Genetic Diversity and Dissection of Agronomic Traits in Durum Wheat Grown Under Contrasting Environments in Algeria

Durum wheat productivity in Mediterranean regions faces growing challenges from drought and heat stress. Understanding the genetic architecture of diverse germplasm is therefore essential to support pre-breeding efforts and enhance stress adaptation. In this context, 125 durum wheat genotypes were evaluated for agro-morphological traits across two contrasting Algerian locations over two growing seasons. A subset of 94 genotypes, selected on the basis of phenotypic characterization, was genotyped using the Illumina 7K SNP array. Population structure analysis revealed two to four subgroups, with linkage disequilibrium decaying at 4.09 Mb. Genome-wide association analysis identified 27 distinct significant SNPs associated with eight traits, with most associations detected for spike length, thousand-kernel weight, and plant height. The marker TGWA25K-TG0010 on chromosome 4A showed pleiotropic effects on plant height and peduncle length and co-localized with the Dwarf8 and gibberellic-acid-insensitive genes. Additionally, wsnp_Ex_c2033_3814035 on chromosome 2A was associated with heading earliness and the number of fertile spikelets per spike, and wsnp_Ku_c51039_56457361 on chromosome 5A with plant height and peduncle length in a single site and season. Several other environment-specific associations were also identified. These results support future studies in which the identified markers may be deployed in breeding strategies aimed at improving yield stability and stress adaptability in durum wheat under Algerian conditions.