Genetic analysis and molecular mapping of a male sterile mutant in rice.

Male sterility is an important inheritance phenomenon in plants and widely used in hybrid seed production. The male sterile plant can't produce normal male gametophyte for reproduction, while the female counterpart is normal. So far, more than 100 of male sterile mutants or genes have been reported in rice. Ms-np is a male-sterile mutant derived from a spontaneous muta- tion. The filaments of the mutant are long and thin, and the withered anthers are white and transparent. Ms-np was confirmed to be a none-pollen type mutant of male sterility, for no pollen grains were stained with I2-KI solution and the anther locules were al- ways hollow. Genetic analysis of five F2 populations and two BC1F1 populations revealed that the mutation was controlled by a single recessive gene. To uncover the molecular basis of ms-np, the F2 population derived from the cross of ms-np/M63 was used for genetic mapping. Screening of 227 F2 mutant individuals with simple sequence repeat (SSR) markers indicated that ms-np(t) was located between the molecular markers RM541 and RM343, on chromosome 6, with the distances of 15.2 and 7.9 cM, re- spectively. The results provide a basis for further gene cloning and understanding of the molecular mechanism underlying rice male fertility.