Spatial Variation and Adaptive Responses of Tall-Type Field Peas (Pisum sativum L.) Across Indian Subcontinent.

Understanding crop performance across diverse agro-ecologies is crucial for developing region-specific breeding strategies. This multi-location study examined the impact of diverse environments on crop eco-phenology and genotype-by-environment interactions (GEI) of tall-type field pea breeding lines. Empirical methods were employed to identify strategic locations that support higher yields and unique genotypic traits. The results revealed significant variations across locations, with coefficients of variation for key traits as follows: days to flowering (31%), days to maturity (20%), reproductive period (19%), yield (35%), and seed weight (31%). Environmental component accounted for the largest yield variation (78%), followed by GEI (13%). Correlation analysis indicated a significant influence of both temperature extremes, particularly maximum temperature during flowering, on crop yields. Higher minimum temperatures during flowering and reproductive period were associated with reduced yields, while extended crop duration in cooler regions also negatively impacted yields. A significant quadratic relationship between seed weight and yield underscored the importance of seed weight as a yield-stabilising trait. GGE-biplot analysis identified four mega-environments, and designated Faizabad, Pantnagar, Varanasi, and Kota as ideal testing sites for selecting genotypes with broader adaptability. These findings provide valuable insights for redesigning field pea breeding programmes at the national level.