Table of Content

01 February 2025, Volume 58 Issue 3

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Construction of Single and Dual-Segment Substitution Lines from Rice CSSL-Z492 and Genetic Dissection of QTL for Grain Size

LI Lu, XIE Zhuang, XIE KeYing, ZHANG Han, ZHAO ZhuoWen, XIANG AoNi, LI QiaoLong, LING YingHua, HE GuangHua, ZHAO FangMing

Scientia Agricultura Sinica. 2025, 58(3):  401-415.  doi:10.3864/j.issn.0578-1752.2025.03.001

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【Objective】Rice grain size is a quantitative trait controlled by multiple genes. They can be dissected into a single segment substitution line (SSSL), which is of great significance for their genetic mechanism study and breeding by design. 【Method】Z492, a chromosome segment substitution line in the genetic background of Nipponbare, was used as material to dissect QTL for rice grain size by mixed linear model (MLM) method. 【Result】The F₂ population was constructed from Nipponbare/Z492 to identify four QTL for grain size, including qGL6 and qGL7 for grain length and qRLW7 and qRLW12 for rate of grain length to width. Then three single-segment substitution lines (SSSL, S1-S3) and 3 dual-segment substitution lines (DSSL, D1-D3) carrying these QTL were further constructed. And the SSSL were then used to detect eight QTL for grain size, including qGL6, qGL7 and six newly identified QTL (qGW6, qRLW6, qGW7, qGWT7, qGL12, qGW12). Simultaneously, the genetic model of different QTL in 3 DSSL were analyzed. The results showed that interaction of qGL6 (a=0.26 mm) and qGL7 (a=0.21 mm) produced -0.21 mm of grain length epistatic effect, which resulted in the genetic effect (0.26 mm) of D1 equal to the additive effect of each QTL. Thus, the grain length (7.98 mm) of D1 displayed no difference from those (7.89 and 7.98 mm) of S2 with qGL7 and S1 containing qGL6, while significantly longer than that (7.47 mm) of Nipponbare. The result indicated that it is not necessary to pyramid qGL6 and qGL7 in breeding by design for increasing grain length. qGW6 (a=0.07 mm) and qGW12 (a=0.06 mm) belonged to independent inheritance in D2, thus, the genetic effect (0.13 mm) after pyramiding of qGW6 and qGW12 caused the grain width (3.65 mm) of D2 broader significantly than any of the SSSL with the single QTL. So, qGW6 and qGW12 can be selected to increase grain width in breeding by design. Interaction of qGW7 (a=0.11 mm) and qGW12 (a=0.06 mm) yielded -0.10 mm of epistatic effect, causing the grain width genetic effect (0.07 mm) of D3 parallel to the additive effect of qGW12. Thus, the grain width (3.59 mm) of D3 exhibited no difference with that (3.56 mm) of S3 carrying qGW12, while wider significantly than that (3.44 mm) of Nipponbare and narrower significantly than that (3.66 mm) of S2. 【Conclusion】It is very necessary for breeding by design to identify QTL for different important traits using SSSL and DSSL. Pyramiding different QTL produce various genetic models. Some display independent inheritance, and others exhibit various epistatic effects. In addition, to cross with S1 and S3 can realize the goal of longer, wider and heavier rice grain, and to cross with S1 and S2 can reach the target of heavier grain weight, while to cross with S2 and S3 have no any effects in grain size.

Iron Concentrations in Grain and Its Different Parts of Newly Developed Wheat Varieties (Lines) in China and Influencing Factors

LUO YiNuo, LI YanFei, LI WenHu, ZHANG SiQi, MU WenYan, HUANG Ning, SUN RuiQing, DING YuLan, SHE WenTing, SONG WenBin, LI XiaoHan, SHI Mei, WANG ZhaoHui

Scientia Agricultura Sinica. 2025, 58(3):  416-430.  doi:10.3864/j.issn.0578-1752.2025.03.002

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【Objective】 The study aims to measure the iron (Fe) concentration in the grain, flour, and bran of newly developed high-yielding wheat varieties (lines) in major wheat production regions of China. It investigates the impact of yield, yield components, and soil factors on Fe absorption and distribution within the wheat, and determine the effects of these variables on Fe concentrations in its different parts. The objective is to provide a basis for grain Fe nutritional fortification in wheat. 【Method】A study was conducted on 104 newly developed wheat varieties (lines) through multi-point trials across 17 provinces in major wheat production regions of China. The research analyzed Fe concentration in wheat grain, flour and bran, along with yield, yield components, Fe absorption and distribution, soil physicochemical properties, and fertilizer application rates during the 2021-2022 and 2022-2023 growing seasons, to study the Fe concentration in different parts of the grain of newly developed wheat varieties (lines) in China, as well as the absorption and distribution of Fe and environmental influencing factors. 【Result】Significant variations for Fe concentrations were observed in the wheat grain, flour and bran among new varieties (lines) in the major wheat production regions of China,with the range of 20.2-57.1, 2.1-37.5, and 31.2-144.5 mg·kg^-1, and the average of 34.6, 10.8, and 72.8 mg·kg^-1, respectively. Wheat varieties (lines) in the southern wheat regions exhibited higher Fe concentrations in grains and its different parts compared to that in the northern regions, and the Fe concentration in flour and bran showed a positive correlation with its in grain. For every 1.0 mg·kg^-1 increase in grain Fe, flour saw a 0.2 to 0.3 mg·kg^-1 rise, and bran experienced a 1.9 to 2.3 mg·kg^-1 increase. The Fe concentration in grains was negatively correlated with yield, biomass, and spike number. With each 1.0 t·hm^-2 increase in yield, there was a decrease of 1.2 mg·kg^-1 in grain Fe concentration. For every 100×10⁴/hm² increase in spike number, the grain Fe concentration decreased by 0.3 mg·kg^-1. The flour Fe concentration showed negative relationship with Fe absorption in grain, straw, glume and bran. The grain Fe concentration was negatively correlated with calcium, and positively with manganese, copper, and zinc. The grain Fe concentrations varied over locations, and different locations contributing 39% to 70% to the variation in grain Fe concentration. Soil pH, available phosphorus, Fe and manganese as major environmental factors affecting Fe nutrition in wheat grains. Grain Fe concentrations were negatively correlated with soil available phosphorus. Meanwhile, flour Fe concentrations were negatively correlated with soil pH, and positively correlated with soil available iron and manganese. 【Conclusion】High-Fe varieties (lines) were found among the newly developed high-yielding wheat varieties (lines) in China. Maintaining stable spike number, regulating soil pH, increasing grain Fe harvest index, soil available phosphorus, iron, manganese and appropriately applying N, P to enhance soil fertility were conducive to achieving a synergistic enhancement of both yield and Fe concentrations in wheat grain and flour.

