Growth response of four hard red spring wheat cultivars to date of seeding

Abstract

An increasing number of spring wheat cultivars released for production in western Canada are daylength insensitive. In contrast, until a decade ago virtually all Canada Western Red Spring (CWRS) wheat cultivars were daylength sensitive. The impact of photoperiod response on CWRS wheat growth and yield has not been studied to date. A growth analysis study was conducted in each of 3 yr at Saskatoon. Growth and yield traits of the photoperiod-sensitive cultivars Conway and Katepwa and photoperiod-insensitive cultivars Laura and Leader were compared in early versus late plantings. Laura had the highest leaf area index at anthesis and produced more spikelets and kernels per spike than the other cultivars. Laura, however, had a higher tiller mortality, producing fewer spikes per square metre. The cultivars did not respond uniformly to delayed seeding from one year to the next. Significant crossover cultivar × seeding date interaction was detected in each of the 3 yr. The cultivar × seeding-date interactions did not appear to follow a pattern that might be ascribed to differing cultivar photoperiod sensitivity. Conway was involved in one case of significant (P = 0.10) cultivar × seeding cross-over interaction for grain yield, while Katepwa and Leader were each involved in two cases and Laura in three cases. This study failed to determine whether differing photoperiod responses would translate into gross differences in cultivar growth and yield. Thus, there is a need to develop near-isogenic lines to determine whether photoperiod insensitivity is detrimental to yield stability in CWRS wheats. Key words: Canada Western Red Spring wheat, growth analysis, seeding date, genotype × environment interaction