The Effect of Mineral N Fertilization and Bradyrhizobium japonicum Seed Inoculation on Productivity of Soybean (Glycine max (L.) Merrill)

Soybean yields can be considerably improved by inoculation with selected Bradyrhizobium japonicum strains and fertilization. The aim of this study was to assess the productivity of two soybean cultivars depending on the applied N mineral fertilizers and seed inoculation with B. japonicum. The study showed that on average, for both cultivars, the soybean yield was most favorably affected by the combined use of inoculation and nitrogen fertilization (increase in seed yield by 42%, protein yield by about 28%). The application of mineral nitrogen at the dose of 30 or 60 kg·ha−1 allowed the increase in the seed yield by about 17% and protein content by about 14% compared to the control. Inoculation of soybean seeds with B. japonicum increased the yield of soybeans by about 20%, proteins by about 10% compared to the control, and inoculation of Hi®Stick Soy favored a better yield than Nitragina. Inoculation of seeds with Nitragina or Hi®Stick Soy and fertilization with mineral nitrogen increased the content of protein and fiber in seeds of both soybean cultivars, as well as reduced the amount of ash and fat. The seeds of cv. Aldana had a higher amount of protein and ash than cv. Annushka, but a similar amount of fat and fiber.

Enhanced Soybean Productivity by Inoculation With Indigenous Bradyrhizobium Strains in Agroecological Conditions of Northeast Germany

Commercial inoculants are often used to inoculate field-grown soybean in Europe. However, nodulation efficiencies in these areas are often low. To enhance biological nitrogen (N) fixation and increase domestic legume production, indigenous strains that are adapted to local conditions could be used to develop more effective inoculants. The objective of this study was to assess the ability of locally isolated Bradyrhizobium strains to enhance soybean productivity in different growing conditions of Northeast Germany. Three indigenous Bradyrhizobium isolates (GMF14, GMM36, and GEM96) were tested in combination with different soybean cultivars of different maturity groups and quality characteristics in one field trial and two greenhouse studies. The results showed a highly significant strain × cultivar interactions on nodulation response. Independent of the Bradyrhizobium strain, inoculated plants in the greenhouse showed higher nodulation, which corresponded with an increased N uptake than that in field conditions. There were significantly higher nodule numbers and nodule dry weights following GMF14 and GMM36 inoculation in well-watered soil, but only minor differences under drought conditions. Inoculation of the soybean cultivar Merlin with the strain GEM96 enhanced nodulation but did not correspond to an increased grain yield under field conditions. USDA110 was consistent in improving the grain yield of soybean cultivars Sultana and Siroca. On the other hand, GMM36 inoculation to Sultana and GEM96 inoculation to Siroca resulted in similar yields. Our results demonstrate that inoculation of locally adapted soybean cultivars with the indigenous isolates improves nodulation and yield attributes. Thus, to attain optimal symbiotic performance, the strains need to be matched with specific cultivars.

Changes in soybean cultivars released over the past 50 years in southern Brazil

On-farm soybean yield has increased considerably in the last 50 years in southern Brazil, but there is still little information about how selection and breeding for yield increase has changed the agronomic attributes of cultivars. The objectives of this study were to evaluate the changes in soybean yield, seed oil and protein concentration, and changes in plant attributes that might be associated with yield improvement of 26 soybean cultivars released over the past 50 years in southern Brazil, sown simultaneously in a common field environment for two growing seasons. The average rate of yield gain was 45.9 kg ha−1 yr−1 (2.1% ha−1 yr−1), mainly due increased seed number per area and harvest index. Over year of cultivar release, cultivars became less susceptible to lodging, as well as plant mortality reduced. Meanwhile, the seed oil concentration increased, and seed protein concentration decreased, which could have negative consequences for soybeans use and requires further attention for breeding of future cultivars. Breeders have successfully contributed to the annual rate of soybean yield increase in southern Brazil. By our results, as well as the official on-farm production data, there is no evidence of soybean yield reaching a plateau in the near future in southern Brazil.

