Production and evaluation of bread wheat doubled haploid lines with resistance to stem rust (Puccinia graminis f. sp. tritici)

Stem rust, caused by Puccinia graminis f. sp. tritici, is a devastating wheat disease, which can cause serious grain yield reduction. Doubled haploid (DH) technique reduces the time required for the development of new varieties by up to almost five years. In this study, three F1 wheat hybrids including W1: Ghods*3/MV17, W2: Flanders/3*Ghods and W3: Hybrid de Bersee/3*Ghods along with three maize genotypes, H1: KSC 108, H2: SC 301 and H3: SC 704, along with a mixture of pollen grains of these three genotypes (H4) were used to generate DH lines. During DH lines production some characteristics, such as percentage of seed set, haploid embryo and haploid plantlets, were studied. In total, 150 DH lines resulting from all crosses, along with their parents and three check cultivars, Parsi, Mihan and Bolani, were evaluated for their infection type to Pgt races PTMNC, TTSTK and TTKSK. Results indicated that differences between check cultivars for coefficient of infection induced with race PTMNC at the adult plant stage was significant. Also, for infection type at the seedling stage, differences between check cultivars inoculated with race TTSTK were significant (P<0.01), but non-significant reactions were observed for races PTMNC and TTKSK. Cluster analysis based on infection type and coefficient of infection showed that DH lines were classified into two major groups of susceptible and resistant when induced with all three races. In general, out of 150 DH lines that were evaluated at the adult plant stage with race PTMNC, 41 lines were resistant, and 109 lines were susceptible, while more than 50% of resistant lines belonged to the W3 population.