Molecular Characterization of heat tolerance in bread wheat ( <i>Triticum aestivum</i> L.) cultivars/lines using genomic SSR markers
Abstract
Wheat (Triticum aestivum L.) production is increasingly threatened by rising global temperatures. This study evaluated heat tolerance in six wheat varieties/lines using phenotypic and molecular approaches. Seedling and root length responses to optimal (25°C) and heat stress (35°C) conditions were assessed, revealing significant variation in heat tolerance. Notably, KR12-5003 exhibited high tolerance based on seedling length (HTI = 71.8%) and moderate tolerance by root length (HTI = 36.6%). Molecular analysis with 40 SSR markers (24 polymorphic) generated 87 alleles, demonstrating substantial genetic diversity (average 3.6 alleles/locus, PIC: 0.01-0.81, He: 0.05-0.83). Cluster analysis revealed a marked genetic distance between KR12-5003 and the other genotypes, suggesting unique alleles for heat tolerance in this line. Two sub-clusters were observed within the remaining genotypes, indicating varying degrees of genetic similarity. This research highlights the value of combining phenotypic and molecular methods to dissect heat tolerance and identifies KR12-5003 as a potentially valuable genetic resource for improving heat tolerance in wheat. Further research on these genotypes will facilitate the development of climate-resilient varieties.