LOSSES IN WHEAT GRAIN YIELD DUE TO LEAF RUST, CAUSED BY Puccinia triticina Eriks

This work was carried out at Gemmeiza Agriculture Research Station during 2010/11 and 2011/12 growing seasons, to study losses in grain yield of five susceptible wheat cultivars i.e. Gemmeiza 7, Gemmeiza 10, Gemmeiza 11,Sakha 93 and Sakha 94, to leaf rust caused by Puccinia triticina Eriks under field conditions. Artificial inoculation was performed using a mixture of urediospores and talcum powder (1/20) ,in addition to treated plots of the same cultivars with fungicide (Sumi-eight 5Ec) served as a protected control .Disease severity was recorded each 10 days and area under disease progress curve( AUDPC ) were estimated . The tested cultivars exhibited different disease severity, 5-80%. High values of area under disease progress curve( AUDPC ) were detected on Gemmeiza-7 , Sakha-93 ( 1225 ,925).Whereas the lowest values of yield loss were recorded on cvs. Gemmeiza 11 and Gemmeiza 10 that mean these two cultivars were tolerant to leaf rust infection under field conditions. Correlation and regression coefficions were tested between yield losses and values of AUDPC of the tested cultivars.