Genetics of winter wheat response to two freezing treatments

With 1 figure and 3 tables Abstract The inheritance of the ability of winter wheat (Triticum aestivum) plants to survive two kinds of freezing stress was investigated in a five-parent diallel cross. Cold-acclimated plants were frozen to damaging temperatures with or without a -3 degrees C, 16-h prefreezing (PF) period. Test temperatures were adjusted such that the overall mean survivals were the same under the two PF treatment conditions (-10 to -12 degrees C without PF; -14.5 to -16.5 degrees C with PF). Lines that survived freezing tests with PF as well or better than without PF developed significantly more freezing tolerance during the PF treatment and tolerated the lower test temperatures of the PF tests. Diallel analysis indicated most variation under either kind of freezing stress was because of additive genetic effects, but non-additive effects were significant in two of the 20 crosses. It may be possible to combine additive and non-additive effects to develop cultivars that are exceptionally tolerant of freezing episodes with or without an extended PF period.