Soybean Cultivars Research Articles

Genetic diversity of 30 soybean cultivars based on microsatellite markers

Abstract Increasing soybean production presents a significant challenge within soybean breeding endeavors. The foundation for achieving success in plant breeding lies in comprehensive knowledge of genetic diversity. Thus, this study aimed to assess the genetic diversity among 30 soybean cultivars by employing microsatellite markers. DNA extraction was conducted using a modified version of the Doyle & Doyle method, followed by amplification of each sample with nine pairs of microsatellite primers. Gel visualization of the amplified samples facilitated scoring, distinguishing between polymorphic and monomorphic primers. The analysis unveiled the detection of 59 alleles, varying from 2 to 15 alleles per locus, with an average of 6.6 alleles per marker. The resulting gene diversity averaged at 0.63, with a mean main allele frequency of 0.44. Moreover, the obtained PIC values ranged from 0.18 to 0.92, with an average value of 0.60. Notably, four microsatellite markers exhibited high informativity (PIC > 0.7). Cluster analysis based on genetic similarity coefficients grouped the 30 soybean cultivars into three main clusters, demonstrating the genetic variability within the utilized soybean genetic material.

Поиск информативных SSR-маркеров для паспортизации сортов сои

Soybean is one of the important crop contributing to food security. The development of new soybean cultivars and their including into the State Register will be confirmed by genetic passportization. The purpose of the research was a search of informative SSR-loci too add the existing system of DNA-markers for soybean passportization. We selected 27 SSR-loci from SoyBase using an online instrument Primer-BLAST. The information capacity of microsatellite loci was estimated in 20 soybean cultivars. PCR-products were divided in PAAG in denaturing conditions. We allocated 13 highly informative (PIC 0.50–0.72) and five informative (PIC 0.44–0.49) microsatellite loci from 27 ones selected in silico. Selected in the research loci can be used for genotyping and jointly with tested earlier DNA-markers for soybean passportization.

Seed Longevity of Soybean (Glycine max L.) Cultivars Under Lightless Storage

Soybean seeds in tropical countries are prone to rapid deterioration due to environmental condition during storage, leading to a decrease in seed quality and ultimately resulting in low potential yield. Longevity of seed during storage is influenced by genetic and environmental factors such as light. Therefore, this study aimed to determine the effect of light on the vigour of two soybean seeds cultivars (Demas 1 & Devon 1 cvs) stored for three months. The investigation was conducted from February to May 2022 at Seed Technology Laboratory, Faculty of Agriculture, Universitas Padjadjaran. A correlational method was employed to assess the relationship between seed quality of Demas 1 and Devon 1 in light and lightless storage. Furthermore, data were analyzed using correlation regression and t-test to compare the two populations. The results showed that there was a high correlation between the physical and physiological quality of seeds. There were also differences in seed response to light, and this was observed from the moisture content, weight of 100 seeds, germination rate, and simultaneous growth percentage traits. Considering the seed quality traits, Demas 1 had the best vigour value after storage in dark conditions. It is worth noting that both cultivars exhibited signs of deterioration during storage. However, the rate of deterioration was slowed down due to lightless condition.

Attracting Scelionidae egg parasitoids to enhance stink bug egg parasitisation in soybean crops using methyl salicylate and (E,E)-α-farnesene.

