수도의 재배 환경차이에 따른 탈립성 변이를 조사한 결과는 다음과 같다. 1. 출수후 일수에 따른 탈립율 변이는 품종간에 다소 상이한 경향이었으나 역탈립성 품종에서 수확시기별 탈발률 변이가 큰 편이었다. 2. 수확후 건조일수에 따른 탈립률 변리는 수확직후보다는 6 일간 건조시켰을 때 탈립률이 훨씬 높게 나타났다. 3. 재배시기별 탈립률 변리는 재배시기가 늦어질수록 탈립률이 낮아졌으며 이러한 경향은 역탈립성품종에서 더욱 뚜렷하게 나타났다. 4. 탈립성의 연차간 변이도 유의한 변이가 인정되었으며 역탈립성 품종에서 더욱 높게 나타났다. 5. 질소 시비수준 증가함에 따라 대체로 탈립률이 높아지는 경향이었으며 역탈립성 품종에서 그 변이정도가 컸다. 6. 출수전 11∼5일 사이의 저온처리와 저온 및 차광처리에서 탈립률이 가장 높게 나타났으며 밀양2003는 저온처리에 비해 저온과 차광을 동시에 처리했을 때 탈립률이 더욱 높게 나타났다.
To obtain the basic informations on the variation of rice grain shattering under different environmental conditions, several experiments were carried out from 1982 to 1985. The degree of grain shattering was significantly differed depending upon the harvesting time after heading in some rice varieties. It appeared that the ratio of grain shattering was greatly affected by the drying period after harvesting; the ratio of grain shattering of sun-dried seeds for 6 days after harvesting was higher than those of the just harvested seeds. Grain shattering was increased at high level of nitrogen and decreased with delay in transplanting date. Yearly differences in grain shattering was more clearly recognized in easy-shattering varieties in comparison with those of non-shattering varieties. Rice grain shattering also increased by the low temperature treatment (l7/15~circC , day/night) at booting stage, 5 to 11 days before heading. A rice variety, Milyang 23, belong to easy shattering group was more pronounced at the low temperature condition with shading. In general, it was always possible to classify the cultivar differences between easy-shattering and non-shattering groups regardless of any environmental condition. Thus results suggested that rice grain shattering will be largely governed by genetic factors.