Postulation of leaf rust resistance genes in selected soft red winter wheats. Crop Sci

ABSTRACT ever, relatively few studies of leaf rust resistance have been conducted with soft red winter wheat cultivars thatLeaf rust, caused by the fungus Puccinia triticina Eriks., is a major are grown in the southern USA. The objective of thisdisease nearly wherever wheat (Triticum spp.) is grown in the USA. Soft red winter wheat (T. aestivum L.) cultivars with varying degrees study was to provide an initial description of leaf rust of leaf rust resistance are grown in the southern USA. The objective resistance in a group of soft red winter wheat cultivars of this study was to characterize the seedling leaf rust resistance and breeding lines that are adapted to the southern present in a group of 35 soft red winter wheat cultivars and 17 breeding USA. The approach used in this study is based on gene-lines. Leaf rust infection types (ITs) produced on the cultivars and for-gene specificity (Flor, 1971; Person, 1959) and has lines by 16 P. triticina isolates were compared with the ITs produced been used to quickly determine the probable identity on a standard set of ‘Thatcher ’ near-isogenic lines that differed for of seedling leaf rust resistance genes in a group of wheatsingle leaf rust resistance genes. Seedling resistance genes Lr1, Lr2a, lines. The low and high ITs produced by a diverse groupLr9, Lr10, Lr11, Lr18, and Lr26 were postulated to be present in of P. triticina isolates on the lines under study werethe soft red winter wheat cultivars and lines. Adult plant leaf rust compared with ITs produced by the isolates on a stan-resistance for the cultivars and lines was assessed in field plots at two locations in North Carolina in 2000. Wheat cultivars postulated or dard set of near-isogenic Thatcher wheat lines that diffe