تفکیک فاکتورهای بیماری زایی در پنج نژاد پر آزار زنگ زرد گندم (Puccinia striiformis f.sp. tritici) و شناسایی منابع مقاومت نسبت به آنها

Identifying the virulence factors of stripe rust (Puccinia striiformis f. sp. tritici) disease, awareness of numbers and identification of resistance genes in wheat breeding materials, accelerate the process of producing the resistance cultivars which are sustained against different races. To study the genetic and pathogenic and non-pathogenic spectrum of genes, five hot races of stripe rust which were collected from Mashhad, Sari, Ardabil, Moghan and Zarghan were determined using the international standard and differential genotypes and isogenic or near isogenic lines with separate race identification experiments. According to reactions, the races were­ called­ 6E158A+, ­230E158A+, ­6E142A+, 166E150A+, and 198E130A+. Based on the results for the plants carrying the genes Yr2, Yr2+, Yr6, Yr7, Yr7+, Yr9, Yr11, Yr17, Yr18,Yr22, Yr23, Yr25 and YrA, virulence was observed in all studied races and in plants carrying genes Yr1, Yr3, Yr4, Yr5, Yr10, Yr15, Yr24, YrSP and YrCV, however, no virulence was observed against none of races. Then resistance reaction of 45 wheat genotype was separately evaluated against 5 studied races, based on a randomized complete block design with three replicates in the seedling stage. In study of the components resistance to stripe rust, latent period and infection type traits were recorded in greenhouse studies. Analysis of variance showed that there were significantly different in genotypes against pathotypes, but genotypes did not show similar reactions to different pathotypes. Probably, the YrND, YrSD, YrSU, Yr32 and Yr27 genes alone or in combination with each other, or with other unknown genes are either cause strength in genotypes with race-specific resistance caused resistance to races that were not pathogenic to these genes. The use of resistance genes in genotypes with seedling resistance is likely to be widespread in areas where similar races are common. While, the possibility of observing resistant adult plants in field conditions despite showing susceptibility under greenhouse conditions is not ruled out.