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    16 December 2019, Volume 52 Issue 24
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Genetic Analysis of Panicle Related Traits in Wheat with Major Gene Plus Polygenes Mixed Model
    SongFeng XIE,WanQuan JI,ChangYou WANG,WeiGuo HU,Jun LI,YaoYuan ZHANG,XiaoXi SHI,JunJie ZHANG,Hong ZHANG,ChunHuan CHEN
    Scientia Agricultura Sinica. 2019, 52(24):  4437-4452.  doi:10.3864/j.issn.0578-1752.2019.24.001
    Abstract ( 359 )   HTML ( 55 )   PDF (2804KB) ( 277 )   Save
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    【Objective】 Panicle traits are important yield traits of wheat, occupying an important position and role in wheat yield composition. Carrying out genetic research on wheat panicle traits and analyzing its genetic mechanism provide theoretical and practical guidance for formulating high-yield breeding strategies and improving breeding efficiency. 【Method】 Based on the length of the main stem, the number of spikelets, the number of grains per spike, and the number of spikelets, the main gene + polygene mixed genetic model of quantitative traits was used to obtain the parental product 34 and the male parent under different ecological conditions. BARRAN and its derived F7:8, F8:9 generation recombinant inbred line population (RIL) were used for genetic model analysis and genetic parameter estimation of panicle traits to determine the number of genes controlling various traits, and to estimate genetic effect values and heritability. 【Result】The best genetic model for panicle length and spikelet number were B-2-1 (PG-AI), which was consistent with two pairs of linked major genes + additive-epistasis polygene genetic model. The polygenic heritability of spike length was 90.64%, the polygenic heritability of spikelet number was 89.52%, the average of environmental variation of spike length accounted for 9.39% in phenotypic variation, and the average of environmental variation of spikelet number accounted for 10.50% in phenotypic variation; Major gene heritability was 69.39%, Polygenes heritability rate was 29.94%, and the average environmental variation accounted for 2.18% in phenotypic variation. Additive effect value of the first pair of main genes controlling the number of spikes and the additive effect value of the third pair of major genes are equal, and the same was 4.56, which has a positive effect. The additive effect value of the second pair of major genes was the same as the additive effect of the first pair of major genes × the second pair of major genes × the third pair of major genes, both of which were -1.44, and are negative effects. The additive and additive × additive epistasis interaction values were equal to the additive and the second pair of major gene additions × the third pair of major gene additive epistatic interactions, both of which were -6.02. Additive and the first pair of major gene additive × the third pair of main gene additive epistatic interaction effect value is 0.18, the multi-gene additive effect value is 0.15, showing a lower positive genetic effect; H-1(4MG-AI) was best-fitting genetic model for the spikelet number traits, which showed that their inheritance was controlled by incorporating four major genes additive-epistasis genetic model. The heritability of the main gene was 81.50%. The additive effect values of the main genes in the first to fourth pairs were 0.22, 0.18, -0.20, and 0.24, respectively, the additive and epistatic interactions of the first pair of major genes × the first pair of major genes were -0.170, the additive effect value of the additive and the first pair of major genes × the third pair of major genes was 0.240. the additive effect value of the additive and the first pair of major genes × the fourth pair of major genes was -0.200, additive and the second pair of major genes × the third pair of major genes × additive effect value and additive and the second pair of major gene additive × fourth pair of major gene additive epistatic interaction value absolute value, the effect in contrast, the former value was 0.030, and the latter value was -0.030. The additive effect value of the additive and the third pair of major genes × the fourth pair of major genes was 0.060. 【Conclusion】The panicle traits of wheat are mainly polygenic genetic effects, which are in line with quantitative genetic characteristics and are susceptible to environmental influences. The number of spikelet grains has the genetic characteristics of the main gene. The main gene has high heritability and is affected by the environment. The number of spikelets can be used as a direct indicator to effectively improve the early selection of panicle traits, achieving single plant directional selection and improving breeding efficiency.

    Associated Loci Detection and Elite Allelic Variations Analysis of Main Agronomic Traits in Foxtail Millet (Setaria italica L.) Based on SSR Markers
    JianFeng LI,Bo ZHANG,JianZhang QUAN,YongFang WANG,XiaoMei ZHANG,Yuan ZHAO,XiLei YUAN,XiaoPing JIA,ZhiPing DONG
    Scientia Agricultura Sinica. 2019, 52(24):  4453-4469.  doi:10.3864/j.issn.0578-1752.2019.24.002
    Abstract ( 241 )   HTML ( 28 )   PDF (3107KB) ( 260 )   Save
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    【Objective】Through the investigation of 10 major traits in foxtail millet at Ledong, Hainan province, Luoyang, Henan province, Jilin and Gongzhuling, Jilin province, totally four different geographical environments, association analysis between SSR markers and the ten traits was performed to obtain loci expressed in single environment or multiple environments, excavate elite allelic variations, explore the probable mechanism forming ecological adaptation and provide foundation for launching molecular-assistant selection breeding in foxtail millet.【Method】Based on the survey of ten traits (plant height, panicle length, number of leaves, panicle diameter, heading stage, spikelet number, grain number per branch, spike weight, grain weight per panicle and 1000-grain weight) from 102 foxtail millet varieties at Jilin and Gongzhuling, Jilin province, Luoyang, Henan province and Ledong, Hainan province for two consecutive years, correlation analysis of ten traits at each geographical environment was first performed by SPSS 19.0 software, then the 102 foxtail millet varieties were genotyped by 70 polymorphic SSR markers, and further genetic diversity and population genetic structure of these varieties were analyzed. Finally, linkage disequilibrium analysis among markers and association analysis between molecular markers and phenotypic traits were carried out by GLM and MLM models of TASSEL 5.0 software. 