Soybean (Glycine max) variety Heihe 54 has played a crucial role in the Heihe soybean breeding program in China, contributing to the development of over 85 cultivars. To elucidate the genetic changes that have occurred across multiple generations of selection during soybean breeding, we conducted comprehensive genotyping analysis using the 180K Axiom SoyaSNP array on 42 varieties from the Heihe breeding program, as well as eight parental lines. Cluster analysis revealed four distinct groups, reflecting various breeding phases that incorporated diverse genetic resources as parental lines within the pedigree. A detailed examination of the graphical genotype profile across the genome identified preferred chromosome segments for specific breeding phases. These conserved blocks, which have been consistently maintained in descendant varieties during the extensive breeding period, likely harbor genes related to critical agronomic traits. This is exemplified by the consistent transmission of two segments located on chromosomes 18 and 20, which harbor the stem growth habit-related gene Dt2 and the leaflet shape-related gene Ln, respectively. The widespread cultivation of Heihe 43, a soybean cultivar developed within this pedigree, is attributed to its broad genetic base and the pyramiding of elite alleles from its parental lines. The identification of favorable chromosome segments provides valuable insight for agronomic trait-related gene mining and targeted breeding in the future.

Salinity greatly affects the production of soybeans in arid and semi-arid lands around the world. The responses of soybeans to salt stress at germination, emergence, and other seedling stages have been evaluated in multitudes of studies over the past decades. Considerable salt-tolerant accessions have been identified. The association between salt tolerance responses during early and later growth stages may not be as significant as expected. Genetic analysis has confirmed that salt tolerance is distinctly tied to specific soybean developmental stages. Our understanding of salt tolerance mechanisms in soybeans is increasing due to the identification of key salt tolerance genes. In this review, we focus on the methods of soybean salt tolerance screening, progress in forward genetics, potential mechanisms involved in salt tolerance, and the importance of translating laboratory findings into field experiments via marker-assisted pyramiding or genetic engineering approaches, and ultimately developing salt-tolerant soybean varieties that produce high and stable yields. Progress has been made in the past decades, and new technologies will help mine novel salt tolerance genes and translate the mechanism of salt tolerance into new varieties via effective routes.

Soybean is a leguminous crop that provides oil and protein. Exploring the genomic signatures of soybean evolution is crucial for breeding varieties with improved adaptability to environmental extremes. We analyzed the genome sequences of 2,214 soybeans and proposed a soybean evolutionary route, i.e., the expansion of annual wild soybean (Glycine soja Sieb. & Zucc.) from southern China and its domestication in central China, followed by the expansion and local breeding selection of its landraces (G. max (L.) Merr.). We observed that the genetic introgression in soybean landraces was mostly derived from sympatric rather than allopatric wild populations during the geographic expansion. Soybean expansion and breeding were accompanied by the positive selection of flowering time genes, including GmSPA3c. Our study sheds light on the evolutionary history of soybean and provides valuable genetic resources for its future breeding.

Vining growth (VG) and high plant height (PH) are the physiological traits of wild soybean that preclude their utilization for domesticated soybean breeding and improvement. To identify VG- and PH-related quantitative trait loci (QTLs) in different genetic resources, two populations of recombinant inbred lines (RILs) were developed by crossing a cultivated soybean, Zhonghuang39 (ZH39), with two wild soybean accessions, NY27-38 and NY36-87. Each line from the two crosses was evaluated for VG and PH. Three QTLs for VG and three for PH, detected in the ZH39 × NY27-38 population of the RILs, co-located on chromosomes 2, 17 and 19. The VG- and PH-related QTL in the ZH39 × NY36-87 population co-located on chromosome 19. A common QTL shared by the two populations was located on chromosome 19, suggesting that this major QTL was consistently selected for in different genetic backgrounds. The results suggest that different loci are involved in the domestication or adaptations of soybean of various genetic backgrounds. The molecular markers presented here would benefit the fine mapping and cloning of candidate genes underlying the VG and PH co-localized regions and thus facilitate the utilization of wild resources in breeding by avoiding undesirable traits.

