Identification of some Monogenic Lines Resistant to Stem Rust Disease Using Molecular Markers

Ten stem rust monogenic lines and 14 commercial wheat cultivars were estimated under natural infection of stem rust disease for adult plant resistance (APR) during the 2019 – 2021 growing seasons at Gemmeiza Agricultural Research Station, ARC. Obtained results showed that Sr 46, Sr 47, and Sr 51 were completely resistant along the three seasons, however, Sr 50 showed zero to trace % resistance. The rest of the Srs tended to have a susceptibility ranging between 20% and 80%. The genes Sr 54 and Sr 45 had the highest mean values of area under disease progress curve (AUDPC) and rate of disease increases (r-value) followed by Sr 49, Sr 52, Sr 48, and Sr 53, respectively. Local wheat cultivars Gemmeiza-9, Gemmeiza-10, Gemmeiza-11, Gemmeiza-12, Giza-171, Sakha-94, Sakha-95, Sids-14, and Shandweel-1 showed different resistance values ranging from (immune) zero to 10 moderately resistance (MR). While, Giza-168, Sids-12, Misr-3, Misr-2, and Misr-1 cultivars respectively displayed susceptibility ranging between moderately susceptible Tr-MS to susceptible 60S. Six simple sequence repeat (SSR) markers linked to stem rust resistance genes i.e. Sr 45, Sr 46, Sr 47, Sr 49, Sr 50, and Sr 52, respectively were selected to test their presence/absence in fourteen Egyptian wheat cultivars. The SSR results indicated the presence of Sr 45, Sr 46, and Sr 49 in the tested Egyptian cultivars. Sr 47 was positive in all cultivars except in Misr-2, while Sr 50 was present only in Gemmeiza-12, Gemmeiza-9, Gemmeiza-11, Gemmeiza-10, Shandweel-1, and Sakha-94 cultivars. However, Sr 52 is present in all tested cultivars except Gemmeiza-11. Sr 49, Sr 50, and Sr 52 displayed high levels of polymorphism (75, 100, and 100%, respectively) as analyzed the iMEC software.