Genome-Wide Association Study of Husk Traits in Maize

ZHOU GuangFei, MA Liang, MA Lu, ZHANG ShuYu, ZHANG HuiMin, SONG XuDong, ZHANG ZhenLiang, LU HuHua, HAO DeRong, MAO YuXiang, XUE Lin, CHEN GuoQing

Scientia Agricultura Sinica. 2025, 58(3):  431-442.  doi:10.3864/j.issn.0578-1752.2025.03.003

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【Objective】Husk is an important trait that affects the mechanical harvesting of maize grain, and identification of the genetic loci and candidate genes can provide theoretical basis for genetic improvement of maize husk traits. 【Method】To identify significantly associated single nucleotide polymorphisms (SNPs) and predict candidate genes for three husk traits, 251 maize inbred lines were used as plant materials and evaluated for husk number (HN), length (HL), and coverage (HC) in two environments. The genome-wide association study (GWAS) was conducted by multi-locus random-SNP-effect mixed linear model (mrMLM) with 32 853 SNPs across entire genome. 【Result】The three husk traits exhibited abundant variation among 251 maize inbred lines with 10.65%-40.60% of phenotypic variation coefficients. The variances of genotype, environment, and the genotype×environment interactions were significant at P<0.01 for each trait, and the broad-sense heritability for each trait was more than 80%. A total 92 SNPs significantly associated with three husk traits were identified in two environmental and best linear unbiased predictors (BLUP) across two environments values by GWAS. Among these SNPs, 35 SNPs were significantly associated with HN, and the phenotypic variance explained by single SNP ranged from 1.48% to 10.53%. 33 SNPs were significantly associated with HL, and the phenotypic variance explained by single SNP ranged from 1.61% to 21.69%. 24 SNPs were significantly associated with HC, and the phenotypic variance explained by single SNP ranged from 2.17% to 20.86%. However, none of SNP could be significantly associated with two husk traits. Five of 92 SNPs were stable, as they were repeatedly detected in two environments and BLUP, also they were novel loci for first reported in this study. Based on the five stable SNPs and qRT-PCR analysis for husk tissue of 17 maize inbred lines, three candidate genes (Zm00001d003850, Zm00001d033706 and Zm00001d025612) related to maize husk were screeded out, which encoded BOI-related E3 ubiquitin-protein ligase, GeBP transcription factor, and protein of unknown function, respectively. 【Conclusion】A total of 92 SNPs significantly associated with three husk traits were identified, including five stable SNPs. Three candidate genes were predicted that might be involved in maize husk growth and development.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Compensatory Effects of Multiple Cropping Green Manure on Growth and Yield Loss of Nitrogen-Reduced Spring Wheat in Oasis Irrigation Areas of Northwest China

QIU HaiLong, LI Pan, ZHANG DianKai, FAN ZhiLong, HU FaLong, CHEN GuiPing, FAN Hong, HE Wei, YIN Wen, ZHAO LianHao

Scientia Agricultura Sinica. 2025, 58(3):  443-459.  doi:10.3864/j.issn.0578-1752.2025.03.004

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【Objective】Aiming at the problems of large amount of nitrogen fertilizer input, low utilization rate and single fertilizer source in traditional spring wheat planting in the oasis irrigation area of Northwest China, the effects of multiple cropping green manure after spring wheat on photosynthetic source, growth characteristics and yield of spring wheat under the condition of reduced nitrogen application were studied, with a view to provide the technical support for the construction of a nitrogen-saving and high-yield green planting model of spring wheat in the experimental area. 【Method】The split plot experiment was carried out in the oasis irrigation area of Hexi Corridor from 2021 to 2023. The main area was set up with two planting modes: post-wheat fallow (W) and post-wheat multiple cropping of hairy leaf (W-G), and the split plot was the traditional full nitrogen application of 100% (N1, 180 kg·hm^-2), reduced nitrogen application of 15% (N2, 153 kg·hm^-2) and reduced nitrogen application of 30% (N3, 126 kg·hm^-2). The photosynthetic source, stay-green of leaves, growth characteristics and yield performance related indicators of spring wheat under different treatments were measured and calculated. The Logistic equation of dry matter accumulation, the correlation between different indicators and the compensation index were constructed. The objective was to explore the compensation effect of multiple cropping green manure on the growth and yield of nitrogen-reduced spring wheat. 【Result】Post-wheat multiple cropping of green manure could compensate for the loss of photosynthetic source, growth characteristics and yield caused by nitrogen reduction to a certain extent. Among them, the compensation effect was the best under the condition of multiple cropping green manure after spring wheat combined with 15% nitrogen reduction (W-GN2), which showed super compensation and equal compensation effect. Multiple cropping of green manure significantly increased leaf area index, leaf area duration and stay-green of leaves in spring wheat at the late reproductive stage. Compared with the traditional post-wheat fallow total nitrogen fertilization (WN1), W-GN2 increased the average leaf area index, leaf area duration and stay-green of leaves by 17.7%, 17.5% and 7.6% on the 75-90 days after seedling, respectively. W-GN2 optimized the growth characteristics of spring wheat. Compared with WN1, the average dry matter accumulation, the maximum growth rate of dry matter and crop growth rate under W-GN2 increased by 6.2%, 6.9% and 5.1%, respectively, and the net assimilation rate decreased by 6.2%. Due to the compensation of multiple cropping green manure for photosynthetic source and growth characteristics, the photosynthesis, population growth and material accumulation rate of spring wheat remained high in the late growth stage, which was conducive to the improvement of grain yield. The grain yield under W-GN2 was 14.7% higher than that under WN1, which was mainly attributed to the compensation of the spike number, 1000-grain weight and harvest index by multiple cropping green manure, and W-GN2 was 6.5%, 6.9% and 13.2% higher than that under WN1, respectively. According to the correlation analysis, it was found that W-GN2 treatment had better performance in photosynthetic source, growth characteristics and grain yield formation, and mainly promoted the formation of yield by compensating the photosynthetic source of spring wheat. 【Conclusion】Multiple cropping of hairy vetch after spring wheat with 15% reduction of nitrogen application could be used as a perfect production technology to regulate the photosynthetic source and growth characteristics of spring wheat in the northwest oasis irrigation area to achieve nitrogen saving and yield increase.

