|KRUSE, ERIKA - Washington State University|
|CARLE, SCOTT - Washington State University|
|WEN, NUAN - Washington State University|
|MURRAY, T - Washington State University|
|CARTER, ARRON - Washington State University|
Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2016
Publication Date: 1/30/2017
Citation: Kruse, E.B., Carle, S.W., Wen, N., Skinner, D.Z., Murray, T.D., Garland Campbell, K.A., Carter, A.H. 2017. Genomic regions associated with freezing tolerance and snow mold tolerance in winter wheat. G3, Genes/Genomes/Genetics. 7:775-780.
Interpretive Summary: In the Northwest United States, farmers grow a lot of wheat over the winter. They do this because they don’t have irrigation and need to take advantage of winter precipitation. However, this means that the wheat plants are exposed to winter conditions and have to survive both freezing temperatures and a disease called snow mold that infects the plants when they’re buried under the snow. Both of these stresses can damage or kill the plants before they have a chance to produce grain. Some kinds of wheat plants are better than others at surviving these conditions. In this study, we identified some of the genetics that control how well plants can tolerate freezing and snow mold stress. We found three places the wheat genome that are important for freezing tolerance and two places that are important for snow mold tolerance. One of these places is shared between the two. This is useful to plant breeders because it can help them develop new kinds of wheat that are better at dealing with these stresses. Additionally, this was an important step towards identifying the genes themselves that contribute to the traits.
Technical Abstract: Crops grown through the winter are subject to selective pressures that vary with each year’s unique conditions, necessitating tolerance of numerous stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L. em Thell) associated with tolerance of two of these stresses, subfreezing temperatures and snow mold, a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars 'Finch' and 'Eltan' were evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 674 molecular markers were used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL) associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was located at approximately the Fr-A2 (Frost-Resistance A2) locus; its significant association with both traits may have resulted from pleiotropic effects or from greater low temperature tolerance enabling the plants to better defend against the snow mold pathogens. The QTL on 4B associated with freezing tolerance and the QTL on 6B associated with snow mold tolerance have not been reported previously and may be useful in the identification of sources of resistance for these traits.