秈稻白葉枯病抗病育種及遺傳之研究 III．抗白葉枯病與耐寒性相關性之研究

Abstract

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=0,1859 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.