Mapping QTL for Pre-Harvest Sprouting (PHS) Traits in a DH Population of RL4452/AC Domain

Pre-harvest sprouting (PHS) of wheat seeds leads to a reduction in grain yield and quality. A lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Identifying molecular markers linked to QTL controlling PHS traits would greatly benefit breeding programmes, providing a means to rapidly identify lines expressing appropriate sprouting resistance. Two Canadian spring wheat genotypes RL-4452 and AC Domain (high dormancy) were hybridized to generate a doubled haploid (DH) progeny population of 182 individuals. These were screened with 1358 markers (SSRs, SNPs, DArTs and ESTs) and genetic maps of all 21 chromosomes were created using MapDisto®. Qgene® software was used for QTL mapping of three PHS traits (Germination Index (GI), Sprouting Index (SI) and Falling Number (FN)) measured at four environments in Manitoba, Canada. QTL corresponding to the above three traits were mapped on chromosomes 2A, 3B, 4A and 7D. Across four environments, 14 QTL were identified in eight of 12 data sets. These eight data sets comprised QTL on 2A (one), 3B.1 (three), 4A (seven) and 7D (two). A major QTL controlling dormancy and sprouting was identified on the long arm of 4A. Two SSR markers tightly linked to this QTL were used to identify recombinants in a DH population of 960 progeny from the cross AC Majestic x Glenlea. Analysis of these recombinants will assist in further narrowing the genomic region of interest.