Plant volatile organic compounds (VOCs) play a crucial role in mediating interactions between plants, herbivores and natural enemies. Among these VOCs, methyl salicylate and (E,E)-α-farnesene are emitted as herbivore-induced plant volatiles (HIPVs) by soybean plants in response to feeding by the brown stink bug Eushistus heros. These HIPVs function as synomones, influencing the foraging behaviour of the egg parasitoid, Telenomus podisi, the main natural enemy of E. heros, one of the major soybean pests in Brazil. Laboratory experiments showed that two soybean cultivars, BRS 7580 and BRS 7880, produced similar qualitative blends of HIPVs, with methyl salicylate, (E,E)-α-farnesene and (Z)-3-hexenyl acetate being produced by both cultivars. Soybean cultivar BRS 7580 produced a significant lower amount of HIPVs compared to BRS 7880 but this difference did not affect the attractiveness of the egg parasitoid Telenomus podisi. Field experiments using these two cultivars and synthetic applications of methyl salicylate and (E,E)-α-farnesene showed a substantial increase in egg parasitism in all treated areas. Parasitism rates ranged from 50% to 80% in areas where these HIPVs were deployed, compared to only 10% in untreated control areas. The egg parasitoid Telenomus podisi demonstrated an adept ability in recognising between HIPVs in soybean blends, even in the presence of significant quantitative differences. The results from the field experiment showed the potential of HIPVs in attracting natural enemies to specific target areas within fields. (E,E)-α-Farnesene showed an improved action during the later stages of soybean growth, notably at R6. In addition, this volatile attracted other families of natural enemies. © 2024 Society of Chemical Industry.

Oviposition patterns of primary lepidopteran defoliators in soybean and the impact on structured refuge recommendations.

Transgenic Bt technology in soybean, with plants expressing Cry1Ac, has been adopted as an insect pest management tool. It was first adopted in large areas of South America and Asia in 2013. The risk of resistance in target pests to this technology demands insect resistance management (IRM) programs. In Brazil, a structured refuge (area of non-Bt soybean) planted adjacent to the Bt soybean crop has been an important IRM recommendation, particularly for the primary lepidopteran defoliators Anticarsia gemmatalis (Lepidoptera: Erebidae) and Chrysodeixis includens (Lepidoptera: Noctuidae). The overall goal of this study was to validate IRM recommendations to Bt soybean. The objectives were to document the impact of soybean phenology, cultivar choice and non-Bt soybean defoliation on moth oviposition. In addition, a mark-release-recapture study estimated the dispersal capacity of these species. Five field experiments per species were performed for 3 years. Our results revealed an increase in A. gemmatalis and C. includens oviposition, respectively, on Bt plants as a consequence of the difference in plant growth stage at the time of oviposition. Defoliation of non-Bt plants significantly increased the oviposition preference of both moth species for Bt plants. The mark-release-recapture experiment indicated an average dispersal distance of ~300 m from the release point for A. gemmatalis, with maximum recapture at 1000 m. Overall, our findings emphasize the importance of planting synchronization of Bt soybean and the structured refuge. In addition, when operational aspects in large soybean areas challenge this recommendation, the priority should be for planting the refuge area first. This approach will minimize the impact of selective oviposition of A. gemmatalis and C. includens. © 2024 Society of Chemical Industry.

Genotypic differences in soybean (Glycine max L.) in yield response to phosphorus fertilizer are associated with difference in biomass and phosphorus content

The soybean seed yield response to phosphorus (P) fertilizer has significantly increased during soybean breeding but the underlying mechanisms remain elusive. In this study, we used two soybean cultivars with high (Andou 8 (AD8)) and low (Qiandou 5 (QD5)) seed yield response to P fertilizer to compare their yield and yield components, biomass accumulation and partitioning, P content and partitioning and P-use efficiency in Shiqian (SQ) and Dafang (DF) during the growing season in 2020 under 0 (P0) and 35 (P35) kg P ha−1 supply. The results show that AD 8 had a greater seed yield, pod biomass, filled-pod number, seed number, pod P content and P partitioning to pods, and P-use efficiency based on seed yield (PUESY) but lower P-use efficiency based on biomass (PUEB) than QD5 at two experimental sites. The seed number was positively correlated with total biomass and P content, especially with greater pod biomass accumulation and its partition to pods which showed a positive correlation with seed number. Seed number was negatively correlated with stem dry weight and its partitioning to stem, and stem P partition. We conclude (1) different yield response to P fertilizer are explained by different biomass and P content and their partitioning to pod; (2) high biomass and P-conversion efficiency increased the seed number, which accounted for a high yield response to P fertilizer. Our results highlight that soybean breeding increased biomass and nutrient content and their conversion efficiency to achieve high seed yield with P-fertilizer supply.

