Logistic Regression Analysis of Freezing Tolerance in Winter Wheat

Authors: Skinner, Daniel; Bellinger, Brian

Submitted to: International Symposium on Plant Cold Hardiness
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2007
Publication Date: 8/1/2007
Citation: Skinner, D.Z., Bellinger, B.S. 2007. Logistic Regression Analysis of Freezing Tolerance in Winter Wheat. International Symposium on Plant Cold Hardiness. Aug 3-9, 2007, Saskatoon, Saskatchewan, Canada, pg 93.

Interpretive Summary:

Technical Abstract: Four winter wheat cultivars, Eltan, Froid, Kestrel, and Tiber, were cold-acclimated for five weeks and then tested for freezing tolerance in a programmable freezer. The temperature of the soil was recorded every two minutes and the freezing episode was described as five parameters: the minimum temperature reached, rate of cooling from 0C to the minimum temperature, the time held at the minimum temperature, the rate of warming from the minimum to 0C, and "degree minutes", determined by multiplying the temperature by the minutes at that temperature, summed over the entire freezing episode (0C or less). Logistic regression equations were developed for each cultivar with survival as the response and these five parameters as independent variables. Comparisons of predicted vs. observed survival showed that the equation describing survival of one cultivar generally poorly predicted survival of a second cultivar. This result may suggest that different mechanisms are involved in the response of the different cultivars to the freezing process. F2-derived F4 populations were generated from crosses of these cultivars. At least one of the F4 populations from the Kestrel X Tiber cross was significantly more freezing tolerant than Kestrel, the more hardy parent, suggesting a combination of genes conditioning different response mechanisms had been recovered.