Commercialization of bio-breeding soybean is regarded as an important strategy to increase domestic soybean production and guarantee national food security. Based on the information obtained from survey in parts of pilot areas, we analyzed the necessity of commercialization of bio-breeding soybean in China, and put forward the existing problems, which including the insufficient of cost-benefit advantage, and the adaptability of varieties needs to be enhanced. We suggest that government strengthen the publicity of bio-breeding technology, promote breeding of high-yield and high-oil soybean varieties, and improve the support policy for bio-breeding soybean industry, in order to accelerate the commercialization of bio-breeding soybean on the basis of guaranteeing a stable supply of conventional soybeans.
Asian soybean rust, caused by the pathogen Phakopsora pachyrhizi, represents a significant threat to global soybean production. Consequently, there is an urgent imperative to develop rust-resistant soybean cultivars to enhance control strategies, particularly in light of the increased production costs and environmental pollution associated with the reliance on chemical spraying as the primary control method. To date, eight rust resistance loci (Rpp1, Rpp2, Rpp3, Rpp4, Rpp5, Rpp6, Rpp7, and Rpp6907) have been identified. Ongoing research is focused on the cloning and elucidation of the molecular mechanisms underlying these resistance genes in soybean. In this paper, we provide a comprehensive review of recent advancements in identification and characterization of soybean rust resistance genes. We summarize current research on localization and functional analysis of these genes, examine their primary functions, and underlying molecular mechanisms. Additionally, we discuss potential applications of these findings in the context of breeding for rust resistance, aiming to offer valuable insights for future research and cultivar development in this field.
As one of the most important oil, food and feed crop worldwide, soybean is the main source of vegetable oils and proteins for human beings. Soybean viral diseases are widely distributed in soybean-producing areas all over the world, which seriously affect yield and quality of soybean. At present, there is no effective chemical agent for controlling them. Viral infectious clone is a powerful tool for reverse genetic research on viral gene function and mechanisms of interaction between virus and plant, and it can be modified to virus-mediated overexpression (VOX) vector or virus-induced gene silencing (VIGS) vector for rapid analysis of plant gene function. In this paper, we summarized research progresses of construction of viral infectious clone and its application in VOX and VIGS for 6 soybean viruses including Soybean mosaic virus (SMV), Bean pod mottle virus (BPMV), Apple latent spherical virus (ALSV), Tobacco rattle virus (TRV), Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV) and Cowpea severe mosaic virus (CPSMV), in order to provide reference for research.
Soybean is a cornerstone crop for China's grain and oil security strategy. The northern high-latitude cold regions of Northeast China as a vital production area, accounting for one-third of the nation's total output. However, the short frost-free period and low-temperature environment severely constrain yield improvement. This study systematically reviews the genetic basis and breeding practices of soybean variety improvement in this region, with a focus on the molecular mechanisms underlying growth period regulation. The soybean varieties in this region belong to the early-maturity to super-early-maturity groups of northern spring soybeans, with maturity group ranges of MG0000-MG0. From 2004 to 2024, a total of 609 soybean varieties were approved in this region, including 15 high-yield varieties such as Heihe 43 and Henong 95, each achieving annual planting areas exceeding approximately 33 333.3 hectares, whose development and industrial application have significantly boosted the region's soybean production capacity. Molecular mechanism studies on latitudinal adaptation revealed that during the northward expansion of soybeans, loss-of-function variations in genes such as E1-E4 and GmPRR3a/3b reduced photoperiod sensitivity, forming a photothermal response network centered on E3/E4-GmPRR3a/3b-LHY/CCA1-E1s-Tof5-FT, which elucidates the molecular genetic basis of high-latitude adaptation. While conventional breeding techniques have achieved some breakthroughs, the mission to enhance domestic soybean productivity by improving varieties' high-latitude adaptability remains formidable. To address this, the study proposes integrating modern breeding technologies—such as CRISPR/Cas9-based genome editing, genome-wide association studies (GWAS), and genomic selection (GS)—to optimize key loci governing photoperiod and temperature responses. Additionally, establishing genotype-phenotype-environment interaction models will enhance germplasm utilization strategies. These approaches will facilitate the pyramiding of early-maturing superior haplotypes and precise improvement of photothermal adaptation. The resulting broadly adaptive varieties will support soybean production expansion in northern Northeast China, the Qinghai-Tibet Plateau, and Eurasian high-latitude regions, thereby advancing sustainable soybean industry development in high-latitude areas.
