Genome wide association study for stripe rust resistance in elite spring bread wheat genotypes (Triticum aestivum L.) in Morocco

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases affecting wheat (Triticum aestivum L.) worldwide. Developing and deploying resistant cultivars is the most cost-effective and environmentally friendly method of combating this disease. However, because the pathogen continues to mutate, resistance genes are quickly overpowered by newly virulent Pst races, requiring the continuous identification and introduction of resistance genes to create resistant wheat varieties. To identify closely linked markers for possible use in marker-assisted selection a genome-wide association study was conducted using rust data at adult plant stages for 200 elite spring bread wheat genotypes and 13151 SNP markers. Stripe rust resistance was evaluated under rainfed conditions at the ICARDA Merchouch station in Morocco during the 2019–2020 and 2020–2021 crop seasons. The genotypes were classified into five distinct categories based on the coefficient of infection (CI), 18 genotypes were highly resistant, while 42 were moderately resistant (21%), additionally, 73 were intermediate (37%), while 26 were moderately susceptible (13%), and the remaining 41 genotypes highly susceptible. Thirteen markers were associated with stripe rust resistance through GWAS analysis using a general linear model. Four of these markers for adult plant resistance (Kukri c8390 1515, CAP7 c5481 96, Excalibur c35203 334, and BS00017187 51) on chromosomes 1B, 5B, 3B, and 7B, correspondingly, are of particular importance and could be used for marker-assisted selection to pyramid rust resistance genes in wheat breeding programs.