A Consistent QTL for Flour Yield on Chromosome 3B in the Soft Winter Wheat Variety, Kitahonami

The soft winter wheat variety, Kitahonami, shows a superior flour yield in comparison to other Japanese soft varieties. In order to map quantitative trait loci (QTL) associated with the flour-yield trait, association mapping was performed using panel lines in Kitahonami’s pedigree, along with leading varieties and advanced breeding lines. Using a mixed linear model corrected for kernel types and familial relatedness, 62 marker-trait associations were identified and classified into 21 QTLs. Five out of eight QTLs tested were validated by linkage analyses using three sets of doubled haploid populations from crosses in which Kitahonami was used as a parent. Among them, QTLs on 3B and 7A chromosome showed highly significant effects and consistency across the three populations. A joint linkage map of 3B showed that the QTL on this chromosome was located at the same interval across the populations. By applying a meta-analysis approach, we have succeeded in identifying QTLs with consistent contributions to high flour yield across various genetic backgrounds.