Genetic analysis of pre-harvest sprouting resistance in a wheat x spelt cross

Breeding for pre-harvest sprouting (PHS) resistance in wheat (Triticum aest ivum L.) and spelt (Triticum spelta L.) is difficult because PNS is quantit atively inherited and strongly affected by environmental factors. The aim o f this study was to detect molecular markers linked to quantitative trait l oci (QTL) involved in PHS resistance to improve the breeding process. We me asured falling number (FN) and alpha-amylase activity (AA) of 226 F-5 recom binant inbred lines (RILs) originating from a cross between the Swiss wheat cultivar Forno and the Swiss spelt cultivar Oberkulmer in four environment s. QTL analysis was performed with 204 RILs and based on a genetic map of 1 83 loci. Across environments, 12 and 13 QTL were detected for FN and AA, re spectively. Altogether the QTL explained more than 75% of the phenotypic va riance. The two traits were highly correlated (r = -0.91) and of the 13 QTL for AA, nine coincided with QTL for FN. Three of the six QTL with major ef fects (R-2 greater than or equal to 15%) on PHS resistance coincided with Q TL for ear length. The QTL with the strongest impact had the positive allel e from Oberkulmer and was located on 5AL at the q locus, which is responsib le for the typical ear morphology of spelt. The QTL on 6A (with the positiv e allele from Forno), 3B, and 7B (both with the positive allele from Oberku lmer) improve PHS resistance without changing the ear morphology, Thus, the se QTL could be important for marker assisted selection for PHS resistance in both the wheat and the spelt germplasm.