Preliminary study on Indica-compatibility in the rice restorer materials with American, French or Australian long-grain Japonica genetic background and their application

With Indica MS line——Pei'ai 64S as tester, the Indica-compatibility of the 38 progenies from the crosses between Gui 99 and the long-grain Japonica rices from the USA, France and Australia was tested. The results showed that all the materials tested belonged to fertility group and had good general compatibility with Indica,also. Most of their F_1 hybrids with the Indica tester showed much higher than common Indica/Japonica F_1 hybrids in terms of seed setting rate, significant heterosis in number of spikelets per panicle and grain yield, and relatively huge potential value for commercial application. It was proposed that priority should be given to the development of Indica-compatible Japonica-prone lines by utilizing long-grain Japonica rice or long-grain tropical Japonica rice as parent in the breeding of slender intersubspecific hybrid rice,which met the demands for production and consumption in southern tropical regions.