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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Capsaicinoids are pungent compounds used for industrial and medical purposes including food, medicine and cosmetics. The Indian local variety ‘Bhut Jolokia’ (Capsicum chinense Jacq.) is one of the world's hottest chilli peppers. It produces more than one million Scoville heat units (SHUs) in total capsaicinoids. In this study, our goal was to identify quantitative trait loci (QTLs) responsible for the high content of capsaicin and dihydrocapsaicin in ‘Bhut Jolokia’. Capsicum annuum ‘NB1’, a Korean pepper inbred line containing 14 000 SHUs, was used as a maternal line. An F2 population derived by crossing between ‘NB1’ and ‘Bhut Jolokia’ was generated to map QTLs for capsaicinoids content. A total of 234 markers, including 201 HRM, 21 SSR, 2 CAPS and 10 gene‐based markers of the capsaicinoid synthesis pathway, were mapped. The final map covered a total distance of 1175.2 cM and contained 12 linkage groups corresponding to the basic chromosome number of chilli pepper. Capsaicin and dihydrocapsaicin content were analysed in 175 F2 pepper fruits using the HPLC method. The maximum total capsaicinoids content was 1389 mg per 100g DW (dry weight), and the minimum content was 11 mg per 100g DW. Two QTLs (qcap3.1 and qcap6.1) for capsaicin content were identified on LG3 and LG6, and two QTLs (qhdc2.1 and qdhc2.2) for dihydrocapsaicin content were located on LG2. We did not detect QTLs for total capsaicinoids content. The QTL positions for capsaicin content were different from those for dihydrocapsaicin content. These results indicate that the complexity of selecting for more pungent chilli peppers must be considered in a chilli pepper breeding programme. The QTL‐linked markers identified here will be helpful to develop more pungent pepper varieties from ‘Bhut Jolokia’, a very hot pepper.

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As one of the genic male sterility (GMS) materials in chili pepper (Capsicum annuum L.), GMS1 has been used for commercial F 1 hybrid seed production. The male sterility of GMS1 is controlled by a recessive nuclear gene, named ms 1 . In this study, we developed DNA markers linked to the ms 1 locus using a combination of bulked segregant analysis and amplified fragment length polymorphism (AFLP) in a segregating sibling population. From the screening of 1024 AFLP primer combinations, the AFLP marker E-AGC/M-GTG (514 bp) was identified as being linked to the ms 1 locus at a distance of about 3 cM. Based on internal sequencing analysis of the E-AGC/ M-GTG marker between male fertile and sterile plants, we identified three small deletions with a size of altogether 42 bp in the male-fertile plant and developed a codominant sequence characterized amplified region (SCAR) marker. This SCAR marker may be valuable for marker-assisted breeding in the hybrid seed production system of chili pepper using the GMS1 line.