Effects of Different Mulching Methods on the Production of Photosynthetic Substances and Water Use Efficiency of Intercropped Maize

WANG JiaXin, HU JingYi, ZHANG Wei, WEI Qian, WANG Tao, WANG XiaoLin, ZHANG Xiong, ZHANG PanPan

Scientia Agricultura Sinica. 2025, 58(3):  460-477.  doi:10.3864/j.issn.0578-1752.2025.03.005

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【Objective】This study explored the effects of different mulching methods on the production of photosynthetic substances and water use of maize under the intercropping mode of maize and soybean, aiming to determine the suitable mulching method for maize and soybean plantation in dryland agriculture in northern Shaanxi, so as to provide a basis for high-yield and efficient production of maize and soybean and ecological environment protection. 【Method】This study was conducted in irrigated land and nonirrigated land in 2022, using 'Zhonghuang 30' soybean and 'Xianyu 335' maize as materials. The two-factor complete randomized design was carried out, and the control group combined single crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J”), and the test group combined intercropping crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J” and whole film “Q”), with a total of 13 treatment groups. The characteristics changes of growth, photosynthesis, and water use efficiency of intercropped maize under different mulching methods were studied. 【Result】 (1) From jointing to silking stage, the growth space of intercropped maize was limited, resulting in a disadvantage in aboveground biomass of intercropped maize compared with monoculture. The biomass during the jointing stage of S/MQ, SQ/MJ, and SQ/MQ was 5.1%, 6.3%, and 1.7% higher than that of monoculture M, respectively; under intercropping, SJ/MJ maize plants had the fastest growth rate and a sharp increase in growth. SQ/MQ S/M, S/MJ, SQ/MJ, and SJ/M in dry land had a better promoting effect on the photosynthetic products of maize during the silking stage, and the aboveground biomass was 0.6%-105.9% higher than that of monoculture M. (2) To some extent, intercropping and mulching treatments improved the photosynthetic characteristics of maize, and the net photosynthetic rate (Pn) content of paddy maize. There was a certain degree of positive relationship between stomatal conductance (Gs), cellular CO₂ concentration (Ci) and transpiration rate (Tr). The photosynthetic parameters of SQ/MJ and SJ/MQ were relatively high, while SJ/M and SQ/MQ were lower than non film coated S/M; there was a weak negative correlation between Pn and Ci in dryland maize, and the effect of maize mulching was not significant among different treatments. The Gs of intercropping treatment was 5.7% -38.1% lower than that of monoculture M, and Tr was also reduced by 5.6% -25.6%. Only the Pn of SJ/M and SQ/M, as well as the Ci of SQ/MJ and S/M, were higher than monoculture M. (3) The intercropping film mulching had a significant impact on water use efficiency (WUE). The WUE of the intercropping treatment was 41.1% -74.0% higher than that of monoculture M, among which SJ/M, S/M and S/MJ were relatively high; among all treatments in arid land, SQ/MJ had the highest WUE (19.04 kg∙mm^-1∙hm^-2), followed by SJ/MJ (17.07 kg∙mm^-1∙hm^-2), and the WUE of SJ/M and SQ/M was significantly lower than that of monoculture M by 26.7% and 20.6%, respectively. (4) Compared with monoculture M, intercropping S/MJ between irrigated land and dry land SJ/M and SJ/MJ maize increased yields by 76.8%, 73.0%, and 72.3%, respectively, while soybean yield reduction was relatively less among all intercropping treatments, demonstrating higher economic benefits; dry land intercropping SJ/MJ and SJ/MQ maize increased production by 17.1% and 23.5%, respectively, while economic benefits decreased by 17.5% and 22.8%, respectively. 【Conclusion】Compared with single cropping M, SJ/MJ model improved the photosynthetic performance, biomass, and yield of maize in irrigated land, and improved system economic benefit and promoted water use efficiency. In dry land, through the complementary effect and resource allocation in the intercropping system, it maintained maize yield and improved water use efficiency, but the increase of total input in agricultural materials reduced the economic feasibility. Therefore, in the dryland agriculture of Northern Shaanxi, the intercropping planting pattern of maize with degradable film and soybeans with degradable film was recommended for both irrigated land and moderately irrigated dry farm, aiming to enhance water use efficiency, increase production and profitability, and promote sustainable ecological agriculture development.

