Abstract
To elucidate the suitable seeding rate for early sowing of winter type wheat Iwainodaichi, the effect of sparse sowing on growth and grain yield was investigated for 2 years. Although the number of shoots, leaf area index (LAI) and total dry weight at maximum tiller stage were smaller in sparse sowing than in standard sowing, LAI, total dry weight and sink size at flowering stage with sparse sowing were not different from those in standard sowing. These results show that sparse sowing did not affect the yield potential at the flowering stage as compared with the standard sowing. Sparse sowing did not affect culm length, the number of internode and the length of each internode, but increased the number of spikelets and flts per spike, leaf length and width, and diameter of internode. During ripening, SPAD value was higher in sparse sowing. The number of spikes per area was smaller in sparse sowing but the number of grains per spike was larger in sparse sowing than those in standard sowing, and thousand grain weight was not different between sparse and standard sowing. As a result, grain yield in sparse sowing was similar to or m than that in standard sowing. Sparse sowing, also, gave high lodging resistance. These results suggest that sparse sowing is superior to standard sowing in early sowing of Iwainodaichi.
