NEW BIOTYPES OF THE BROWN PLANTHOPPER AND INTERACTION BETWEEN BIOTYPES AND RESISTANCE IN RICE

在室內連續應用抗蟲水稻品種Mudgo（抗褐飛蝨遺傳行為受一對顯性因子所控制），H 105， IR9-60及Samba（三品種抗蟲行為均受一對隱性因子所支配）等分別飼餐自然棲羣褐飛蝨，經20世代陸比較各蟲羣成蟲壽命、緊殖後裔蟲數、生存率，以及偏好性與為害等結果，頭示各蟲重分別能完全適應於用於連檢飼養該蟲羣之水稻品種而形成三種不同的生物小種。生物小種間並無明頭之形態上差異，但劉抗褐飛蝨遺傳質不同水稻的反應卻有極明顯的差異。應用上述三種主物小種間對不同抗蟲遺傳質水稻品種為害反應的差異，本試驗己將以往選出之抗蟲品種的抗蟲遺傳類型加以鑑定，並縫現有水稻Mathumanikan及DF1等兩品種對上述三種生物小種兼具抵抗佳，其抗蟲遺傳因子與以往發現者可能具有明顯的差別。 Three biotypes of the brown planthopper have been developed, by feeding caged insects successively on rice having different genes for resistance. The biotypes have been designated Biotype I, Biotype II, and Biotype III. Although biotype II was generally smaller than the others, no distinct differences in morphological characters among biotypes were observed. However the differences in plant-wilting capabilities were obvious. The individuals of Biotype 1, the dominant biotype in the natural population, are capable of wilting rice with the T (N) 1-type resistance (susceptible to all biotypes). Biotype III individuals can wilt rice with T (N) 1-type resistance and H 105 type resistance (resistance control by single recessive gene, which are, resistant to biotype I, moderatelysusceptible to biotype II, and susceptible to biotype III) but can not wilt the rice with Mudgo type resistance (resistance control by single dominant gene, which are resistant to biotype I and biotype III, but susceptible to biotype III). Brown planthoppers of biotype II are capable of wilting rice with T (N) 1-type and Mudgo-type resistance, and also can severely infest rice with H 105-type resistance. With the differences in the reactions of biotypes on rice varieties having different genes for resistance, the resistant genes of varieties Screened previously for resistant to biotype I have been indentified, and the varieties mathumanikan and DF1 are recorded resistant to all mentioned biotypes