Discerning Genetic Diversity in Soybean (Glycine max L.) Genotypes Using Morphological Descriptors and Molecular Markers

Background: Soybean is an important oilseed crop of India with 56% share in total oil production, whose improvement relied on the availability of diverse germplasm. Aim: In order to find diverse genotypes of soybean for future breeding programs, a diversity study was conducted with 24 soybean genotypes using qualitative, quantitative traits and SSR markers. Study of Design: The experiment was laid out at Crop Research Centre, Govind Ballabh Pant University of Agriculture and Technology in randomized block design with three replications during kharif 2017. Methodology: The experimental material was planted in five rows per plot, each with a length of four meters spaced at 45 cm. Plant-to-plant distance was maintained at 5-7 cm after thinning. Result: Among nine qualitative characters, hilum colour categorised genotypes into four groups. The estimated values of the PCV were higher than GCV with a narrow difference for all the characters studied. Harvest index showed the highest PCV (29.37%), GCV (28.07%), and genetic advance as per cent mean (55.30%) while days to maturity (93.44%) showed the highest heritability in a broad sense (h2b). SSR characterization furnish total of 61 alleles, including unique alleles where the highest alleles and PIC values were found in 12 (Satt 281) and 0.922 (Satt 228), respectively. Based on qualitative traits, the UPGMA dendrogram categorised 24 genotypes in four major clusters, where genotypes PS1024 showed the highest diversity with Shilazeet, PK262, PS19 and UPSM534. Dendrogram of quantitative traits showed the maximum D2 distance between genotypes of cluster IV and I. SSR dendrogram produced five clusters where the following genotypes (Alankar and PS23, PK1029 and PS20, PS20 and UPSM534) showed maximum diversity with each other. The clustering pattern did not have congruency at qualitative, quantitative and SSR characterisation levels. Nevertheless, few genotype pairs, i.e. Bragg and UPSM534, PS20 and PK1029, PS20 and UPSM534, PS1347 and UPSM534, shared a distinct clustering group in all three clustering patterns. Conclusion: The combined morphological and molecular characterisation identified genetically diverse parental lines that can be effectively utilised in soybean breeding programmes aimed at yield improvement and genetic enhancement.