Environmental adaptation of small-seeded lentils (Lens culinaris) in Indian climates: Insights into crop–environment interactions, mega-environments, and breeding approaches

This study aimed to evaluate the impact of diverse environments on agronomic traits of small-seeded lentils in India and to identify strategic environment(s) for crop improvement using empirical approaches. Sixteen small-seeded lentil genotypes were tested across 16 locations, covering North Hill Zone (NHZ), North Western Plain Zone (NWPZ), and North Eastern Plain Zone (NEPZ). Crop yield exhibited a quadratic response to maximum temperature during flowering (TMAX_F) and minimum temperature during reproductive period (TMIN_RP), indicating that both higher and lower TMAX_F (optimal = 23.5°C) and TMIN_RP (optimal = 12.0°C) negatively affected yield. Low temperatures extended crop duration, and correlation analysis confirmed that environment-induced variations in vegetative or maturity periods significantly influenced yield, as further validated by regression models and principal component analysis. While an extended reproductive period increased seed weight, its association with grain yield was non-significant. Among the tested zones, NWPZ recorded the highest average yield (1359 kg ha⁻¹), while NEPZ (1269 kg ha⁻¹) demonstrated greater yield consistency across locations. Genotype, environment, and genotype-by-environment interaction (GEI) contributed 6%, 53%, and 36% of the total yield variation, respectively. Biplot analysis identified three distinct mega-environments, with Durgapura (NWPZ), Varanasi (NEPZ), Faizabad (NEPZ), and Berthin (NHZ) emerging as ideal testing sites. This study highlights the significant influence of diverse agroclimatic conditions on crop yield and emphasizes the need for region-specific breeding to harness positive GEI (at mega-environment scale) and to prioritize early flowering and optimal seed traits to achieve broader adaptability across Indian climates.