Scientia Agricultura Sinica

Comprehensive Evaluation of Agronomic Traits and Quality Traits of Foxtail Millet Landrace in Shanxi

LIU SiChen,CAO XiaoNing,WEN QiFen,WANG HaiGang,TIAN Xiang,WANG JunJie,CHEN Ling,QIN HuiBin,WANG Lun,QIAO ZhiJun

Scientia Agricultura Sinica. 2020, 53(11): 2137-2148. doi:10.3864/j.issn.0578-1752.2020.11.001

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【Objective】 The comprehensive evaluation of the agronomic traits and quality traits of Shanxi foxtail millet landrace resources were used to analyze the diversity characteristics and distribution laws of Shanxi foxtail millet. The comprehensive analysis of traits of millet germplasm resources provided scientific basis for evaluation and selection of new varieties of foxtail millet resources. 【Method】 The diversity evaluation of 15 traits in 212 Shanxi foxtail millet germplasm resources were carried out. Variation coefficients, Shannon-Weaver Information index cluster analysis, principal component analysis, correlation and regression analysis were comprehensively used to evaluate the relationship of characteristics and select important characteristics. 【Result】 The result showed that diversity indexes range of 212 Shanxi foxtail millet germplasm resources was 0.92-2.15, and all of them was greater than 1.00 except of grain color (GC); Variation coefficients ranged from 3.35%-38.66%, large variations were found in the traits of plant height (PH), panicle length (PL), stem length (SL), stem diameter (SD), panicle diameter (PD), stem node number (SNN), spike number (SN), grain number per spike (GNS), single spike weight (SSW), spike grain weight (SGW), thousand-grain weight (TGW), amylase/amylopectin ratio, and GC. The less variation was showed in starch and protein. Shanxi millet landrace were divided into 3 groups by cluster analysis, the first group was northern varieties from Datong and Shuozhou, the second group central varieties from Yangquang, Taiyuan, Jinzhong and Yuci, the third group southern varieties from Linfen and Yuncheng; the clustering was consistent with their geographical distribution. The mean value was higher in the traits of SSW, SGW, and TGW in northern varieties. The varieties were more abundant in the traits of GNS, SSW, TGW, protein, starch, and amylase/amylopectin ratio in the southern varieties. Principal component analysis showed that the variation cumulative contribution rate of the first nine principal components was accounted for 89.26%. The average F value from the comprehensive evaluation of traits of 212 Shanxi foxtail millet germplasm resources was 0.521. Huanggeda is the highest (0.709), and Niumaohuang is the lowest (0.315). The correlating analysis between the 15 traits and F value showed that the phenotypic traits (PH, PL, SL, SD, PD, SNN, SN, GNS, SSW, and SGW) were significantly correlated with the F value. The ratio of amylase/amylopectin was also significantly correlated with the F value. Nine traits, including PH, PL, SL, SN, GNS, SSW, protein, amylase/amylopectin ratio, and GC, were selected out as evaluation indexes by stepwise regression analysis. 【Conclusion】 Shanxi foxtail millet landrace resources presented large phenotypic diversity. Cluster analysis can divide Shanxi millet germplasm resources into three groups, southern varieties, central varieties, and northern varieties. The results of the division and geographical sources coincide. The amylase/amylopectin ratio can be used as an index for the evaluation of Shanxi foxtail millet germplasm resources. The variation of the southern varieties in Shanxi presented higher level of phenotypic diversity, which can be used as a resource base for the quality and characteristic breeding of the millet.

Mixed Inheritance Analysis and QTL Mapping for γ-Tocopherol Content in Soybean

LIANG HuiZhen,XU LanJie,DONG Wei,YU YongLiang,YANG HongQi,TAN ZhengWei,LI Lei,LIU XinMei

Scientia Agricultura Sinica. 2020, 53(11): 2149-2160. doi:10.3864/j.issn.0578-1752.2020.11.002

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【Objective】Inheritance and main QTL for the content of γ-tocopherol were detected by genetic analysis and QTL mapping. The results lay a genetic foundation for the selection of soybean varieties with high γ-tocopherol content in soybean. 【Method】The RILs were derived from a cross between Jindou23 of commercial cultivar as the female parent and Huibuzhi of farm variety from Shanxi Province as the male parent that construct genetic linkage map. The map consisting of 232 marker loci spanned a total of 2 047.6 cM in length with an average spacing of 8.8 cM between adjacent marker loci. The parent lines and the RILs were cultivated in summer at Yuanyang experimental farm of Henan Academy of Agricultural Sciences, and in winter at Sanya of Hainan province in 2011, 2012, 2015. Random block design was adopted in field experiment, and the entire planting experiment was replicated twice. 15.00 g fully filled and uniform soybean seeds from each RILs in six environments were sampled. The content of γ-tocopherol was quantitatively and qualitatively analysis by High Performance Liquid Chromatography (HPLC). The content of γ-tocopherol in soybean was analyzed by major gene plus polygene mixed inheritance model approach. QTL for the content of γ-tocopherol in soybean were detected by composite interval mapping model using WinQTLCart 2.5. 【Result】The results showed that the content of γ-tocopherol was controlled by two pairs of main overlapping major gene × additive polygenes using major gene plus polygene mixed inheritance analysis. According to the data of Sanya, the epistasis effect value between two major genes was 0.4010-0.5169, and the additive effect value of polygene was 0.1797-0.2146. The results of Sanya experiment showed that the heritability of major gene and polygene were 11.27%-13.05% and 82.51%-86.55%, respectively. The polygene effect was greater than that of major gene effect. The data of Yuanyang experiment showed that the epistasis effect between the two major genes was 0.9646-1.8455, and the heritability of the major genes was 39.51%-58.96%. No polygenic effect was detected. QTLs resolved by using WinQTLCart 2.5 Compound Interval Mapping (CIM) analysis. Nine QTLs for the content of γ-tocopherol were mapped on chromosomes A1(Ch.5), A2(Chr.8), C1(Chr.4), K(Chr.9), M(Chr.7) and G(Chr.18), respectively. These QTL individually explained 7.29%-29.55% of the total phenotypic variation. The QTL of qγ-G-1 flanked by Satt275 and Satt038 (0.01 cM) on chromosome 8, were detected in three environmental conditions of 2011 at Yuanyang, 2012 and 2015 at Sanya, and explained 8.97%, 8.12%, 7.91% of the phenotypic variation, respectively. The QTL of qγ-A1-1 flanked by Satt276 and Satt364 (0.01 cM) on chromosomes 5, were detected in three environmental conditions of 2011 and 2015 at Yuanyang, and explained 29.54%, 28.23% of the phenotypic variation, respectively. qγ-G-1 and qγ-A1-1 can be stably expressed in different genetic backgrounds. 【Conclusion】The content of γ-tocopherol was controlled by two pairs of overlapping major Gene × additive Polygenes genetic model (MX2-Duplicate-A). Its inheritance was influenced by gene, environment, and epistasis. The two stable inheritance main-effect QTL for the content of γ-tocopherol were co-localization with marker Satt275-Satt038 and Satt276-Satt364 intervals in soybean, respectively. The co-localization marker interval has certain reference value for molecular marker assisted soybean breeding.