【Result】There existed significant or very significant positive correlations among most of the nine agronomic traits except 1000-grain weight across four geographical environments. Only significant or very significant positive correlations were found between 1000-grain weight and grain weight per panicle, plant height, panicle length, spike weight at Jilin, Gongzhuling and Luoyang, no significant correlations were found between 1000-grain weight and other nine traits at Ledong environment. Totally 397 alleles were detected in 70 pairs of SSR primers, giving average observed allele number, effective allele number, expected heterozygosity, Shannon index of 6, 2.24, 0.4637 and 0.7738 per marker respectively. Both genetic diversity analysis and population structure analysis divided 102 foxtail millet materials into 4 groups, and the varieties from Henan province scattered in each of the four groups, showing more abundant genetic diversity. Linkage disequilibrium analysis showed that no obvious LD structures were found among 70 SSR markers. Totally 10 associated markers were detected by GLM and MLM models, combined with allele effect analysis results, it could be determined that b115, MPGC13, b227, b194 and p56 were associated with spike weight, panicle length, number of leaves and heading stage at Jilin, Gongzhuling, sigms9034 and b125 were associated with panicle length and spikelet number at Luoyang, P18 and p59 were associated with spike weight at Ledong, p6 was associated with number of leaves and spikelet number at Jilin, Gongzhuling and Luoyang respectively. The average contribution rates of single marker to phenotypic variation ranged from 7.76% to 34.05%. Three alleles, sigms9034-168, P18-166 and p56-244, could increase panicle length and spike weight, shorten heading stage significantly, which would be used to improve panicle traits and shorten growth period by marker-assisted selection breeding.【Conclusion】Five marker loci (b115, MPGC13, b227, b194 and p56) were steadily detected at Jilin and Gongzhuling, two marker loci (sigms9034, b125), two marker loci (P18, p59) were steadily detected at Luoyang and Ledong respectively for two consecutive years. One marker locus (p6) was steadily detected at Jilin, Gongzhuling and Luoyang, three geographical environments for two consecutive years. Three elite alleles (sigms9034-168bp, P18-166bp, p56-244bp) that could be used to carry out marker-assisted selection for panicle traits and growth period were obtained.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY
    Canopy Equivalent Water Thickness Estimation of Cotton Based on Hyperspectral Index
    YanChuan MA, Hao LIU, ZhiFang CHEN, Kai ZHANG, Xuan YU, JingLei WANG, JingSheng SUN
    Scientia Agricultura Sinica. 2019, 52(24):  4470-4483.  doi:10.3864/j.issn.0578-1752.2019.24.003
    Abstract ( 287 )   HTML ( 23 )   PDF (3472KB) ( 344 )   Save
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    【Objective】 The objective of the experiments is to develop a key method for fast and nondestructive monitoring canopy equivalent water thickness (CEWT) in cotton (Lumian 54) and to further improve the estimation accuracy of CEWT in cotton monitored by remote sensing technology. 【Method】 Through setting irrigation gradient treatment in different growth period, canopy spectral reflectance and canopy equivalent water thickness and other information were measured simultaneously. Firstly, we comprehensively analyzed the correlation between CEWT and various spectral parameters, including original spectral reflectance, first derivative spectral reflectance, all-band combined spectral index and existing spectral index. Then, we determined the optimal spectral indices of bud stage, flowering and bolls stage, and full growth period. Finally, we constructed a hyperspectral monitoring model of cotton CEWT by linear regression. 【Result】 The canopy equivalent water thickness and the original spectral reflectance show continuous sensitive bands in the near infrared band (NIR) of 780-1130 nm and the short wave infrared band (SWIR) of 1 450-1 830 nm and 1 950-2 450 nm, the sensitivity of the first derivative spectrum to CEWT was enhanced in NIR band than that of the original spectrum, but was weaker in SWIR band than that of the original spectrum. The correlation between the spectral index constructed by the original spectral reflectance and CEWT is stronger than that of the first derivative spectrum, and the ratio spectral index (RSI) is more suitable for the monitoring of CEWT than the normalized difference spectral index (NDSI). During the whole growth period, the inversion accuracy of CEWT by (R1135-5R1494)/R2003 was the best (R 2=0.7878, RRMSE=0.1803). In the bud stage, RSIb(1130,1996) has the best estimation effect on CEWT (R 2=0.7258, RRMSE=0.1444). RSIa (904,1952) was the optimal spectral index (R 2=0.7853, RRMSE=0.2454) for estimating CEWT at the flowering and bolls stage.【Conclusion】The new hyperspectral indexes proposed in this study in different growth stages can be used for quantitative monitoring of canopy equivalent water thickness in cotton. The results of this study can provide reference for the application of hyperspectral technology in monitoring water content of cotton canopy, and provide technical basis for precision irrigation of cotton.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY
    Effects of Soaking Seeds with Lanthanum Nitrate on Seed Germination and Seedling Growth of Quinoa Under Salt Stress
    ChunHua PANG,Yuan ZHANG,YaNi LI
    Scientia Agricultura Sinica. 2019, 52(24):  4484-4492.  doi:10.3864/j.issn.0578-1752.2019.24.004
    Abstract ( 255 )   HTML ( 13 )   PDF (567KB) ( 224 )   Save
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    【Objective】 With the formation of soil salinization, not only causes the resource-wasting, but also restricts the agricultural production. Quinoa has salt-tolerant properties, It can alleviate salt stress. China is the country with the most rare earth content. There is a study that lanthanum may alleviate the effects of salt stress on plants. In this study, quinoa was treated with salt stress, which seed had been soaked with lanthanum nitrate before. The effects of soaking seeds with lanthanum nitrate on seed germination and seedling growth of quinoa under salt stress were examined to find a way to improve salt resistance of the species. 【Method】 In this study, quinoa was used as the research material and greenhouse potted planting method was adopted in order to study the effects of different lanthanum nitrate leaching species (25, 50, 100 mg·L -1) on seed germination and seedling growth under different salt stresses (100, 200, 300 mmol·L -1 sodium chloride solution). 【Result】(1) When lanthanum nitrate was 50 mg·L -1, the effect of quinoa seeds were the optimal, the germination percentage, germination potential, and germination index of quinoa seeds were the highest, and there were significant differences compared with other concentrations. (2) At the same socking concentration, plant height and root length of seedlings decreased with the increase of salt concentrations within 300 mmol·L -1 NaCl, while peroxidase (POD), superoxide dismutase (SOD), malondialdehyde (MDA), soluble sugar, proline and other physiological and biochemical indexes increased with the increase of salt concentrations. (3) At the same salt concentration, plant height, root length and other growth indicators of quinoa seedlings showed the tendency of first increasing and then decreasing with the increase of soaking concentrations, as well as POD, SOD, soluble sugar, soluble protein, proline and other physiological and biochemical indexes. For MDA, the trends were reversed. (4) Quinoa seedlings survived and grown in the NaCl solutions less than 300 mmol·L -1, but optimal concentration was 300 mmol·L -1. At the same time 300 mmol·L -1 salt concentration, the growth index were the best when lanthanum nitrate was 50 mg·L -1.【Conclusion】 Under salt stress, quinoa seeds socked in low concentration solution of lanthanum nitrate could promote the seed germination and the shoot growth, strengthen the antioxidant enzyme activities of seedlings, and improve the content of the osmotic adjustment material, resulting in increasing resistance to salt stress. However, seedling growth was inhabited by high concentration solution of lanthanum nitrate. This study suggested that the resistance of quinoa to salt stress was enhanced by adding adequate lanthanum nitrate.