Soybean, as a significant crop for both grain and oil, contain not only beneficial components like vitamin E and isoflavones but also pathogenic factors such as allergens, flatulence factors, and high purine levels that impact human health. Notably, soybean seeds and their products, being rich in purines, are often restricted in diets of gout patients. This article reviews soybean purine content from 4 perspectives, including biosynthesis and metabolic pathways of purines in soybean, role of purines in plant growth and response to environmental stress; methods for analyzing and identifying purine content in soybean seeds, and strategies and technologies to reduce purine levels in soybean. Research based on purine detection technology has shown that advanced processing techniques and genetic improvement could effectively reduce purine content in soybean seeds and their products. These series of studies on purine synthesis, detection technologies, and reduction methods aim to provide technical references for development of new low-purine soybean varieties and safe soybean-based food products.
In order to enhance the self-sufficency of Chinese soybeans and identify saline-alkali tolerant varieties, 50 soybean germplasm materials, mainly from Huanghuai summer soybean producing areas, were subjected to salt stress treatment at seedling stage using a 1.6% NaCl solution. The salt damage index was investigated, and agronomic indexes inclduing plant height, root length, dry/fresh weight of above-ground biomass, dry/fresh weight of root, area of top second leaves, main root diameter and main stem diameter were measured. Salt tolerance evaluation and screening of soybean germplasm resources at seedling stage were carried out. Results revealed significant variations in the agronomic traits of soybean seedlings under salt stress, with a coefficient of variation ranging from 17.14% to 35.16%. By employing salt damage index evaluation method, 2 highly salt-tolerant materials and 29 salt-tolerant materials were identified. 9 salt-tolerant materials were identified by D-value comprehensive evaluation method. 7 salt-tolerant materials, namely Youhuayu 6, Linxuan 3, Lindou 21, Qihuang 39, Jidou 12, Xudou 18 and Linxuan 2 were comfirmed by both methods. Correlation analysis was conducted between the rankings of soybean salt tolerance obtained from two eualuation methods. It was found that the 2 evaluation methods had extremely significant positive correlation in determining the ranking of soybean salt tolerance. Meanwhile, D-value comprehensive evaluation method had a higher salt tolerance threshold and was more reliable than salt damage index evaluation method, which could provide a basis for high-throughput screening of soybean salt tolerance germplasm.
For fully use of soybean landraces, 205 soybeans were collected from all over Zhejiang Province during the 3rd National Crop Germplasm Resources Census and Collection Action. They were used as materials for diversity analysis and comprehensive evaluation through 40 agronomic traits. Results showed that these 205 landraces in Zhejiang Province had rich phenotypic variation. 15 morphological traits had a total of 51 variant types, with coefficients of variation ranging from 20.57% to 60.81%, Shannon's indices ranging from 0.449 to 1.397, and Simpson's indices ranging from 0.277 to 0.731. The coefficients of variation of 19 agronomic and 6 quality traits ranged from 4.40% to 60.96%, and the Shannon indexes ranged from 0.03 to 7.46. Cluster analysis divided them into 8 clusters. Among them, Cluster Ⅶ and Ⅷ had the best overall performance of yield traits. Comprehensive scores of 205 landraces were calculated by affiliation function method, with the scores range of 3.436 to 7.435. According to their comprehensive scores, 10 soybean cultivars were selected, and expected to be applied in producing and germplasm innovation for seed grain and vegitable soybean in the future.
Soybean is an important grain and oil crop in China. Shading directly impacts the yield of intercropped soybeans. To investigate the response of various soybean germplasm resources to shading environment, comprehensively analyze their shade tolerance, and select those with strong shade tolerance, this study employed 227 soybean germplasm resources from diverse ecological regions in Sichuan as test materials. Natural field light served as the control, whereas artificial sunshade nets with a 60% light transmittance facilitated the shading treatment. At the seedling stage, measurements were taken for plant height, stem diameter, leaf area, leaf length, leaf width and leaf petiole length. At maturity, the number of branches, pod number per plant, grain number per plant and 100-seed weight were recorded. Based on the shade tolerance coefficients of each individual indicator under both natural light and shading treatments, the shade tolerance of soybean germplasm resources from different ecological regions in Sichuan was comprehensively evaluated through principal component analysis, correlation analysis, and cluster analysis. The results indicate that the principal component analysis reduced 10 individual indicators into 4 mutually independent comprehensive indicators, with a contribution rate of 76.67%. By calculating the weighted sensitivity index and conducting cluster analysis, the 227 soybean germplasm resources from various ecological regions were classified into five categories based on their shade tolerance strength: strong shade tolerance, relatively strong shade tolerance, medium shade tolerance, weak shade tolerance and no shade tolerance. A total of 52 soybean germplasm resources exhibiting strong shade tolerance were identified, providing a valuable germplasm foundation and reference for further research on soybean shade tolerance mechanisms and the breeding of shade-tolerant soybean varieties.
