Drought Susceptibility Index; a Preferred Criterion in Screening for Tolerance in Soybean

Soybean (Glycine max L.) yield and yield related traits are constrained by drought. Adaptation of soybean to changing environment could be improved by exploitation and introgression of diverse germplasm in breeding program. In present study, the response to drought conditions, especially at flowering stage, was evaluated to determine the potential soybean germplasm for future soybean breeding programs in Pakistan. Field experiment was conducted under two water regimes i.e. well-water and water-limited, to assess the effect of drought in seed yield and yield related traits. Although, drought led to overall reduction of ~15 % in thousand seed weight but still some soybean genotypes performed relatively better under water-limited conditions. These genotypes were also tolerant to drought, with a drought susceptibility index of \u3c 0.5. PCA also explained the pattern of variation existing in soybean germplasm grown under given water regimes i.e. well-water and water-limited conditions. The identified soybean genotypes could be a favorable resource to introduce high yielding soybean in local environment

Genome-Wide Characterization and Sequence Polymorphism Analyses of <i>Glycine max</i> Fibrillin (<i>FBN</i>) Revealed Its Role in Response to Drought Condition

The fibrillin (FBN) gene family is widely distributed in all photosynthetic organisms. Members of this gene family are involved in plant growth and development and their response to various biotic and abiotic stress factors. In this study, 16 members of FBN were identified in Glycine max and characterized by using different bioinformatics tools. Phylogenetic analysis classified FBN genes into seven groups. The presence of stress-related cis-elements in the upstream region of GmFBN highlighted their role in tolerance against abiotic stresses. To further decipher the function, physiochemical properties, conserved motifs, chromosomal localization, subcellular localization, and cis-acting regulatory elements were also analyzed. Gene expression analysis based on FPKM values revealed that GmFBNs greatly enhanced soybean drought tolerance and controlled the expression of several genes involved in drought response, except for GmFBN-4, GmFBN-5, GmFBN-6, GmFBN-7 and GmFBN-9. For high throughput genotyping, an SNP-based CAPS marker was also developed for the GmFBN-15 gene. The CAPS marker differentiated soybean genotypes based on the presence of either the GmFBN-15-G or GmFBN-15-A alleles in the CDS region. Association analysis showed that G. max accessions containing the GmFBN-15-A allele at the respective locus showed higher thousand seed weight compared to accessions containing the GmFBN-15-G allele. This research has provided the basic information to further decipher the function of FBN in soybean