    Real-Time Estimation of Citrus Canopy Volume Based on Laser Scanner and Irregular Triangular Prism Module Method
    Peng LI,Ming ZHANG,XiangSheng DAI,Teng WANG,YongQiang ZHENG,ShiLai YI,Qiang LÜ
    Scientia Agricultura Sinica. 2019, 52(24):  4493-4504.  doi:10.3864/j.issn.0578-1752.2019.24.005
    Abstract ( 227 )   HTML ( 17 )   PDF (2921KB) ( 208 )   Save
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    【Objective】Accurate measurement of volume and structure of fruit tree canopy can provide important reference for variable application of pesticide and fertilizer, as well as yield estimation. In order to accurately measure the canopy volume, a scanning platform based on laser sensor (LMS111-10100, SICK) was built. Aiming at the problem of irregular canopy shape, the poor accuracy of the existing real-time measurement methods of canopy volume and difficult to measure and estimate the canopy volume, a new estimation method based on irregular triangular prism modules was proposed in this work. 【Method】Five spherical landscape trees with regular canopy and ten citrus trees with irregular canopy were scanned by the laser sensor at the speeds of 0.5, 1.0 and 1.5 m·s -1, respectively. The canopy volume was measured by two methods: cuboid module method (CMM) and irregular triangular prism module method (ITPMM), and the error analysis was conducted based on manual measurement. 【Result】 The results showed that the error ranges of CMM for measuring landscape trees at the different speeds of 0.5, 1.0 and 1.5 m·s -1were 4.17%-6.59%, 4.56%-7.42% and 4.17%-9.86%, respectively, while the error ranges of the ITPMM for measuring landscape trees were 2.37%-4.63%, 3.18%-5.00% and 4.10%-5.73%, respectively. The distance range of the relative error of the two methods for measuring citrus trees was -0.28%-4.22%%, and the average difference was 1.78%. The error ranges of CMM for measuring citrus trees at the different speeds of 0.5, 1.0 and 1.5 m·s -1 were 11.63%-31.02%, 11.88%-33.23% and 13.28%-33.30%, respectively. The error ranges by ITPMM for measuring citrus trees were 3.25%-6.69%, 4.50%-8.31% and 5.66%-11.55%, respectively. The distance range of the relative error of the two methods for measuring citrus trees was 6.43%-26.20%, and the average difference was 13.04%. 【Conclusion】 The research showed that the estimation error of the ITPMM was significantly smaller than the CMM. For the same target, when the speed was 0.5 m·s -1, both of the estimation accuracy for the two methods were the highest. As the sensor speed increased, laser scanning points on the canopy decreased. So, the relative error of volume estimation increased with increase of advance speed of the laser sensor. When scanning the regular target, the accuracy difference between the two methods was small; when scanning the irregular target, the error of the CMM was larger. The processing time of a frame laser data by the CMM was 2.86 ms, and the processing time by the ITPMM was 4.73 ms, which were less than the scanning period of 20 ms of the laser sensor. The data processing time could match the acquirement of real-time collection and processing of laser data.

    PLANT PROTECTION
    Control Efficacy of Broccoli Residues on Cotton Verticillium Wilt and Its Effect on Soil Bacterial Community at Different Growth Stages
    WeiSong ZHAO,QingGang GUO,SheZeng LI,YaJiao WANG,XiuYun LU,PeiPei WANG,ZhenHe SU,XiaoYun ZHANG,Ping MA
    Scientia Agricultura Sinica. 2019, 52(24):  4505-4517.  doi:10.3864/j.issn.0578-1752.2019.24.006
    Abstract ( 261 )   HTML ( 15 )   PDF (1010KB) ( 373 )   Save
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    【Objective】The objective of this study is to research the effects of broccoli residues (BR) on cotton verticillium wilt and soil bacterial community structure at different growth stages, and to provide new ways and ideas for green ecological control of cotton verticillium wilt and reduction of chemical pesticides.【Method】In the field plot experiment, the soil planted with cotton was treated with broccoli residues and no broccoli residues (CK). The incidence dynamics of cotton verticillium wilt in different treatments were monitored at different growth stages. The number of DNA copies of Verticillium dahliae was determined by real-time quantitative PCR, and the structure of soil bacterial communities was measured by high-throughput sequencing (Illumina MiSeq). The effects of broccoli residues returning to soil on the quantity of pathogen and the community of soil bacteria were analyzed. Principal component analysis (PCA) was used to explore the characteristics and rules of structural changes of soil bacterial community at the level of phylum and genus in different growth stages.【Result】The incidence and disease index of cotton verticillium wilt showed a downward trend after the return of broccoli residues to soil, respectively. Moreover, the peak period of verticillium wilt was delayed, and 70.77% control efficacy was achieved at the peak period. The development curve of disease index and time course of disease in the whole growth period was established, and the average control efficacy was 57.21%. Compared to the blank control, the number of DNA copies of V. dahliae was decreased by 10.96%, 11.11%, 25.95% and 11.25% at the 4 stages of cotton growing and non-growing season, respectively, after the return of broccoli residues to soil. Illumina MiSeq analysis showed that broccoli residues treatment significantly increased soil bacterial diversity. The richness index Chao1 was increased significantly at all growth stages, and the ACE index was significantly increased at the pre-sowing stage, flowering and boll stage and boll-opening stage. Compared to the blank control, the relative abundance of Actinobacteria was increased significantly at different growth stages after the return of broccoli residues to soil. Meanwhile, the results showed that there were differences in the composition of dominant microorganisms at different growth stages after the return of broccoli residues to soil. For example, Firmicutes increased to the dominant microflora at the pre-sowing stage and seedling stage, and Cyanobacteria became the dominant microflora at the bud stage and flowering and boll stage. Principal component analysis showed that broccoli residues to soil changed the structure of bacterial community at seedling stage, bud stage, flowering and boll stage and boll-opening stage. Further analysis showed that the relative abundance of Streptomyces and Bacillus was significantly increased after the return of broccoli residues to soil.【Conclusion】Broccoli residues returning to soil can effectively inhibit the occurrence of cotton verticillium wilt, reduce the number of DNA copies of V. dahliae in soil, change the structure of soil bacterial community, and increase the relative abundance of beneficial microorganisms, which is an effective green measure to control cotton verticillium wilt.

    Pathogenicity and Gene Expression Pattern of the Exocrine Protein LtGH61A of Grape Canker Fungus
    JunBo PENG,XingHong LI,Wei ZHANG,Ying ZHOU,JinBao HUANG,JiYe YAN
    Scientia Agricultura Sinica. 2019, 52(24):  4518-4526.  doi:10.3864/j.issn.0578-1752.2019.24.007
    Abstract ( 290 )   HTML ( 10 )   PDF (1781KB) ( 334 )   Save
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    【Objective】Grape canker disease, caused by Botryosphaeria genus fungi, occurs in a wide range of grape-producing areas in China and seriously threatens the yield and quality of grape. The objective of this study is to analyze the function of a hypothetical exocrine protein, LtGH61A, in grape canker fungus Lasiodiplodia theobromae, and to lay a foundation for in-depth analysis of the pathogenic mechanism and disease control of grape canker fungus.【Method】The signal peptide of LtGH61A protein was predicted by SignalP 4.0. The function of LtGH61A protein was predicted by the homologous comparison and functional annotation. The exocrine characteristic of LtGH61A protein was analyzed by yeast complementary experiment. The quantitative real-time PCR (qRT-PCR) was used to analyze the expression of LtGH61A in vegetative hyphae and different infection processes. The expression of LtGH61A was inhibited through RNA interference (RNAi). The effect of LtGH61A protein on the pathogenicity of L. theobromae was analyzed by in vitro inoculation test of grape shoots. The effect of LtGH61A protein on the hyphal growth rate of L. theobromae was analyzed by comparing the colony diameter.【Result】Amino acid sequence analysis predicts that the N-terminal of the LtGH61A protein contains a signal peptide with a length of 18 amino acids. The gene function annotation suggests that LtGH61A belongs to glycoside hydrolase family 61 (GH61) and can degrade cellulose as a substrate. Yeast complementary experiments showed that the signal peptide of LtGH61A protein could guide the secretion of invertase of yeast YTK12. Compared with the vegetative hyphae, the expression of LtGH61A was increased significantly at the infectious stages, and the mRNA accumulation of LtGH61A at 48 h post inoculation was 19 times of that in the vegetative hyphae. Moreover, RNAi lines were constructed for LtGH61A and two lines RNAi-LtGH61A1 and RNAi-LtGH61A2 were confirmed by qRT-PCR. The results of in vitro inoculation test of wild-type and RNAi transformants on wounded grape shoots showed that the lesion length caused by both RNAi-LtGH61A1 and RNAi-LtGH61A2 was significantly shorter than that of wild type (WT) CSS-01s, which was about 55% of WT, indicating that LtGH61A affected the pathogenicity of L. theobromae. The colony diameter comparison showed that compared with WT, the colony diameter of RNAi-LtGH61A1 and RNAi-LtGH61A2 transformants became smaller, about 85% of WT, indicating that LtGH61A affected the hyphal growth rate of L. theobromae.【Conclusion】LtGH61A affects the pathogenicity and hyphal growth of grape canker pathogen. LtGH61A protein can be secreted outside the cell. The expression level of LtGH61A during infectious stages is significantly increased, suggesting that LtGH61A can destroy the host plant tissue by exerting its own enzyme activity function, thus promoting pathogen infection.

