Genetic analysis of resistance to stripe rust in some Iranian bread wheat cultivars and elite lines

Stripe rustis the most important disease of wheat in many wheat growing areas in Iran. Good knowledge of thegenetic basis of resistance to stripe rust in commercial bread wheat cultivars and selected elite lines is an important objective in wheat breeding programs. This study aimed to identify resistance genes and modes of inheritance of stripe rust resistance in recently released Iranian commercial wheat cultivars (Aflak, Parsi, Sivand, Uroum, and Pishgam) and elite bread wheat lines (M-84-14 and M-83-6). Crosses were made between these cultivars and elite lines with Avocet S and the F1, F2, and F3 generations were developed. Two F3-derived families (one adult plant stage and one seedling stage), as well as parents and controls, were grown under field and greenhouse conditions and inoculated with stripe rust pathotypes 134E158 A+, 166E150 A+, and 6E150 A+, Yr27. The adult plant responses of parental cultivars Aflak, Uroum, Parsi, Pishgam, Sivand, and elite lines M-84-14 and M-83-6 to stripe rust in the field were 40MR, 10R, 50M, 10R, 50MS, respectively, in 2011, and 60MR, 5R, 40MR, 30MR, and 40M, respectively, in 2013. Cultivars and elite lines were resistant to stripe rust at the seedling stage test. Avocet S was susceptible at both adult plant and seedling stages. In addition to the seedling resistance responses of the parents, frequencies of F3 lines for each of the crosses in both adult plant and seedling stages conformed well with those expected for segregating for a trait at two loci, indicating that all five cultivars and two elite lines carry two dominant seedling resistance genes that have so far been effective for controlling stripe rust in Iran.