Identification of resistance sources for brown rust disease (Puccinia recondiata f. sp. Tritici Eriksson) in Aegilops tauschii accessions

Identification of resistance gene sources in seedling and adult plant stages is important to developing durable wheat cultivars. In this study, 100 genotypes of Aegilops tauschii, collected from natural habitats were evaluated in the experimental field of the Iraqi-mahaleh, Gorgan. Seeds were planted on one meter length lines and inoculated with Golestan leaf rust pathotypes in a randomized complete block design with three replications. The reaction of genotypes was also evaluated in greenhouse, by six Iranian pathotypes based on a completely randomized design with two replications in seed and plant improvement institute (SPII). To evaluate resistance in filed, we used infection type, AUDPC, final disease severity and coefficient of infection indices. The results showed that in greenhouse, the frequency of resistant, moderately resistant, moderately susceptible and susceptible genotypes were 7, 13, 13 and 67 percent, respectively. In field, the regarding frequencies were 14, 49, 7 and 30 percent. The correlation coefficient between final severity of infection, with the values of coefficient of infection and area under the disease progress curve, were 0.97 and 0.95, respectively. Accordingly, 57 genotypes with the desired characteristics, namely final infection intensity of 3.5-40, infection coefficient of 1.4-30 and rAUDPC, 1-32% were identified with MS and MR responses for resistance. Forty-six genotypes were susceptible in seedling stage and resistant in adult plant stage. Some genotypes originated from Afghanistan, Azerbaijan, China and Uzbekistan were resistant to all isolates which could be considered as appropriate sources of resistance to leaf rust disease for breeding of cultivated wheat species.