Interspecific hybridization is essential to introgress resistance genes from Capsicum baccatum, a related species of cultivated pepper (C. annuum), since reliable genetic resources resistant to anthracnose have recently been identified within the C. baccatum germplasm. In conventional interspecific hybridization between the two species, hybrids could not be generated due to embryo abortion, which has been known to be a postfertilization genetic barrier. Some partially compatible cross combinations, determined through observations of embryo development after pollination, were identified using a large number of accessions of C. annuum as pistillate parents. Embryo rescue technique was successfully employed to produce hybrids in these partially compatible crosses. Immature seeds bearing torpedo or early cotyledonary embryos, developed 35-40 days after pollination, were excised and the embryos were cultured on MS medium with sucrose and plant growth regulators. Hybridity was confirmed by observation of corolla yellow spot as a dominant speciesspecific trait of C. baccatum and using random amplified polymorphic DNA (RAPD) marker analysis. All the hybrid plants displayed vigorous growth but complete pollen sterility. The hybrid sterility was overcome through intensive backcrossing using C. annuum as the pollen parent. Consequently, hundreds of interspecific BC 1 F 1 progenies were raised, and introgression of anthracnose resistance was confirmed in this segregating population.
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Abstract
The characteristics of male sterility (MS) are used in breeding programmes to achieve economical seed production. Male sterility is divided into genic male sterility (GMS) and cytoplasmic male sterility (CMS), which are used to breed commercial pepper varieties. The CMS system, however, is not feasible in some pepper varieties, including bell peppers, because of the absence of a restorer source. GMS is thus important for seed production in bell peppers. In this study, a GMS‐linked marker from bell peppers was developed using the bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) method using F2 and sibling individuals. We used 1024 AFLP primer sets and found a polymorphism from EcoRI ACG/MseI GTT among the siblings. An internal sequence‐based primer was designed from the 395 bp sequence for high‐resolution melting (HRM) analysis, and the marker score of 87 of 92 F2 individuals corresponded to their phenotypes. The marker was mapped on chromosome 5 on the AC99 map.
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