From landraces to haplotypes, exploiting a genomic and phenomic approach to identify heat tolerant genotypes within durum wheat landraces

Abstract

Dry and hot climates severely impact wheat yields, necessitating the development of innovative solutions to accelerate the breeding and selection of more adaptable durum wheat genotypes. The aim of this study was to identify new wheat ecotypes that can bridge the gap between commercial varieties and adaptability to ongoing climate change. In this study, advanced genomic and phenomic techniques were combined to characterize a set of durum wheat landraces derived from single seed descent (SSD). This approach enabled the identification of novel variability in the TdHsp26-A1 and -B1 genes. As a result, 38 durum wheat genotypes were analyzed using targeted enrichment PCR, leading to the identification of 17 novel haplotype combinations with SNPs in the TdHsp26 genes. The response of these SSD haplotypes to heat stress was characterized at both the seedling and tillering growth stages. Phenotypic analysis of contrasting genotypes led to the selection of two distinct genotypes: SSD69 and SSD397. During heat stress, SSD69 exhibited altered accumulation of H₂O₂ and MDA content under both growth conditions, providing new insights into the oxidative response to heat stress. Additionally, this work identifies phenotypic traits that are suitable for detecting differences between variants. The geographic distribution of the different alleles aligned with the spread of durum wheat from its center of origin.