PHYSIOLOGICAL, BIOCHEMICAL AND MULTIVARIATE CHARACTERIZATION IN HORSE GRAM (MACROTYLOMA UNIFLORUM (LAM.) VERDC.) GENOTYPES FOR SEED LONGEVITY

Abstract

Seed longevity is crucial for maintaining seed viability and vigour during storage, but the extent of storage induced deterioration varies among genotypes. Identifying physiological and biochemical traits associated with better seed longevity is essential for characterizing superior horse gram genotypes for seed production and breeding programmes. Therefore, the present study was undertaken to evaluate physiological, lipid peroxidation and antioxidant changes associated with seed longevity in 20 horse gram genotypes. Seeds were evaluated for seed germination, seedling vigour indices, test weight, electrical conductivity of seed leachate, volatile aldehydes, malondialdehyde, catalase and superoxide dismutase activities before and after six months of storage under ambient conditions. Freshly harvested seeds exhibited higher seed quality, whereas progressive deterioration occurred with storage. After six months of storage, genotypes GPM-6, TCR-1635, TCR-140, Indira Kulthi-1 and CRHG-8 maintained higher seed germination, seedling vigour, superoxide dismutase and catalase activities, with lower electrical conductivity of seed leachate, volatile aldehyde and malondialdehyde production, indicating comparatively better seed longevity. In contrast, genotypes CRHG-17, CRIDA-18R, IC-100938, VLG-8, CRHG 22 and KGP-14-9 exhibited greater deterioration and poorer storage performance. Correlation analysis indicated positive associations of seed germination and seedling vigour with antioxidant activities, whereas deterioration through lipid peroxidation related parameters showed negative associations with seed quality attributes. Principal component analysis revealed substantial multivariate variation, with the first four principal components explaining 84.05% of the total variation. Hierarchical cluster analysis grouped the genotypes into four distinct clusters, with Cluster 4 showing comparatively superior storage performance and KGP-14-9 exhibiting the poorest. These findings demonstrate that antioxidant defence, membrane stability and oxidative damage related traits are important indicators of differential seed longevity in horse gram genotypes.