MOLECULAR CLONING OF X LOCUS AND MARKER-ASSISTED SELECTION OF NON-RESTORING ALLELE FOR OWEN CYTOPLASMIC MALE STERILITY

摘要

According to Owen (1945), fully male sterile plants have the genotype (S)xxzz, while the remaining eight genotypes usually show varying degree of pollen fertility. To obtain offspring from male-sterile plants, which are themselves male sterile, cytoplasmic male sterility (CMS) plants must be pollinated by so-called maitainer plants (O-type), which carry the same nuclear genes as the male-sterile plants but with normal cytoplasm (N)xxzz. To develop marker-assisted selection (MAS) method, we investigated genetic variation at the Rfl locus (Matsuhira et al. 2012), one of the two i?/loci known in sugar beet. After digestion with Hindlll, DNAs from beet plants known to have a restoring Rfl allele yielded a range of hybridization patterns on Southern blots, indicating that Rfl is a multiallelic locus. However, 22 of 23 maintainer lines showed the same hybridization pattern. The sequences of the rfl coding regions of these 22 maintainer lines were found to be identical, confirming that they shared the same rfl allele (Moritani et al, 2013). Two PCR markers targeting a downstream intergenic sequence and the first intron of Rfl, respectively, were developed. The electrophoretic patterns of both markers showed multiple Rfl alleles. One of these alleles, named the dd(L) type, was associated with the maintainer genotype.