Association Mapping of Seedling and Adult Plant Resistance for Stripe Rust Resistance in Spring Bread Wheat ( Triticum aestivum L.)

Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici, is one of the major diseases of wheat in the world. Development and use of resistant wheat cultivars is the most economical and environmentally friendly solution in combating wheat stripe rust. Field experiments were carried out at two sites in Ethiopia (Kulumsa and Meraro) and seedling tests were conducted at KARC green house during the 2015 cropping season to evaluate the response of 198 elite spring bread wheat genotypes and two checks to the prevailing races of stripe rust at adult plant and seedling stages. The genetic profile of the 198 genotypes was assessed using 13006 SNP markers and an Association mapping was explored to determine marker-trait association. About 72.5% and 42.5% of the lines exhibited resistance to stripe rust during the field screening at Kulumsa and Meraro, respectively. Only 8,966 of the SNPs were polymorphic and hence used for association mapping analysis. Almost half of these markers were on known chromosomes but had no position on the consensus map of bread wheat. Analysis of population structure revealed the existence of three clusters. Fifty-three SNPs and 21 SNP markers in ten genomic regions were significantly associated with yellow rust resistance at adult plant st and seedling stages, respectively. The locus on chromosome 1 AL appeared to be a novel quantitative trait locus (QTL) not reported so far. The locus on chromosome 1 AL appeared to be a novel quantitative trait locus (QTL) not reported so far there are different markers that are associated to resistance like, BS00022733_51, wsnp_Ex_rep_c69738_68695568, wsnp_Ex_rep_c108951_9195419, CAP12_c1906_217 and TA003955-1138.