GENOTYPIC VARIATION IN SOME PHYSIOLOGICAL TRAITS IN WINTER WHEAT GROWN IN THE HUMID CONTINENTAL CLIMATE OF ONTARIO

Abstract

Several experiments were conducted with winter wheat (Triticum aestivum L. em. Thell.) during 1978 and 1979 to characterize genotypic variation in some physiological and morphological traits, and to evaluate the magnitude of the relationships between grain yield and the various traits studied. Straw weights of cultivars grown in Eastern Canada were similar to, and harvest indices generally lower than, those reported for high yielding varieties from other countries. Highest grain weights were also lower than the upper values recorded for some cultivars in the U.K. and Mexico, and were little affected by spikelet removal in most cases. All experiments were consistent in showing highly significant correlations between grain yield and grains per square metre, straw weight, harvest index, spikes per square metre, and flag leaf area index, and significant correlations between grain yield and grain weight. Diffusive resistance of the adaxial surface of the flag leaves differed between genotypes, but correlations between diffusive resistance and yield were low and nonsignificant in all cases, with the exception of the preanthesis period in one experiment.Key words: Wheat (winter), Triticum aestivum L. em. Thell., yield, physiological-morphological traits.