DETERMINATION OF HERBAGE YIELD AND QUALITY OF DIFFERENT SOYBEAN VARIETIES

Objectives of the present study are to determine the variations in forage yield and quality of soybean cultivars. Experiments were conducted in randomized complete blocks design with 3 replications during the growing season of 2016. A total of 10 cultivars were used as the plant material of the experiments (Bravo, A3127, Traksoy, İlksoy, Mersoy, Nova, SA-88, Arısoy, Safir, Atakişi). Cultivars had a significant effect on yield and chemical composition. Results revealed that green herbage yields varied between 826.39 - 1199.17 kg/da, dry hay yields between 247.71 - 357.90 kg/da, crude protein yields between 16.91 - 39.86 kg/da, acid detergent fiber (ADF) ratios between 26.56 - 34.61%, neutral detergent fiber (NDF) ratios between 38.43 - 44.85%, crude ash contents between 7.20 - 11.22%, crude protein contents between 6.66 - 13.53%, dry matter digestibility (DDM) values between 61.94 - 68.21%, dry matter intake (DMI) values between 2.68 - 3.12% and relative feed values (RFV) between 2.68 - 3.12. The results of the study showed that A3127 cultivar was found to be prominent with green herbage yield (1199.17 kg/da) and dry hay yield (357.90 kg/da) and Safir cultivar was found to be prominent with crude protein yield (39.86 kg/da). It was concluded that the soybean cultivars A3127 and Safir could be recommended for hay production.

Effects of phosphorus and iron on biomass production and nutrients partitioning in soybean cultivars under water stress condition

A pot experiment was conducted to investigate the effects of P and Fe application on the biomass production and nutrients partitioning of two soybeans (Glycine max. L. Merr) cultivars grown in carbonated chernoziom (low in Fe and P) under water stress conditions. P and Fe were applied at two levels (0 and 100 mg P kg-1 soil; 0 and 5 mg Fe kg-1 soil). Control plants were grown at 70% water holding capacity (WHC) while their counterparts were subjected to 35% WHC water stress at initial flowering stage for two weeks. Considerable variability was observed in leaves, roots dry mass accumulation and nodulation among the soybean cultivars (Zodiac, Licurici) at both P and Fe levels in relation to water regimes. The results showed that drought significantly reduced biomass production irrespective of nutrient supply and its adverse effect was more pronounced at low nutrient supply. Leaf development and nodules growth were the most sensitive to water deficit and insufficient nutrient supply. Adequate P and Fe supply increased dry matter production and nutrient concentrations for soybean cultivars. Phosphorus concentration in plant parts was significantly higher at nil Fe compared with Fe application. Phosphorus application decreased Fe allocation to the leaves. The experimental results demonstrated that there was a positive effect of P and Fe adequate nutrition on P use efficiency. Hence, the sufficient phosphorus and iron supply maintained growth at high level, improved P and Fe status and partially alleviated drought effect on soybean plants.

Search of the new SSR-loci of DNA for development of effective technology for soybean genotyping

Soybean is the major protein-oil crop of a huge economic importance. Currently, to describe the new cultivars being applied for a patent there are used the modern methods based on an analysis of microsatellite (SSR) loci of DNA. The purposes of this work were a search of the new microsatellite markers to optimize the existing technology of soybean cultivars certification and identification as well as selection of conditions for PCR analysis and to test them on cultivars from the VIR’s collection. Seven microsatellite loci demonstrated the high polymorphism level on soybean cultivars and located in the different chromosomes were chosen in the literary sources and librarian data bases. The optimal temperatures for annealing were selected empirically for all the pairs of SSR-markers. The results of DNA amplification of 20 soybean genotypes showed all seven studied SSR-loci were polyallel. In general, we revealed 22 alleles that on average are 3.1 per a locus. The effective number of alleles Ne for the studied soybean genotypes varied from 1.69 to 2.27 and on average was equal to 2.01. An average meaning of an index of the polymorphic information content (PIC) was 0.50. All the investigated soybean samples have the unique sets of alleles by the studied loci. Seven approbated loci can be used in development of an effective technology for identification and certification of the soybean genotypes.

