Genetic structure and marker-trait association analysis for agro-morphological and physiological characteristics in germplasm of wild barley (Hordeum vulgare subsp. spontaneum)

Wild barley (Hordeum vulgare subsp. spontaneum) germplasm is a valuable genetic resource for improving cultivated barley. The western regions of Iran, natural habitats for diverse wild barley populations, offer rich genetic diversity for enhancing economically important traits. This study examined 114 genotypes from western Iran, assessing their agro-morphological and physiological traits under both irrigated and rainfed conditions. The goal was also to identify informative SSR markers associated with these traits. Field trials were conducted over two agricultural years (2020-2021 and 2021-2022) using an augmented design with nine control genotypes. Significant variations in agronomic and physiological traits were observed, highlighting the interactive effects of genotype and environmental conditions. Genotype by environment interaction revealed significant differences at the 1% and 5% probability levels for traits other than spike length, number of seeds per spike, and flag leaf length. Population structure analysis classified these genotypes into 7 subpopulations. Marker-trait associations identified SSR markers linked with stress tolerance and yield-related traits. Notably, markers EBMAG0781, BMAG0323, and SCSSR04163 exhibited significant associations with various morphological and physiological traits under both conditions. These findings emphasize the extensive genetic diversity present in wild barley and its potential for breeding programs aimed at enhancing barley's adaptation to diverse environmental.