Quantitative trait loci for lodging resistance in a segregating wheat x spelt population

Lodging can strongly affect both the grain yield and the quality of wheat. Lodging represents a quantitative trait and is difficult to assess on a phe notypic basis. Marker-assisted selection (MAS) could therefore become an im portant tool in breeding for lodging resistance. In this study, we mapped a nd characterised quantitative trait loci (QTLs) for lodging resistance, as well as morphological traits correlated with lodging, in a segregating popu lation of 226 recombinant inbred lines derived from the cross of the lodgin g-resistant wheat variety Forno with the susceptible spelt variety Oberkulm er, Lodging, plant height, leaf width, leaf-growth habit, culm stiffness, c ulm swinging, culm thickness, days to ear emergence and days to flowering w ere assessed in field trials at two locations in 1996 and at one location i n 1997, Additionally, at one location weight and length parameters were als o assessed. Plant height and culm stiffness explained 77% of the phenotypic variance of lodging in a multiple regression model over all three environm ents. QTL analysis of lodging and morphological parameters was based on a g enetic map containing 230 loci with 23 linkage groups (2469 cM). With the m ethod of composite interval mapping nine QTLs for lodging resistance were d etected, explaining 63% of the phenotypic variance in a simultaneous fit. S even of these QTLs coincided with QTLs for morphological traits, reflecting the correlations between these traits and lodging. In our population the m ast efficient way to improve lodging resistance would be by a combination o f indirect selection on plant height and culm stiffness together with MAS o n the two QTLs for lodging resistance which did not coincide with QTLs for morphological traits.