A Correlation Study on In Vitro Physiological Activities of Soybean Cultivars, 19 Individual Isoflavone Derivatives, and Genetic Characteristics

The functionality of soybeans is an important factor in the selection and utilization of excellent soybean cultivars, and isoflavones are representative functional substances in soybeans, which exhibit effects on antioxidants, estrogen activity, and cancer, and prevent cardiovascular diseases. This study analyzed ABTS, DPPH, estrogen, ER (ER) alpha, UCP-1, and NO inhibition activities in 48 types of soybean cultivars, as well as the relationship with 19 isolated types of individual isoflavone derivatives. Statistical analysis was conducted to find individual isoflavone derivatives affecting physiological activities, revealing the high correlation of three types of derivatives: genistein 7-O-(6″-O-acetyl)glucoside (6″-O-acetylgenistin), genistein 7-O-(2″-O-apiosyl)glucoside, and glycitein. Based on these results, 15 types of soybean cultivars were selected (one control type, seven yellow types, six black types, and one green type), which have both high physiological activities and a high content of individual isoflavone derivatives. In addition, these high correlations were further verified through a genome-wide association study (GWAS) to determine the association between activities, substances, and genetic characteristics. This study comprehensively describes the relationship between the specific physiological activities of soybean resources, individual isoflavone derivative substances, and SNPs, which will be utilized for in-depth research, such as selection of excellent soybean resources with specific physiological activities.

Molecular characterization and genetic diversity studies of Indian soybean (Glycine max (L.) Merr.) cultivars using SSR markers

Background The genetic base of soybean cultivars in India has been reported to be extremely narrow, due to repeated use of few selected and elite genotypes as parents in the breeding programmes. This ultimately led to the reduction of genetic variability among existing soybean cultivars and stagnation in crop yield. Thus in order to enhance production and productivity of soybean, broadening of genetic base and exploring untapped valuable genetic diversity has become quite indispensable. This could be successfully accomplished through molecular characterization of soybean genotypes using various DNA based markers. Hence, an attempt was made to study the molecular divergence and relatedness among 29 genotypes of soybean using SSR markers. Methods and results A total of 35 SSR primers were deployed to study the genetic divergence among 29 genotypes of soybean. Among them, 14 primer pairs were found to be polymorphic producing a total of 34 polymorphic alleles; and the allele number for each locus ranged from two to four with an average of 2.43 alleles per primer pair. Polymorphic information content (PIC) values of SSRs ranged from 0.064 to 0.689 with an average of 0.331. The dendrogram constructed based on dissimilarity indices clustered the 29 genotypes into two major groups and four sub-groups. Similarly, principal coordinate analysis grouped the genotypes into four major groups that exactly corresponded to the clustering of genotypes among four sub-groups of dendrogram. Besides, the study has reported eight unique and two rare alleles that could be potentially utilized for genetic purity analysis and cultivar identification in soybean. Conclusion In the present investigation, two major clusters were reported and grouping of large number of genotypes in each cluster indicated high degree of genetic resemblance and narrow genetic base among the genotypes used in the study. With respect to the primers used in the study, the values of PIC and other related parameters revealed that the selected SSR markers are moderately informative and could be potentially utilized for diversity analysis of soybean. The clustering pattern of dendrogram constructed based on SSR loci profile displayed good agreement with the cultivar’s pedigree information. High level of genetic similarity observed among the genotypes from the present study necessitates the inclusion of wild relatives, land races and traditional cultivars in future soybean breeding programmes to widen the crop gene pool. Thus, hybridization among diverse gene pool could result in more heterotic combinations ultimately enhancing genetic gain, crop yield and resistance to various stress factors.

Genetic Relationships and Genome Selection Signatures Between Soybean Cultivars from Brazil and United States After Decades of Breeding

Soybeans are one of the most important crops worldwide. Brazil and the United States (US) are the world’s two biggest producers of this legume. The increase of publicly available DNA sequencing data as well as high-density genotyping data of multiple soybean germplasms has made it possible to understand the genetic relationships and identify genomics regions that underwent selection pressure during soy domestication and breeding. In this study, we analyzed the genetic relationships between Brazilian (N=235) and US soybean cultivars (N=675) released in different decades, and screened for genomic signatures between Brazilian and US cultivars. The population structure analysis demonstrated that the Brazilian germplasm has a narrower genetic base than the US germplasm. The US cultivars was grouped according to the maturity groups, while Brazilian cultivars were separated according to decades of releases. We found 73 SNPs that differentiate Brazilian and US soybean germplasm. Maturity-associated SNPs showed high allelic frequency differences between Brazil and US accessions. Other important loci were identified separating cultivars released before and after 1996 in Brazil. Our data showed important genomic regions under selection during decades of soybean breeding in Brazil and the US that should be targeted to adapt lines from different origins in these countries.