PLANT PROTECTION

Identification of Hypovirus in Apple Ring Rot Fungus Botryosphaeria dothidea and Detection of Virus-Carrying Status in China

CONG QiQi, ZHANG JingYi, MENG XiangLong, DAI PengBo, LI Bo, HU TongLe, WANG ShuTong, CAO KeQiang, WANG YaNan

Scientia Agricultura Sinica. 2025, 58(3):  478-492.  doi:10.3864/j.issn.0578-1752.2025.03.006

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【Objective】Apple ring rot is one of the serious fungal diseases in apple production caused by Botryosphaeria dothidea. The aim of this study is to obtain strains of B. dothidea with weak pathogenicity carrying dsRNA viruses, identify the types of viruses, and clarify the distribution of these viruses in China, so as to provide new biological control resources for the prevention and control of apple ring rot and new insights into the diversity and systematic evolution of fungal viruses. 【Method】Samples of branches with typical symptoms of apple ring rot were collected from across China, and pure cultures were obtained through tissue isolation and single-spore isolation. Virus-carrying strains were identified through dsRNA band analysis, and the types of dsRNA viruses carried by the virus-carrying strain WH-2L were identified using high-throughput sequencing and molecular cloning techniques. The presence of two types of dsRNA viruses in B. dothidea from six provinces (autonomous region) in China was determined by RT-PCR. Pathogenicity differences among representative strains carrying different viruses were clarified through pathogenicity tests. Finally, the transmission characteristics of the two viruses were revealed through analysis of vertical and horizontal transmission properties. 【Result】For the first time in apple-producing regions of China, strains of B. dothidea causing apple ring rot were found to be co-infected with two viruses: Botryosphaeria dothidea chrysovirus 1 (BdCV1), belonging to the family Chrysoviridae and genus Chrysovirus, and Botryosphaeria dothidea victorivirus 2 (BdVV2), belonging to the family Totiviridae and genus Victorivirus. It was clarified that BdCV1 and BdVV2 are widely distributed in B. dothidea causing apple ring rot in China. BdCV1 was detected in strains from Liaoning, Shandong, Henan, Hebei, Shaanxi, and Xinjiang, except for Yan’an in Shaanxi and Shijiazhuang in Hebei, with an average detection rate of 53.6%. BdVV2 occurred in Liaoning, Shandong, Henan, Hebei, and Shaanxi, but was not detected in Yan’an in Shaanxi, Shijiazhuang and Handan in Hebei, Aksu in Xinjiang, Taian and Qingdao in Shandong, with an average detection rate of 28.6%. It was clarified that the pathogenicity of strains with co-infection of the two viruses and single infection of BdCV1 on branches, apple fruits, and pear fruits was significantly reduced. The vertical transmission efficiency of BdCV1 and BdVV2 was 100%, and the horizontal transmission efficiency was 9% and 3%, respectively. 【Conclusion】The strain WH-2L of B. dothidea with weak pathogenicity carries two viruses, BdCV1 and BdVV2. The detection rates of BdCV1 and BdVV2 in B. dothidea causing apple ring rot in six apple-producing regions in China were 53.6% and 28.6%, respectively. Both viruses can cause reduced pathogenicity in their hosts, with high vertical transmission efficiency and certain horizontal transmission efficiency, and have potential for development as biological control resources for apple ring rot.

The Relationship Between Occurrence of Hulless Barley Ear Rot and Population Migration of Grass Mite (Siteroptes spp.)

TONG ZhaoYang, LIU WenHua, ZHANG GuoXin, DONG ChunYan, ZHANG YanXia, XU XiaoWei, HE Dong, LIU HeChun, LI Yang, WANG FengTao, FENG Jing, YAO XiaoBo, LIU MeiJin, LIN RuiMing

Scientia Agricultura Sinica. 2025, 58(3):  493-506.  doi:10.3864/j.issn.0578-1752.2025.03.007

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【Background】Hulless barley ear (or spike) rot epidemically occurs only in the Qinghai-Xizang Plateau, which has been getting heavier and spreading more widely in recent years. It has become one of the major diseases in the staple food crop, hulless or naked barley (Hordeum vulgare var. nudum), referred to as Qingke in local areas. It seriously threatens the guarantee of high yield and stable production of hulless barley crops. Grass mite (Siteroptes spp.) plays the role of inoculum transmission vector of the pathogen Dactylobotrys graminicola. The disease cycle is still unclear, and a control method is not available at present. 【Objective】In this study, the migration and clustering of grass mites were investigated in order to disclose the processes of pathogen inoculum transmission and the infection of inflorescence of hulless barley. The results obtained here will serve as a scientific basis for developing technologies for ear rot control. 【Method】Variations in the number of mites in samples of surface soil and on hulless barley plants, as well as their distributions, were detected. The fungi carried by grass mites were microscopically observed and isolated for species identification, and the infection processes of hulless barley inflorescences were also detected under a microscope. The fungal spores stored in the sporothecae of grass mite vectors near the lesions of inflorescences and those collected from the soil were tested using the lactophenol cotton blue dyeing method. The initial invasion time of grass mites into hulless barley seedlings and their distribution within the plants were verified in the greenhouse. The pathogen D. graminicola was inoculated onto hulless barley tissues for testing its pathogenicity. 【Result】The overwintering mites initially moved in from the horn-shaped opening of the first leaf after the blade unfolded and gathered at the adaxial side of its basal part. About 87.63%-99.34% of the grass mites found in hulless barley plants were distributed in their main stems, with only 0.66%-12.37% in tillers. The majority of mites in the main stems (95.48%-99.74%) were gathered around the basal parts of young leaves, over 30% of which moved onto inflorescences at the early booting stage. The incidence of ear rot in the main stem was 6.37 times that of the tiller. Greenish yellow, water-soaked lesions appeared on the glumes and awns of young spikelets, and adult mites were usually found near them at the early booting stage; 28.57% of these mites contained fungal spores in their sporothecae, significantly lower than the 46.70% ratio of spore-carrying mites in the soil. After seedling emergence, the mite density in the soil remained at a relatively low level for a long time until hulless barley was harvested, and it abruptly increased by 2.85 times compared to before sowing. About 88.66% of the fungal isolates from grass mites and 76.47% of those from lesion tissues of inflorescences were identified as D. graminicola, and the pathogen was only strongly pathogenic to the inflorescences. 【Conclusion】The overwintering mites mainly migrated from the soil and flocked to hulless barley seedlings during the early stage after plant emergence, first entering the basal part of the first leaf through the horn-shaped opening formed after leaf blade unfolded. Over 30% of mites clustering around the newly born leaves of a main stem subsequently moved onto the inflorescence at the early booting stage and then released D. graminicola spores to cause infection. The disease cycle of D. graminicola was completed with the essential aid of grass mite mediator. Ear rot mainly infected the main stems of hulless barley plants. It was not until at the repining stage that there were plenty of adult mites produced on the diseased ears, resulting in a significant increase in the mite density in surface soil after harvesting. Therefore, ear rot of hulless barley is a monocyclic disease mediated by vector grass mite.

SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT

Effects of Long-Term Mulching Practices on Maize Yield, Soil Organic Carbon and Nitrogen Fractions and Indexes Related to Carbon and Nitrogen Pool on the Loess Plateau

ZHANG FangFang, SONG QiLong, GAO Na, BAI Ju, LI Yang, YUE ShanChao, LI ShiQing

Scientia Agricultura Sinica. 2025, 58(3):  507-519.  doi:10.3864/j.issn.0578-1752.2025.03.008

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【Objective】The aim of this study was to clarify the effects of long-term mulching practices on crop yield, soil carbon and nitrogen physical fractions and carbon and nitrogen pool-related indexes, with a view to providing a scientific basis for long-term maintenance of high crop yields and soil fertility in dry-crop farmlands on the Loess Plateau. 【Method】 Based on a field experiment of more than 10 years in Changwu County, Shaanxi Province, three treatments of no mulching (CK), gravel mulching (GM) and film mulching (FM) were set up. From 2018 to 2020, in situ soil samples in the 0-20, 20-40 and 40-60 cm soil layers were collected, and soil samples from each soil layer were grouped by using the physical method. The variation characteristics were investigated, including spring maize yield, and soil organic carbon (SOC), total nitrogen (TN), particulate organic carbon (POC), particulate organic nitrogen (PON), mineral-bound organic carbon (MAOC) and mineral-associated organic nitrogen (MAON) in each soil layer. Based on carbon pool management index (CPMI), nitrogen pool management index (NPMI), and carbon stability index (CSI), the nitrogen stability index (NSI). Combined with correlation analysis, the relationships between the yields and the soil carbon and nitrogen fractions and the related indexes were clarified. 【Result】Compared with CK treatment, the GM treatment showed a decrease in yield, with a 5.8% decrease in mean yield, while the FM treatment continued to increase yield, with a significant 13.6% increase in mean yield. The mean SOC and TN content of the topsoil (0-20 cm) were decreased under both the GM and FM treatments compared with CK treatment, with a significant reduction of 7.3% in the mean SOC content of the topsoil under FM treatment, while it was not significant under GM treatment. Both GM and FM treatments significantly decreased mean POC and PON content in the topsoil and significantly increased MAOC and MAON content in the topsoil compared to CK treatment, i.e. long-term mulching practices significantly decreased labile carbon and nitrogen contents in the topsoil and significantly increased recalcitrant carbon and nitrogen content in the topsoil. Compared with CK treatment, the GM treatment significantly decreased CPMI in the topsoil and significantly increased CSI in the topsoil, whereas the FM treatment significantly decreased CPMI and NPMI and significantly increased CSI and NSI in the topsoil, indicating that the GM treatment significantly increased carbon pool stability of the topsoil, whereas the FM treatment significantly increased both carbon pool stability and nitrogen pool stability of the topsoil. Correlation analyses showed that in addition to POC and MAOC being related to carbon pool indexes, POC was also closely related to NPMI and NSI, while MAOC was also closely related to yield and NPMI. 【Conclusion】Long-term film mulching maintained high crop yields and improved the stability of soil carbon and nitrogen pools, but it reduced topsoil fertility and could be made more sustainable by combining it with other measures to replenish soil organic matter.

Effects of Long-Term Nitrogen Fertilizer Application on the Rhizosphere Microbial Community Structure and Function in Black Soil and Sandy Soil

WANG Zhao, ZHANG Bing, DONG SiQi, HU YuXi, QI ShuYu, FENG GuoZhong, GAO Qiang, ZHOU Xue

Scientia Agricultura Sinica. 2025, 58(3):  520-536.  doi:10.3864/j.issn.0578-1752.2025.03.009

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【Objective】This study investigated the differential responses of rhizosphere microbial communities, keystones and indicators to nitrogen fertilizer application in black and sandy soils under identical climatic conditions. The aim of this study was to provide a scientific basis for guiding precision fertilization and promoting green production. 【Method】This study was based on a long-term field experiment (12 years) involving nitrogen fertilizer application in a maize continuous cropping system in Jilin Province. The experimental design included two main treatments: sandy soil and black soil. Under each main treatment, three nitrogen levels were applied: 0 (N0), 168 kgN·hm^-2 (N168), and 312 kgN·hm^-2 (N312). Utilizing high-throughput sequencing technology, the differential impacts of long-term nitrogen fertilizer application on the composition, structure, and functional attributes of rhizosphere microbe communities in both black soil and sandy soil were studied. 【Result】Long-term nitrogen fertilizer application significantly decreased the Alpha diversity and changed the community structure of rhizosphere microbes in both black and sandy soils. The greatest impact was observed under N312 treatment, which significantly reduced Alpha diversity by 2.6%-7.5%. The impact of the same nitrogen application on the rhizosphere microbes was more pronounced in sandy soil than in black soil. Species analysis indicated that nitrogen fertilizer application significantly increased the relative abundance of Bacteroidetes and Patescibacteria phylum and decreased the relative abundance of Frimicutes and Chloroflexi, with the N312 treatment having the greatest impact (80%-90%) in both black and sandy soils. Co-occurrence network analysis revealed that the impact of nitrogen fertilizer application on the network structure was greater in sandy soil than in black soil. Moreover, nitrogen fertilizer application significantly influenced 43% of the keystone species in black soil and all keystone species in sandy soil. Random forest analysis indicated that the impact of nitrogen fertilizer application on indicators was more pronounced in sandy soil than in black soil. Compared with N0, the N168 and N312 treatments had no specific indicator species in black soils, whereas two specific indicators were identified under these two treatments in sandy soil, belonging to the Intrasporangiaceae family of the Actinomycetes phylum and the Noviherbaspirillum genus of the Proteobacteria phylum. PICRUSt2 functional prediction revealed that nitrogen fertilizer application significantly affected 88.5% of nitrogen transformation-related functional genes in black soil and 96.2% in sandy soil, with a greater influence observed at higher nitrogen application rates. 【Conclusion】The research findings suggested that nitrogen fertilizer application significantly reduced the diversity of rhizosphere microbial communities, and changed the community structure and species composition characteristics, resulting in significant differences in nitrogen transformation-related functional genes. The overall impact of nitrogen fertilizer application on rhizosphere microbes was more pronounced in sandy soil than in black soil, with a greater influence observed at higher nitrogen application rates. Therefore, it was important to further promote N fertilizer reduction in black and sandy soils to maintain the stability of rhizosphere microbial community structure in farmland.

