Adaptability for late transplanting of rice varieties in the Tohoku region of Japan
2018
Fukushima, A. (Agri-Food Business Innovation Center; NARO, Tsukuba, Ibaraki (Japan)) | Ohta, H. | Yokogami, N. | Tsuda, N.
As the population of rice farmers decreases in Japan, the management scale of rice cultivation is expected to enlarge and the large-scale rice farmers in the Tohoku region need to continue transplanting late. In the present study, we examined the effects of late transplanting on yield, grain quality, eating quality, and the adaptability of varieties to late transplanting. Late transplanting in mid-June delayed heading for 18 days, decreased the number of panicles per area and the percentage of ripened grain, increased the thousand grain weight slightly, and did not affect the number of spikelets per panicle, compared with conventional transplanting in mid-May. As a result, late transplanting decreased grain yield by 15%. On the other hand, late transplanting improved appearance grain quality slightly and did not affect eating quality. These results suggest that late transplanting could be introduced into the rice cultivation system in the Tohoku region if it is effective from the perspective of management. Among nine varieties in the late transplanting, the percentage of ripening grain decreased and the weight of immature grain increased, as the heading became later. These results suggest that the use of extremely early varieties would effectively minimize the yield decline in late transplanting.
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