Seedling-stage Heat Stress Adaptation in Indian Dwarf Wheat (Triticum sphaerococcum Perc.): Implications for Wheat Improvement

Heat Stress Adaptation in Indian Dwarf Wheat

Abstract

Heat stress is a major limitation to wheat establishment and productivity, particularly under increasing global temperatures. Seventy Triticum sphaerococcum genotypes along with nine bread wheat checks were evaluated at the seedling stage for heat tolerance using physiological (root and shoot length, relative water content, membrane stability index, seed vigour) and biochemical (proline, total protein, nitrogen content) traits. Heat stress significantly affected growth, water relations, and metabolic stability; however, several TS lines, notably TS 70, TS 31, and TS 21, outperformed bread wheat checks, including C 306 and PBW 677. Correlation analyses identified root length, MSI, RWC, proline content, and seed vigour as key determinants of tolerance. K-means clustering effectively distinguished tolerant and sensitive genotypes. The results highlight the inherent adaptive potential of T. sphaerococcum and its utility as a genetic resource for breeding heat-resilient wheat. Elite TS lines identified in this study can serve as donor material in early-generation crossing programs aimed at developing cultivars capable of maintaining physiological stability and productivity under heat stress, contributing to climate-resilient wheat improvement.