    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Spatiotemporal Variation of Winter Wheat Yield and Nitrogen Management in Five Provinces of North China Plain
    SiYang REN,QingSong ZHANG,TingYu LI,FuSuo ZHANG
    Scientia Agricultura Sinica. 2019, 52(24):  4527-4539.  doi:10.3864/j.issn.0578-1752.2019.24.008
    Abstract ( 355 )   HTML ( 22 )   PDF (5310KB) ( 408 )   Save
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    【Objective】By analyzing the spatial and temporal changes of winter wheat yield and nitrogen management differences in North China Plain, the evolution of winter wheat yield, efficiency and environmental impacts in the five provinces of North China Plain from 2005 to 2014 were clarified. 【Method】 Based on the farmer household survey data in 2005-2014, the time and space variation of yield, yield gap and nitrogen management differences of winter wheat in the five provinces of North China Plain was analyzed. In addition, the evaluation system of nitrogen sustainable management in North China was designed from three dimensions of food security resource efficiency and environmental protection, and the current status of nitrogen management in the five provinces of North China Plain was evaluated. 【Result】(1) The average of winter wheat yield in the five provinces of North China Plain from 2005 to 2014 was 6.5 t·hm -2, showing an increasing trend year by year, with an overall increase of 7% in ten years. The ten-year average of yield from high to low was Henan, Northern Anhui, Shandong, Hebei, Northern Jiangsu. The average yield gap of North China Plain in the past ten years was 1.4 t·hm -2, which was a downward trend. The decline in the decade was as high as 47%. The average of yield gap from high to low, it was Shandong, Hebei, Northern Jiangsu, Henan, Northern Anhui. The yield gap of Northern Anhui had the largest decline, which was the smallest; the difference of the yield gap in Shandong Province was large, showing a trend higher in the east than in the west. (2) The average nitrogen application in North China Plain was 226 kg·hm -2, which was increasing year by year except for Northern Jiangsu. The average growth rate was 3% in ten years. And the order of Northern Jiangsu>Hebei>Shandong>Northern Anhui>Henan was maintained. The nitrogen application in the same province had changed little and the inter-provincial difference was obvious. (3) The average nitrogen use efficiency (NUE) in North China Plain was 44%, from high to low was Henan, Northern Anhui, Shandong, Hebei, Northern Jiangsu. The spatial variation of NUE was large; while the NUE in areas with high nitrogen application was low. (4) The mean value of nitrogen surplus was 165 kg·hm -2. The order of Northern Jiangsu>Hebei>Shandong>Henan>Northern Anhui was maintained, which was similar to the regional distribution trend of nitrogen application. (5) Based on comprehensive evaluation of the North China Plain during 2005-2014, the number of counties that met the safety boundary of the sustainable management evaluation system for nitrogen was only 2% of the total. The nitrogen surplus and yield mean of the region were divided into four zones. The mean value of Henan was in the high yield area with low nitrogen surplus. The mean values of Shandong and Northern Anhui were in low nitrogen surplus and low yield zone. Hebei and Northern Jiangsu were in high surplus and low production zone. 【Conclusion】 During 2005-2014, the yield of winter wheat in North China Plain increased year by year, and the yield gap decreased year by year. At the same time, the input of nitrogen application increased, the nitrogen surplus was too high, and the nitrogen use efficiency was low. The nitrogen management in Henan was relatively reasonable, while nitrogen surplus in Northern Anhui and Shandong were low, and there were a large space for production improvement. High nitrogen fertilizer input in Hebei and Northern Jiangsu led to high environmental pressure of low nitrogen use efficiency, which would be the key areas for nitrogen management in North China Plain in the future.

    Quality Change of Cinnamon Soil Cultivated Land and Its Effect on Soil Productivity
    YanHua CHEN,Le WANG,ShuXiang ZHANG,Ning GUO,ChangBao MA,ChunHua LI,MingGang XU,GuoYuan ZOU
    Scientia Agricultura Sinica. 2019, 52(24):  4540-4554.  doi:10.3864/j.issn.0578-1752.2019.24.009
    Abstract ( 529 )   HTML ( 11 )   PDF (1016KB) ( 293 )   Save
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    【Objective】The quality of cultivated land is a key factor affecting soil productivity, which serves also as scientific basis for rational fertilization. Cinnamon soil is the main soil type at the production area of wheat and corn in China. This study examined the current status of cultivated land quality and the evolution characteristics of cinnamon soil during the past 31 years (1988-2018). Though considering the evolution of fertilizer application rate, their influence on productivity was studied, and the guidance for reducing fertilizer input and increasing efficiency in cinnamon soil area was proposed.【Method】Using the data of 103 long-term (31 years) location test points in China, the evolution of cinnamon soil cultivated land quality was analyzed by combining physical and chemical indexes. The factors influencing the yield were compared through the redundancy analysis (RDA). Based on these results, reasonable suggestions were put forward to reduce fertilizer input and increase efficiency in cinnamon soil area.【Result】(1) The present situation and evolution of soil physical and chemical properties in cinnamon soil area were shown in the study. Specifically, the average values of organic matter content, available phosphorus and available potassium in 2018 were 17.9 g·kg -1, 29.2 mg·kg -1-and 164 mg·kg -1, respectively, which represented an increase of 21.2%, 200.9% and 52.0% during 31years, respectively. The average values of total nitrogen and slow available potassium in 2018 were 1.1 g·kg -1 and 945 mg·kg -1, respectively, which remained relatively stable during the monitoring period. The contents of soil secondary elements and micronutrient elements and heavy metals were in an acceptable range. The pH was reduced by 0.3 unit. Topsoil thickness was 21.9 cm and bulk density was 1.33 g·cm -3, which belonged to the middle level. (2) The fertilizer application rate in cinnamon soil area was 730.2 kg·hm -2 in 2018. The proportion of N (N):P (P2O5):K (K2O) was about 2:1:1, and the proportion of chemical fertilizer to organic fertilizer was about 3.45:1. The nitrogen fertilizer application rate was 378.9 kg·hm -2, which was stable during the past 31 years. The application rate of phosphate and potassium fertilizer decreased by 24.1% and 50.8%, respectively. (3) The wheat yield showed an upward trend during 31 years, and the maximum reached 6 651 kg·hm -2 at the end of monitoring, which was 27.6% higher than the value at the initial stage. The corn yield was stable, reaching 8 851 kg·hm -2 at the end of monitoring. The contribution rate of soil fertility in wheat season and corn season was 49.0% and 59.6%, respectively. The yield was influenced by soil physical factors, including the thickness of plough layer (which could explain the wheat production for 2.7%, denoted as explanation rate), bulk density (explanation rates of wheat and corn productions for 1.2% and 1.5%, respectively) and chemical index, such as organic matter explanation rates of wheat and corn productions for 2% and 1.7%, respectively, and available phosphorus (explanation rate of corn for 3.6%). The explanation rates of potassium fertilizer were the highest for wheat and corn productions, which reached 5.6% and 6%, respectively. The explanation rates of phosphorus fertilizer for wheat yield (1.3%) and of nitrogen fertilizer for corn yield (1.3%) were also relatively high.【Conclusion】The cultivated land quality in cinnamon soil area has been improved in 31 years, but the overall fertility was low and the physical properties were in middle level. Considering the impact of land quality on productivity, different fertilization schemes needed to be formulated for wheat and corn. Both of which needed to increase the input of potassium fertilizers, and focused on ensuring the supply of phosphorus fertilizers for wheat and nitrogen fertilizers for corn. Physical indicators needed to be highly concerned. The topsoil thickness and bulk density were at a medium level, but there was no need to continue to optimize, and maintaining the status quo was more conductive to obtaining high yield.

