GRAIN-YIELD AND BREADMAKING QUALITY OF WHEAT LINES WITH THE LEAF RUSTRESISTANCE GENE LR41

Some of the many disease-resistance genes transferred into common whea t (Triticum aestivum L.) by interspecific hybridization have been unde rutilized in agriculture because of associated negative effects on pro ductivity and end-use quality. The Lr41 gene conferring resistance to leaf rust (caused by Puccinia recondita Rob. ex Desm.) was transferred from the wild diploid goatgrass [Triticum tauschii (Coss.) Schmal], t he chromosomes of which recombine readily with those of common wheat ( Fritz et al., 1995a). Thus its chromosomes recombine readily with thos e of wheat. This study had three objectives: (i) to determine the dire ct and linked effects of Lr41 on 15 productivity and quality traits in hard red winter wheat under disease-free conditions; (ii) to determin e the effects of resistance conferred by Lr41 under a severe leaf rust epidemic and under a light infection; and (iii) to determine the amou nt of damage inflicted by diseases other than leaf rust in those envir onments. Six BC2F2-derived common wheat lines with Lr41, along with th eir recurrent parents (hard red winter wheat cultivars TAM 107, TAM 20 0, and Century), were evaluated in three field experiments with and wi thout fungicide treatment in 1992 and 1994. Lr41 increased grain yield and milling quality under heavy leaf rust infection with no negative effects on those traits in disease-free plots. However, Lr41 was assoc iated with reduced bake-mixing time and water absorption in the absenc e of disease. Effects of other diseases depended heavily upon the gene tic backgrounds (i.e., recurrent parents) of backcross lines. There sh ould be no serious impediments to the use of Lr41 in breeding programs .