Evaluation of Texture Quality of Sweetpotato Storage Roots Based on PCA-Entropy TOPSIS

LI Ling,XU Shu,CAO RuXia,CHEN LingLing,CUI Peng,LÜ ZunFu,LU GuoQuan

Scientia Agricultura Sinica. 2020, 53(11): 2161-2170. doi:10.3864/j.issn.0578-1752.2020.11.003

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【Objective】Texture quality are important indicators for the evaluation of sweetpotato root quality, which directly affects its fresh food and post-harvest processing. Texture quality evaluation is not only an important procedure of sweetpotato variety breeding and comprehensive utilization, but also to provide an important reference for sweetpotato breeding and its utilization. 【Method】Texture qualities (hardness、adhesiveness, cohesiveness, springiness, gumminess, and chewiness) of 45 sweetpotato varieties were analyzed with texture profile analysis method by using texture analyzer, and the correlation among the texture parameters was analyzed. The weight index of each parameter was determined by principal component analysis, and the texture quality of 45 sweetpotato tubers was evaluated by TOPSIS. 【Result】The results showed that textural parameters of 45 sweetpotato varieties were different from each other. The variation coefficient of chewiness and adhesiveness were 35.23% and 49.15%, respectively. Chewiness ranged from 60.30 to 284.66 N, with an average values of 149.29 N. Zheshu 13 has the maximum value of 284.66 N, while 166-7 and Longshu 14 have the minimum values of 60.30 N, 77.28 N, respectively. Adhesiveness ranged from -10.40 to -0.80 J, with an average value of -4.71 J. Longshu 31 has maximum value of -1.34 J, while Jizishu 2 and Pushu 32 have minimum values of -9.34 J, -10.40 J, respectively. The variation coefficient of cohesiveness and springiness were 14.27% and 15.75%, respectively. Cohesiveness ranged from 0.15 to 0.28, with an average value of 0.21. Shangshu 19 has maximum value of 0.28, while Hongpibaixin has minimum value of 0.15. Springiness ranged from 5.01 to 8.93 mm, with an average value of 6.59 mm. Xinong 431 has the maximum value of 8.93 mm, while 166-7 has the minimum value of 5.01 mm. The variation coefficient of hardness and gumminess were 19.47% and 23.84%, respectively. Gumminess ranged from 11.97 to 32.78 N, with an average value of 22.20 N. Pushu 32 has maximum value of 32.78 N, while 166-7 has minimum value of 11.97 N. Hardness ranged from 59.79 to 143.41 N, with an average value of 105 N. The value of Mianfen 1, Shangxuzi 1 and Sushu29 was more than 140.00 N, and 166-7 has minimum value of 59.79 N. Correlation analysis showed that hardness was significantly positively correlated with gumminess and chewiness. Gumminess had significant positively correlation with chewiness. Cohesiveness was significantly positively correlated with springiness, gumminess, and chewiness. Springiness had significant positive correlation with gumminess and chewiness. Six texture parameters were analyzed by principal component analysis method. The cumulative variance contribution rate of the three principal components was 94.674%. The weight index of hardness, adhesiveness, cohesion, elasticity, adhesiveness and mastication were 0.121, 0.161, 0.102, 0.232, 0.162 and 0.223, respectively. 【Conclusion】According to the comprehensive evaluation, starch-type sweetpotato varieties with better texture quality were Longshu 31, Shangshu 19 and Qishu 982. Fresh-type sweetpotato varieties with better texture quality were Sushu 16, Ziluolan and Xushu32.

Effects of Wide-Range Distance and Genotype on Yield and Water Use Efficiency of Winter Wheat

ZHAO Gang,FAN TingLu,LI XingMao,ZHANG JianJun,DANG Yi,LI ShangZhong,WANG Lei,WANG ShuYing,CHENG WanLi,NI ShengLi

Scientia Agricultura Sinica. 2020, 53(11): 2171-2181. doi:10.3864/j.issn.0578-1752.2020.11.004

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【Objective】This study was carried out to clarify the interaction between wide range strip sowing and wheat cultivar, so as to improve the yield and water use efficiency. 【Method】 In this study, two different genotypes were selected in the dry farming area of the Loess Plateau. Five different sowing spacing and two factor interaction were used to measure the soil moisture, dry matter accumulation, light transmittance and yield of winter wheat. After three consecutive years of data accumulation, the effects of different spacing of wide sowing and different plant type interaction on yield and water use were analyzed. 【Result】 There was no significant difference in light transmittance at flag leaf position and bottom of canopy between cultivars at filling stage. The transport capacity and contribution rate of straw and glume dry matter were higher in C6359 than that in Longjian 117, which was a tall wheat cultivar. Compared with conventional drilling sowing, the wide range sowing had high light transmittance at flag leaf position and dry matter transport when ranges spacing was 18 cm. There was no difference in water consumption during the whole growth stage between cultivars. When the width spacing was 18 cm, the water consumption decreased by 10.8 mm and water use efficiency increased by 8.91% compared with conventional drilling sowing. There was no significantly different in grain yield between wheat cultivars. The grain yield was increased by expanding the sink capacity in C6359 and by increasing the number of spikes per unit area in Longjian 117, respectively. The interaction of cultivar and width spacing had no significant effect on grain yield. The wide range strip sowing could adapted to different genotypes of winter wheat cultivars by adjust the range spacing. When the range spacing was 18 cm, the yield increases by 139.2 kg·hm ^-2 compared with conventional drilling sowing. 【Conclusion】 When the width range spacing was 18 cm, the yield and water use efficiency were increased in different genotypes of wheat winter cultivars. However, the water consumption was not significant increase. These results provided a theoretical basis for the winter wheat high-yield cultivation technology with new cultivars in loess dry plateau area

Evaluation Method of Spring Maize Waterlogging Disaster in Northeast China Based on Improved Weight Moist Index

LIU Cong,WU YongFeng,LIU PingHui,LIANG LiJiang

Scientia Agricultura Sinica. 2020, 53(11): 2182-2194. doi:10.3864/j.issn.0578-1752.2020.11.005