The sucrose transporter protein (SUT) plays a vital role in plants by creating a sucrose transmembrane transport pathway on the membrane for the distribution of sucrose from source organs to sink organs during different developmental and physiological processes. This research endeavors to investigate the potential functions of the soybean GmSUT gene family. Through comprehensive whole-genome analysis, 11 GmSUT genes have been identified, located on chromosomes 2, 4, 8, 10, 16, and 18, and grouped into Type I~III. These GmSUT members exhibit notable conservation, characterized by the MFS_2 and Sucrose/H+ symporter domains; prediction of transmembrane domains indicates that all GmSUT genes consist of 11 or more transmembrane domains. Analysis of subcellular localization predicts that all members are situated on the plasma membrane. RNA-seq study reveals that GmSUT genes are mainly expressed in flowers and seeds. Quantitative real-time PCR assays reveal that the expression profiles of GmSUT genes are influenced by salt and alkali stresses. Specifically, GmSUT2.2/2.4/2.5/2.6/2.7/4.1/4.2 were downregulated under salt stress, while GmSUT2.1/2.4/2.5/2.6/2.7/3.1/4.2 were upregulated under alkali stress. Notably, GmSUT2.5 displays significant expression levels, implying its crucial role in responding to salt and alkali stresses. In summary, the discovery of the GmSUT gene family and its modulation under salt and alkali stresses offer valuable genetic reservoirs for the development of salt-alkali tolerant soybeans. This work lays a solid groundwork for further investigations into the functionalities of soybean GmSUT genes.
Nitrogen is a key mineral nutrient that significantly influences crop yield. Enhancing crop nitrogen utilization efficiency and breeding new varieties with high nitrogen efficiency are important ways to achieve the goals of reducing fertilizer application and increasing efficiency, and sustainable agriculture development. In this study, the new high-yield soybean variety Zhongdou 63 (ZD63) and its parental lines You 6019 (Y6019) and Zheng 196 (Z196) were used as experimental materials. Three nitrogen levels, i.e., normal nitrogen (N, 3.75 mmol/L), 1/5 normal nitrogen (1/5N), and 1/10 normal nitrogen (1/10N), were established to evaluate plant height, chlorophyll content, dry weight, nitrogen content, and root system architecture after 12 days of treatment in hydroponic assay. In plot experiment assay, the number of pods per plant, number of grains per plant, and yield per plant were analyzed at maturity. The results indicated that under 1/5N treatment, ZD63 and Y6019 exhibited significantly higher low-nitrogen tolerance indices than Z196 for plant height, chlorophyll content, shoot dry weight, total dry weight, root total nitrogen, plant total nitrogen, pod number per plant, seed number per plant, and seed weight per plant. Under 1/10N treatment, among the sixteen traits of ZD63 and Y6019, the low-nitrogen tolerance indices of fifteen traits were significantly greater than those of Z196. Notably, there was no significant differences in the low-nitrogen indices for thirteen traits between ZD63 and Y6019. The low-nitrogen tolerance indices for total dry weight and seed weight per plant of ZD63 under 1/10N conditions were 0.93 and 0.83, respectively, indicating that the variety had relatively strong low nitrogen tolerance. This study found that ZD63 exhibited a strong ability to adjust its root architecture under low nitrogen stress, and determined that the low nitrogen tolerance trait of ZD63 inherited from its maternal line Y6019. This finding provides a theoretical foundation for analyzing the formation of high-yield and stable-yield characteristics in ZD63.