Salt tolerance is an important trait that affects the growth and yield of plants growing in saline environments. The salt tolerance gene GmSALT3 was cloned from the Chinese soybean cultivar Tiefeng 8, and its variation evaluated in Chinese wild soybeans and landraces. However, the potential role of GmSALT3 in cultivation, and its genetic variation throughout the history of Chinese soybean breeding, remains unknown. Here we identified five haplotypes of GmSALT3 in 279 Chinese soybean landraces using a whole genome resequencing dataset. Additionally, we developed five PCR-based functional markers: three indels and two cleaved amplified polymorphic sequences (CAPS) markers. A total of 706 Chinese soybean cultivars (released 1956–2012), and 536 modern Chinese breeding lines, were genotyped with these markers. The Chinese landraces exhibited relatively high frequencies of the haplotypes H1, H4, and H5. H1 was the predominant haplotype in both the northern region (NR) and Huanghuai region (HHR), and H5 and H4 were the major haplotypes present within the southern region (SR). In the 706 cultivars, H1, H2, and H5 were the common haplotypes, while H3 and H4 were poorly represented. Historically, H1 gradually decreased in frequency in the NR but increased in the HHR; while the salt-sensitive haplotype, H2, increased in frequency in the NR during six decades of soybean breeding. In the 536 modern breeding lines, H2 has become the most common haplotype in the NR, while H1 has remained the highest frequency haplotype in the HHR, and H5 and H1 were highest in the SR. Frequency changes resulting in geographically favored haplotypes indicates that strong selection has occurred over six decades of soybean breeding. Our molecular markers could precisely identify salt tolerant (98.9%) and sensitive (100%) accessions and could accurately trace the salt tolerance gene in soybean pedigrees. Our study, therefore, not only identified effective molecular markers for use in soybean, but also demonstrated how these markers can distinguish GmSALT3 alleles in targeted breeding strategies for specific ecoregions.

Salinity is an important abiotic stress factor that affects growth and yield of soybean. NY36-87 is a wild soybean germplasm with high salt tolerance. In this study, two F2:3 mapping populations derived from NY36-87 and two salt-sensitive soybean cultivars, Zhonghuang39 and Peking, were used to map salt tolerance-related genes. The two populations segregated as 1 (tolerant):2 (heterozygous):1 (sensitive), indicating a Mendelian segregation model. Using simple sequence repeat (SSR) markers together with the bulked segregant analysis (BSA) mapping strategy, we mapped a salt tolerance locus on chromosome 03 in F2:3 population Zhonghuang39×NY36-87 to a 98-kb interval, in which the known gene GmSALT3 co-segregated with the salt tolerance locus. In the F2:3 population of Peking×NY36-87, the dominant salt tolerance-associated gene was detected and mapped on chromosome 18. We named this gene GmSALT18 and fine mapped it to a 241-kb region. Time course analysis and a grafting experiment confirmed that Peking accumulated more Na+ in the shoot via a root-based mechanism. These findings reveal that the tolerant wild soybean line NY36-87 contains salt tolerance-related genes GmSALT3 and GmSALT18, providing genetic material and a novel locus for breeding salt-tolerant soybean.

草甘膦(Glyphosate),是全球范围内应用最广、销售量最大的除草剂,草甘膦处理后的新叶黄化和莽草酸积累现象是草甘膦作用于植物最显著的标志性药害症状,同时存在于常规大豆和商业化抗草甘膦转基因大豆中,继而直接影响植株的光合生物量和产量.当前,已商业化的抗草甘膦转基因大豆仍以单独利用草甘膦抗性基因CP4EPSPS或草甘膦降解基因GAT为主.以我国具有自主知识产权的草甘膦抗性基因G2EPSPS和草甘膦降解基因GAT为研究对象,利用优化的农杆菌介导大豆转化技术创制共表达G2EPSPS和GAT基因转基因植株.

