Seed Coat Permeability Studies in Wild and Cultivated Species of Soybean

Soybean [Glycine max (L.) Merr.] Seeds loose viability at a rapid pace under tropical and subtropical conditions. Poor seed longevity in cultivated soybean genotypes may associates with seed size, testa colour and seed coat permeability. Present study aims to understand kinetics of imbibation and evaluate the seed coat permeability in Glycine tomentella, Glycine soja and Glycine max. Out of all 125 genotypes of three species, 20 genotypes of wild annual and perennial species were small and hard seeded. All black seeded genotypes of three species including cultivated soybean were small in size, suggesting positive correlation of testa colour with seed size. There was strong positive correlation between 100 seed weight and seed coat permeability percentage based on 6 hours rapid imbibation test (0.83) and Seed coat permeability assessment in germination paper after 7 days (0.81). Kinetics of Imbibation suggest that G. max starts uptake water after some minutes, but seeds of G.tomentella imbibes water after 78 hours. Seed weight of G. soja genotype remained constant even after 4 days. Genotype of G. max (DS 9712) imbibes water up to 24 hours with steady linear curve, after that it becomes constant up to germination. Variability in seed coat permeability (44%) after 7 days slow imbibation in G. soja (DC 2008-1) suggests its use in introduction of optimum permeability behavior in G. max to slow down the extra leaching for improvement in seed longevity.