiAi, LIU ZhongHua, CHEN YuHua, ZHANG XiuJie, MA YingXue, YANG XuHong, DENG Chao, XU ZhenJiang
    Scientia Agricultura Sinica    2024, 57 (11): 2227-2242.   DOI: 10.3864/j.issn.0578-1752.2024.11.014
    Abstract279)   HTML7)    PDF (3886KB)(187)       Save

    【Objective】In order to provide a practical support for authenticity identification, purity identification and protection of new variety rights of bitter gourd, a set of SSR core primers were screened, and then, the molecular identification system and SSR fingerprint database were established.【Method】Firstly, by using 8 representative varieties with large phenotypic differences, the preliminary 138 pairs SSR primer screening were carried out through 6% polyacrylamide-gel electrophoresis, and the preliminarily screened primers were synthesized into fluorescent primers. Secondly, the primer re-screening was carried out by fluorescence capillary electrophoresis against 95 bitter gourd varieties with diverse geographical sources. Then, the discrimination rate, PIC value, number of alleles, and other parameters of each re-screened primer were calculated respectively, and a set of SSR primer combinations with high discrimination rate and good polymorphism were selected. Finally, the total of 208 bitter gourd varieties were tested by the re-screened primers and a set of SSR core primers were further selected and used to construct a DNA fingerprint database of bitter gourd varieties.【Result】45 pairs of SSR primers with high specificity, high polymorphism and clear bands were screened by polyacrylamide gel electrophoresis. 20 pairs of SSR core primers were finally screened from small populations to large populations by fluorescence capillary electrophoresis. The core primers were divided into 4 groups for multiple electrophoresis, and DNA fingerprint data of 208 bitter gourd varieties were collected. The total of 65 alleles and 102 genotypes were detected by 20 pairs of SSR core primers. 12 reference varieties were selected, which could cover all alleles. Through phylogenetic tree construction, 208 bitter gourd varieties were divided into 2 categories, indicating that 20 pairs of SSR core primers were suitable for genetic diversity analysis of bitter gourd population. 202 of 208 bitter gourd varieties could be identified by core primers, and the discrimination rate was 97.11%. 11 groups of parents and hybrid materials were used to analyze genetic relationship and then conformed to Mendel’s genetic law. There were only 1 locus of fragment loss in each 2 groups, which provided a reference for the decision threshold value of identification of bitter gourd hybrids.【Conclusion】In this study, the identification system of bitter gourd varieties constructed based on 20 pairs of SSR core primers had superior applicability and excellent identification effect, and could also be used for authenticity identification, purity identification, hybrids identification of bitter gourd varieties, similar varieties selection in DUS test and protection of new variety rights of bitter gourd.

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