1963年8月26日至9月3日,中国作物学会在江苏徐州召开了全国豆类作物学术讨论会,出席会议的有47位代表,收到论文42篇,会后编印了论文集,王金陵、张子金、费家骍、王国勋等大豆知名专家出席会议。会议期间除学术交流活动,重点讨论了黄淮地区夏大豆生产。当时黄淮地区大豆面积很大,最多时有7 000多万亩,冬小麦收后主要种植夏大豆,当时玉米极少种植。生产上利用的大豆品种主要还是地方品种,土地条件较差,有盐碱斑,豆田菟丝子危害严重,豆天蛾、

大豆是世界上种植最广泛的转基因作物.然而经器官发生途径再生植株难和基因型依赖严重等限制性因素导致大豆遗传转化困难、转化效率低.抗性不定芽率和瞬时表达效率是体现再生效率和转化效率的重要指标.以中黄10号和Jack为受体,比较了超声波与表面活性剂协同处理及单因素处理对抗性不定芽形成和瞬时表达效率的影响.结果表明,超声波2 s与表面活性剂SilwetL-770.02％同时处理时,抗性不定芽得率和瞬时表达率最高(见附图).利用该方法建立了一种稳定的超声波与表面活性剂协同辅助农杆菌介导大豆子叶节遗传转化体系,转化效率为2.5％～5.7％,显著高于传统子叶节对照.超声波与表面活性剂协同处理能促进抗性不定芽的形成,提高瞬时表达效率和稳定转化效率,进而为大豆遗传转化体系的改良提供参考.

我国大豆生产起伏较大,面积最大时达1.9亿亩(1957年),三年困难时期面积下降,1962年只有1.07亿亩,改革开放以后,大豆种植面积虽有起伏,但多数年份都在800～900万公顷,2004年大豆面积950.9万公顷,应是改革开放后面积最大的一年.但近些年来由于玉米效益显著高于大豆,又由于早熟玉米杂交种的引进推广,玉米面积增加,挤压了大豆,2015年大豆面积低至610万公顷.这两年调整种植结构,大豆面积又缓慢增加.我从1971年参加"东北地区大豆生产调查",到2012年参加"促进我国大豆生产稳定发展专题会议",多次参加有关我国大豆生产的考察和研讨,见证过国家各级领导和部门对大豆生产的关心,在此仅把几次印象深刻的做个简单回顾.

Salinity is an important factor affecting crop production. Screening salt tolerant soybean germplasm is of great significance for the utilization of salinized soil in major soybean production regions. In order to select salt tolerant soybean, a screening method was developed by using six soybean accessions, including Zhonghuang 35, Zhonghuang 39, Williams 82, Tiefeng 8, Peking, and NY27-38. Seeds were grown in vermiculite and treated with 0, 100, and 150 mmol L NaCl solution. Seedling rate (SR), plant height (H), fresh weight of shoot and root (FWS and FWR), dry weight of shoot and root (DWS and DWR) were decreased significantly under 150 mmol L NaCl treatment, with significant difference among varieties. Therefore, 150 mmol L NaCl was suitable to identify salt tolerant soybean at emergence stage. The salt tolerance index (SI) based on the growth and development of seedlings and the salt tolerance coefficient (ST) were significantly correlated with the salt tolerance. The method using salt tolerance index is non-destructive and does not require planting control, which could save time and labor in salt tolerant germplasm identification. Twenty-seven soybean resources were screened, in which three were highly tolerant (grade 1) and seven tolerant (grade 2) at emergence stage. Among them, Yundou 101, Zheng 1311, Wansu 1015, and Tiefeng 8 also showed salt tolerance (grade 1) at seedling stage. In summary, an effective method for screening salt tolerant soybean at emergence stage was developed, with vermiculite as the substrate, 150 mmol L NaCl as suitable treatment solution, and salt tolerance index as the indicator. Four soybean accessions were found to be salt tolerant at both emergence and seedling stages. This screening method will be useful for identification of salt tolerant soybean germplasm.