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【Objective】The aim of this study investigated the evaluation methods of spring maize waterlogging disasters in Northeast China, so as to provide a scientific basis for the rational production and management of spring maize in Northeast China under the background of climate change. 【Method】Based on the Weight Moist Index (WMI), the crop water demand, instead of the reference crop evapotranspiration, was used to construct an Improved Weight Moist Index (IWMI). The coupling method of waterlogging disaster events and IWMI during the growth period of spring maize in Northeast China from 1986 to 2015, the normal distribution significance test method based on K-S test, and the estimation method of t-distribution interval were used to determine the thresholds for waterlogging intensity grading of different growth stages in spring maize. The correlation and fitting relationship of soil relative humidity and IWMI, the consistency of the evaluation results on IWMI and WMI and waterlogging disaster statistics results, and the accuracy of the assessment on dynamic process of waterlogging disasters in typical years were analyzed to evaluate the IWMI precision. The spatial pattern of waterlogging at different growth stages of spring maize in Northeast China was analyzed, and then its regular characteristics were revealed. 【Result】 (1) IWMI was significantly correlated with soil relative humidity at different depths (P<0.001). Except for the rapidly developmental period of maize, in the other stages, the maximum correlation coefficient of both appeared at 20 cm depth. Through fitting the IWMI and the soil relative humidity at 20 cm depth based on a Slogistic model, it was found that the maximum coefficient of determination (R ²) appeared in the middle period (0.46), followed by the end period (0.34), the rapidly developmental period (0.31) and the initial growth period (0.21). The minimum root mean square error (RMSE) appeared in the end period (0.49), followed by the middle period (0.51), the initial growth period (0.52), and the rapidly developmental period (0.56). The values of the IWMI corresponding to soil relative humidity of 90% at 20 cm depth were 0.77 in the initial growth period, 1.12 in the rapidly developmental period, 1.21 in the middle period, and 1.25 in the end period. (2) Compared with the disaster diagnosis results in the test samples of the spring maize waterlogging disaster events randomly reserved, the complete accuracy rate and partial accuracy rate of the WMI evaluation results were 26.7% and 66.7%, respectively, while the complete accuracy rate and partial accuracy rate of the IWMI were 66.7% and 93.3%, respectively. (3)Taking the waterlogging disasters during the growth period of spring maize in 1998 in Nenjiang, Baicheng and Shenyang stations as examples, changes of the precipitation, WMI and the IWMI with the days of the year were compared, and it was found that the time of occurrence and intensity level of the waterlogging evaluated by the IWMI were more consistent with the disaster records, and IWMI could also be used to represent the dynamic change of the waterlogging intensity. (4) The frequency of waterlogging of the different intensity levels in spring maize had a great difference. The central part of Heilongjiang, southeastern Jilin, and southeastern Liaoning were high-incidence areas with moderate and above waterlogging, and the middle period was a period of high frequency of moderate and above waterlogging. 【Conclusion】Based on the IWMI, the method of determining the thresholds of waterlogging intensities at different growth stages of spring maize in Northeast China was reliable, which could be used to characterize the actual occurrence of farmland waterlogging. Compared with the WMI, IWMI not only had a higher accuracy, but also was more suitable to track and evaluate the dynamic assess of waterlogging disasters, which was of great significance to reveal the catastrophic mechanism and spatio-temporal evolution of spring maize waterlogging disasters in Northeast China under the background of climate change.

Induction of Cold Tolerance in Rice at the Breeding Stage by Gongzhulingmycin

AN JunXia,ZHAO Yu,ZHANG ZhengKun,SHI HaiPeng,JI DongMing,CAO HongYi,DU Qian,LI QiYun

Scientia Agricultura Sinica. 2020, 53(11): 2195-2206. doi:10.3864/j.issn.0578-1752.2020.11.006

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【Objective】The objective of this study is to investigate the effects of gongzhulingmycin on rice seedling growth, cold tolerance genes expression and defense enzyme activities based on chilling stress exposure, and to elucidate the change in cold tolerance induced by gongzhulingmycin at the breeding stage of rice. 【Method】Rice variety ‘Jijing88’ was used as the experimental material, the seed germination and seedling growth were investigated under different temperatures and the critical temperature of seed germination was calculated after seed priming by gongzhulingmycin. The solid fermentation product of gongzhulingmycin was powdered and added into the rice seedling substrate before sowing. Taking ‘Jijing88’ as the experimental material, the rice seedlings were subjected to cold stress treatment in simulated cold environment in late spring at the needle appearance stage of rice. Gradually warmed up and sampled continuously within 1-8 d after treatment and sampled every 7 days when plant temperature raised to 28℃. Taking ‘Jihong 6’ as the experimental material, the rice seedlings were raised in the greenhouse and sampled when the seedlings grew to one leaf at a time. The expression of 4 cold tolerance genes (OsNAC6, OsSADMC, OsETR4 and OsZFP151) under the simulated cold environment in late spring and greenhouse seedling environment was analyzed by real-time quantitative PCR (RT-qPCR). The changes of defense enzyme activities such as superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) in greenhouse seedlings before transplanting were detected. 【Result】The gongzhulingmycin could improve seed germination rate and germination index, shorten mean germination time, and its promoting effect on seedling growth was gradually obvious with the decrease of temperature. G-500x showed the best performance, which reduced the critical temperature of rice seed germination by 4.09%, and the subsequent experimental study was carried out based on this concentration. At the condition of low temperature simulation of the late spring cold, the application of gongzhulingmycin significantly increased the expression of OsNAC6, OsSADMC, OsETR4, and rapid response could be achieved to cope with low temperature stress by accelerating the response speed. The control mainly regulated the response speed and expression of OsZFP151 to cope with low temperature stress, but the expression of OsZFP151 was also increased after gongzhulingmycin application compared to the control. After the rice seedlings were subjected to low temperature stress at the needle appearance stage of rice, the expression peaks of OsNAC6, OsSADMC and OsETR4 in the seedlings treated with gongzhulingmycin appeared 1-2 d earlier than that in the control, and were increased by 38.57%, 74.66% and 130.61%, respectively, compared with the control. The maximum expression of OsZFP151 was 2 d later than that of the control, but the maximum expression was 34.91% higher than that of the control. The optimum added weight of the solid fermentation productive powder of gongzhulingmycin was 8 g·m ^-2 in rice seedling substrate in the greenhouse seedling raising. When the seedlings grew to one leaf at a time after the addition of gongzhulingmycin, the expression levels of OsNAC6, OsSADMC, OsETR4 and OsZFP151 in the leaves were higher than those in the control group. The expression of OsNAC6, OsSADMC and OsETR4 was significantly increased. When the added weight was 8 g·m ^-2, the expression level of OsNAC6 was the highest (261.20). When the added weight was 5 g·m ^-2, the expression level of OsSADMC was the highest, which was increased by 126.30% than that of the control. When the added weight was 8 g·m ^-2, the expression level of OsETR4 was the highest, which was increased by 359.81% than that of the control. Gongzhulingmycin could increase the defense enzyme activities of rice seedlings at the four-leaf stage before transplanting. The activities of SOD, POD, PPO and PAL were all increased, especially the SOD and PPO activities increased by 57.18% and 28.53%, respectively. 【Conclusion】Proper application of gongzhulingmycin before sowing can decrease the critical temperature of germination, promote the growth of seedlings, significantly improve the seedling quality, increase the expression levels of cold tolerance genes, improve the response speed to low temperature stress and raise defense enzyme activities to stimulate the cold tolerance in rice seedlings.