Development of high protein soybean varieties is one of the top issues in soybean breeding. Wild soybean is a valuable gene pool to broaden genetic background of soybean cultivars due to its higher genetic diversity and higher seed protein. In this paper, a RIL population from the cross of Suinong 14 and ZYD01015 were used for QTL identification conferring seed protein content. ZYD01015 is a wild soybean accession with seed protein content of 51.57%. Large variations among the RILs were found both in 2020 and 2021, with normal distributions. BSA (bulked segregant analysis) pools were made according to the protein content of RILs in 2020 and 2021. A protein content-associated region locating in Chromosome 20 (Chr20):3 100 000-33 360 000 was identified by using BSA sequencing technology, and then 12 markers in the region were developed for QTL mapping. A QTL was identified in the interval between WS185 and WS205, which could explain 14.00% (2020) and 13.26% (2021) of phenotypic variation. Significant differences were found in protein content among the RILs with different alleles at the both two flanking markers, showing that the markers could be used in molecular assistant selection for high protein lines. Among the RILs which had the same alleles with ZYD01015, above 62.7% of them had 45% or higher protein content.
To deeply understand transcription factor GmWRI1b on soybean yield and oil production, both GmWRI1b-overexpressed and -RNAi transgenic soybean plants were used to further analysis of its regulatory effects. Results indicated that seed oil of GmWRI1b-overexpressed lines increased by 4.66% to 9.80%, while that of the RNAi lines decreased by 7.9%. By using gas chromatography, their fatty acid compositions data showed that GmWRI1b expression mainly promoted accumulations of palmitic acid (C16:0) and linoleic acid (C18:2). Quantitative RT-PCR results showed that genes related to glycolysis pathway and fatty acid synthesis pathway, including GmPKP1, GmCAC, GmACP, and GmLPD, were upregulated in GmWRI1b-overexpressed plants. Furthermore, dual-luciferase reporter assays and electrophoretic mobility shift assays confirmed that GmWRI1b could directly bind to promoter of GmCAC2. This study was expected to an in-depth understanding of the multifunctional properties of transcription factor GmWRI1b during soybean growth and development.
CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats /CRISPR-associated protein 9) genome editing technology has been widely applied in various plants. However, conventional method of target site detection is often a tedious, time-consuming, and costly process. Developing simpler and high-throughput methods could significantly enhance the efficiency of target site detection. In this experiment, we used the southern soybean variety Tianlong 1 as the experimental material and developed a rapid leaf DNA extraction method termed "Water-Grinding Method", which significantly shortened the time required for DNA extraction and detection. Notably, the DNA extracted using this method remained stable for up to 20 days. Furthermore, we conducted a study to analyse the stability of DNA when the extraction solution was replaced with TE buffer and subjected to boiling conditions. The results indicated that DNA samples stored at 4°C or -20°C remained stable for 45 days after boiling for 1, 3, 5, and 10 minutes, respectively. Subsequently, we performed capillary electrophoresis on PCR products of the target sequences from the test materials. By comparing the results with those from control materials, we were able to observe any differences in base sequences, which allowed us to determine whether gene editing had occurred in the test materials and identify the possible types of edits. By combining rapid plant leaf DNA extraction method with capillary electrophoresis technology, this study presents a more efficient and high-throughput approach for screening mutations and their types in soybean materials. This integrated methodology is expected to provide valuable technical support for the functional analysis of important trait genes in soybeans.
For large scale in vitro purification of highly active mGmEPFL6a (MATURE EPIDERMAL PATTERNING FACTOR LIKE6a) protein, we optimized prokaryotic expression conditions for the protein. Real-time fluorescence quantitative PCR was used to detect homologous gene GmEPFL6 expressions under shade treatment. GmEPFL6a, with the highest shade response degree, its mature parts mGmEPFL6a was selected to construct prokaryotic expression vector pCold-mGmEPFL6a, which was then transformed into BL21(DE3) expression strain. Induction expression was carried out using isopropyl β-D-thiogalactoside (IPTG), and then expression level of target protein was analyzed using enzyme marker, SDS-PAGE, and Western blot. The optimal expression conditions were determined through single-factor and orthogonal experiments. Real-time fluorescence quantitative results showed that GmEPFL6a highly responded to shade in hypocotyl and petioles. Its response level varied with different light qualities. The optimal expression conditions for the recombinant protein were as follows: 0.5 mmol·L-1 IPTG inducer, incubation at 28°C, 120 r/min for 24 h. Order of influence factors was in induction temperature > induction time > IPTG concentration. The above results were expected to provide basis on mGmEPFL6 function on shade avoidance response mechanism of soybean.
