Allelic discrimination of the <Emphasis Type="Italic">Restorer-of-fertility</Emphasis> gene and its inheritance in peppers (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.)

Cytoplasmic male sterility (CMS), one of the most important traits in crop breeding, is used for commercial F₁-hybrid seed production in peppers (Capsicum annuum L.). A nuclear gene, Restorer-of-fertility (Rf), can induce normal pollen production in CMS plants resulting in fertility. Since the first report of fertility restoration in peppers, various inheritance modes have been suggested, including the presence of a third haplotype of the locus. The pepper Rf gene has not been cloned, and calculated genetic distances of linked markers have varied between research groups. A more precise allelic test and additional genetic mapping are needed to accurately select recombinants for use in marker-assisted backcrossing (MAB). Therefore, the reliability and application of these markers for allelic selection of the Rf gene was tested. Two different F₂ populations, Buja and Tamna, were used for the construction of a linkage map. From these linkage groups, a new closely linked flanking marker of the Rf gene were identified. Previous allelic testing revealed the existence of a third haplotype, Rfls ⁷⁷⁰¹ , which can function as dominant (Rf) or recessive (rf). In a previous report, Rfls ⁷⁷⁰¹ was considered to be linked to unstable male sterility (MS). However, our results suggest that unstable MS was induced by a gene residing at another locus rather than by Rfls ⁷⁷⁰¹ haplotype-linked allele.