Assessment of Hardseededness and Its Seasonal Dynamics Through Scanning Electron Microscopy in Green Gram (Vigna radiata) Genotypes

Abstract

Hardseededness is attributed by impermeable seed coats which mechanically restricts embryo growth and delays germination even under suitable conditions. The presence of larger proportion of hard seeds delays germination and can reduce crop yield due to uneven growth and stand establishment. The information regarding the seed surface characteristics in regulating the hardseededness in green gram is still insufficient. This study addressed the knowledge gap by examining the seasonal impact on development of hard seed and seed surface characteristics in green gram. In predominantly hardseeded (HS) genotypes, there was a decrease in hard seeds during the summer season compared to Kharif season. Scanning electron microscope analysis revealed that HS genotypes had smoother surfaces, closely packed hilum cells, and closed strophioles, while non-hardseeded (NHS) genotypes had rougher surfaces, opened strophioles, and loosely packed hilum cells. Seeds from HS genotypes in the summer season had characteristics of non-hard seeds like opened strophioles and loosely packed hilum cells, making them permeable to water. Scanning electron microscope features effectively differentiated between HS and NHS genotypes and seeds produced in different seasons. This information may be used for identification of genotypes and seed lots with desirable hard seed percentage through high-throughput image analysis.