Complete Nucleotide Sequence Analysis and Genetic Characterization of the Sweet potato feathery mottle virus O and RC Strains Isolated from China

QIN YanHong,WANG YongJiang,WANG Shuang,QIAO Qi,TIAN YuTing,ZHANG DeSheng,ZHANG ZhenChen

Scientia Agricultura Sinica. 2020, 53(11): 2207-2218. doi:10.3864/j.issn.0578-1752.2020.11.007

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【Objective】The objective of this study is to clone the complete nucleotide sequence of Chinese isolate of Sweet potato feathery mottle virus (SPFMV) O and RC strains, elucidate the genomic structural characterization and variation of SPFMV-O-Ch1 and SPFMV-RC-Ch1, and to lay a foundation for the study of pathogenic mechanism of SPFMV. 【Method】According to the SPFMV genome sequences available in GenBank database, 2 pairs of degenerate primers and 3 pairs of specific primers were designed, the whole genome of SPFMV O and RC strains isolated from China was amplified by RT-PCR from sweet potato leaves infection with SPFMV and subsequently cloned into vector pMD19-T and sequenced. The complete genome sequences of SPFMV-O-Ch1 and SPFMV-RC-Ch1 isolates were assembled by using DNAMAN. Genetic variation analyses of complete genomic sequences, polyproteins, and individual protein sequences were performed using DNAMAN. Neighbor-joining phylogenetic tree of SPFMV-O-Ch1 and SPFMV-RC-Ch1 isolates with other isolates was constructed using MEGA7.0 software. Recombination analyses were carried out using RDP software. 【Result】The amplification and sequencing revealed that the complete nucleotide sequence of SPFMV-O-Ch1 and SPFMV-RC-Ch1 isolates was 10 992 nucleotides (nt) and 10 851 nt in length, respectively. The viral genome of SPFMV-O-Ch1 isolate contained a single open reading frame (ORF) of 10 557 nt encoding a polyprotein of 3 518 aa. SPFMV-RC-Ch1 isolate polyprotein consisted of 10 482 nt and encoded 3 493 aa. Two small ORFs, P1N-PISPO and P3N-PIPO were identified in the P1 and P3 proteins of these two isolates. Pairwise comparisons of the complete genome nucleotide sequence showed that O-Ch1 had 87.3% identity with RC-Ch1 isolate and shared 86.0%-95.8% sequence identity with other SPFMV isolates. It was most closely related to the isolate Ruk73 with 95.8% nt identity and lowest nt identity with 11-1 isolate (86.0%). RC-Ch1 and other SPFMV isolates shared 85.9%-98.7% sequence identity at the complete genome nucleotide sequence level. It had the highest nt identity with IS90 isolate (98.7%), and had lowest nt identity with Aus1-2B isolate (85.9%). Phylogenetic tree analysis based on polyprotein gene indicated that SPFMV-O-Ch1 formed a branch with the isolates of O strain containing Ordinary, 10-O and 17-O, and SPFMV-RC-Ch1 formed a branch with the isolates of RC strain containing S, IS90 and CW137. Recombination analysis showed that there were three potential significant recombination events occurred in 7 731- 9 710, 135-10 012 and 4 825-6 948 nt of O-Ch1 isolate genome, respectively. No recombination event was detected in the complete genome of RC-Ch1 isolate. 【Conclusion】The genomic organizations of SPFMV-O-Ch1 and SPFMV-RC-Ch1 isolates were same to other isolates. O-Ch1 isolate was closely related to the isolates of O strain and RC-Ch1 isolate was closely related to those isolates of RC strain. Three recombination events were detected in O-Ch1 isolate, but no recombination event was detected in RC-Ch1 isolate.

Molecular Characteristics and Function Analysis of Nuclear Receptor Gene LmE75 in Locusta migratoria

LIU XiaoJian,GUO Jun,ZHANG XueYao,MA EnBo,ZHANG JianZhen

Scientia Agricultura Sinica. 2020, 53(11): 2219-2231. doi:10.3864/j.issn.0578-1752.2020.11.008