Phytochrome interacting factors (PIFs) represent a family of bHLH transcription factors, which regulate downstream gene expression by directly interacting with phytochrome, thereby affecting important biological reactions. Soybean is a typical photoperiod sensitive crop. To understand the function of PIFs family in soybean on light signal transduction, we used bioinformatics methods and tools, including MEGA-X and Expasy-Prot Param, to predict and analyze the genetic relationship, protein characteristics and subcellular localization. We explored the interaction between 13 GmPIF proteins and biorythm regulatory protein GmSIC by yeast two-hybrid technique. Results showed that, 21 GmPIF proteins were divided into 5 clusters, which have evolutionary differences in primary and secondary structures. Subcellular localization and transmembrane structure analysis showed that all GmPIF proteins except GmPIF5D were hydrophilic, non-transmembrane and located in nucleus. Meanwhile, yeast two-hybrid results showed that GmSIC could interact with GmPIF3A, GmPIF8B and GmPIF8C.
To improve crop yield, effects of potassium application and density were investigated on matter accumulation distribution of intercropping soybean. In this study, soybean-maize belt was taken as research object. 3 soybean densities (D1: 10.99×104 plants·hm-2, D2: 13.99×104 plants·hm-2, D3: 17.1×104 plants·hm-2) and 4 potassium application treatments (CK: no potassium application, K1: base fertilizer application K2O 53.2 kg·hm-2, K2: foliar potassium dihydrogen phosphate application 1.5 kg·hm-2, K3: base fertilizer application K2O 53.2 kg·hm-2+foliar potassium phosphate monobasic spray 1.5 kg·hm-2) were designed. Results showed that lodging rate increased with the density, while stem bending resistance decreased. Number of effective plants and seed yield were the highest under D2 density. At the same density, the lodging rate of K3 treatment was the lowest, and the stem bending resistance, grain filling, soybean matter accumulation and distribution and yield were the highest. The grain filling rate of soybean was the highest in D1K1 and the lowest in D3CK. The active period of grouting reached the maximum under D1K3 and could be extended by 4-5 days compared to D3CK. With the passage of growth, dry matter gradually transferred from both stems and leaves to pods, among them pods proportion was the highest under D1K3 treatment. Soybean yield under different potassium application treatments showed an order of K3> K2> K1> CK, and the yield under D2K3 was the best as 2075.5 kg·hm-2 . Thus to say, under D2K3 treatment, both effective soybean plants and soybean population yield could be increased, and the high yield and high efficiency of soybean-maize strip intercropping system could be realized.
To address excessive growth of soybeans under soybean-corn strip intercropping mode, this study screened uniconazole and diethyl aminoethyl hexanoate compound agents (namely SD in this study) regulating better plant type of soybean. Cultivar Qihuang 34 was used as material, and 3 densities of 10.2×104 plants·hm-2 (D1), 13.0×104 plants·hm-2 (D2) and 15.9×104 plants·hm-2 (D3) were set up. Soybean and corn were sprayed with uniconazole and diethyl aminoethyl hexanoate compound 1 (SD1, concentration ratio of 23∶30), uniconazole and diethyl aminoethyl hexanoate compound 2 (SD2, concentration ratio of 40∶30), uniconazole and diethyl aminoethyl hexanoate compound 3 (SD3,concentration ratio of 56∶30), uniconazole (S3307), diethyl aminoethyl hexanoate (DA-6) and water (CK), respectively. Effects of soybean planting density and uniconazole and diethyl aminoethyl hexanoate compounds on soybean stem and leaf growth and crop yield were investigated. Results showed that plant height, average internode length and lodging rate of the soybean were in order of D3 > D2 > D1, and stem diameter, branch number, leaf SPAD value and net photosynthetic rate were in D1 > D2 > D3. Plant height and lodging rate treated with SD3 were the lowest, followed by SD2, and S3307 was better than DA-6. Stem diameter and branch number of SD2 treatment were higher than those of other regulator treatments. Leaf SPAD values in DA-6 treatment was higher than that in S3307. All regulators increased net photosynthetic rate, stomatal conductance and transpiration rate of soybean leaves, among them, SD2 was the best. The dry matter distribution rate of soybean pods was the highest in SD2 treatment, which increased by 35.65% compared with CK under D3 density. Under the same regulator, soybean yield was D2 > D3 > D1 between densities. SD2 significantly increased soybean grain numbers per branch, and also corn grain numbers per plant and 1000-grain weight. Under D2, soybean yield increased by 36.30%, corn yield and system yield increased by 12.41% and 17.88%, respectively. Therefore, in soybean-corn strip intercropping system, under 13.0×104 soybean plants·per hectare, application of uniconazole and diethyl aminoethyl hexanoate compound agents with concentration ratio of 40:30 could better reduce soybean lodging rate, increase branch number, improve photosynthetic characteristics, promote dry matter accumulation and distribution, and thus increase crop yield.
