Isolating a Milling QTL from a Soft Red Winter Wheat Mapping Population

Milling quality in soft wheat is highly heritable yet difficult to track genetically since traits such as break flour and milling yield are influenced by multiple genetic loci.  Quantitative trait loci (QTL) for milling quality map to chromosome 2BS in a number of bi-parental populations as well as in an association mapping population of soft wheats grown in the northeastern U.S.  Backcrossed recombinant inbred lines from a bi-parental mapping population produced at Cornell University derived from soft red winter wheat parents Foster (good miller) and Kanqueen were selected using SSR markers surrounding the 2B QTL from the Foster parent to BC₁F₅ to isolate the genetic region of the milling QTL.  A single nucleotide polymorphism (SNP) in a sucrose synthase 2 gene, TaSus2 located on chromosome 2B very close to the QTL region, segregates in this population as well as an SSR marker, wmc477 that identifies a translocation from T.timophevee providing resistance to stem rust.  The Foster parent carries the sucrose synthase haplotype associated with high test grain weight as well as the 2B translocation.  Recombinant lines carrying the good milling QTL from Foster in the poor milling background from Kanqueen will be harvested and tested for milling quality in 2012.   These lines will be further evaluated to elucidate the genetic components of the 2B milling QTL.