Impact of seed hardness on quality in variety VBN- 8 of black gram (Vigna mungo L. Hepper) during maturation

The present study was performed to record the formation of hard seeds during the development and maturation of Blackgram variety VBN-8 under field conditions, which were then assessed and evaluated under laboratory conditions. It also focused on analyzing the biochemical properties, seed quality parameters and structural characteristics using Scanning Electron Microscopy (SEM). The findings could help develop strategies to improve germination rates and overcome seed dormancy. The present study on complex seed formation in black gram variety VBN-8 during the development and maturation stage was carried out using seed samples collected from standing crops 3 to 38 Days after Anthesis. The formation of hard seeds was assessed and evaluated from the seed sample taken from the different stages of development and maturation (3 to 38 DAA) of the black gram variety VBN-8. The physical and physiological parameters were studied as per the ISTA rules. The biochemical properties were estimated using the fractionation method and histological studies were conducted using SEM analysis. The present investigation revealed that a higher percentage of complex seed formation was observed at 33 DAA when the seed attained physiological maturity. The biochemical analyses showed that hard seeds have much higher quantities of pectin (4.68%), cellulose (4.27%), hemicellulose (2.55%), lignin (2.30%) and phenolic contents (5.78%) as compared to non-hard seeds of lower quantities of pectin (2.01%), cellulose (1.27%), hemicellulose (1.87%), lignin (0.54%) and phenolic contents (3.68%). The SEM analysis revealed that hard seeds have a thick cuticle (60.96 µm), a waxy layer, a compartmentalized pattern, amorphous deposits and a rough texture, all hindering water uptake.In contrast, non-hard seeds exhibit a smoother surface with fewer deposits and thinner cuticles (33.81 µm), enhancing their permeability. Additionally, in hard seeds, water entry points like the micropyle and hilum are often obscured or blocked, making water absorption difficult. Conversely, non-hard seeds feature a more visible hilum and an open micropyle, readily allowing water to enter. Understanding these changes in seed coat qualities can help agricultural experts regulate dormancy, provide suitable germination conditions and plan for sowing seed storage and crop management techniques.