To select appropriate row ratio configurations for intercropping soybeans and maize in the northwestern region of Shandong Province, and to further promote application of strip intercropping technology, effects of different row ratios of soybean and maize intercropping were investigated. By using sole-cropped soybean (SS) and sole-cropped maize (SM) as controls, 5 different row-ratio treatments (4S2M, 4S3M, 4S4M, 6S3M, and 6S4M) were set up. The effects included soybean dry matter accumulation, photosynthetic parameters, and other growth traits, yield and quality, also as impact on intercropping system productivity, land equivalent ratio, competition ratio, and actual yield loss. Results showed that under 4S4M model, soybean dry matter accumulation, photosynthetic parameters, population yield, and quality performance were optimal. Its productivity of the intercropping system, land equivalent ratio, competition ratio, and actual yield loss were all the highest, with an economic yield of 31 581.10 CNY per hectare, demonstrating the greatest intercropping advantage. Thus the 4S4M (4 rows soybean and 4 rows of maize) model is the best row ratio configuration for intercropping soybeans and maize in this region and might be suitable for promotion and application in similar ecological areas.
To optimize the population structure of soybean-maize intercropping system and strive for high yield, the effects of maize varieties (three varieties: large-spike variety V1: Jinheyu 202, medium-spike variety V2: Su 57, and small-spike variety V3: MY73) and densities (five densities: D52500: 52 500 plants/hm², D60000: 60 000 plants/hm², D67500: 67 500 plants/hm², D75000: 75 000 plants/hm², and D82500: 82 500 plants/hm²) on the population and yield of the soybean-maize intercropping system were analyzed based on the 4∶4 row ratio planting pattern in Jiangsu region.The results showed that the population yield of the intercropping system increased first and then decreased with maize density. The optimal densities for large-spike (V1), medium-spike (V2), and small-spike (V3) maize varieties were 60 000-67 500 plants/hm², 67 500 plants/hm², and 67 500-75 000 plants/hm², respectively. Under optimal densities, the average population yields and land equivalent ratios (LER) over two years were 10 686 kg/hm2 and 1.47, 9667.5 kg/hm2 and 1.32, 10 317 kg/hm2 and 1.43, respectively. Appropriately increasing the maize planting density improved the accumulation of post-flowering photosynthetic product in the intercropping system, and thereby increased population yield. However, excessive density led to intensified intraspecific competition within the maize population and interspecific competition between maize and soybean, which was detrimental to the accumulation and transport of post-flowering photosynthetic product in both maize and soybean, resulting in a decrease in population yield. Analysis of the canopy structure characteristics of high-yield intercropping systems indicated that when the maize leaf area index (LAI) during the silking and grain filling (20 days after-silking) periods was between 4.5-4.8 and 4.1-4.3, respectively, and the light transmittance from the maize canopy to the soybean canopy during the silking and grain filling periods was approximately 63.3% and 59.7%, respectively, the canopy structure was more reasonable, and the system photosynthetic efficiency was stronger.The relevant analysis shows that the population yield is significantly positively correlated with maize yield, maize kernel weight, post-anthesis dry matter accumulation, and maize LAI during the grain filling period, and is significantly negatively correlated with maize plant height and ear position. The land equivalent ratio is significantly positively correlated with maize yield, soybean yield, maize kernel weight, soybean plant seed number, soybean kernel weight, maize LAI during the grain filling period, light transmittance from the maize canopy to the soybean canopy during the grain filling period, and net photosynthetic rate of maize during the silking period, and is significantly negatively correlated with maize plant height and ear position. In conclusion, selecting maize varieties with high kernel weight potential and relatively dwarf stems, and adopting appropriate planting densities according to variety type, by dynamically monitoring LAI and light transmittance to regulate the population structure of the intercropping system, ensuring efficient accumulation of photosynthetic products during the grain filling period, is an effective way to achieve high yield in soybean-maize intercropping production in this region.
