Identification of Molecular Markers Associated with Genomic Regions Controlling Agronomic Traits in Bread Wheat Genotypes Under Different Moisture Conditions

The study of the association between polymorphism at the DNA level and the diversity of phenotypic traits is an essential tool in breeding programs. To identify informative microsatellite markers related to agronomic traits, this research including 25 bread wheat genotypes was carried out. The experiment was set up in a randomized complete block design with three replications in rainfed and irrigated conditions during two cropping seasons (2018-2020) in the cold Mediterranean climate of Iran. Variance analysis showed significant differences between genotypes for most of the traits. The 16 microsatellite primers out of 20 had considerable polymorphisms, and three markers, namely XCFD168-2D, XGWM350-7D, and XGWM136-1A, were introduced as the most significant markers for subsequent studies. Cluster analysis by the UPGMA method classified 25 wheat genotypes into four groups. Genotypes 1, 3, and 25 have the most significant genetic distance with genotypes 13, 7, and Pishgam. Association analysis by stepwise regression showed that in both years under rainfed conditions, the XGWM350 marker for 1000-grain weight, the XCFD5 marker for spike length, and the XGWM165 and XGWM70 markers for spike dry weight, and under irrigated conditions, the XGWM265 marker for grain yield exhibited significant associations. Also, the XGWM136 and XCFD5 were found to be common markers associated with agronomic traits for all the test environments. In addition, most of the markers were associated with 1000-grain weight, mitt penalty length, and spike grain weight in rainfed conditions and 1000-grain weight in irrigated conditions. After identifying molecular markers related to increased yield and drought tolerance, they can be used as selection criteria to accelerate wheat breeding programs. Also, these marker-trait associations can help wheat improvement programs through marker-assisted selection.