Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2013
Publication Date: 3/28/2014
Citation: Case, A.J., Skinner, D.Z., Garland Campbell, K.A., Carter, A.H. 2014. Freezing tolerance-associated QTL in the Brundage × Coda wheat recombinant inbred line population. Crop Science. 54:982-992. DOI: 10.2135/cropsci2013.08.0526. Interpretive Summary: Winter wheat is planted in the fall and harvested the next summer, so it is essential that the plants are able to tolerate exposure to subfreezing temperatures during the winter months. The goal of this study was to identify genetic markers associated with freezing tolerance, such that the markers can be used to assist breeding efforts. Starting with 268 wheat lines, over 2000 markers, and testing the plants to three challenge temperatures, seven chromosome regions that significantly influenced freezing tolerance at one or more subfreezing temperature(s) were identified. These chromosome regions may provide new molecular markers that will be useful to freezing tolerance improvement efforts.
Technical Abstract: Freezing tolerance is an essential trait for winter wheat (Triticum aestivum L.) cultivars. A genetic analysis of a Brundage × Coda winter wheat recombinant inbred line (RIL) mapping population was undertaken to identify quantitative trait loci (QTL) associated with freezing tolerance. Five- to six-week old, cold-acclimated plants were frozen to -10.5, -11.5, or 12.5°C. The standardized mean percent survival of the RIL within each temperature was 61, 44 and 28% respectively. A total of 2,391 polymorphic DNA markers including 1,984 SNP (single nucleotide polymorphism), 232 DArT (Diversity Array Technology) and 175 SSR (simple sequence repeat) markers were used to create a genetic linkage map representing all chromosomes except 1D. QTL analysis identified seven QTL that were associated with freezing tolerance at either a specific temperature or a combination of temperatures. The QTL QFrbr.wak-5A was associated with freezing tolerance at all temperatures tested. QFrbr.wak-5A is located on chromosome 5A in the same region as known frost tolerance genes Fr-A1 and Fr-A2 and may be an effect of variation at the Vrn-A1 locus. Other QTL were located on chromosomes 2A, 3A, 5B and 6D, and were temperature-specific. Identification of QTL associated with freezing tolerance may lead to useful genetic markers for marker-assisted selection, allowing for more efficient development of freezing tolerant cultivars.