    SOIL&FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY&ENVIRONMENT
    Technical Review of Fast Detection of Heavy Metals in Soil
    XueFei MAO,JiXin LIU,YongZhong QIAN
    Scientia Agricultura Sinica. 2019, 52(24):  4555-4566.  doi:10.3864/j.issn.0578-1752.2019.24.010
    Abstract ( 377 )   HTML ( 22 )   PDF (487KB) ( 328 )   Save
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    Recently, with the high-speed development of industry and agriculture in China, the contamination of heavy metal has become a severe environmental problem caused by immoderate mining operation, "three wastes" emissions, vehicle exhaust, and misuse of agricultural chemical inputs. So, it is very important to monitor the contamination of heavy metals in soil. However, the national and industrial standards of detecting heavy metals in soil mainly focus on the traditional analytical approaches employed in laboratory at present. So, it is still difficult to achieve the on-site and fast detection of heavy metals in soil, which gives rise to such difficulty of monitoring and preventing the source contamination effectively and timely. In view of the matrix of soil sample, solid sampling analysis should be feasible to the fast detection of heavy metals, including electrothermal vaporization (ETV), X-ray fluorescence spectrometry (XRF), laser ablation (LA), laser induced breakthrough spectrometry (LIBS), X-ray photoelectron spectroscopy (XPS), and instrumental neutron activation analysis (INAA). The solid sampling techniques do not require digestion treatment and is thereby fast and efficient. However, among them, the detection limit and stability of XRF, LA, and LIBS cannot satisfy the all demands in standards of soil quality; on the other hand, it is too difficult to reach the miniaturization and on-site testing for LA, XAS, and INAA. By comparison, ETV is a kind of solid sampling tool with excellent advantages such as high analytical sensitivity, favorable stability, and being easy to be miniaturized, using electric heating to introduce analyses via aerosol from the sample into the atomizer or exciter for measurement. ETV is able to introduce heavy metals fast and efficiently, which is versatile to atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), atomic emission spectrometry (AES), and induced coupled plasma mass spectrometry (ICP-MS). As usual, many materials such as carbon, metals, and quartz can be utilized for ETV, which are frequently processed into graphite furnace, porous carbon tube, tungsten coil, rhenium coil, quartz tube and so on. Among various ETV approaches, electromagnetic induction ETV is characterized with no cold zone, fast heating or cooling and miniaturization. Considering the complicated soil matrices, however, ETV has been always confronted with the bottleneck problem, namely matrix interference. Through integrating these advanced techniques including gas phase enrichment (GPE), dielectric barrier discharge, matrix modifier, background correction and so on, the matrix interference will be eliminated completely for the detection of heavy metals in soil when solid sampling by using ETV atomic spectrometers. Especially for GPE, it can realize both two aims at one time: eliminating matrix interference and improving analytical sensitivity. This review is about to bring some valuable suggestions for innovating the fast detection of heavy metals in soil, to play parts in the environmental monitoring and protection in the future.

    HORTICULTURE
    Genome Identification of PpGRAS Family and Expression Pattern Analysis of Responding to UV-B in Peach
    Chen LI,XueHui ZHAO,QingJie WANG,XuXu WANG,Wei XIAO,XiuDe CHEN,XiLing Fu,Ling LI,DongMei LI
    Scientia Agricultura Sinica. 2019, 52(24):  4567-4581.  doi:10.3864/j.issn.0578-1752.2019.24.011
    Abstract ( 243 )   HTML ( 19 )   PDF (7636KB) ( 361 )   Save
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    【Objective】 GRAS transcription factor family genes play a key role in the regulation of plant growth and development. The objectives of this study were to analyze the distribution, structure and evolution of GRAS in the peach genome by bioinformatics, to study the expression specificity of family members in different tissues and their responses to UV-B optical signal, and to investigate the biological function of GRAS transcription factor family genes in peach. 【Method】 The facility nectarine ‘Prunus persica var. nectarina cv. Zhongyou5 was supplemented with an appropriate dose of UV-B (Ultraviolet-B). The peach GRAS gene in the peach genome was identified by using the Plant TFDB database. Phylogenetic tree, chromosome localization, relative mass and isoelectric point and other physical and chemical properties of GRAS member were analyzed with Clustal W, MEGA6.0, ProtParam tool, MCScanX, Circos, SMART, NCBI-CDD, ExPASy, GSDS2.0, and MEME, respectively. The expression pattern of GRAS gene family in different tissues was analyzed, and the expression of some members of GRAS gene family in peach treated with UV-B was detected by real-time fluorescence quantitative PCR (qRT-PCR).【Result】48 members of GRAS transcription factor family were identified from the whole genome of the peach, and they could be divided into 9 categories by constructing a phylogenetic tree. The PpGRAS gene showed uneven distribution on 8 chromosomes of peach. The theoretical isoelectric point of the family protein was ranged from 4.36 to 7.56, and the average number of amino acids encoded was 590.52. Gene’s structure analysis showed that 40 genes contained no introns, and 8 genes contained 1 intron. Conservative elemental analysis revealed that the GRAS family contains 20 conserved elements, of which Motif 2 and Motif 4 were highly conserved in the GRAS family. Members of the same subfamily contained the same conserved elements, suggesting that members of the same subfamily might have similar functions. However, some subfamily members had different expression patterns, which might be related to sequences other than the conserved motif. The PpGRAS genes had different expression patterns in different tissues; and most of PpGRAS genes could respond to UV-B treatment, but the expression changes were different in different tissues. In leaves, PpGRAS5 was up-regulated after UV-B treatment, while up to 15 genes were down-regulated. In the fruit, PpGRAS13 was up-regulated by UV-B treatment, but 9 genes were down-regulated. In the phloem, 14 genes were up-regulated after UV-B treatment, while PpGRAS16 was most down-regulated in the phloem after treatment. 【Conclusion】A total of 48 GRAS gene family members were identified from the peach genome and distributed on 8 chromosomes; most PpGRAS genes responded to UV-B treatment, but the expression changes were different in different tissues. This study laid the foundation for further analysis of the PpGRAS family of genes in response to UV-B light signals and other potential functions.

