Quantitative trait loci and epistasis for oat winter-hardiness component traits
Winter hardiness is a complex trait and poor winter hardiness limits commercial production of winter oat (Avena spp.). The objective of this study was to identify quantitative trait loci (QTL) for five winter-hardiness component traits in a recombinant inbred line population derived from a cross between the winter-tender cultivar Fulghum and the winter-hardy cultivar Norline. Crown freezing tolerance, vernalization response, and photoperiod response were evaluated in controlled environment studies. Heading date and plant height were evaluated over two seasons in Kinston, NC, and winter field survival was evaluated in five environments over two seasons in the mountains of North Carolina and Virginia. A partial genetic linkage map of regions believed to affect winter hardiness was developed using restriction fragment length polymorphism and simple sequence repeat markers. Most QTL were located on linkage groups FN3, FN22, and FN24. Quantitative trait loci were identified for all traits except photoperiod response, and epistatic interactions were identified for winter field survival, crown freezing tolerance, vernalization response, and plant height. Major QTL for winter field survival (R2 = 35%) and crown freezing tolerance (R2 = 53%) were identified on linkage group FN3, which was associated with an intergenomic reciprocal translocation between chromosomes 7C and 17.