초록
깨씨무늬병에 심하게 이병된 병팔굉 공시종자는 배양 $5\~7$일에 호영, 내외영 및 주병의 $86\~92\%$ 그리고 과피의 $74\~83\%$가 Helminthosporium oryzae에 감염 되어 있음을 보였다. 동균은 종립전면에 분생포자를 형성하였으며 배유의 약10여세포층까지 감염되어 있었으나 배조직에서는 검출되지 않았다. Fusarium moniliforme는 과피, 경유 및 배조직에서 검출되었으며 F. roseum, Trichoconis padwicku, Curvularia spp., Alternaria tenuis, Cladosporium cladosporoides 및 Phoma sp.는$ 3\%$ 이하의 영 및 과피에서 검출되었다. 배양일주일에 $60\~87\%$가 깨씨무늬 병징을 나타냈으며 $13\~40\%$는 외관상 건전하였다. 깨씨무늬병균은 감염된 종자의 제점으로부터 과피를 거쳐 시아및 유근에 전염 발병케 하였다.
From the sample seeds of rice cultivar Palkoeng with the brown spot symptom, Helminthosporium oryzae was detected in $86\~92\%$ of hulls including empty glumes, lemma, palea, and rachilla in five to seven days of incubation. When the seeds were dehulled, the percentage detection decreased to $74\~83\%$ of pericarps. The fungus sporulated on whole surface of the seed and was detected within about ten cell layers deep of endosperm but not detected in embryo. Fusarium moniliforme was found in embryo as well as pericarp and endosperm. The frequency of F. roseum, Trichoconis padwickii, Curvularia spp., Atternaria tenuis, Cladosporium cladosporoides and Phoma sp. was less than three percent of hulls and pericarps. In seven days of incubation, $60\~87\%$ of the germinating seeds showed the symptom of H. oryzae while $13\~40\%$ were apparently healthy. This fungus in hilum of infected rice transmitted through pericarp to plumule shoot and radicle of the germinating seed.