Summary Landraces often contain genetic diversity that has been lost in modern cultivars, including alleles that confer enhanced local adaptation. To comprehensively identify loci associated with adaptive traits in soya bean landraces, for example flowering time, a population of 1938 diverse landraces and 97 accessions of the wild progenitor of cultivated soya bean, Glycine soja was genotyped using tGBS ® . Based on 99 085 high‐quality SNPs, landraces were classified into three sub‐populations which exhibit geographical genetic differentiation. Clustering was inferred from STRUCTURE, principal component analyses and neighbour‐joining tree analyses. Using phenotypic data collected at two locations separated by 10 degrees of latitude, 17 trait‐associated SNPs (TASs) for flowering time were identified, including a stable locus Chr12:5914898 and previously undetected candidate QTL/genes for flowering time in the vicinity of the previously cloned flowering genes, E1 and E2 . Using passport data associated with the collection sites of the landraces, 27 SNPs associated with adaptation to three bioclimatic variables (temperature, daylength, and precipitation) were identified. A series of candidate flowering genes were detected within linkage disequilibrium (LD) blocks surrounding 12 bioclimatic TASs. Nine of these TASs exhibit significant differences in flowering time between alleles within one or more of the three individual sub‐populations. Signals of selection during domestication and/or subsequent landrace diversification and adaptation were detected at 38 of the 44 flowering and bioclimatic TASs. Hence, this study lays the groundwork to begin breeding for novel environments predicted to arise following global climate change.

Mutagenized populations have provided important materials for introducing variation and identifying gene function in plants. In this study, an ethyl methanesulfonate (EMS)-induced soybean (Glycine max) population, consisting of 21,600 independent M-2 lines, was developed. Over 1,000 M-4(5) families, with diverse abnormal phenotypes for seed composition, seed shape, plant morphology and maturity that are stably expressed across different environments and generations were identified. Phenotypic analysis of the population led to the identification of a yellow pigmentation mutant, gyl, that displayed significantly decreased chlorophyll (Chl) content and abnormal chloroplast development. Sequence analysis showed that gyl is allelic to MinnGold, where a different single nucleotide polymorphism variation in the Mg-chelatase subunit gene (ChlI1a) results in golden yellow leaves. A cleaved amplified polymorphic sequence marker was developed and may be applied to marker-assisted selection for the golden yellow phenotype in soybean breeding. We show that the newly developed soybean EMS mutant population has potential for functional genomics research and genetic improvement in soybean.

The development of a core set of SNP molecular markers that could be widely used in soybean genetic research would greatly facilitate research into the genetic diversity of soybean. We conducted an analysis of Tokachi nagaha and 137 of its descendant soybean cultivars using 4044 SNP markers with the goal of determining the appropriate number of single-nucleotide polymorphisms (SNPs) needed to construct unambiguous molecular IDs and characterize genetic diversity based on a genetic distance matrix correlation method. When the number of SNPs was held constant, the number of accession pairs that could be distinguished increased as the polymorphism informative content (PIC) value of the SNPs increased. A core panel of 20 selected SNPs from 11 linkage groups with a mean PIC value of 0.3703 and a range of 0.3640–0.3749 was able to identify almost all of the accession pairs in our study [9445 pairs (99.92%)]. The eight accession pairs that could not be identified with this core SNP set all originated from the same province and some of them had the same parental cultivars. The molecular IDs of the 138 accessions were constructed using the core 20 SNPs. It is known that both the number of SNPs and PIC values should be considered when SNPs are selected for use in the analysis of genetic diversity. In this study, when the PIC value was 0.3460, the correlation coefficient between the genetic distance matrices associated with a panel of 200 SNPs and the total population was >0.800, indicating satisfactory correlation. Our high-accuracy, high-resolution core SNP panel for germplasm fingerprinting and our findings about assessing genetic diversity will likely markedly improve the management and utilization efficiency of soybean germplasm resources.