To explore the changes of carbon metabolism enzymes activity and photosynthetic characteristics of leaves in the process of genetic improvement of soybean varieties, 22 varieties bred in Jilin Province from 1923 to 2022 were selected as experimental materials, and respectively determined gas exchange parameters, chlorophyll fluorescence parameters, and activities of carbon metabolism enzymes at different growth stages were determined respectively. The results showed that the activities of RUBP carboxylase (Rubisco) and sucrose synthase (SS) in soybean leaves of different growing ages followed the trend: recent varieties > middle varieties > early varieties in V2 and R4 stages, with significant differences. In R2 stage, the maximum photochemical efficiency (Fv/Fm), chlorophyll content, sucrose phosphate synthase (SPS) and SS activities of recent varieties were significantly higher than those of early varieties, which were 10.84%, 23.31%, 10.19% and 15.48% higher, respectively. In R6 and R8 stages, the net photosynthetic rate of leaves, SPS and SS activities of recent varieties were significantly higher than those of early varieties. There was no significant difference between recent and middle varieties in R2, R6 and R8 stages. During the whole growth period, SPS had significant positive correlation with released years and yield. In the later stages of growth, UDP-glucose pyrophosphorylase (UGPase) activity increased, and the activities of Rubisco, ADP-glucose pyrophosphorylase (AGPase) and granule-bound starch synthases (GBSS) were significantly positively correlated with the growing age, while SS activity was not significantly positively correlated with the growing age. With the development of the growing age, the photochemical efficiency of PSⅡ reaction center, photosynthetic capacity and sucrose metabolic efficiency were improved.
Targeting 3 major abiotic stresses: soil salinization, drought, and waterlogging, which currently affect soybean production, this study aimed to comprehensively evaluate drought tolerance, saline-alkali tolerance, and waterlogging tolerance of 20 soybean varieties with certain application areas or potential, and to screen out soybean varieties with strong comprehensive stress resistance, in order to provide a reference for soybean stress-resistant production and stress-resistant breeding. The experiment was conducted in a rain shelter using a pot-culture method, with the 20 soybean varieties planted separately in black calcareous soil (pH 7.93, EC 20.3 μs·cm-1) and saline-alkali soil (pH 8.95, EC 73.4 μs·cm-1). Principal component analysis and fuzzy mathematics membership function methods were used to comprehensively evaluate the drought tolerance, saline-alkali tolerance, and waterlogging tolerance of the varieties. Cluster analysis was performed to screen out soybean varieties with strong comprehensive stress resistance. The results demonstrated that 6 sybean varieties exhibited exceptional adaptability under diverse stress conditions, among them, Henong 165 and Henong 144 exhibited Grade 1 drought resistance and grade 3 salt-and-alkali tolerance, rendering them suitable for cultivation areas prone to light salt and alkali as well as drought. Heike 88 and Keshan No.1 exhibited Grade 1 waterlogging tolerance and Grade 3 saline-alkali tolerance, suitable for planting areas with mild salinization, frequent waterlogging, or low-lying terrain. Shengdou 15 exhibited Grade 2 drought tolerance, Grade 3 saline-alkali tolerance, and Grade 3 waterlogging tolerance, suitable for planting areas with moderate drought, mild salinization, and mild waterlogging or low-lying terrain. Jinshan No.3 exhibited Grade 2 waterlogging tolerance, Grade 3 drought tolerance, and Grade 3 saline-alkali tolerance, suitable for planting areas with moderate waterlogging, mild drought, and mild salinization.
The discovery and utilization of soybean rhizosphere bacterial resources are critical for the sustainable and green development of soybeans. The Yangtze River Basin has superior geographical conditions, which are beneficial for the cultivation and growth of soybeans. In this study, we isolated and purified 124 strains of bacteria from rhizosphere soil and root nodules of soybean in the Yangtze River Basin. Among them, 4 strains (ZM-3, S1-7, B2-9 and M2-5) were found to have inhibitory ability against Aspergillus flavus via plate confrontation method. 16S rDNA sequencing and phylogenetic analysis revealed that these four strains were belong to Acinetobacter pittii, Nanobacteria, Bacillus subtilis and Microbacterium thalassium, respectively. Further infection experiments showed that trearment with 4 bacterial stains could reduce the infection of Aspergillus flavus to varying degrees, with infection indices of 50%, 57.33%, 23.33% and 66.33%, respectively, which were significantly lower than the control of index 74.33%. Finally, pot experiment has shown that four strains also had promoting effects on soybean growth and nodulation ability. The research results can provide strain resources and theoretical basis for improving soybean quality, increasing yield, and reducing toxicity in the Yangtze River Basin.