Optimization of N₂O Emission Parameters in Dryland Spring Wheat Farmland Soil Based on Whale Optimization Algorithm

MU ShuJia, DONG LiXia, LI Guang, YAN ZhenGang, LU YuLan

Scientia Agricultura Sinica. 2025, 58(3):  537-547.  doi:10.3864/j.issn.0578-1752.2025.03.010

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【Objective】In order to improve the simulation accuracy of N₂O emissions by using APSIM model, this study used Whale Optimization Algorithm (WOA) to optimize the default parameters related to soil N₂O emissions in the APSIM model to improve the accuracy and applicability of the model in simulating soil N₂O emissions in the semi-arid agricultural region of northwest China, for providing support for precise assessment and management of greenhouse gas emissions in agricultural activities. 【Method】This study used field experimental data measured by the Anjiapo integrated long-term positioning test station in Anding District, Dingxi City, Gansu Province from 2020 to 2021, combined with meteorological data provided by the Meteorological Bureau from 1970 to 2021, to optimize the four key parameters of N₂O formation stage in the APSIM model (soil nitrification potential (nitration_pot), concentration of ammonium nitrogen at semi maximum utilization efficiency (nh4_at-half_pot), denitrification coefficient (dnit_rate-coeff), and power term of denitrification water coefficient (dnit_wf_power) using the WOA for single objective and multi parameter optimization. The accuracy of the optimized APSIM soil N₂O emission model was evaluated by comparing the errors between the default parameter simulation values, optimized parameter simulation values, and measured values of the APSIM model. 【Result】Through multiple executions of the optimization program, the optimal combination of four parameters was ultimately determined. Among them, the soil nitrification potential was 7.62 mg·kg^-1·d^-1, the concentration of ammonia nitrogen at semi maximum utilization efficiency was 49.3 mg·kg^-1, the denitrification coefficient was 0.00063, and the power term of the denitrification water coefficient calculation was 0.64. Compared with the default parameters of the APSIM model, the coefficient of determination R² increased from 0.432 to 0.719, the root mean square error (RMSE) decreased from 39.42 to 25.37 μg·m^-2·h^-1, and the normalized root mean square error (NRMSE) decreased from 18.51% to 11.92%. The whale algorithm exhibited significant global search capability and fast convergence during the optimization process. The optimized APSIM model significantly improved the accuracy of simulating soil N₂O emissions, indicating that this method could achieve rapid and accurate calibration of model parameters. 【Conclusion】By applying WOA, four key parameters were precisely adjusted, which significantly reduced the prediction error of the model and significantly improving the performance of the APSIM soil N₂O emission model. The optimized model has shown higher accuracy and applicability in the semi-arid agricultural region of northwest China, which also proved the effectiveness of the optimization strategy.

HORTICULTURE

Effect Analysis of SmWRKY30 in Eggplant Resistance to Ralstonia solanacearum by Virus Induced Gene Silencing (VIGS)

ZHANG LinLin, GONG Rui, CUI YanLing, ZHONG XiongHui, LI Ye, LI RanHong, QIAN ZongWei

Scientia Agricultura Sinica. 2025, 58(3):  548-563.  doi:10.3864/j.issn.0578-1752.2025.03.011

