USE OF CONTROLLED ENVIRONMENTS FOR WINTER CEREAL COLD HARDINESS EVALUATION: CONTROLLED FREEZE TESTS AND TISSUE WATER CONTENT AS PREDICTION TESTS

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Abstract
Field survival is the most commonly employed method of evaluating the winter hardiness of cereals. However, the inherent difficulties with field trials have stimulated a continued interest in the use of controlled environments and prediction tests for the evaluation of cold hardiness. In the present studies, cold hardiness expression of wheat (Triticum aestivum L.) cultivars acclimated in controlled environments was found to be similar to that reported for field conditions in Saskatchewan, Canada. LT50 and tissue water content measurements on wheat and rye (Secale cereale L.) cultivars acclimated in controlled environments were highly correlated with cultivar field survival ability. Investigation of the relationship between field survival and tissue water content during cold acclimation in controlled environments indicated that, to be effective as a screening method for cold hardiness, measurements of tissue water content should be made on fully acclimated plants for which the acclimation conditions have been rigorously controlled. Level of acclimation was not as critical for cold hardiness screening when LT50 measurements were utilized; however, maximum resolution also required fully acclimated plants. Although a strong relationship (r = −0.80 to −0.89) was found to exist with field survival potential, an inability to detect small, but important, differences without excessive replication would generally restrict the use of LT50 and tissue water content to situations where large homogeneous plant populations were available and only coarse screens for cold hardiness were required.Key words: Cold acclimation, winter wheat, winter rye, cold hardiness, water content, replication