    Factor Analysis and Comprehensive Evaluation of the Fruit Quality of ‘Yangjiaocui’ Melons
    JiaHao WANG,YaQian DUAN,LanChun NIE,LiYan SONG,WenSheng ZHAO,SiYu FANG,JiaTeng ZHAO
    Scientia Agricultura Sinica. 2019, 52(24):  4582-4591.  doi:10.3864/j.issn.0578-1752.2019.24.012
    Abstract ( 276 )   HTML ( 16 )   PDF (419KB) ( 256 )   Save
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    【Objective】The aim of this study was to identify the typical indices of fruit quality and high quality materials of ‘Yangjiaocui’ melons to provide reference and basis for melon quality evaluation and breeding. 【Method】Eighteen indices, including economic trait and flesh quality of fruits from 6 cultivars and 26 high-generation inbred lines of ‘Yangjiaocui’ melons were determined. Based on factor analysis, stepwise regression, correlation analysis and two-dimension ordination map, the typical indices of fruit quality and high quality materials were identified. 【Result】 Among the 18 indices, single fruit mass, hardness, vitamin C (VC) content, titratable acid content, sugar-acid ratio and solid acid ratio showed greater variability, and the variation coefficients were more than 20%. However, the variability of fruit transverse diameter, flesh thickness rate and pH were relatively lower and the variation coefficients were less than 10%. Three common factors were extracted from economic trait indices with 87.71% cumulative variance contribution rate and the explanatory indices were fruit longitudinal diameter, fruit transverse diameter, fruit shape index, fruit cavity longitudinal diameter, fruit cavity transverse diameter and flesh thickness rate. From quality indices, 4 common factors were extracted with 90.03% cumulative variance contribution rate and the explanatory indices were VC content, hardness, total soluble solids content, total sugar content, titratable acid content, sugar-acid ratio and solid-acid ratio. Based on the comprehensive analysis of these selected 6 economic trait indices and 7 flesh quality indices, 5 common factors were extracted with 87.35% cumulative variance contribution rate. According to the correlation among the indices and the principle of simplicity and ease of use and avoidance of overlapping information, 5 indices, including fruit longitudinal diameter, flesh thickness rate, hardness, total sugar content and titratable acid content, could be used as typical indices to evaluate the fruit quality of ‘Yangjiaocui’ melons. The comprehensive quality score of all materials were ranked depended on scores and variance contribution rate of the above 5 common factor and two-dimension ordination map. Finally, 10 materials were selected as high quality materials. 【Conclusion】 Fruit longitudinal diameter, flesh thickness rate, hardness, total sugar content and titratable acid content could be used as typical indices to evaluate fruit quality of ‘Yangjiaocui’ melons. Inbred lines 25, 24, 22, 21, 8, 1, 17, 18, 20 and 23 were high quality materials.

    FOOD SCIENCE AND ENGINEERING
    Fractionation Effect of Stable Isotopic Ratios in Tsamba Processing
    JiRong LI,TangWei ZHANG,DeJi CIREN,XiaoJun YANG,Dun CI
    Scientia Agricultura Sinica. 2019, 52(24):  4592-4602.  doi:10.3864/j.issn.0578-1752.2019.24.013
    Abstract ( 256 )   HTML ( 9 )   PDF (488KB) ( 268 )   Save
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    【Objective】 Our study mainly analyzed the difference of stable carbon, nitrogen, hydrogen, and oxygen isotopes, and revealed the characteristics and correlations of stable carbon, nitrogen, hydrogen, and oxygen isotopes in raw highland barley material, highland barley stir-frying, and milling tsamba in tsamba processing, which could provide a theoretical and technical basis for geographical origin traceability of highland barley and its products. 【Method】 We collected 11 samples of both stir-frying highland barley and milling tsamba from Xigaze (Tibet) tsamba processing workshop in 2018, and 11 samples of raw highland barley material were collected simultaneously from corresponding sites; 8 samples of both raw highland barley material and stir-frying highland barley were collected by the simulation of tsamba processing in the laboratory. Stable carbon, nitrogen, hydrogen, and oxygen isotopes were measured by element analysis-isotope ratio mass spectrometer (EA-IRMS). The one-way analysis of variance was combined with LSD or Games-Howell multiple comparison analysis to analyze the difference of stable carbon, nitrogen, hydrogen, and oxygen isotopes from perspectives of raw highland barley material, stir-frying highland barley, and tsamba. Stepwise discriminant analysis was employed to distinguish highland barley and its products from Yarlung Tsangpo River and Nianchu River. We used independent - sample T test to discover the difference of stable carbon, nitrogen, hydrogen, and oxygen isotopic between water milling tsamba and electric grinding tsamba. Paired T test was adopted to analyze the difference of stable carbon, nitrogen, hydrogen, and oxygen isotopes in raw highland barley material and stir-frying highland barley samples in the simulation experiment. And Pearson correlation analysis was used to analyze the correlation of stable carbon, nitrogen, hydrogen, and oxygen isotopes in raw highland barley material and stir-frying highland barley. 【Result】 No significant difference was found in stable carbon, nitrogen, hydrogen, and oxygen isotope ratios among raw highland barley material, stir-frying highland barley, and tsamba. The highland barley discrimination rate of stable nitrogen isotope from different watersheds was 72.7%, and the stir-frying highland barley discriminant rate of stable nitrogen and oxygen isotopes from different watersheds was 90.9%, whereas the tsamba discriminant rate was 100%. No significant difference was found in stable carbon, nitrogen, hydrogen, and oxygen isotope ratios between water milling tsamba and electric grinding tsamba. In the simulation experiment, there was no difference in stable carbon, nitrogen, hydrogen, and oxygen isotope ratios between raw highland barley material and stir-frying highland barley, while significant positive correlation was found in stable carbon and nitrogen isotope ratios between raw highland barley materials and stir-frying highland barley (P<0.05). 【Conclusion】 The fractionation effect of the stable carbon, nitrogen, and oxygen isotopes between stir-frying highland barley and tsamba was not significant. The stable isotopes in highland barley and its products were regional. In the tsamba processing, the use of either electric grinding or water milling had no effect on the stable carbon, nitrogen, hydrogen, and oxygen isotope ratios of tsamba. Simulation of tsamba processing experiment results showed that stable carbon and nitrogen isotopes in raw highland barley material could reflect the stable isotopes characteristics of those in tsamba. Therefore, stable isotope technology could be used for realizing the geographical origin traceability of tsamba.