Soil salinity reduces soybean growth and yield. The recently identified GmSALT3 (Glycine max salt Tolerance-associated gene on chromosome 3) has the potential to improve soybean yields in salinized conditions. Here we evaluate the impact of GmSALT3 on soybean performance under saline or non-saline conditions. Three sets of near isogenic lines (NILs), with genetic similarity of 95.6-99.3% between each pair of NIL-T and NIL-S, were generated from a cross between two varieties 85-140 (salt-sensitive, S) and Tiefeng 8 (salt-tolerant, T) by using marker-assisted selection. Each NIL-T; 782-T, 820-T and 860-T, contained a common ~1000 kb fragment on chromosome 3 where GmSALT3 was located. We show that GmSALT3 does not contribute to an improvement in seedling emergence rate or early vigor under salt stress. However, when 12-day-old seedlings were exposed to NaCl stress, the NIL-T lines accumulated significantly less leaf Na+ compared with their corresponding NIL-S, while no significant difference of K+ concentration was observed between NIL-T and NIL-S; the magnitude of Na+ accumulation within each NIL-T set was influenced by the different genetic backgrounds. In addition, NIL-T lines accumulated less Cl- in the leaf and more in the root prior to any difference in Na+; in the field they accumulated less pod wall Cl- than the corresponding NIL-S lines. Under non-saline field conditions, no significant differences were observed for yield related traits within each pair of NIL-T and NIL-S lines, indicating there was no yield penalty for having the GmSALT3 gene. In contrast, under saline field conditions the NIL-T lines had significantly greater plant seed weight and 100-seed weight than the corresponding NIL-S lines, meaning GmSALT3 conferred a yield advantage to soybean plants in salinized fields. Our results indicated that GmSALT3 mediated regulation of both Na+ and Cl- accumulation in soybean, and contributes to improved soybean yield through maintaining a higher seed weight under saline stress.

The cultivated soybean（Glycine max（L.） Merr.） was distinguished from its wild progenitor Glycine soja Sieb.＆ Zucc.in growth period structure,by a shorter vegetative phase（V）,a prolonged reproductive phase（R） and hence a larger R/V ratio.However,the genetic basis of the domestication of soybean from wild materials is unclear.Here,a panel of 123 cultivated and 97 wild accessions were genotyped using a set of 24 presence/absence variants（PAVs） while at the same time the materials were phenotyped with respect to flowering and maturity times at two trial sites located at very different latitudes.The major result of this study showed that variation at PAVs is informative for assessing patterns of genetic diversity in Glycine spp.The genotyping was largely consistent with the taxonomic status,although a few accessions were intermediate between the two major clades identified.Allelic diversity was much higher in the wild germplasm than in the cultivated materials.A significant domestication signal was detected at 11 of the PAVs at 0.01 level.In particular,this study has provided information for revealing the genetic basis of photoperiodism which was a prominent feature for the domestication of soybean.A significant marker-trait association with R/V ratio was detected at 14 of the PAVs,but stripping out population structure reduced this to three.These results will provide markers information for further finding of R/V related genes that can help to understand the domestication process and introgress novel genes in wild soybean to broaden the genetic base of modern soybean cultivars.

