Comparison of a branched spike wheat with the cultivars Neepawa and HY320 for grain yield and yield components

Abstract

Branched-spike spring wheat (Triticum turgidum L.) genotypes are periodically promoted in western Canada as having very high grain yield capacity. These "Miracle" wheats tend to have a low tillering capacity and may require higher plant populations in order to achieve maximum grain yield. This study was conducted to critically evaluate the high-yield claims of a branched-spike wheat (BSW) and to determine whether this cultivar has a higher optimum seeding rate requirement than the spring wheat (Triticum aestivum L.) cultivars Neepawa and HY320. The three cultivars were seeded at rates of 150, 250, 350, 450, and 550 seeds m−2 in each of three experiments: two dryland and one irrigated. Averaged over experiments and seeding rates the BSW yielded 45% less than the conventional cultivars. Significant (P < 0.05) cultivar × experiment cross-overs were detected for spikes m−2, spikelets spike−1, and kernels spike−1. BSW and HY320 switched ranks for spikes m−2, spikelets spike−1 and kernels spike−1 in 1988 and 1989. In 1988, on average, BSW produced 230% as many fertile spikelets as the other cultivars, but 40% fewer spikelets in 1989. Similarly, BSW produced more kernels spike−1 than Neepawa and HY320 in 1988 while the reverse was observed in 1989. The three cultivars responded differently to seeding rate, as indicated by significant (P < 0.01) cultivar × seeding rate interaction for spikelets spike−1 and kernel weight. Neither of these interactions involved significant changes in cultivar rank from one seeding rate to the next. BSW yielded less grain than either Neepawa or HY320, regardless of seeding rate. Attempts to increase the grain yield of a BSW cultivar by manipulating yield components via increased seeding rates were not successful.Key words: Branched-spike, spring wheat, seeding rate, Triticum turgidum L.