Isolation of Genetic Male Sterile Mutants in a Semidwarf Japonica Rice Cultivar¹

Abstract

Genetic male sterility was induced in the semidwarfjaponica rice (Oryza sativa L.) cultivar M‐101 by treatment of seeds with 30 kR of gamma rays. In the X2 generation, 251 partially sterile plants which presumably were true steriles that were setting seed due to outcrossing, were selected and designated as Group I lines. Fertile progenies of these X2 plants were considered to beputative Fl's from natural crosses. By a series of progeny tests, which eventually involved confirmed crosses, eight lines which carried single recessive genes for male sterility were derived from these putative F1's. In the X2 generation 18 completely sterile plants, designated Group II lines, also were selected. One single‐gene, recessively‐inherited genetic male sterile was derived from these 18 lines. Seed set on the male steriles from open pollination by sib plants ranged from 12 to 40% on the eight final Group I lines in 1980, and was less than 1% on the single Group II line. In 1981 open pollination seed set was lower, ranging from 1 to 18%, but evidence of crossing was confirmed by the use of pollinators with a marker gene.

Pollen Characteristics and Genetics of Induced and Spontaneous Genetic Male‐Sterile Mutants in Rice

“…Data collected from the segregating populations at Davis in 1987 also confirmed that the sterility in each of the seven previously reported mutants (MESE et al 1984), Gl to G7 in the present study, was controlled by a single recessive gene (Table 3).…”

“…Lack of desirable ms mutants was one of the major reasons for carrying out this project in rice. MESE et al (1984) reported that 1-2, one of the 11 gamma ray induced ms mutants would be useful for its high outcrossing rate. Their results was confirmed by the present study: 1-2, coded as Gl in this study, was identified as one of the best in terms of stableness and completeness of the male sterility and the outcrossing rate.…”

“…Many different spontaneous and induced mutant genes leading to male sterility have been reported in rice (TREES and RUTGER 1978, Ko and YAMAGATA 1980, 1987, MESE et al 1984, FUJIMAKI and HIRAIWA 1986. Japanese scientists have designated as many as 45 ms genes, including 6 spontaneous and 39 induced mutants (FUJIMAKI andHIRAIWA 1986, Ko andYAMAGATA 1987).…”

“…Information on the allelic relationships among these mutants is limited. Reported but undesignated ms genes include four spontaneous monogenic ms mutants described by TREES and RUTGER (1978), three induced ms mutants reported by SINGH and IKEHASHI (1981) and 11 induced ms mutants developed by MESE et al (1984).…”

“…Gl through G7 were gamma-ray induced from cultivar 'M-101'. Detailed procedures of seed treatment and mutant isolation were described by MESE et al (1984). These mutants were described as 1-2,1-1, 1-17, 1-3, 1-5, 1-8, 1-13, 1-15, 1-16, respectively.…”