(28(1):1-6)Breeding and genetic studies for the resistance to bacterial leaf blight disease in indica rice III. on the relationship between the resistance to bacterial leaf blight disease and cold tolerance

Abstract

利用抗白葉枯病耐寒之Pl 162319 ，分別與感病不耐寒之嘉農秈11 號與嘉農秈育12 號等品種雜交，由其F2及F3 後裔，分別測定其耐寒性及對白葉枯病之反應，以探討控制該兩性狀之遺傳因子是否有相關關係存在，以供育成抗病、耐寒及豐產品種之參考。試驗結果得知F2 族群中抗白葉枯病個體出現之頻度，不因供試材料經低溫處理而顯著的減少或增加。又由F3 後裔檢驗之結果得知，供試兩組合之抗病與耐寒性間之簡單相關係數分別為r =0.1859 與-0.1874 ，均為不顯著。由此可推知，耐寒與抗白葉枯病因子之分離係獨立，似無相互牽制連鎖現象。因此吾人欲育成抗病耐寒之秈稻品種，可以一般育種方法，將稉稻抗病耐寒因子轉移於秈稻品種。 Most of the indica rice varieties in Taiwan are found susceptible to bacterial leaf blight (Xanthomonas oryzae ) and sensitive to low temperature, especially during the nursery of first crop and ripening stage of second crop. The bacterial leaf blight disease seems to be associated with low temperature. It may become severe in indica rice. In order to clear genetic correlation between bacterial leaf blight disease and cold tolerance, experiment was carried out by using introduced rice variety PI 162319 (resistance to B. L. B. and low temperature) to cross with the local varieties Chianung Sen 11 and Chianung Sen yu 12 (Susceptible to disease and sensitive to low temperature). Two F2 populations and their F3 progenies were subjected to genetic analyses. Results obtained from this experiment were as follows : It was found that the differences of the bacterial leaf blight reaction of the two F2 populations between cold treatment and control were not significant at 5% of probability. This means that the two characters segregated independently. There were no significant correlations between bacterial leaf blight resistance and cold tolerance ( r=1,859 and _0,1874 for respective cross) in their F3 progenies. It is recommended to use the japonica rice for varietal improvement of indica rice. Most indica rice varieties are susceptible to cold temperature which can be improved by transfering the cold tolerant gene from the japonica rice