Growth and production of M6 and M7 black soybean mutant genotypes

Abstract. Anwar S, Kusmiyati F, Lukiwati DR, Sas MGA, Arifah YN. 2024. Growth and production of M6 and M7 black soybean mutant genotypes. Biodiversitas 25: 2541-2546. The seed coat colors of soybeans are yellow, black, green, brown, or bicolor, and in Indonesia, black seed coat color is for used soy sauce. Our black soybean mutation breeding research started with irradiating soybean cultivar Detam 3 with gamma rays at 160, 208, 256, 304, 352, 400, 448, 496, 544, and 592 Gy. Genotypes were selected from M1 (first generation) to M5 (fifth generation) based on saline and/or nonsaline soil productions. This research aims to evaluate the growth and production of sixth-generation (M6) and seven-generation (M7) black soybean mutant genotypes. The research was conducted in Karangharjo Village, Pulokulon Sub-district, Grobogan District, Central Java Province, Indonesia. The plant material was three genotypes of M6 black soybean mutants (BSMG VQ 05-256/1-6-2-28, BSMG VQ 05-400/1-2-2-6 and BSMG VQ 05-256/1-2-9-29), four genotypes of M7 black soybean mutants (BSMG VQ 06-256/1-6-2-28, BSMG VQ 06-400/1-2-2-6 and BSMG VQ 06-256/1-2-9-29 and BSMG VQ 06-256/1-4-2-21) and three cultivar checks (Detam 1, Detam 3/parent variety and Detam 4 variety). The parameters measured consist of plant growth, components, and production. All data collected were subjected to statistical Analysis of Variance (ANOVA); if significantly different, it continued by Duncan Multiple Range Test (DMRT). The results showed that the genotype treatment affected all observed characters except plant height. Selected lines based on the number of leaves, number of pods, number of seeds, weight of 100 seeds, weight of seed, and production were BSMG VQ 05-256/1-2-9-29, BSMG VQ 05-256/1-2-9-29 and BSMG VQ 06-256/1-4-2-21. These selected genotypes provided the prospective source of soy sauce material and needed to examine its stability at different locations (multilocation test).

Quality assessment of soybean seeds submitted to industrial seed treatment and stored in a natural and controlled environment

Seed quality is a limiting factor in the search for high soybean yields. However, fungi and insect pests can negatively interfere with their performance, and industrial seed treatment (IST) is a tool used to minimize the attack of pathogens and pests. The treated seeds are often stored until sowing, which can lead to a reduction in their quality. This work aimed to evaluate the physical and physiological quality of soybean seeds submitted to IST, with subsequent storage in a natural and controlled environment. The experiment was conducted in a split-split-plot design in a completely randomized scheme (time x storage systems x IST) with four replications. Soybean cultivar 55I57RSF IPRO was subjected to IST with fungicide (metalaxyl-M, thiabendazole, and fludioxonil) and insecticide (thiamethoxam and cyantraniliprole), combined or not with polymer and dry powder, with subsequent storage in a controlled and natural environment. The moisture content, thousand-seed weights, germination, first germination count, germination speed index, accelerated aging, seedling length, dry matter transfer, and emergence sand test were evaluated. IST did not affect the moisture content and weight of a thousand seeds. However, storage in a controlled environment provided a greater reduction in moisture content and a smaller reduction in the weight of a thousand seeds. IST negatively affected germination, first germination count, germination speed index, and accelerated aging test. IST negatively affected plant length, except in the treatment where only insecticide was applied. The dry mass transfer was negatively affected but with less intensity in seeds subjected only to the application of insecticide or fungicide and the combination of insecticide, fungicide, and polymer. Seed emergence in the sand was negatively affected by all treatments. Regardless of the treatments, all responses evaluated showed a reduction throughout storage, with greater intensity in seeds stored in the natural environment.

