Breeding hard red spring wheat in western Canada: Historical trends in yield and related variables

Abstract

The Western Bread Wheat Cooperative test and Central Bread Wheat Cooperative test are the bases of evaluation for cultivar registration in the Canada Western Red Spring (CWRS) wheat class. Historical data from these tests were analyzed with the objectives of comparing grain-yield-related variables of recently registered cultivars with those of earlier cultivars and determining the yield advances made within the CWRS wheat class. Canadian cultivars increased maximum yield potential approximately 6–9 kg ha−1 yr−1 during a 90–yr period. Yield potential of sawfly-resistant cultivars has been increasing at a rate of 11 kg ha−1 yr−1, although they consistently yielded less than the highest yielding hollow-stem cultivars. In general, the genetic yield increases resulted from an increase in the number of kernels produced rather than an increase in kernel size. This suggests that bread wheat grown on the prairies has been sink limited during grain filling. Breeding efforts focused on increasing Canadian production through the development of numerous CWRS cultivars with specific traits (e.g., early maturity, disease resistance) to allow hard red spring wheat to be grown over a broad geographical range. Plant height, time to maturity, and hectolitre weight did not change significantly during the 1947–1992 period. Key words:Triticum, kernel number, kernel weight, height, hectolitre weight