    ANIMAL SCIENCE·VETERINARY SCIENCE·RESOURCE INSECT
    Optimization of Solid State Fermentation for Rapeseed Meal with Mixed Strains
    ZhengKe WU,GuoHua LIU,Yang LI,AiJuan ZHENG,WenHuan CHANG,ZhiMin CHEN,HuiYi CAI
    Scientia Agricultura Sinica. 2019, 52(24):  4603-4612.  doi:10.3864/j.issn.0578-1752.2019.24.014
    Abstract ( 317 )   HTML ( 24 )   PDF (520KB) ( 301 )   Save
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    【Objective】 The aim of this study was to optimize the solid state fermentation conditions for rapeseed meal with mixed strains and to improve the feeding value of rapeseed meal. It would provide a reference for the application of fermented rapeseed meal in animal husbandry in China.【Method】The rapeseed meal used in this study was conventional rapeseed meal. Three strains of Lactobacillus acidophilus, Bacillus subtilis and Saccharomyces cerevisiae were used, and the glucosinolates degradation rate (X%), total acid increase rate (Y%), polypeptide increase rate (Z%) were used as evaluation indexes. Method M was used as the comprehensive evaluation index (M=0.7*X+0.15*Y+0.15*Z). In the experiment one, the effects of different strains addition levels and the best mixed ratio of the three strains in fermented rapeseed meal were investigated through L9 (3 4) three-factors and three-levels orthogonal array design methods. Based on the result of experiment one, an L16 (4 5) four-factors and four-levels of orthogonal array design experiment was designed to explore the optimal conditions of mixed strains solid state fermentation of rapeseed meal, and the fermentation temperature, feed water ratio, time, and inoculation quantity were selected as experimental factors. 【Result】The results showed as follow: (1) L9 (3 4) orthogonal array design showed that the optimal mixed strains ratio of fermented rapeseed meal were Lactobacillus acidophilus : Bacillus subtilis : Saccharomyces cerevisiae = 1:3:2. Under these condition, the contents of glucosinolates was degraded by 23.5%, the total acid and polypeptide increase rate were 179.2% and 375.0%, respectively. (2) Based on the result of experiment one, the range analysis of experiment two showed that the optimal conditions of mixed strains solid state fermentation of rapeseed meal were as follows: fermentation temperature was 33 °C, feed water ratio was 1:1, time was 84h and inoculation quantity was 6%. The pilot test of this conditions showed that the contents of glucosinolates was degraded by 48.8%, the total acid increase rate was 499.7%, the polypeptide increase rate was 148.4%, and the total change rate M was 131.4%. The results were in line with our expectation. The lowest total change rate M was noted when the temperature was 31 °C, and the total change rate M in temperature 33 °C was higher than 35 °C and 37 °C, but the difference between groups was not significant (P > 0.05). The higher M was also noted when feed water ratio was 1:1.0 and fermentation time was 84h. No significant differences in M were observed between conditions in different levels of inoculation quantity. (3) The fermentation of rapeseed meal by mixed strains also increased the content of CP (37.05% vs. 40.90%) and decreased the concentration of crude fiber (17.47% vs. 16.72%). The amino acid composition of rapeseed meal and fermented rapeseed meal showed that fermentation increased the content of several amino acids in rapeseed meal, especially Asp, Thr, Ser, Glu, Pro, Ala, and Lys. The greatest change caused by fermentation was for glucosinolates, which decreased from 36.08 μmol·g -1 to 18.48 μmol·g -1. The fermentation of rapeseed meal increased the content of polypeptides (from 0.84% to 2.09%) and increased the content of total acid (from 1.01% to 6.05%) compared to unfermented rapeseed meal. The concentration of crude fat was similar in rapeseed meal and FRSM (4.31% and 4.39%).【Conclusion】The optimal fermentation conditions could effectively degrade the glucosinolates and increase the content of polypeptide and total acid in rapeseed meal, so the nutritional value of rapeseed meal was significantly improved.

    Simultaneous Determination of 18 β-agonists in Blood Products for Feeds by Liquid Chromatography Tandem Mass Spectrometry
    DeCheng SUO,ShuLin WEI,ZhiMing XIAO,PeiLong WANG,RuiGuo WANG,Yang LI
    Scientia Agricultura Sinica. 2019, 52(24):  4613-4623.  doi:10.3864/j.issn.0578-1752.2019.24.015
    Abstract ( 339 )   HTML ( 9 )   PDF (1375KB) ( 218 )   Save
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    【Background】 Blood product for feeds is a kind of unconventional animal-derived feed material. It is made through coagulating the blood of livestock or poultry, cooking at high temperature, pressing out juice, drying and grinding. However, due to the existence of illegal use of β- agonists, the use of blood product from blood containing β-agonists may become a potential source of harm to human health. In order to reduce the safety risk, it is necessary to study the methods of β-agonists in blood product for feeds. The detection methods of β-agonists include enzyme-linked immunosorbent assay (ELISA), high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). At present, most of the methods or standards are aimed at commercial finished feed or animal-derived food, however there is a lack of relevant research on the detection technology of β-agonists in blood product for feeds. 【Objective】 In order to study and monitor the status of β-agonists in blood product for feeds, a method of LC-MS/MS combined with solid phase extraction (SPE) was developed for the determination of 18 β-agonists in blood product for feeds.【Method】2 g (accurate to 0.01 g) blood product sample was weighed in 50 mL centrifugal tube, and then 20 mL ammonium acetate extract (pH=5.2) and 50 mL beta-glucuronidase/arylsulfatase were added accurately. The eddies were mixed evenly hydrolyzed overnight at 37 (>16 hours), then centrifuged for 5 min at 8 000 r/min, the supernatant was transferred to another centrifugal tube, and 0.5 mL 30% perchloric acid solution was added. After vortex mixing for 30 seconds and centrifugation for 5 minutes at 8 000r/min, supernatant was reserved. PCX solid phase extraction column was activated with 3 mL methanol and 3 mL water in turn. The supernatant was load and washed by 3 mL water and 3 mL methanol, then drained, eluted by 3 mL 5% ammonia methanol solution. The eluent was blown to near dry by nitrogen at 50 °C, dissolved by 1.0 mL 0.1% formic acid water + acetonitrile solution (95+5) and filtered through 0.22 μm filter membrane, then detected by Waters TQ liquid chromatography tandem mass spectrometer. The column ACQUITY UPLC BEH C18 (100 mm, 2.1 mm, 1.7 μm) was used as analysis column; acetonitrile and 0.1% formic acid solution were used as mobile phase for gradient elution. The ionization modes of mass spectrometry were electron spray ion source, positive ion detection method and multi reaction monitoring (HRM), the spray voltage was 3.5 kV, the dissolvent temperature was 480 °C, the source temperature was 150 °C, flow rate of the dissolvent gas was 600L·h -1, and flow rate of the cone gas was 5 L·h -1. The dissolvent gas, cone gas and collision gas were all high purity nitrogen gas.【Result】18 β-agonists showed a good linear relationship between 5 and 100 μg·L -1, with correlation coefficients ranging from 0.99 to 0.999. The average recovery of blood powder, plasma protein powder and globulin powder was 65.1%-110% at the levels of 5, 10 and 50 μg·kg -1, and the relative standard deviation below 15%. The coefficient of variation between batches was less than 20%. The detection limit was less than 5 ng·g -1.【Conclusion】The results of recovery, precision and actual samples showed that the method was suitable for monitoring β-agonists in blood products for feed.