BACKGROUND:Flowering time is a domestication trait of Glycine max and varies in soybeans, yet, a gene for flowering time variation has not been associated with soybean domestication. GIGANTEA (GI) is a major gene involved in the control of flowering time in Arabidopsis, although three GI homologs complicate this model in the soybean genome.RESULTS:In the present work, we revealed that the geographic evolution of the GIGANTEAa (GIa) haplotypes in G. max (GmGIa) and Glycine soja (GsGIa). Three GIa haplotypes (H1, H2, and H3) were found among cultivated soybeans and their wild relatives, yet an additional 44 diverse haplotypes were observed in wild soybeans. H1 had a premature stop codon in the 10(th) exon, whereas the other haplotypes encoded full-length GIa protein isoforms. In both wild-type and cultivated soybeans, H2 was present in the Southern region of China, and H3 was restricted to areas near the Northeast region of China. H1 was genetically derived from H2, and it was dominant and widely distributed among cultivated soybeans, whereas in wild populations, the ortholog of this domesticated haplotype H1 was only found in Yellow River basin with a low frequency. Moreover, this mutated GIa haplotype significantly correlated with early flowering. We further determined that the differences in gene expression of the three GmGIa haplotypes were not correlated to flowering time variations in cultivated soybeans. However, only the truncated GmGIa H1 could partially rescue gi-2 Arabidopsis from delayed flowering in transgenic plants, whereas both GmGIa H2 and H3 haplotypes could significantly repress flowering in transgenic Arabidopsis with a wild-type background.CONCLUSIONS:Thus, GmGIa haplotype diversification may have contributed to flowering time adaptation that facilitated the radiation of domesticated soybeans. In light of the evolution of the GIa gene, soybean domestication history for an early flowering phenotype is discussed.

The growth periods (GPs, from planting/emergence to reproductive stage 8 (R8) of soybean cultivars vary in different ecological regions, especially in China with a very complex soybean cropping system. In this study, a 3-yr experimental study was undertaken in three geographical locations of China from 2008 to 2010, including the Northeast (40.66–45.85°N), Huang-Huai (34.75–38.04°N) and southern (22.82–30.60°N) eco-regions with about 250 accessions in each region to clarify the classification of maturity group (MG) and identify the cultivars with stable GP to increase the knowledge about the GP distribution of soybean cultivars in China. GPs of soybean cultivars in different eco-regions were significant different with a gradual decrease from 115–125 d in the Northeast part to the 85–100 d in the southern part of China. The geographical location was the major factor for GP of cultivars from the Northeast, while the year of planting was the major factor affecting the stability of GPs in Huang-Huai summer and southern summer soybean. AMMI2 (additive main effects and multiplicative interaction)-Biplot analysis showed that the GPs of soybean cultivars from the Northeast eco-region have a comparatively satisfactory environmental stability. Moreover, soybean cultivars with moderate GP/MG and stable environment adaptability in different eco-regions were identified based on the linear regression and AMMI analysis, which was important for the accurate classification of soybean MGs in future. Taken together, our results reflected the genetic diversity, geographical distribution and environmental stability of the Chinese soybean GP trait. Soybean cultivars with stable GP for various Chinese eco-regions would be beneficial for Chinese soybean genetic improvement, varietal introduction, exchange, and soybean breeding program for wide adaptability.

The growth period traits are important traits that affect soybean yield. The insights into the genetic basis of growth period traits can provide theoretical basis for cultivated area division, rational distribution, and molecular breeding for soybean varieties. In this study, genome-wide association analysis (GWAS) was exploited to detect the quantitative trait loci (QTL) for number of days to flowering (ETF), number of days from flowering tomaturity (FTM), and number of days to maturity (ETM) using 4032 single nucleotide polymorphism (SNP) markers with 146 cultivars mainly from Northeast China. Results showed that abundant phenotypic variation was presented in the population, and variation explained by genotype, environment, and genotype by environment interaction were all significant for each trait. The whole accessions could be clearly clustered into two subpopulations based on their genetic relatedness, and accessions in the same group were almost from the same province. GWAS based on the unified mixed model identified 19 significant SNPs distributed on 11 soybean chromosomes, 12 of which can be consistently detected in both planting densities, and 5 of which were pleotropic QTL. Of 19 SNPs, 7 SNPs located in or close to the previously reported QTL or genes controlling growth period traits. The QTL identified with high resolution in this study will enrich our genomic understanding of growth period traits and could then be explored as genetic markers to be used in genomic applications in soybean breeding.