Identification of putative markers from within a chromosome 3D stem-solidness QTL in spring wheat

The wheat stem sawfly, C. cinctus (Norton), is a major insect pest of wheat (Triticum spp.) causing economic losses through reduction in yield. A common strategy to mitigate yield loss is to grow solid- stemmed wheat varieties. Establishing and maintaining good stem-solidness in hexaploid wheat is an important yet challenging component in the development of new solid-stemmed varieties. At SCRDC, a doubled haploid (DH) breeding population was generated from the cross of Concord and Hughes where Sst1 (the most common source of stem-solidness) was fixed and an alien source (3Ag) was introduced from Concord. 204 DH lines were genotyped with the Infinium iSelect 90K wheat assay and a subset of lines (135) was phenotyped for stem-solidness from two locations during the 2016 growing season.
Composite interval mapping analysis (CIM) revealed a QTL with major effect for stem-solidness on chromosome 3D. The QTL, contributed by AAC Concord accounted for 49.4% of the total phenotypic variation. Putative KASP markers have been developed from within the QTL interval. Upon validation the markers should be a convenient tool to assist with selection of improved stem solidness and sawfly resistance.