Analysis of Growth Characteristics as Affected by Air Temperature Variation in Dasanbyeo, a Indica/Japonica High Yielding Rice Cultivar

기온변리에 따른 다수성 품종 '다산벼'의 생육특성 분석

This experiment was carried out to find out the responses of the growth characteristics to various air temperature in a high yielding indica/japonica rice cultivar, 'Dasanbyeo'. Five different transplanting dates with 30 day-old seedlings were tried to induce various environmental conditions, starting from 10th May to 19th June in the interval of 10 days at National Crop Experiment Station, in 1998. Planting densities with different plants per hill but same hill spacing were tested. The daily mean air temperature during 30 days after transplanting was 19.0, 20,8, 21.9, 24.4 and 25.2$^{\circ}C$ when transplanted on the 10th May, the 20th May, the 30th May, the 9th June and 19th June, respectively. The number of tillers per hill at 30 days after transplanting was affected by the daily mean air temperature during 30 days after transplanting. The higher the daily mean air temperature, the more tillers per hill at 30 days after transplanting were. The growth duration from transplanting to heading was greatly changed according to the transplanting dates. It was shortened as the transplanting date was delayed until transplanted on the 9th June, but it was prolonged when transplanted on the 19th June compared to that of the 9th June. The number of panicles per hill increased with the increase of the transplanted plants per hill up to 7 plants per hill. The number of panicle per unit area was closely related to the number of tillers per unit area at maximum tillering stage. It was found that the average effective temperature during first 10 tiller formation related to the days to the tenth tiller formation with the relationship of y = 1.071x$^2$ - 37.307x + 342.38($R^2$ = 0.9823).

본 시험은 다산벼를 공시하여 작물시험장 수도재배 포장에서 1998~1999년에 단위면적당 수수화보를 위하여 5월10일부터 10일 간격으로 6월 19일까지 5회 이앙을 하여 생육환경 변화에 따른 경수증가와 재식본수를 1, 3, 5본 및 7본으로 하였을 때 출수기의 변화를 구명하고 재배 기술 개발의 기초자료로 활용하고자 시험하여 몇 가지 결과를 얻었기에 보고하고자한다. 1. 다산벼는 초기 생육기온이 높을수록 분얼에 유리하여 이앙 후 30일 경수가 5월 10일 이앙 9.7개 보다 6월 19일 이앙이 18.3개로 8.6개가 많았다. 2. 재식묘수에 따른 경수는 7묘까지 많을수록 많았으며, 수수는 분얼 경수가 많을수록 많은 경향이었다. 3. 출수기는 이앙기가 늦어질수록 6월 9일 까지는 출수일수가 단축되었으나 6월 19일 이앙은 늦어졌다. 주당묘수에 따른 변화는 y = 2.65$x^2$-31.36x+1957.5 ($R^2$=0.9795)관계로 변화하였다. 4. 경당 건물중은 평균기온의 변화에 따라 y = -0.1285$x^2$+6.6717x-83.423($R^2$=0.9223$^{**}$ ) 관계가 있고, 경당 건물중이 가장 높은 최적 기온은 26$^{\circ}C$이었다. 5. 수수와 수량과의 관계는 수수가 증가하면 수량은 증가하였고, 그 관계는 y=1.6292x+11.701($R^2$=0.6342$^{**}$ )이었다.