Abstract
Grain discoloration, caused by several microorganisms, is a minor disease, but it is gaining importance in almost all rice growing areas of the world in recent years. Such grains are of low market value and consumption appeal in addition to their abnormal performance as seed of source of nutrient value. When the casual agents were inoculated on rice plant,'Ilmi-byeo'(at right before heading time and on heading time), the incidence of rice ear blight caused by Alternaria alternate and Nigrospora oryzae was higher in a plot inoculated at right before heading time than (in n plot inoculated) on heading time. Meanwhile, the incidence of rice ear blight caused by Bipolaris oryzae and Curvularia lunate was higher in a plot inoculated on heading time than in a plot inoculated at right before heading time. In rice quality, the ratio of imperfect grains was increased at right before heading time or on heading time by Nigrospora oryzae or Alternaria alternata, respectively. As discoloration rate of rice grains increased on 'Ilmi-byeo', the percentage of perfect grains decreased proportionally and the percentage of damaged rice grains increased remarkably.
일미벼는 착색정도가 심할수록 완전미 비율이 낮아지고, 변색미, 사미, 청미, 쇄미의 비율이 높아지며, 착색정도가 심할수록 현미의 진균 오염정도가 높았으며, 진균종류도 다양하였으며, 출수 직전과 출수시 병원균을 접종한 결과 주당 수량은 무처리 대비 큰 차이는 없었으며, A. alternata, A. padwickii, N. oryzae는 출수 직전에, B. oryzae와 C. lunata는 출수시 접종할 경우 발병이 높았다. 출수 직전 병원균 접종시 N. oryzae가 현미의 완전미 형성에 가장 크게 영향을 주었으며, 출수시 병원균 접종시에는 A. alternata가 현미 품질에 가장 크게 영향을 주었으며, 발병정도가 수량에 미치는 영향은 적은 편이나, 병원균 접종량이 많아질수록 발병율은 매우 높아지고 품질도 저하되었다.
