Unlocking qualitative traits diversity in soybean [Glycine max (L.) Merrill] genotypes

Glycine max (L.) Merrill is a vital leguminous oilseed crop valued for its high protein and oil content, contributing significantly to human and animal nutrition. Understanding genetic diversity exist within soybean germplasm lines is essential for breeding, conservation and crop improvement. This study aimed to assess the qualitative trait variability present among 153 soybean genotypes to aid in genotype classification and conservation strategies in future crop improvement programmes. The experiment was conducted at Zonal Agricultural Research station ZARS, Morena, RVSKVV, Gwalior, Madhya Pradesh, India during the Kharif 2024, using an augmented block design. Ten morphological traits viz., hypocotyl colour, leaf shape, leaf colour, plant growth habit, flower colour, pod pubescence, seed shape, seed colour, seed lustre and hilum colour were evaluated following the Protection of Plant Varieties and Farmers’ Rights Authority (PPVFRA) and Distinctiveness, Uniformity and Stability (DUS) testing criteria. The results indicated existence of considerable phenotypic variation among the genotypes. For instance, the semi-erect growth habit, which was predominant and observed in 122 genotypes and dark green leaf colour, which was the most common and recorded in 102 genotypes. The Shannon diversity index (H′) identified seed hilum colour as the most variable trait, suggesting its potential utility in genetic improvement. Cluster analysis (UPGMA) classified the genotypes into two major clusters, providing insights into genetic relationships and aiding in parental selection for hybridization. These findings underscore the importance of morphological characterization in genotypic classification, germplasm conservation and utilization in breeding programmes. This study provides a scientific foundation for soybean genetic resource management, supporting breeding efforts for improved yield, adaptability and sustainability.