トウガラシ属(Capsicum spp.)におけるカプサイシノイドの種間および種内変異の解析(育種・遺伝資源)  [in Japanese] Inter- and Intra-Specific Variation of Capsaicinoid Concentration in Chili Pepper (Capsicum spp.)(Breeding & Germplasm Resources)  [in Japanese]

世界各地から収集されたトウガラシ属栽培種5種145系統のカプサイシノイド含量をHPLCで定量分析し, 総含量と成分組成の種間および種内変異を解析した.C. annuumは'シシトウ'なみの野菜用低含量系統を多く含み, 比較的低含量の範囲に分布した.C. chinenseとC. frutescensは全体的にC. annuumより高含量の系統が多かった.しかし, カプサイシノイドの検出されない系統から著しく高含量の系統まで幅広い変異を示し, 種々の程度の辛味を持つ品種を育成するための育種素材として有用と考えられた.C. baccatumにはC. annuumと同様に低含量の系統が多く, 野菜用品種育成の新しい育種素材としての可能性が考えられた.カプサイシノイドの成分組成を比較したところ, C. chinenseとC. frutescensはCAP>DCであるのに対し, C. pubescensではCAP<DCで, 明らかな種間差が認められた.C. annuumは他4種を包含する幅広い変異を示した.C. annuumにおいて成分組成の地域間差が認められ, 日本産系統にはCAP<DCの系統が特異的に多かった.カプサイシノイド含量と果実形態との関係を解析したところ, C. annuumとC. baccatumで果実の大きさとの間に有意な負の相関係数が得られた.しかし, カプサイシノイド生産部位である胎座の果実に占める割合が, 果実が大きくなるほど低下することに起因する表現型相関であり, 両形質は独立した遺伝的支配を受けていると考えられた.

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 1000μg/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.