EVIDENCE OF A MAJOR GENETIC FACTOR CONDITIONING FREEZING SENSITIVITY IN WINTER WHEAT

Authors: Skinner, Daniel; Garland-Campbell, Kimberly

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2007
Publication Date: 5/21/2008
Citation: Skinner, D.Z., Garland Campbell, K.A. 2008. Evidence of a major genetic factor conditioning freezing sensitivity in winter wheat. Plant Breeding 127:228-234.

Interpretive Summary: Winter wheat plants must be planted in the fall and survive the winter in order to produce grain the following summer. Without exposure to cold winter temperatures, the plants do not produce grain. The ability to withstand freezing is a major determinant of winter survival. Historically, very few genes have been identified in winter wheat that have a major impact on freezing tolerance. In this study, we identified an gene with major effect. The presence of the dominant form of the gene results in about 20% less survival when plants are frozen to -13 degrees centigrade. The plant line carrying this gene is a winter wheat, but includes spring wheat in its ancestry. Spring wheat does not require exposure to a cold period in order to produce grain and typically has very little freezing tolerance. It is likely the gene we have identified originated from spring wheat, i.e. the plant line is a winter wheat with a spring wheat form of a gene conditioning freezing tolerance. Further study of this gene likely will lead to increased understanding of specific genes conditioning freezing tolerance.

Technical Abstract: Freezing tolerance was measured in cold-acclimated F2 – derived F4 lines of winter wheat (Triticum aestivum L.) crosses 'Eltan' X Oregon Feed Wheat #5' (ORFW) and 'Tiber' X ORFW. ORFW had essentially no freezing tolerance, while 'Eltan' and 'Tiber' had about 50% survival, as measured in this study. A small, but significant, cytoplasmic effect was evident, resulting in reduced freezing tolerance. The density distributions of the percentage survival of the F2:4 populations suggested two categories were present and survival in about one-fourth of the F2:4 populations was not significantly different from the more hardy parent. Results of chi-square tests were consistent with the presence of a single dominant gene in ORFW conditioning a reduction on freezing tolerance manifested by a 20% reduction in survival in F2:4 populations.