Eco-phenological drivers of black gram (Vigna mungo (L) Hepper) productivity in diverse environments and their implications for crop improvement

Abstract

Context

Insights into crop eco-phenology and genotype-by-environment interaction (GEI) are essential for advancing crop improvement strategies.

Objectives

This study aimed to (i) elucidate the impact of diverse climatic conditions on the eco-phenology and productivity of black gram and their associations and (ii) evaluate GEI to identify mega-environments for targeted breeding.

Methods

Twenty-nine black gram genotypes were evaluated across twenty-seven locations spanning five agro-climatic zones of India to delineate crop-environment associations and assess the contribution of GEI factors. Empirical methods were employed to identify mega-environments and ranking genotypes’ stability.

Results

Substantial variability in crop traits across locations, measured as coefficients of variation, were observed for days-to-flowering (14 %), days-to-maturity (10 %), reproductive period (RP) (20 %), grain yield (30 %), and 100-seed weight (13 %). Environmental factors accounted for the largest proportion of yield variability (61 %), followed by GEI (31 %). Minimum temperature during flowering and RP significantly influenced grain yield, with high cumulative heat units and low humidity during RP favoring higher productivity. Grain yield demonstrated a positive association with extended RP. The study identified six mega-environments as well as ‘ideal’ testing locations with high desirability indices to enhanced selection efficiency. Among the tested genotypes, IU 92–14 emerged as the most stable across diverse Indian climates.

Conclusion and significance

The findings underscore the substantial influence of climatic factors on the phenological developments and productivity of black gram. Strategic breeding program tailored to the identified mega-environments will be pivotal in leveraging positive GEI effects to improve yields in India, with the potential for extrapolation to international contexts.