Characterization of yellow rust (Puccinia Striiformis) resistance in A F6 durum wheat population

Abstract

Nearly half of the agricultural land in Turkey is devoted to wheat. Turkey is one of the leading durum wheat producers in the Middle East and one of the most important biotic stress factors restricting the production is yellow rust. An F6 recombinant inbred line durum wheat population from a Kunduru-1149 X Cham-1 cross was previously characterized for field resistance by Göçmen et al. (2003). The 150 lines of the population showed differing reactions to yellow rust in the field. The work done in this M.S. thesis was aimed at characterizing the yellow rust seedling resistance of this population and developing markers linked to this resistance. The 150 lines were tested for seedling resistance using a yellow rust isolate virulent on yellow rust resistance genes Yr2, Yr6, Yr7 and Yr9 representing the virulence profile of the yellow rust isolate used by Göçmen et al. (2003). The 150 lines were categorized based on their seedling resistances, 4 categories were formed, the majority of the lines being resistant. Based on the ratios observed in the seedling test, 53 of the 150 lines were chosen to constitute a sub-population. This subpopulation was used to screen for SSR and NBS-profiling markers. Three linkage groups were formed and alleles of the SSR and NBS-profiling markers were compared to seedling and adult phenotypes (Göçmen et al., 2003) using the Kruskal-Wallis single marker regression analysis program in MapQTL version 5 for Windows. Two QTLs were found on chromosome 1BL where the NBS-profiling band NBS3 290 was linked to three SSR markers. Three of the NBS-profiling bands were excised and cloned into a pGEM-T Easy vector and sequenced. The obtained sequences were analyzed using the BLASTX program. These sequences show homology to known NBS-LRR resistance genes in plants. Due to this sequence homology and results of the linkage analysis, we predict the presence if two QTLs on chromosome arm 1BL.