2017 Volume 86 Issue 1 Pages 35-40
Rice cultivars with short panicles, “Tachiayaka” and “Tachisuzuka”, were developed for silage use because of their improved feed value due to a radical decrease in hard to digest spikelets. However, these cultivars produce an insufficient number of seeds for propagation. Nitrogen application at the panicle formation stage or late transplanting improves unhulled rice yield in “Tachisuzuka”. However, this has not been confirmed in “Tachiayaka”. Therefore, the effects of the amount of total and top-dressed nitrogen fertilizer, on the yield components of “Tachiayaka” were studied in 2014 and 2015. The method of fertilization did not affect the panicle number and the ratio of selection by specific gravity. However, spikelet numbers per panicle and per unit area were increased by increasing the amount of top-dressed nitrogen fertilizer compared with that of basal dressing. Therefore, the spikelet number should be increased by reducing the basal dressing and increasing the top dressing to improve the seed production in “Tachiayaka”. However, late-emerging panicles were observed in top dressing more than 10 g m–2 nitrogen.
