Association analysis of yellow rust, fusarium head blight, tan spot, powdery mildew, and brown rust horizontal resistance genes in wheat

Abstract

Identification of resistance sources in wheat germplasm is necessary to control prevalent disease. In order to, detecting resistant individual, cluster analysis, genetic diversity, population structure, and also for identifying novel molecular markers associated with horizontal resistance genes, 297 wheat genotypes were examined. To this end, five separate experiments were conducted in Gharakhil-Qaemshahr using α‐lattice design with three replications. The five experiments evaluated the genotypes’ resistance to wheat diseases. The genotype by trait biplot demonstrated that genotype 19 had the highest single disease resistance to yellow rust, fusarium head blight, and tan spot diseases. Moreover, Genotypes 27 and 3 had the highest single disease resistance to powdery mildew and brown rust diseases, respectively. The genotypes 27, 17, 27, and 19 had the highest joint disease resistance of yellow rust-brown rust, yellow rust-powdery mildew, brown rust-powdery mildew and fusarium head blight-tan spot, respectively. Furthermore, the former, genotype 17, was introduced as the most resistant genotype in the studied germplasm because it had the shortest distance from the ideal genotype. Cluster analysis using iPBS and SSR showed four and five different clusters, respectively. The iPBS2383 and BARC1027 markers had the highest values of genetic diversity indices. The structure analysis demonstrated four and five potential subgroups using iPBSs and SSRs, respectively. The iPBS2226C and BARC275 (yellow rust resistance), iPBS2080A and BARC17 (fusarium head blight resistance), iPBS2383D and BARC87 (tan spot resistance), iPBS2271A and BARC318 (powdery mildew resistance), iPBS2217B and BARC303 (brown rust resistance) had the highest R2 (P < 0.01) and were detected by both general and mixed linear models. Overall, the 37 and 6 novel marker-trait associations were traced for single and joint diseases resistance, respectively. To suggest that after the confirmation and validation of the informative markers identified in the current study, they can be used in fine mapping and marker-assisted selection to provide cultivars resistant to prevalent diseases.