Heat shock protein 70 is associated with duration of cell proliferation in early pod development of soybean

Pod is an important organ for seed production in soybean. Pod size varies among soybean cultivars, but the mechanism is largely unknown. Here we reveal one of the factors for pod size regulation. We investigate pod size differences between two cultivars. The longer pod of ‘Tachinagaha’ is due to more cell number than in the short pod of ‘Iyodaizu’. POD SIZE OF SOYBEAN 8 (GmPSS8), a member of the heat shock protein 70 (HSP70) family, is identified as a candidate gene for determining pod length in a major QTL for pod length. Expression of GmPSS8 in pods is higher in ‘Tachinagaha’ than ‘Iyodaizu’ and is highest in early pod development. The difference in expression is the result of an in/del polymorphism which includes an enhancer motif. Treatment with an HSP70 inhibitor reduces pod length and cell number in the pod. Additionally, shorter pods in Arabidopsis hsp70-1/-4 double mutant are rescued by overexpression of GmPSS8. Our results identify GmPSS8 as a target gene for pod length, which regulates cell number during early pod development through regulation of transcription in soybean. Our findings provide the mechanisms of pod development and suggest possible strategies enhancing yield potential in soybean.

Sowing Date as a Factor Affecting Soybean Yield—A Case Study in Poland

Soybean is the crop of the future, especially for countries with a high demand for food and feed protein. Therefore, soybean cultivation is moving north to countries at higher latitudes, where temperatures, photoperiodism, and rainfall distribution are not always able to meet soybean requirements. The aim of this study was to evaluate three sowing dates as a factor influencing soybean cultivars yield and seed chemical composition in agroclimatic conditions of south-western Poland. In the years 2016–2019, a field experiment was conducted in Lower Silesia region, near Wroclaw, with three sowing dates: early (mid-April), 10-day delayed (at the turn of April and May), and 20-day delayed (first half of May), and two soybean cultivars: Merlin and Lissabon. In this location, soybean sowing is recommended in mid-April, possibly at the turn of April and May. The cultivars tested differed in yield and yield component values in the years of research, but generally, the Lissabon was better suited to local conditions. Results were discussed with findings of other domestic research, to investigate the problem of the soybean sowing date in Poland. The recommended sowing date for soybean was found to vary from region to region. These differences are due to the length of the growing season in each location and the varied adaptation of cultivars to the local climatic conditions.

Connecting detailed photosynthetic kinetics to crop growth and yield: a coupled modelling framework

Abstract Photosynthesis and crop growth are inseparable processes that govern plant carbon assimilation and allocation. An accurate model description of these processes can bridge dynamics at the leaf and canopy levels, assisting in identifying potential photosynthetic improvements that can be converted into increased yield. Integrating multiscale biophysical processes and achieving computational effectiveness for seasonal simulations, however, are challenging. Here, we present a fully coupled modelling framework that integrates a metabolic model of C3 photosynthesis (ePhotosynthesis) and a semi-mechanistic crop growth model (BioCro). We replaced the leaf-level Farquhar photosynthesis model in BioCro with the ePhotosynthesis model that mechanistically describes the photosystem electron transport processes and the C3 carbon metabolism including the Calvin–Benson–Bassham cycle and the photorespiratory pathway. The coupled BioCro-ePhotosynthesis model was calibrated to represent a soybean cultivar and developed to be operationally fast for seasonal simulations. As an example of model application, we conducted a global sensitivity analysis of 26 enzymes under an average daytime intercepted radiation of 400 µmol m−2 s−1, identifying 2 enzymes, phosphoglycerate kinase (PGK) and phosphoribulokinase (PRK), which had the largest impact on the leaf-level assimilation. Increasing PGK and PRK by 2-fold was predicted to increase the leaf-level assimilation by 8.3 % and the final seed yield by 6.75 % ± 0.5 % over 4 years of observed field climate data. The coupled BioCro-ePhotosynthesis model provides a seamless and efficient integration between the leaf-level metabolism and the field-level yield over a full growing season. The coupled model could be further applied to investigate non-steady-state photosynthetic processes such as non-photochemical quenching.