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【Objective】Nuclear receptors (NRs) act as ligand-inducible transcription factors, which play an important role during growth and development in insects. Locusta migratoria is an important agricultural pest. The objective of this study is to analyze the molecular characteristics and biological function of the nuclear receptor gene LmE75 in L. migratoria, and to provide a new molecular target for pest control. 【Method】The cDNA sequences of three LmE75 genes were obtained based on the transcriptome database of L. migratoria. The open reading frames, predicted amino acid sequences, physicochemical properties and conserved domains of each gene were analyzed using Blast and ExPASy websites. Using MEGA 6.0 software, the neighbor-joining (NJ) method was used to construct a phylogenetic tree with the homologous sequences of E75 from other insects. Specific primers of three LmE75 isoforms were designed using Primer 3.0 software. Reverse transcription-quantitative PCR (RT-qPCR) was used to analyze the expression characteristics of three LmE75 isoforms in different tissues and developmental days from 4th to 5th instar nymphs. To further test whether LmE75 was regulated by 20-hydroxyecdysone (20E), the expression of LmE75 was detected by RT-qPCR after injected with 20E in vivo and interfered with the 20E receptor gene LmEcR by RNAi. The double-stranded RNA (dsRNA) of the common region of three LmE75 isoforms was synthesized in vitro, and then was injected into the 5th instar nymphs. The total RNA of integument was extracted after 48 h, and the first strand cDNA was synthesized as the template of RT-qPCR. The silencing efficiency of LmE75 was detected by RT-qPCR technology and the phenotype was observed. The effect on the structure of cuticle after injected with dsLmE75 was analyzed by H&E staining method. 【Result】Three cDNA sequences of LmE75 were obtained based on the transcriptome database of L. migratoria. According to structural characteristics, they were named LmE75A, LmE75B and LmE75C, respectively. The GenBank accession numbers were MN584732, MN584733 and MN584734. Each of the three LmE75 isoforms had typical nuclear receptor conserved domains, and DBD (DNA binding domain) and LBD (ligand binding domain) were highly conserved among insects. Phylogenetic tree analysis showed that E75 isoforms of different orders of insects were preferentially clustered into one group. RT-qPCR results showed that three LmE75 isoforms had different tissue and developmental expression characteristics. LmE75A was highly expressed in the integument and muscle. LmE75B was highly expressed in the integument, followed by the foregut. LmE75C was specifically expressed in the integument. The expression level of LmE75A increased first and then decreased at the 4th and 5th instar nymphs. The expression levels of LmE75B were the highest in N4D3 and N5D5, and lower before and after molting. The expression level of LmE75C increased gradually at both the 4th and 5th instar nymphs, with the highest expression before molting. Compared with the control group, the expression level of LmE75 significantly increased by 4.2 and 4.5 times after 20E induction for 3 h and 6 h, respectively. The expression level of LmE75 was significantly down-regulated by 59% after interference with LmEcR for 48 h by RNAi. After injection of dsLmE75 on the 1st day of 5th instar nymphs, L. migratoria exhibited obvious developmental delay phenotype and all L. migratoria could not molt to adults. The H&E staining of the integument found that the cuticle of dsLmE75-injected L. migratoria showed no apolysis. 【Conclusion】There are three LmE75 isoforms in L. migratoria, and they have different tissue and developmental expression characteristics. RNAi results show that LmE75 play an important role in the molting of L. migratoria.

Evolution of Fluvo-Aquic Soil Productivity Under Long-Term Fertilization and Its Influencing Factors

WANG Le,CHEN YanHua,ZHANG ShuXiang,MA ChangBao,SUN Nan,LI ChunHua

Scientia Agricultura Sinica. 2020, 53(11): 2232-2240. doi:10.3864/j.issn.0578-1752.2020.11.009

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【Objective】The fluvo-aquic soil in North China is the main producing area of wheat and corn grain crops in China. The aim of the study was to clarify the changing laws of fluvo-aquic soil productivity and to identify the main factors affecting the productivity of fluvo-aquic soil, so as to provide a theoretical basis for crop yield increase and sustainable development in fluvo-aquic soil. 【Method】This study used the long-term monitoring points of national fluvo-aquic soil as the platform, and used time trend analysis and median analysis methods to summarize the trends of productivity and soil fertility factors in different monitoring periods. 【Result】The monitoring results of fluvo-aquic soil productivity in North China under conventional fertilization in the past 31 years showed: under the conventional fertilization in fluvo-aquic soil, wheat yield increased during the whole monitoring period, and the average wheat yield was 6 443 kg·hm ^-2. The average wheat yield from 1988 to 1993 was 2 814 kg·hm ^-2, and the average wheat yield in 2014-2018 was 6 902 kg·hm ^-2; compared with the initial monitoring period (1988-1993), the wheat yield in 2014-2018 increased by 145%, with an average annual growth of 132 kg·hm ^-2. The maize yield in conventional fertilization area increased significantly with time. The average yield of corn in 1988-1993 was 2 667 kg·hm ^-2, and the average yield of corn in 2014-2018 was 8 267 kg·hm ^-2, which was earlier than the initial monitoring period (1988-1993); which increased by 210%, with an average annual growth of 180 kg·hm ^-2. Corn yield and its yield increase were significantly higher than wheat. The average contribution rate of soil fertility to wheat and maize yield was 48% and 51%, respectively. There was a significant positive correlation between the amount of fertilizer applied and crop yield increase. As the number of years of fertilization increased, the sustainability of crops increased. The results of stepwise regression and path analysis indicated soil available phosphorus was a major factor affecting overall crop yield. The order of factors with a direct effect on wheat yield was organic matter, nitrogen application rate, and potassium application rate. The direct effect of maize yield was total nitrogen, available phosphorus, nitrogen application rate, and phosphorus application rate. 【Conclusion】 During the whole monitoring period, the fluvo-aquic soil productivity was significantly improved in the later stage of monitoring. The soil productivity was mainly affected by nitrogen fertilizer, organic matter and available phosphorus. Therefore, the improvement of productivity in fluvo-aquic soil areas required the improvement of soil fertility and the scientific application of fertilizer.

Comprehensive Evaluation of Different Oxygation Treatments Based on Fruit Yield and Quality of Greenhouse Tomato

ZHU Yan,CAI HuanJie,SONG LiBing,SHANG ZiHui,CHEN Hui

Scientia Agricultura Sinica. 2020, 53(11): 2241-2252. doi:10.3864/j.issn.0578-1752.2020.11.010

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【Objective】 Oxygation is defined as the delivery of aerated water directly to the root zone by subsurface drip irrigation (SDI) and is recognized to increase yield and water use efficiency (WUE) through improving soil aeration around SDI drippers. The specific objective was to assess the effects of oxygation under different irrigation amounts and trickle-buried depths conditions on fruit yield and quality and IWUE (irrigation water use efficiency) of greenhouse tomato, and then the optimal treatment was explored through principal component analysis. 【Method】 Greenhouse-based experiments were conducted during tomato growing season (from Aug. 18, 2016 to Jan. 9, 2017) under the oxygation (O) and unaerated SDI (S, CK) conditions, which included three different irrigation levels correlated with crop-pan coefficients (k_cp) being 0.6 (W1), 0.8 (W2) and 1.0 (W3) and two different emitter depths of 15 cm (D1) and 25 cm (D2), respectively. Consequently, there was a total of 12 treatments (W1D1O, W1D1S, W2D1O, W2D1S, W3D1O, W3D1S, W1D2O, W1D2S, W2D2O, W2D2S, W3D1S and W3D2S) and replied 3 times. 【Result】 The results showed that yield per plant, fruit weight, IWUE, the content of lycopene, vitamin C, soluble sugar and sugar-acid ratio in fruit with oxygation were significantly increased by 21.2%, 23.9%, 21.0%, 28.1%, 36.0%, 22.8% and 28.0%, respectively (P<0.05), compared with the CK. In the principal component analysis, the first principal component was positively affected by lycopene, Vc, IWUE and sugar-acid ratio, and W2D1O and W2D2O were ranked the first and second, respectively. Therefore, compared with other treatments, W2D1O and W2D2O were better in both reducing irrigation water application and improving nutritional quality of tomato fruits. The second principal component was positively influenced by yield per plant and negatively affected by the content of organic acid. Meanwhile, the content of organic acid showed no significant differences among all treatments. What’s more, the yield per plant under W3D1O was the highest. Consequently, the score of the second principal component of W3D1O was the highest. The comprehensive scores of W3D1O were ranked the first among the 12 treatments. 【Conclusion】 Therefore, in this experiment, the combination of k_cp being 1.0 with emitter depths of 15 cm under oxygation conditions could best meet the requirements of reducing irrigation water application and improving fruit yield and quality. In a word, the exploration of optimal treatment provided a theoretical basis for the applying of oxygation.

