Genetic analysis of anther-derived plants of rice

Haploid and diploid plants derived from anther culture of hybrid rice (Oryza sativa L., 2n = 24) heterozygous for narrow leaf and liguleless genes (nal+nal lg+lg) were subjected to genetic analysis. No segregation was observed in self-fertilized progeny of the diploid plants showing dominant traits. Therefore, all anther-derived diploid plants obtained in this study were homozygous; they have arisen from haploid microspores through chromosome doubling during in vitro development. In both haploid and diploid plants, the ratio of normal leaf to narrow leaf and that of liguieness to ligulelessness closely fit the expected 1:1 gametic segregation ratio. However, the frequency distribution of the four genotypic classes departs significantly from a 1:1:1:1 ratio, indicating that the two genes, nal and lg, are linked. Combined data from plants of the two ploidy levels yielded a recombination value of 9.28 ± 1.47 percent. The same F1 used for anther culture also was self-fertilized to produce F2 progeny. The results obtained from the analysis of the F2 population are in good agreement with those from anther-derived plants. The significance of this study in genetics and plant breeding is discussed.