Screen-printed electrode modified with a composite based on Amburana cearensis gum, multi-walled carbon nanotubes, and gold nanoparticles for electrochemical determination of total isoflavones in soybean cultivars

Screen-printed electrode modified with a composite based on Amburana cearensis gum, multi-walled carbon nanotubes, and gold nanoparticles for electrochemical determination of total isoflavones in soybean cultivars

Quantitative trait loci governing seed protein, oil, and linolenic acid concentration in soybean

AbstractSoybean is one of the most economically important crops in the United States. Produced for its oil and protein concentration, it is readily utilized in food products for both human and livestock consumption. Since soybean was first cultivated in the United States, increased yield has been the driving factor in breeding efforts. Though yield and oil have been observed to be positively correlated, protein concentration is negatively correlated with both. An increased effort has been underway recently to produce high‐yielding cultivars that have both elevated oil and protein concentration. This has been accomplished utilizing molecular markers associated with quantitative trait loci (QTL) for both traits. To assist in this effort, more information on QTL associated with quality traits is required. In this study, 180 F4:6 recombinant inbred lines (RILs) segregating for protein, oil, and fatty acids were produced from a cross between TN12‐4098 and TN13‐4303. These lines were grown across three locations in Tennessee: Research and Education Center at Milan (RECM), Highland Rim Research and Education Center (HRREC), and East Tennessee Research and Education Center (ETREC) in 2018 and 2019. Sixteen QTL were found for protein, oil, linolenic acid, and meal protein concentration. Of these identified QTL, six were novel. Developing molecular markers associated with these QTL will assist in breeding efforts to produce high‐quality elite soybean cultivars that meet the demands of both farmers and consumers.

Functional Characterization of the Soybean Glycine max Actin Depolymerization Factor GmADF13 for Plant Resistance to Drought Stress.

Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical roles in plant responses to various stresses. In this study, we found that GmADF13, an ADF gene from the soybean Glycine max, showed drastic upregulation under drought stress. Subcellular localization experiments in tobacco epidermal cells and tobacco protoplasts showed that GmADF13 was localized in the nucleus and cytoplasm. We characterized its biological function in transgenic Arabidopsis and hairy root composite soybean plants. Arabidopsis plants transformed with GmADF13 displayed a more robust drought tolerance than wild-type plants, including having a higher seed germination rate, longer roots, and healthy leaves under drought conditions. Similarly, GmADF13-overexpressing (OE) soybean plants generated via the Agrobacterium rhizogenes-mediated transformation of the hairy roots showed an improved drought tolerance. Leaves from OE plants showed higher relative water, chlorophyll, and proline contents, had a higher antioxidant enzyme activity, and had decreased malondialdehyde, hydrogen peroxide, and superoxide anion levels compared to those of control plants. Furthermore, under drought stress, GmADF13 OE activated the transcription of several drought-stress-related genes, such as GmbZIP1, GmDREB1A, GmDREB2, GmWRKY13, and GmANK114. Thus, GmADF13 is a positive regulator of the drought stress response, and it may play an essential role in plant growth under drought stress conditions. These results provide new insights into the functional elucidation of soybean ADFs. They may be helpful for breeding new soybean cultivars with a strong drought tolerance and further understanding how ADFs help plants adapt to abiotic stress.

Performance of soybean cultivars for the Rio Verde region, Goiás, Brazil - 1st season

Performance of soybean cultivars for the Rio Verde region, Goiás, Brazil - 1st season

A Novel 10-Base Pair Deletion in the First Exon of GmHY2a Promotes Hypocotyl Elongation, Induces Early Maturation, and Impairs Photosynthetic Performance in Soybean.

