Selection for Winterhardiness in Wheat. III. Screening Methods

Abstract

Thirty‐four biochemical, physiological, and morphological characters of winter wheat ( Triticum aestivum L.) were evaluated to determine their usefulness in winter survival prediction tests. Differences among cold acclimated plants from genotypes with a range of cold hardiness potential were significant for most of the characters evaluated. Close linear associations were found among many of these characters indicating that there are a number of possible screens which could be utilized as a supplement to field survival trials. However, at best, they are very coarse screens and, for differences of practical concern, size of experimental errors become a major limitation to their usefulness in selecting for field survival potential. Estimates of field survival (FSI) and LT 50 had the smallest relative experimental errors and the highest heritability values. Crown LT 50 estimates also gave the highest correlation with FSI. However, because LT 50 is a destructive test which requires a large number of plants, it is limited to nonsegregating populations, Tissue water content and LT 50 explained similar variability in FSI. Because tissue water content was not measured with as great a precision as LT 50 , it would appear to be less useful as a screen. However, when combined with a measure of plant erectness, tissue water content provided nearly as much information on FSI as did LT 50 . Both leaf water content and plant erectness can be measured without sacrificing entire plants and therefore they should be helpful winter hardiness screens for use by plant breeders.