Genotype, Environment, and Their Interaction Drive Peanut (Arachis hypogaea L.) Grain Chemical Composition: Stability and Optimal Weather Thresholds Across Multi-Environment Trials

Abstract

Peanut grain quality is shaped by both genetic and environmental factors; however, their combined effects remain poorly understood across diverse production conditions. This study evaluated genotype (G), environment (E), and G × E interactions on oil, protein, mineral, carbohydrate, fatty acids and vitamin E in 26 advanced breeding lines and commercial cultivars across 12 environments in the main peanut production region of Argentina. The experimental design consisted of a randomized complete block design. Genotype stability was assessed using mixed Finlay–Wilkinson models for quality traits and environmental mean. Environment was the primary driver of variation in oil, protein, mineral, and fatty acid profiles, while carbohydrates were predominantly genotype-dependent. Warm conditions during the reproductive growth stage increased oil and mineral accumulation, whereas cooler, wetter environments favored carbohydrate deposition and higher polyunsaturated fatty acid content. Lines G14 and G23 and cultivars ASEM 400 INTA and ASEM 353 INTA showed high stability for oil content, whereas G5, G6, and VICTOR ASEM INTA for protein. Under combined heat and water stress, kernels showed reduced oil, increased protein, and higher fatty acid saturation. These findings support breeding strategies and agronomic decisions aimed at optimizing peanut quality and oxidative stability.