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【Objective】The results showed that WRKY transcription factors play an important regulatory role in the process of plant disease resistance and stress resistance. Tomato SlWRKY30 is a key gene for Ralstonia solanacearum resistance, SmWRKY30 was the homologous gene as SlWRKY30 in eggplant. Through the induction of Ralstonia solanacearum and the establishment of gene silencing system, the regulatory effect of SmWRKY30 gene on Ralstonia solanacearum in eggplant was explored, which laid a foundation for the creation of Ralstonia solanacearum resistant resources and variety breeding of eggplant. 【Method】SmWRKY30 was cloned from eggplant disease-resistant material YS40 and disease-susceptible material ZP80 to analyze the differences in genes, amino acids and promoter sequences. After the induction of Ralstonia solanacearum fungus, the differences in the expression of SmWRKY30 in different tissues of the two materials were analyzed. The expression of STH2 in tomato and eggplant was compared, and the similarities and differences between SmWRKY30 and SlWRKY30 were analyzed. Virus-induced gene silencing system was constructed to compare the changes of disease index, phenotype and gene expression in the water group, the empty vector control and the experimental group. 【Result】The SmWRKY30 open reading frame is 891 bp and has a conserved domain of the WRKY gene family, The phylogenetic tree was constructed and it was found that SmWRKY30 was closely related to Solanum sisymbriifolium and Solanum melongena WRKY65. There were 6 SNPs and 1 Indel differences in the cDNA sequences of the disease-resistant material YS40 and the disease-susceptible material ZP80, the amino acid translation difference was large, and the promoter region was significantly different, and YS40 had one lack of GT1-motif promoter element than ZP80. After inoculation with Ralstonia solanacearum and the expression of SmWRKY30 in roots, stems and leaves of disease-susceptible materials were analyzed, the results showed that the expression of SmWRKY30 in YS40 was significantly higher than that of ZP80 in roots after 14 days of inoculation with Ralstonia solanacearum. However, there was no significant difference in the expression of SmWRKY30 in stems. After 5 and 14 days of inoculation with Ralstonia solanacearum, the expression level of SmWRKY30 in YS40 leaves was significantly higher than that of ZP80, indicating that SmWRKY30 high expression may be related to the resistance of Ralstonia solanacearum in eggplant. The qRT-PCR results showed that the expression level of SmWRKY30 in pTRV1/pTRV2::SmWRKY30 silenced plants was significantly lower than that in clean water treatment and pTRV1/pTRV2::00 no-load treatment plants, indicating that SmWRKY30 in the disease-resistant material YS40 was successfully silenced. Phenotypic observation showed that the leaves of pTRV1/pTRV2::SmWRKY30 silenced plants were obviously yellowish wilted, and the disease index was 2.07 at 14 days after inoculation with Ralstonia solanacearum fungus, indicating that they were susceptible to Ralstonia solanacearum. Through the quantitative analysis of four STH2 genes homologous to eggplant and tomato, it was found that the expression levels of STH2 genes increased firstly and then decreased. After 1 day of inoculation, only the expression level of STH2-3 in the disease-resistant materials was significantly higher than that in the disease-susceptible materials. After 5 days of inoculation, the expression levels of STH2-3 and STH2-4 in the disease-resistant materials were significantly lower than those in the disease-susceptible materials. After 7 and 14 days of inoculation, there was no significant difference in the expression levels of the four STH2 genes in the disease-resistant materials and disease-susceptible materials. Moreover, the expression trends of the four STH2 genes in the resistant materials were significantly different from those of SmWRKY30. 【Conclusion】SmWRKY30 may be involved in and positively regulate the response process of Ralstonia solanacearum resistance in eggplant, but may not make eggplant resistant to Ralstonia solanacearum by interacting with STH2 gene.

Analysis of Differential Aroma Volatiles of Tainong No.1 Mango of Different Ripeness by Non-Targeted Metabolomics Based on Gas Chromatography-Mass Spectrometry

LUO ChaoDan, FENG ChunMei, LI JianQiang, LI XinRong, WEI Yong, YANG LiYi, LIU XiaoJin, TAN He, REN ErFang, LUO XiaoJie

Scientia Agricultura Sinica. 2025, 58(3):  564-581.  doi:10.3864/j.issn.0578-1752.2025.03.012

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【Objective】This study aimed to investigate the differences and variation patterns of volatile metabolites in Tainong No.1 mango at different maturities, and to identify the characteristic aroma components at each maturity stage of mangoes. 【Method】 The samples of Tainong No.1 mango at 6 ripeness stages, including raw fruits (less than 60%-ripened), insufficiently ripe fruits (60%-, 70%-, 80%-ripened), fully ripened fruits (90%-ripened), and overripe fruits (100%-ripened), were used as the research objects. The volatile metabolites during the ripening process of mango were identified by gas chromatography-mass spectrometry (GC-MS) non-targeted metabolomics. The metabolic differences between samples in different groups were analyzed by multivariate statistical analysis methods, and the differential metabolites were determined by variable importance in projection (VIP) and fold change (FC). The metabolic pathway enrichment analysis was carried out according to the Kyoto Encyclopedia of Genes and Gnomes (KEGG). 【Result】 A total of 220 volatile metabolites were identified in Tainong No.1 mango pulp. The content of volatile metabolites was the lowest in 60% ripened mangoes. In terms of 70%- to 90%-ripened mangoes, the content of volatile metabolites showed an increasing trend, and decreased when the fruits were 100%-ripened. Compared with mangoes ripened less than 60%, there were 5 differential metabolites in 60% ripened mangoes, and 67, 77, 81, and 82 differential metabolites in 70%-, 80%-, 90%-, and 100%- ripened mangoes, respectively, among which 63, 73, 71, and 71 were up-regulated differential metabolites. In 70%- to 100%-ripened fruits, the content of 11 terpenoids (phellandrene, 3-carene, limonene, α-pinene, β-pinene, and β-ocimene), 6 kinds of ester (ethyl hexanoate and propyl butyrate), as well as 2 kinds of ketones, 2 kinds of alcohol, and 1 hydrocarbon compound, all showed a significant increasing trend, which could be regarded as the characteristic aroma components when Tainong No.1 mangoes just start to ripen. (E, E)-3,5-Octadien-2-one was significantly up-regulated only in 70%-ripened fruits and could be used as the characteristic aroma component of 70%-ripened Tainong No.1 mangoes; (+)-delta cadinene and cis-calamenene could be used as the characteristic aroma components at 90% ripeness; terpinolene, germacrene D, longifolene, L(-)-borneol, and lavandulol could be used as the characteristic aroma components at 100% ripeness. The KEGG pathway analysis showed that the differential metabolites were mainly enriched in 4 pathways, including the biosynthesis of sesquiterpenes and triterpenes, the biosynthesis of monoterpenes, metabolic pathways, and the biosynthesis of secondary metabolites, and the overall of the these differential metabolites showed an upward trend. 【Conclusion】 The content of volatile metabolites in the pulp of 90%-ripened Tainong No.1 mango was the highest. There were significant differences in the volatile components, especially the metabolism of terpene substances, in mangoes at different ripeness. Using specific differential metabolites as potential markers to distinguish mangoes of specific maturities provided a basis for identifying ripeness of Tainong No.1 mango.

FOOD SCIENCE AND ENGINEERING

Variation of Different Drying Methods on the Quality of Capsicum annuum L.