Plants photoreceptors perceive changes in light quality and intensity and thereby regulate plant vegetative growth and reproductive development. By screening a γ irradiation-induced mutant library of the soybean (Glycine max) cultivar "Dongsheng 7", we identified Gmeny, a mutant with elongated nodes, yellowed leaves, decreased chlorophyll contents, altered photosynthetic performance, and early maturation. An analysis of bulked DNA and RNA data sampled from a population segregating for Gmeny, using the BVF-IGV pipeline established in our laboratory, identified a 10 bp deletion in the first exon of the candidate gene Glyma.02G304700. The causative mutation was verified by a variation analysis of over 500 genes in the candidate gene region and an association analysis, performed using two populations segregating for Gmeny. Glyma.02G304700 (GmHY2a) is a homolog of AtHY2a in Arabidopsis thaliana, which encodes a PΦB synthase involved in the biosynthesis of phytochrome. A transcriptome analysis of Gmeny using the Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed changes in multiple functional pathways, including photosynthesis, gibberellic acid (GA) signaling, and flowering time, which may explain the observed mutant phenotypes. Further studies on the function of GmHY2a and its homologs will help us to understand its profound regulatory effects on photosynthesis, photomorphogenesis, and flowering time.

Performance of soybean cultivars for increased seedling emergence after sowing in dry soil

Performance of soybean cultivars for increased seedling emergence after sowing in dry soil

First report of Macrophomina phaseolina causing сharcoal rot in soybean (Glycine max (L.) Merr.) plants in Uzbekistan.

The soybean production area is expanding in Uzbekistan. Soybeans were planted on an area of 10 thsd ha and the harvest amounted to 30 thsd metric tons in 2023 (IPAD, https://ipad.fas.usda.gov/countrysummary). Macrophomina phaseolina (Mp) is a soil- and seed-borne fungal pathogen causing economically important diseases of legume crops (Pennerman et al. 2024). Drought stress and a warm climate are favorable to this pathogen (Irulappan et al. 2022). Under these conditions, its microsclerotia survive for a longer period and become more virulent (Chamorro et al. 2015). In August 2022, typical symptoms of charcoal rot were observed in about 25% of "Orzu" soybean cultivar affecting 6 ha located on the experimental base "Durmon" of our institute. Diseased plants displayed the following charcoal rot symptoms: leaves turn yellow, then wilt, die, and remain attached to the plant; the lower portion of the stem and tap root have a light gray or ashy black discoloration; tiny black specks on the lower stem and root; after splitting the stem, it has the appearance of fine charcoal powder. In order to determine the causal agent of these symptoms, a total of 17 diseased plants were collected from focal lesions in soybean plantings. From each plant, twelve sections of stem and root tissue were selected, cut into small 5-mm pieces, and surface sterilized with 1% sodium hypochlorite for four minutes, then rinsed three times with sterile distilled water. The disinfected tissues were dried on sterile filter paper for 5 min and placed on PDA Petri plates, which were incubated in an incubation chamber for 3 days (16 h light (26oC) and 8 h dark (18oC)). Fungi were subsequently subcultured on PDA and incubated for 7 days to obtain pure cultures. Six monohyphal colonies were purified. The colonies showed dense growth, with a gray initial mycelium becoming darker with aging. After 8 days on PDA, black-colored microsclerotia with spherical to oblong shapes were observed. On average, they measured 60 µm in width and 130 µm in length (n = 30). From six isolated monohyphal colonies, one has been chosen for molecular-genetic identification. Molecular-genetic analysis was conducted by amplification and sequencing of the ITS region with the ITS1 and ITS4 primers (White et al. 1990). The resulting sequence was deposited in the NCBI database under accession number OQ073450. After BLAST analysis (Altschul et al. 1990) it was 100% identical with the reference sequences of Mp (accession MT039671, MT039663 and MH496040) isolated in sugar beet, maize and sunflower, respectively, from Serbia. In order to verify the pathogenicity, soybean seedlings (cv. Orzu) were dipped into spore suspension (1 × 107 spores/ml) of sequenced strain R-17 for 1 minute and transferred to a 15 cm diameter plastic pot with 350 g of sterilized soil mix. After 25 days, the inoculated plants showed classic charcoal rot symptoms, while the control plants remained healthy. The pathogen was successfully reisolated from the infected seedlings onto PDA, fulfilling Koch's postulate. The identity of the re-isolated strain was confirmed by morphological features and sequencing of the ITS region. It should be noted that in Uzbekistan, Mp has not been documented in any plants. Therefore, according to our knowledge, this is the first report of this fungus affecting soybean plants in Uzbekistan. Since molecular-genetic analysis of the R-17 strain showed clustering with strains from Serbia, we speculate that there may have been a recent introduction of Mp from Serbia into Uzbekistan. This assumption is additionally confirmed by the fact that Serbia is the largest seed exporter in Uzbekistan. The increase in charcoal rot disease poses a major challenge to soybean production in Uzbekistan. Understanding the genetic diversity of Mp can be utilized to manage this disease, improve soybean yield, and help soybean breeding programs in Uzbekistan.

