IDENTIFICATION OF STRIPE RUST RESISTANCE GENES Yr s IN CANDIDATE EGYPTIAN AND CIMMYT WHEAT GENOTYPES BY MOLECULAR MARKERS

Stripe rust is a widespread damaging disease of wheat, causing significant losses in yield and quality. Each monogenic line of Yr1, Yr5, Yr10, Yr15, Yr17, Yr32 and YrSP exhibited high levels of resistance to both 198E56 and 128E28 races, at seedling stage. The same monogenic lines showed adult plant resistance. Whereas, those with Yr17 and YrSP showed a disease severity ranged between 5MR to 10MR. The monogenic line (YrSK) was the only one which recorded susceptible and highly resistant reactions, at seedling and adult stages respectively. Nine Egyptian cultivars and four lines from CIMMYT tested at seedling stage were susceptible (IT 6-8). Misr-1, Misr-2, Gemmezia-10, Line-6043, Line-6085, Line-6086 and Line-6107 showed a range of adult plant responses of TrR–10MR. The remainder had variable degrees of susceptibility (5MS-30S). Fourteen genotypes were screened with three DNA markers to detect the presence of Yr9, Yr17 and Yr18. The 1100bp band diagnostic for Yr9 was present in 7 genotypes, i.e. Misr-1, Misr-2, Sids-12, Sids-13, Gemmeiza-9, Gemmeiza-10 and Gemmeiza-11. At 252bp fragment in Line 6043 (8STEMRRS) from CIMMYT was only indicative of Yr17, and Yr18 was present all tested Egyptian and CIMMYT genotypes at 517bp.