Abstract
Inter- and intra-specific variation of capsaicinoid concentration in five cultivated Capsicum species were investigated. Capsaicinoid concentrations in 145 accessions of C. annuum, C. chinense, C. frutescens, C. baccatum, C. pubescens collected widely around the world were quantified using HPLC. Three components of capsaicinoid, capsaicin (CAP), dihydrocapsaicin (DC) and nordihydrocapsaicin (NDC) were detected by HPLC. C. annuum accessions showed comparatively low concentrations, half of which were for vegetable use with less than 1000 μg/gDW of capsaicinoid. C. chinense and C. frutescens had a range of variation wider than C. annuum, from non-detectable to a remarkably high concentration, Therefore, accessions of these two species are useful breeding materials for varieties with various degrees of pungency. C. baccatum included many low concentration accessions available for breeding vegetable-use varieties. Capsaicinoid composition differed between C. chinense and C. frutescens (CAP>DC) and C. pubescens (CAP<DC). C. annuum showed a broad variation of composition covering the ranges of the other four species and showing a geographical difference. Accessions of CAP<DC were found with high frequency only in Japan. The significant negative correlations among capsaicinoid concentration and fruit size characteristics were recognized in C. annuum and C. baccatum. However, these are not genetic correlations but phenotypic correlation due to negative correlation between the ratio of placenta to fruit and fruit size.