To find biocontrol bacteria against Phytophthora root and stem rot of soybean (PRR), bacterias were isolated from rhizosphere soil, roots, stems and leaves of soybean resistant variety (Williams 82) and susceptible variety (Williams) by dilution coating method. A biocontrol bacterium strain WKT-26 was found by plate confrontation method, which had the inhibition rate of 90.97% against Phytophthora sojae. It was identified as Pseudomonas aeruginosa based on results of morphological characteristics, physiological and biochemical characteristics and phylogenetic analysis of 16S rRNA and gyrB gene sequences. WKT-26 strain had strong motility, could form biofilms, and secrete proteases, celluloses, phosphatases and siderophores. It also had the ability to inhibit soybean root rot pathogen Fusarium oxysporum. Its 10% sterile fermentation broth from hyphal growth had an inhibition rate of 75.00% against P. sojae. For soybean plants, after 4 times root irrigated with 10.0 mL each of WKT-26 fermentation broth (stock solution), the plants had 62.63% control efficacy on PRR. Moreover, soybean plant’s biomass was increased by 57.90%. In conclusion, P. aeruginosa strain WKT-26 had remarkable efficacy in controlling PRR and promoting soybean growth, which showed its potential on disease biocontrol.
To provide technical support for biological breeding and commercializing of CAL16 in China, transgenic soybean CAL16, an insect-resistant soybean with cry1Ab/vip3Da gene developed by Hangzhou RFGENE Co., Ltd., is investigated for event-specific quantitative PCR detection method. By combination fuse probes according to 5'- and 3'-end side sequences, a pair of optimal primer combinations is selected at the 5'-end. The PCR product size is 112 bp. After specificity test, standard curve establishment, accuracy and precision test, LOD and LOQ test, robustness test, and micro-drop digital PCR verification, this method turn out to be strong specificity, high sensitivity and good repeatability. The LOD reaches 0.025%, which is equivalent to 10 copies of CAL16 specific fragments; the LOQ reaches 0.1%, about 40 copies. The inter-laboratory cycle verification shows that this method meets the requirements of national standard methods and could meet the testing requirements. Finally, the uncertainty evaluation of the CAL16 quantitative method is carried out to ensure that the quantitative value is scientific and reliable. Thus this event-specific quantitative PCR detection method of CAL16 could be expected for industrialization of CAL16 and its derivatives in China.
The development of non-destructive testing technology for soybean seed vigor holds significant practical important in ensuring the quality of soybean seeds and enhancing the production capacity. In this study, near-infrared spectroscopy of 43 soybean varieties was collected and used to construct the prediction models for five seed vigor parameters, i.e., germination rate, germination index, normal seedling rate, germination energy and shoot length in soybean. Multiple spectral pretreatment methods and different modelling methods such as multiple linear regression, partial least squares regression, support vector machine regression, XGBoost and BP neural network were applied to construct prediction models. The results showed that independent modelling of dark- and light-colored seed coat soybeans could improve the effectiveness of the models, preprocessing of NIR spectra and selecting of spectral variables could improve the model prediction ability, and the prediction models constructed on the basis of XGBoost and BP neural network performed optimally. The R2 of the optimal prediction model in training set for germination rate, germination index, shoot length and normal seedling rate of light-colored seed coat soybeans was 0.93-0.96, and the corresponding R2 in validation setwas above 0.80. The R2 of the optimal prediction model for germination potential of light-colored seed coat soybeans reached above 0.91 in both training set and validation set. The R2 of the optimal prediction model for normal seedling rate and germination rate of dark seed coat soybean was 0.96 and 0.94 in training set, while the R2 was 0.79 and 0.82 in validation set, respectively. The R2 of the prediction model for germination potential, germination index, and shoot length of dark seed coat soybean were all above 0.90 in both training set and validation set. The prediction models for seed vigour traits constructed in this study showed high generalisation ability and accuracy, providing a scientific foundation for the non-destructive prediction of soybean seed vigour. This methodology might offer promising applications for optimizing sowing quality and ultimately improving crop yield.
