Development and validation of markers linked to genes resistant to <italic>Sitodiplosis mosellana</italic> in wheat

Abstract

Orange wheat blossom midge (OWBM) ( Sitodiplosis mosellana Gehin) has seriously reduced wheat production and processing quality. Breeding midge-resistant wheat has been considered the most effective way to reduce kernel losses caused by OWBM, and marker-assisted selection (MAS) strategy in crop breeding using linked or functional markers of target trait of interest is of great importance in improving breeding efficiency. Based on the InDels and SNPs within the sequences of six midge resistance-related genes discovered from transcriptome data in the previously mapped major QTL ( QSm.hbau-4A ) region, we developed and validated two EST and six KASP markers in a panel of recombinant inbred lines (RILs) and a panel of wheat cultivars with different OWBM resistance levels. These markers were polymorphic between the resistant and susceptible wheat parents, and approximately 90% of RIL lines showed the corresponding marker-based genotypes with their phenotypes. Except for E10-10 , the other seven markers had higher detection efficiency in highly resistant (56.3%−86.7%) and in highly susceptible (85.7%−100.0%) wheat cultivars, thus making them applicable for screening midge-resistant wheat germplasm with locus QSm.hbau-4A . Among the eleven midge-resistant wheat cultivars with all resistance alleles for the seven markers developed, most were historical wheat cultivars, and rarely used in the present production, which suggests how to use old cultivars in wheat germplasm identification and enhancement on midge-resistance through MAS is urgent.