중부 평야지에서 중생종 벼 ‘하이아미’의 기계이앙 시기에 따른 출수기와 수량특성 변화

This study was conducted over a 3-year period from 2013 to 2015 in the central plain area, Suwon, Korea with aims to suggest optimum transplanting date of ‘Haiami’, a mid-maturing rice cultivar, by investigating changes in heading date, climatic factors before and after heading, and yielding characteristics affected by transplanting date. Thirty-day old seedlings were machine-transplanted on four different dates at 15-day interval from May 10 to June 24. Heading dates were August 10 and August 31 at the treatments transplanted on May 10 and June 24, respectively. Late transplanted Haiami rice was subjected to higher daily mean temperature before heading and required fewer days to reach heading stage. However, for 40 days after heading, daily mean temperature decreased as transplanting was delayed. Transplanting date, as a variable, resulted in a great variation in daily mean temperature but a relatively small variation in daily sunshine hours before and after heading of Haiami plants. As transplanting was delayed, number of panicles per unit area decreased but number of spikelets per panicle increased, hence the decrease in days from transplanting to heading due to late planting did not result in a reduced sink size. Sink size affected by transplanting date was not significantly correlated with grain filling percentage. However, 1000-brown rice weight significantly increased as the mean temperature for 40 days after heading decreased. Milled rice yield was similar among the four transplanting date treatments while head rice percentage and consequent head rice yield increased with late transplanting. Therefore, to achieve higher head rice yield in consideration of possible erratic climate at late grain filling period, it is recommended to transplant ‘Haiami’ cultivar at mid-June in the central plain area of Korea.