Quality Evaluation of ‘Fuji’ Apples Cultivated in Different Regions of China

KUANG LiXue,NIE JiYun,LI YinPing,CHENG Yang,SHEN YouMing

Scientia Agricultura Sinica. 2020, 53(11): 2253-2263. doi:10.3864/j.issn.0578-1752.2020.11.011

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【Objective】The aim of this study was to determine the key quality indexes of ‘Fuji’ apple and to establish the comprehensive evaluation model for ‘Fuji’ apple quality. 【Method】 One hundred and seventy six ‘Fuji’ apple samples were collected from orchards of 8 main ‘Fuji’ apple producing areas, including Hebei, Henan, Liaoning, Shandong, Shanxi, Shaanxi, Ningxia and Xinjiang. Fifteen indexes were tested for each sample, including single fruit weight, fruit firmness with skin, fruit firmness without skin, total soluble solid, soluble sugar, titratable acidity, vitamin C, sorbitol, glucose, fructose, sucrose, sweetness value, the ratio of total soluble solid to titratable acidity (RTT), the ratio of soluble sugar to titratable acidity (RST), and the ratio of sweetness value to titratable acidity. The key quality indexes of ‘Fuji’ apple were identified by principal component analysis (PCA) and cluster analysis (CA). The index weight of each quality was estimated by analytic hierarchy process. And the comprehensive evaluation model was established by grey interconnect degree analysis (GIDA). 【Result】 There was a quality difference between ‘Fuji’ apples from different areas. The quality of ‘Fiji’ apple from Xinjiang was superior to those from other areas in indexes of fruit firmness, vitamin C, total soluble solid, soluble sugar, sorbitol, fructose, sucrose, and sweetness value. The variable coefficients of ‘Fuji’ apple quality indexes of vitamin C, sorbitol, sucrose, and sweetness value were all over 30%, and that of quality index of soluble sugar was the smallest one with 9.8%. There was significant correlation coefficient (R) between some ‘Fuji’ apple quality indexes, such as the correlation coefficient between titratable acidity and RTT (-0.844) or RST (-0.854), the correlation coefficient between fructose and sweetness value (0.963), and the correlation coefficient between RTT and RST (0.941). Five quality indexes of ‘Fuji’ apple were screened to be key indexes by PCA and CA, including fruit weight (X₁), fruit firmness without skin (X₂), titratable acidity (X₃), RTT (X₄) and fructose (X₅). The comprehensive evaluation model for ‘Fuji’ apple quality was established by GIDA, which was Y=0.2601X₁+0.1378X₂+0.0819X₃+0.2601X₄+0.2601X₅. 【Conclusion】 Fruit weight, fruit firmness without skin, titratable acidity, RTT and fructose were the key quality indexes of ‘Fuji’ apple, and the established comprehensive evaluation model was useful and valuable for the quality evaluation of ‘Fuji’ apple produced in main producing area in China.

Effects of 4 Dwarfing Rootstocks on Growth, Yield and Fruit Quality of ‘Fuji’ Sapling in Apple Replant Orchard

LI MinJi,ZHANG Qiang,LI XingLiang,ZHOU BeiBei,YANG YuZhang,ZHANG JunKe,ZHOU Jia,WEI QinPing

Scientia Agricultura Sinica. 2020, 53(11): 2264-2271. doi:10.3864/j.issn.0578-1752.2020.11.012

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【Objective】 The effects of four dwarfing rootstocks (G935, G41, G11 and M9-T337) on the growth, early fruiting and yield quality of Fuji apple saplings under the replanting conditions were investigated for four years. The dwarfing rootstocks suitable for continuous cropping in Beijing were evaluated and selected, so as to provide a technical support for the renewal of the cultivation mode of old and inefficient apple orchards in China. 【Method】In the spring of 2016, 6-year-old apple trees (Fuji/SH6/ Malus prunifolia) were planed out and no soil improvement was carried out. 4 dwarfing rootstocks (G935, G11, G41 and M9-T337) Fuji apple seedlings (2-year-old roots and 1-year-dry) were directly planted in the original row, with a row spacing of 1 m×3.8 m. After planting, 4 dwarfing plants were investigated differences of tree growth, early fruiting, yield and quality of Fuji apple on rootstock for 4 consecutive years. 【Result】 The height of Fuji trees on G935 and G41 rootstock was higher than that of G11 and M9-T337; the number of main branches from high to low was: G935>G41>G11>M9-T337; the phenomenon of big feet of G41 and M9-T337 was higher than that of G935 and G11; the difference of height, diameter and number of main branches between G935 and G41 was significantly lower than that of G11 and M9-T337, with the neat garden phase. In the fourth year of continuous cropping, the chlorophyll content and net photosynthetic rate of leaves of G935 and G41 rootstocks were significantly higher than G11 and M9-T337, the fresh weight of leaves of G935 and G41 was significantly higher than G11 and M9-T337, and the dry weight of leaves of G935 and G41 was significantly higher than M9-T337. Within 4 years of continuous cropping, Fuji, the dwarfing rootstock of G935 and G41, grew normally, and the branch composition was in line with the change rule of dwarf rootstock fruit trees. From the second year, the proportion of long branches of G11 and M9-T337 trees was lower than 30%; from the third and fourth year, the proportion of short branches of G11 and M9-T337 trees was higher than 80%, the proportion of long branches was lower than 10%, and the tree vigor was obviously weakened. In the third year of continuous cropping, the flowering rate of G11 young trees was the highest, followed by G935 and G41, and M9-T337 had no flowering. In the fourth year of continuous cropping, the average yield per plant of Fuji on G935 and G41 rootstocks was significantly higher than that of M9-T337 and the average fruit weight and fruit shape index of G935 were significantly higher than those of other rootstocks. There were no significant differences in the soluble solid content, titratable acid content and solid acid ratio of the fruit of each rootstock. 【Conclusion】 Under the condition of replantation, the growth of young trees with G935 and G41 as rootstocks was significantly better than that of G11 and M9-T337. The branch composition was reasonable, the tree potential was moderate but not weak, the difference between single plants was small, and the garden was neat, which was suitable for continuous cropping in Beijing.

