Inheritance of Resistance to Stripe Rust (Puccinia striiformis f. sp. tritici) in some Cultivars and Promising Lines of Wheat

Yellow rust is an important disease of wheat in Iran. The use of resistant cultivars is the most effective, economic and environmentally safe method to control the disease. The main objective of this study was to gain a better genetic understanding of resistance to yellow rust in ten Iranian wheat cultivars and promising lines including Chamran, Marvdasht, Shirodi, Pishtaz, Shiraz, Dez, N-75-16, N-75-15, C-78-7 and C-78-18, which were crossed with the susceptible parent Avocet"S" . Pathotype 134E134A+ with virulence on Yr2, Yr6, Yr7, Yr9 and YrA genes were used in this study. F2 populations and F3 families were studied in the green house (seedling stage) and field (adult plant stage) where they were exposed to artificial inoculation of yellow rust. F2 populations were classified into resistant and susceptible classes. F3 families were classified into three classes: homozygous resistant, segregating and homozygous susceptible. The number of genes involved was then estimated from the frequencies of families classified in each class. The results of F2 and F3 from the crosses Chamran/ Avocet "S" and N-75-16/ Avocet"S" suggested one seedling gene for each one. Crosses between Marvdasht, Shirodi, Pishtaz, Shiraz and Dez with Avocet "S" were segregated for two independent dominant genes, one as seedling resistance and the second as adult plant resistance gene. The F3 families in cross C-78-7 with Avocet"S" were segregated for two genes effective in adult plant stage. The results from the cross C-78-18/ Avocet"S" suggested two complementary dominant genes in adult plant stage, and the Cross N-75-15/Avocet"S" segregated for three dominant genes.