Effect of the Interaction between Cultural Condition and Genotype on Spike Morphogenesis in Spring Wheat

Abstract

The number of grains per spikelet and the number of spikelets per spike are important factors that influence grain yield in wheat. Three wheat genotypes in four foreign groups (OA, OC, OH and OJ) differing in spike type and Japanese cultivars (cvs) were grown under various combinations of seeding densities and fertilization levels. In all groups, the spikelet number per spike and the spike length at maturity were highest at low seeding densities and high levels of fertilization. The OA group (Nepal) and Haruyutaka (Japanese cv) gave a weak response in spikelet number per spike, while the OJ group (Xinjiang Uygur, China) gave a weak response in spike length. The OC group (except for T6), the OH group (Tibet) and Japanese cvs (except for Haruyutaka) responded to treatments in both spikelet number per spike and spike length. The T6 genotype in the OC group (Nepal) gave a weak response in both spikelet number per spike and spike length. Although the OA group had the longest spikes and the OJ group had the shortest spikes, there was no difference in the duration of spike elongation between the OA group and the OJ group. Spike length appeared to be determined mainly by the rate of spike elongation and was not restricted by the dry weight of the spike during the growth phase of the spike.