EFFECTS OF MALE STERILE CYTOPLASMS ON F 1 HYBRIDS IN RICE

Nine combinations were obtained by crossing nine mele sterile lines of three types of male sterile cytoplasms Y, CW, WA with their restorer T54, respectively. The differenced of effects of male sterile cytoplasms on F 1 hybrids with homonucleus backround were compared in a randomized bolck experiment. The effects of three types male sterile cytoplasms on the number of panicles, panicle length and grain yield in the F 1 hybrids were significant. The cytoplasms of Y and CW types were superior than that of WA type. But the effects were controlled by the nuclear gentypes and uncleo-cytoplasmic intoraction. Correlation-path anatysis indicated that the number of panicles, seed seting rate and the number of spikelets per panicle had direct influence on the single plant grain yield significantly. For developing strong superior hybrid rice, superior male sterile cytoplasms and the male sterile lines wtih bigger panicle, strong tiller,more number of panicles and high ability of restoration should be selected. The prollems on exploitation of Y type and CW type cytoplasm and the ability of restoration for make sterile lines were also discussed. It suggested that the fertility restoration may be different between the homoplasmus-allonucleus male sterile lines. This is an important prollem to breeding three lines hybrid rice.