Correlation Analysis Between Amino Acids and Fruity Esters During Spine Grape Fermentation

ZHU ZiJian,CHEN SiYu,SU Jun,TAO YongSheng

Scientia Agricultura Sinica. 2020, 53(11): 2272-2284. doi:10.3864/j.issn.0578-1752.2020.11.013

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【Objective】The aim of this study was to reveal the correlation between amino acid composition and fruity ester production during fermentation of spine grapes, so as to provide the theoretical guidance for aroma enhancement fermentation of spine grape wine. 【Method】A spine grape variety, Xiangzhenzhu, was used to conduct alcoholic fermentation with Saccharomyces cerevisiae, and Cabernet Sauvignon grape was served as control. During fermentation, sampling was carried out every 24 h to analyze the concentrations of amino acids and esters by using HPLC and GC-MS, respectively. Furthermore, the mathematical relationship between these two parameters was analyzed by Pearson correlation analysis. 【Result】Total content of amino acids (except proline) in spine grape was 3 folds higher than that in Cabernet Sauvignon grape, with 2.4, 2.2, 4.2, 7.7 and 3 folds for aspartic acid, valine, glutamic acid, γ-aminobutyric acid and arginine, respectively. However, the content of alanine, phenylalanine and isoleucine in spine grape only accounted for 10%, 35% and 20%, respectively. Compared with Cabernet Sauvignon, fermentation with spine grape only produced 55%, 11% and 69% in the concentrations of acetates, short-chain fatty acid ethyl esters, and medium-chain fatty acid ethyl esters, respectively. Pearson correlation analysis further showed that the correlation coefficient between alanine, phenylalanine, isoleucine and acetate, fatty acid ethyl ester was 0.552-0.837 during fermentation with spine grape, which was significantly lower than that of Cabernet Sauvignon. This might be related to low content of fruity esters in spine grape wine. 【Conclusion】Low content of alanine, phenylalanine and isoleucine could negatively affect ester productions during alcoholic fermentation.

RNA-Binding Motif Protein 3(RBM3) Expression is Regulated by Insulin-Like Growth Factor (IGF-1) for Protecting Yak (Bos grunniens) Cumulus Cells from Apoptosis During Hypothermia Stress

PAN YangYang,WANG Meng,RUI Xian,WANG LiBin,HE HongHong,WANG JingLei,MA Rui,XU GengQuan,CUI Yan,FAN JiangFeng,YU SiJiu

Scientia Agricultura Sinica. 2020, 53(11): 2285-2296. doi:10.3864/j.issn.0578-1752.2020.11.014

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【Objective】 The aim of this study was to verify the relationship between insulin-like growth factor 1 (insulin-like growth factor, IGF-1) and RNA binding motif protein 3 (RBM3) during hypothermia stress and cell freezing in animals, and to investigate the mechanism of IGF-1 involved in inhibiting hypothermia injury of mammalian cells. 【Method】 Yak (Bos grunniens) cumulus cells were cultured in vitro, the effects of different concentrations (0, 50, 100 and 200 ng·mL ^-1) IGF-1 and hypothermia stress (25℃ and 30℃) on RBM3 expression in yak cumulus cells were detected by the methods of real-time fluorescence quantitative PCR (qRT-PCR), Western blot (WB) and immunofluorescence. The expression of RBM3 was compared when the cumulus cells treated with 100 ng·mL ^-1 and 0 IGF-1 for 30 h and then stressed at low temperature (25℃ and 30℃) for 8 h. The difference of apoptosis level of cumulus cells was evaluated from the groups that treated with 0 ng·mL ^-1 IGF-1, 100 ng·mL ^-1IGF-1, 100 ng·mL ^-1 IGF-1+RBM3 inhibitor for 30 h and then stressed at 25℃ for 8 h. The expression of apoptosis-related genes (Bax and Bcl-2) in cumulus cells from three groups was also detected at mRNA and protein levels. 【Result】 (1) The expression level of RBM3 in cumulus cells treated with IGF-1 was significantly higher than that in control group (0 ng·mL ^-1), which was the highest in cumulus cells from 100 ng·mL ^-1 IGF-1 group. The RBM3 protein could be detected in nucleus and cytoplasm of cumulus cells, which only expressed in cytoplasm under 0 and 50 ng·mL ^-1 treatment groups. (2) The levels of RBM3 could be increased by hypothermia stress, and which also could be enhanced when 100 ng·mL ^-1 IGF-1 was added before cold stress. The RBM3 protein could be detected in nucleus and cytoplasm of cumulus cells after hypothermia stress and treated with IGF-1. (3) After stress at 25℃ for 8 h, the apoptosis rate of cumulus cells treated with 100 ng·mL ^-1 IGF-1 was (15.94 ±2.03)%, which was significantly lower than those of cumulus cells without IGF-1 treatment (25.86 ±1.09)% or with 100 ng·mL ^-1 IGF-1+RBM3 inhibitor (20.14±2.65)%. The expression level of Bcl-2 was significantly higher than those in the control and IGF-1+RBM3 inhibitor groups (P<0.05), while the expression level of Bax was significantly lower than control and IGF-1+RBM3 inhibitor groups (P<0.05). 【Conclusion】RBM3 was involved in the regulation of hypothermia stress in yak cumulus cells, and IGF-1 could regulate its expression level in hypothermia stress, which helped to reducing the apoptosis of cumulus cells induced by low temperature. The results in this study provided the key information for revealing the molecular mechanism of IGF-1 and RBM3 involved in the protection of animal bodies or cells from hypothermia damage, and provided theoretical basis for the improvement of somatic and germ cell freezing techniques.