    Expression Pattern of KDM1A in the Development of Yak Follicles
    XiangYue HUANG,XianRong XIONG,Jie HAN,XianYing YANG,Yan WANG,Bin WANG,Jian LI
    Scientia Agricultura Sinica. 2019, 52(24):  4624-4631.  doi:10.3864/j.issn.0578-1752.2019.24.016
    Abstract ( 217 )   HTML ( 14 )   PDF (1456KB) ( 266 )   Save
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    【Objective】 The aim of this study was to analyze the role of the lysine-specific histone demethylase 1A (KDM1A) in follicle development and oocyte maturation of yak. 【Method】 Taking yak follicles as research objects and according to the size of the follicles, they were divided into three groups: large-sized (6.0-9.0 mm), medium-sized (3.0-5.9 mm), and small-sized (1.0-2.9 mm) follicles. And the cumulus-oocyte complexes (COCs) were collected from each group and cultured in vitro. The maturation rate of oocytes was counted and analyzed. The total RNA was extracted from oocyte and granulosa cells in each group of follicles. The real time quantitative PCR (RT-qPCR) was used to detect the relative expression of KDM1A during follicular development. The cell localization and expression of KDM1A in yak follicle were detected by immunohistochemistry, and the correlation analysis was performed by in vitro maturation and RT-qPCR. 【Result】 The maturation rate of oocytes in vitro maturation was positively related to the size of follicles and showed a rising trend with progressing of follicular development. Meanwhile, the oocyte maturation rates of large-sized, medium-sized and small-sized follicle oocytes were 90.53 %, 88.10 % and 55.14 %, respectively. The result of RT-qPCR was found that KDM1A gene of yak was widely expressed during the development of follicles, and its expression level was significantly different in developmental stages of follicles. The relative expression of mRNA in the oocytes of the large and medium-sized follicle was significantly lower than small-sized follicles (P < 0.05), but the relative expression of granulosa cells in the small-sized follicle was significantly lower than large and medium-sized (P < 0.01), and there was no difference in mRNA expression levels between oocytes and granulosa cells in the large and middle-sized (P > 0.05). The results of immunohistochemistry showed that KDM1A was expressed in granulosa cells and membrane cells of follicles, and its expression trend was consistent with RT-qPCR. The expression of KDM1A was the highest in the large follicle and increased with the development of follicles. 【Conclusion】 The expression levels of KDM1A mRNA and protein in oocytes and granulosa cells at the development of yak follicles were dynamic, which indicated that KDM1A played an important role in follicular development and oocyte maturation. It might be related to meiosis of oocytes and proliferation and differentiation of granulosa cells, and these results of study would provide a basic data for further research of the mechanism of KDM1A in the meiosis of yak oocytes.

    RESEARCH NOTES
    Phenotype Character Analysis and Evaluation of Modern Rose Cultivars
    Cong GUO,Wei GUAN,XiangGuo ZENG,QingHua ZHANG,FaYun XIANG,YueJun SONG,YongChao HAN
    Scientia Agricultura Sinica. 2019, 52(24):  4632-4646.  doi:10.3864/j.issn.0578-1752.2019.24.017
    Abstract ( 477 )   HTML ( 18 )   PDF (2053KB) ( 443 )   Save
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    【Objective】The objective of this study was to analyze 11 phenotype indexes of 60 rose cultivars and to illustrate the variation rules and the genetic diversity coefficient of each index and the correlation between them. The principal component analysis was used to select an optimal evaluation and calculation method to provide reference for rational clustering of rose cultivars. 【Method】Taking 11 statistical characters of 60 modern rose cultivars in field as the research object, the variation index and Shannon-wiener genetic diversity index of each character data in rose cultivars were analyzed with SPSS19.0 and Microsoft Excel 2007, and the correlation analysis and principal component analysis of each character were carried out. Based on the composite score of principal components and each principal component score, the clustering of the rose cultivars were done.【Result】The statistical results of phenotypic traits showed that, the majority of the tested roses were erect and expanded shrubs, which accounted for 53% and 35% of the total cultivars respectively. The number of leaflets of mature leaves was 5, accounting for 68% of total cultivars. The average whole leaf length, top leaflet width, internode length and average flower diameter of 60 rose cultivars were 11.6, 3.2, 3.6 and 7.6 cm, respectively. The variation coefficient of each quantitative index ranged from 21% to 25%, which was not large. The main color of rose was pure color, accounting for 82% of the total. Among them, purple and yellow flowers were the most. The cultivars with successive flower heads accounted for 65% of the total number, and the flower shapes were mainly ball-shaped and cup-shaped, accounting for 33% and 32% of the total cultivars, respectively. The main senescence modes of rose flowers were petal abscission and flower withering, accounting for 47% and 43% of the total cultivars, respectively. The variation range of the genetic diversity coefficient of each index was between 0.62 and 3.73, among which the diversity index of 8 traits was above 1, the highest was the whole leaf length, and the lowest was the leaflet number. The genetic diversity coefficient of flower color among qualitative traits was the highest. There was an extremely significant positive correlation between whole leaf length and the top leaflet width, the internode length and the whole leaf length, the internode length and the top leaflet width. The flower head number was very significantly negatively correlated with the internode length. There was a significantly positive correlation between the senescence type and the growth habit, the number of flower heads was significantly positive correlated with the number of leaflets and the flower type, but significantly negative correlated with the flower diameter. The results of principal component analysis showed that the 11 phenotype indexes could be simplified into 4 principal component factors, and the variance contribution rate of the 4 principal components was up to 63.28%, among which the variance contribution rate of the first principal component was up to 21.1%. Each principal component factor mainly represented the index variables, such as leaf shape, flower shape, number of flower heads, number of petals and flower aging mode. Based on the composite score of principal components and each principal component score, the 60 cultivars of roses were clustered, and the distribution range of the composite score of principal components of each cultivar was from -1.878 to 1.522. The rose cultivars could be divided into 4 clusters according to the scores, and each cluster was represented by 8, 36, 15 and 1 cultivars, respectively. The classification of each cluster reflected the comprehensive performance of roses in the field. 【Conclusion】Modern rose had a rich diversity of flower color and leaf shape indexes, and some flower shape indexes were significantly related to leaf shape or growth habit. The conclusions would contribute to rose breeding and selecting. The four principal component indexes and the clustering of cultivars selected in the study provided theoretical basis for the preservation and application of the existing rose cultivars.