Utilising soybean [Glycine max (L.) Merr.] wild and untapped genetic resources through pre‐breeding: Challenges and opportunities

AbstractSoybean is an economically important oilseed crop with diverse uses as food, feed, biofuel and so forth. Although the demand for soybean is growing rapidly worldwide, the narrow genetic base of released cultivars due to meagre utilisation of available wild and untapped genetic resources is a major factor contributing to stagnant production and productivity levels of soybean. Considering the continuously increasing global population, changing dietary habits, ongoing climatic fluctuations, rapidly evolving biotic stresses and shrinking land and water resources, utilisation of novel and diverse sources of variation is required for the genetic enhancement of soybean. To widen the genetic base of commercial soybean cultivars and to improve the genetic gain of the crop focused and systematic pre‐breeding efforts can play a game‐changing role by supplying novel genes in crop improvement programs. This article discusses the rationale of tapping wild and untapped genetic resources of soybean, gene pools, soybean genetic resources conserved ex‐situ and its utilisation status, genetic base of commercial soybean cultivars, identified novel genes and genomic regions in wild genetic resources, pre‐breeding efforts in India and strategies for incorporating desirable traits in the elite cultivated gene pool for fulfilling the requirements of farmers and other end‐users.

Comparative Transcriptome-Based Analysis of the Regulation of Leaf Senescence in the Upper and Middle Canopy of Different Soybean Cultivars

Premature leaf failure is one of the major factors contributing to crop yield reduction. High-yielding soybean cultivars exhibit a longer leaf lifespan during the reproductive period, promoting higher yields. In this experiment, physiological indexes and transcriptomics analysis were carried out on leaves of different canopy parts of two soybean cultivars with different senescence sensitivities of LD32 and SND28 as test materials. The results showed that the leaf senescence rates of the two soybean cultivars, tested at the grain-filling stage, were significantly different, and the senescence rates of the upper and middle canopy leaves of LD32 were significantly lower than those of SND28. In comparison to SND28, LD32 exhibited slower decreases in chlorophyll, net photosynthetic rate, and SPAD values in the upper and middle canopy leaves. The differentially expressed genes for senescence of upper and middle canopy leaves of both cultivars were enriched in four pathways: the photosynthesis pathway, the photosynthesis–antenna protein pathway, the MAPK signaling pathway–plant hormone signal transduction pathway, and the plant hormone signal transduction pathway. The differential expression of 20 genes (Ribose-5-phosphate isomerase, fructose-1,6-bisphosphatase, etc.) in the “carbon fixation in photosynthetic organisms” pathway of LD32 may be involved in the regulation of reducing the rate of leaf senescence in the middle of the canopy at the grain-filling stage of LD32. Ribose-5-phosphate isomerase and fructose-1,6-bisphosphatase in LD32 may reduce the rate of leaf senescence in the middle of the canopy during seed filling.