Study of genetic diversity of resistance to yellow rust in bread wheat germplasm

This research was performed with the purpose of screening of wheat genotypes and identification of resistance sources to yellow (stripe) rust disease. A total of 284 accessions from bread wheat collection of National Plant Gene Bank of Iran, which were previously received from 19 countries, were evaluated at adult plat stage under natural incidence of the disease in field condition of Sari, Iran. Based on components of resistance, 116 genotypes were selected for study in the second year at the same condition, among them 52 accessions were then chosen for evaluation at seedling stage in greenhouse. This evaluation was performed by four races 38E158A+, Yr27, 174E10A+, Yr27, 6E2A+, Yr27 and 238E190A+, Yr27. The results showed that 9 genotypes including 8252 and 8320 (Iran), 8395 and 8396 (Korea), 8103 (Afghanistan), 8150 (Portugal), 8348 (Algeria), 8426 (India) and 8472 (Turkey) were resistant to all the studied pathotypes. The presence of Yr1, Yr4, Yr10, and YrSP genes were postulated for these genotypes. One genotype from each country of Portugal, Iran, Japan, Korea, Italy and five genotype with unknown origin were resistant only against pathotype 6E2A+, Yr27, which are likely to carry YrSD or YrND. The comparison of resistance reactions in genotypes 8257, 8237, 8259 and 8332 (Iran), 8105 and 8108 (Afghanistan), 8169 (Portugal), 8458 (India), 8152 (Portugal) and 8362 (Australia) and virulence factors in the studied pathotypes suggested the presence of some unknown resistance genes in regarding genotypes. In the present study some genotypes with adult plant resistance were also identified. The total results of this research indicated the potential of bread wheat collection of National Plant Gene Bank of Iran to identify new sources and genes for resistance to yellow rust.