WU LiDong, LIN ShuTing, QIU YinHui, LIU YaTing, ZHANG Rui, LI YongQing, SHANG Wei, ZHONG LiuQing

Scientia Agricultura Sinica. 2025, 58(3):  582-599.  doi:10.3864/j.issn.0578-1752.2025.03.013

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【Objective】In order to provide a theoretical basis for the processing and industrialization of dried capsicum products, the differences of different drying methods on the quality characteristics of capsicum were explored. 【Method】With self breeding MJ7 and MJ8 as test materials, differences in their appearance, nutritional components, and volatile components were analyzed based on 3 different methods: natural drying (ND), hot air drying (HAD), and vacuum freeze drying (VFD), and the topsis method was used for comprehensive evaluation. 【Result】With an overall performance of HAD>ND>VFD, capsicum by VFD had the closest appearance to fresh, and the values of L*, a* (red pepper)/b* (yellow pepper), and C were significantly(P<0.05) higher than those of ND and HAD. The content of HAD dihydrocapsaicin were lowest at 1.82和2.06 g·kg^-1, which was significantly different from ND and VFD (P<0.05). VFD had a a good yield of capsaicin in MJ7 with content of 7.01 g·kg^-1. In contrary to red pepper, yellow pepper had a significant difference(P<0.05) in color value, VFD exhibited a highest value of 2.48, which were twice and 1.84 times higher than that of ND and HAD. HAD retained theirs fat and protein better, while ND and VFD difference were marked. ND had the highest retention of sugars at 41.38 and 35.36 mg·g^-1, which were higher than VFD and HAD for 1.03 and 1.1 times. The crude fiber of both two types capsicums showed no obvious significant difference with content at 20.56%-20.61% and 21.91%-21.95%. Meanwhile, 73 volatile components were identified in two types of capsicums, including esters, ketones, alcohols, aldehydes, acids and terpenes. Volatile components in three types of dried capsicums were the same, esters were the main volatile components in capsicums. But their content was different, ND accounted for 40.35% and 58.66%, while HAD and VFD up to 72%, mainly included Hexyl 2-methylbutanoate (D), Hexyl 2-methylpropanoate (D), and n-octyl acetate (D). The result of cluster analysis was consistent with principal component analysis, the three drying methods of capsicums are classified separately. 19 characteristic differential metabolites were identified by partial least squares analysis, among which Hexyl 2-methylbutanoate (D), Hexyl 2-methylpropanoate (D), Acetic acid butyl ester (D), and 4-Methyl-2-pentanone (D) contributed the most. The topsis comprehensive evaluation analysis showed that VFD was the best in quality performance, followed by HAD, and ND had the worst performance. 【Conclusion】The effects of different drying methods exhibited various influences on the appearance, nutritional components, and volatile components of capsicums. Due to its good performance in overall quality, VFD can be used as an ideal drying method for capsicums.

ANIMAL SCIENCE·VETERINARY SCIENCE

The Potential and Mechanism of Chlorogenic Acid to Alleviate Intestinal Inflammation in Chickens Based on Network Pharmacology and Molecular Docking

YAO Hong, SHI ShouRong, ZHAO RuQian

Scientia Agricultura Sinica. 2025, 58(3):  600-616.  doi:10.3864/j.issn.0578-1752.2025.03.014

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【Objective】The study aimed to predict the mechanisms of chlorogenic acid in alleviating intestinal inflammation in chickens by using network pharmacology and molecular docking, so as to provide the reference for the application of chlorogenic acid. 【Method】 Firstly, "caffeoylquinic acid" and "intestinal inflammation" were retrieved from the TCMSP, DisGeNET database, and Gene Cards database, respectively, to obtain targets related to chlorogenic acid and intestinal inflammation. Venn intersection was used to obtain the target set of chlorogenic acid for alleviating intestinal inflammation. CytoNCA program in Cytoscape 3.10 was used to calculate network node centrality and to screen for key chlorogenic acid monomers. A protein-protein interaction (PPI) network targeting intestinal inflammation in chicken was constructed by using the STRING database, and gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on intersecting targets were carried out using the David database. In addition, the molecular complex detection analysis (MCODE) was performed on the above targets to obtain core gene clusters, and a chlorogenic acid target signaling pathway network was constructed. Autodock vina was employed to perform molecular docking between the selected key chlorogenic acid monomers and core targets, and the results were visualized by using the Pymol software. 【Result】 222 chlorogenic acid targets were retrieved from the TCMSP database, 1 453 targets for intestinal inflammation were obtained after quality control in the DisGeNET and Gene Caeds databases, and 78 chlorogenic acid targets in alleviating intestinal inflammation were obtained. The target PPI network for intestinal inflammation in chickens had 53 nodes and 162 edges. The core targets were SRC (Non-receptor tyrosine kinase), CASP3 (Apoptotic protease 3), MMP9 (Matrix metalloprotein-9), EGFR (Epithelial growth factor receptor), ESR1 (Estrogen receptor 1), MMP2 (Matrix metalloprotein- 2), BRAF (Serine/threonine kinase), KDR (Kinase insertion domain protein receptor), and MAPK3 (Mitogen activated protein kinase 3). Molecular docking results showed that the key chlorogenic acid monomers could stably bind to the core targets mentioned above. GO functional enrichment analysis (P<0.05) revealed 87 Biological processes (BP), 20 Cellular components (CC), and 35 Molecular functions (MF). KEGG enriched 26 signaling pathways, while MCODE analysis revealed two major gene clusters. 【Conclusion】Through cross validation and literature support, it was predicted that chlorogenic acid might regulate inflammatory response and alleviate intestinal inflammation in chicken through pathways, such as MAPK, C-type lectin, and Focal adhesion. In addition, two monomers, including neochlorogenic acid and isochlorogenic acid A, might play a crucial role in alleviating intestinal inflammation. This study utilized network pharmacology and molecular docking methods to explore the potential of stevia chlorogenic acid in alleviating intestinal inflammation in chickens, providing theoretical reference for the application of chlorogenic acid and plants rich in chlorogenic acid monomers in production.