Using Random Regression Models to Estimate Genetic Parameters on Body Weights in Layers

GUO Jun,QU Liang,DOU TaoCun,WANG XingGuo,SHEN ManMan,HU YuPing,WANG KeHua

Scientia Agricultura Sinica. 2020, 53(11): 2297-2304. doi:10.3864/j.issn.0578-1752.2020.11.015

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【Objective】 This study was to assess the effect of the orders of Legendre polynominals on the size of the maximum likelihood and the error, to optimize the random regression model, to evaluate the genetic potential and selection knot of layer resource population and to provide parameters for optimal layer breeding scheme for resource population. 【Method】The data set consisted of 26 532 items collected from the layer resource population, which set up by White Leghorn reciprocal crossing with the blue eggshell chickens. The pedigree consisted of 5 871 individuals, including 4 147 chickens with 5 records, 802 chickens with 4 records and 128 chickens without records. The standard of data cleaning included: i. removing outlier; ii. eliminating repeated individuals; iii. getting rid of unknown sexed individuals; iv. individuals with less than 4 records were also excluded. After data cleaning procedures, 25 483 records on body weight could be used in the next step, 2 223 of which collected from blue shelled chickens, 696 of which collected from White Leghorn, 6 002 of which collected from F₁ generation and 16 562 of which collected from F₂ generation. The influence of the nongenetic factors on body weights was analyzed by GLM in SPSS. The fixed effects of animal model included batch and sex factors. Using the random regression model, variance components, genetic parameters and eigenvectors were obtained. The model included general fixed effect and fixed regression, random regression. In this study, batch-sex was the fixed effects, and a fixed regression was fitted for week age body weight effects; the direct additive genetic, permanent environment were the random effects. Comparing with AIC and BIC values, the best model should embed 2nd Legendre polynomials into fixed effects, 5th Legendre polynomials into additive genetic effects and permanent environmental effects. Heterogeneous residual variance was grouped into 5 levels. Each observation was set an initial estimate. The residual variance between the neighboring observations was treated as a linear regression. 【Result】 For the body weights on resource population, heritability was ranged from 0.46 to 0.63, repeatability varied from 0.88 to 0.92, the genetic correlation was ranged from 0.32 to 0.99, and permanent environmental correlation was varied from 0.34 to 0.99. The genetic correlations among the weeks reduced with the intervals increased, high correlations occurred between the neighboring weeks. The genetic variance, permanent environmental variance and residual variance increased with ages. The first three eigenvalues of additive genetic effects was 1 976.91, 161.95, and 42.22, respectively, and these eigenvalues could explain 99% of total variations. 【Conclusion】The genetic parameters on the early body weights in laying chickens were estimated with a random regression model. The individual growth curve could be altered by selection on the coefficients associated with the second eigenfunction. The right time seemed to select on 3 to 6 week. Estimates of heritability in the resource population were larger than the results in the literatures.

Diversity of Endophytic Fungi in Transgenic Rice Seeds from Different Planting Sites Based on PTN System

ZHAO Yan,WANG TianQi,ZHU JunLi

Scientia Agricultura Sinica. 2020, 53(11): 2305-2320. doi:10.3864/j.issn.0578-1752.2020.11.016

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【Objective】To provide scientific bases for study of the unintended variation in seed endophytic fungi community structure of genetically modified (GM) rice and explore the causing factors of variation, comparative analysis of the richness and biodiversity of seed endophytic fungi were conducted, using GM rice relative near-isogenic lines of different varieties in different cultivation sites as materials. 【Method】 Collect transgenic rice line which harboring the glyphosate resistant 2mG2-epsps gene (T) and its corresponding parent variety (P) and non-transgenic tissue culture regeneration control line (NR) to make parent control-transgenic plant line-non-transgenic control (PTN) near-isogenic line. The parent japonica rice Nipponbare (P1) and its corresponding transgenic line T23 and the NR control line NR18 formed the P1 near-isogenic line (P1L), the P2 near-isogenic line (P2L) composed of parent japonica rice PJ574 (P2) and its corresponding transgenic line T23 and the NR control line NR18. All rice samples were planted in two plantations including Hainan province (H) and Fuyang city of Zhejiang province (F) and the resulting seeds were harvested. The rice endophytic fungi were isolated by tissue separation method, strains were classified and identified with morphology and molecular biology methods. The isolation rate (IR), isolation frequency (IF), richness Margalef index (D), diversity Shannon-Wiener index (H') and Evenness index (E) were used to reflect the structure and distribution of rice seed endophytic fungi, and Sorenson similarity coefficient (Cs) and Fisher’s exact test were employed to describe the composition difference of endophytic fungi between rice samples. 【Result】A total of 121 endophytic fungi strains were isolated from rice seed samples of P1L and P2L near-isogenic lines that harvested in Hainan (H) and Zhejiang (F) plantations, they were identified as 15 genera, of which Curvularia, Dendryphiella, Epicoccum, Fusarium were confirmed as the dominant flora, with Fusarium as the common dominant genus of both H and F plantations. The total RF (4.61%) of endophytic fungi from Zhejiang-grown rice seeds is 5.05 times than that of Hainan-grown rice samples (0.83%). The richness Margalef index (D=2.29), Shannon-Wiener diversity index (H'=1.63) and Evenness index (E=0.66) of endophytic fungi flora from rice seeds in F plantation were higher than that (D=1.67, H'=0.63, E=0.29) of samples in H plantation. The seed endophytic fungi communities of P1L and P2L in H plantation had a similarity coefficient of 0.615, and that was 0.737 in F plantation, showing moderate similarity, and the Fisher’s exact test analysis suggested that there were no significant difference (P>0.05) between them. The GM lines except HT16 showed moderate similarity to their corresponding parent controls referring seed endophytic fungi communities, with similarity coefficient ranged between 0.500 and 0.667. But compared with their corresponding parents, the GM rice lines showed notably unintended variations in IF and genus numbers of endophytic fungi, the variation direction and amplitude of IF varied between different plantations. Also, the GM line FT16 increased 2 additional fungi genera Phaeosphaeria and Nigrospora, HT23 and FT23 respectively added 1 genus Letendraea helminthicola and 2 genera including Curvularia and Cladosporium. These genera increasing variations of endophytic fungi in GM rice seeds were derived from transgenic insertion mutation, whose safety needs to be focused on. While the genera decreasing variations of endophytic fungi in GM rice seeds were derived from somaclonal variation of tissue culture, which were safer. The variation amplitude order of total IF of rice endophytic fungi were as follows. Difference between H and F plantations referring to P1 and P2 (30.58%)>Difference between P1 and P2 varieties (27.28%)>Variation of NR lines (23.14%)>Variation of GM lines (22.32%). The genus number variations of rice endophytic fungi ranked as follows. Difference between H and F plantations referring to P1 and P2 (9)>Difference between P1 and P2 varieties (8) = Variation of NR lines (8) = Variation of GM lines (8). 【Conclusion】Rice seeds have abundant and diverse endophytic fungi, with majority of the culturable stains belong to Ascomycetes. Composition of rice seed endophytic fungi community shows geographical differences, and Fusarium is very common dominant genus in rice seeds grown both in Hainan and Zhejiang. The structure of endophytic fungi flora in rice seeds are affected by transgenic manipulation as well as tissue culture technology, while their unintended variation effects are less than that of rice growing locations and variety differences. The genera increasing variations of endophytic fungi in GM rice seeds are derived from transgenic insertion mutation, and the safety needs to be assessed.

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