Physiological and genetical studies on the pungency of capsicum

Abstract

1. Quantitative inheritance of pungency was studied in Capsicum. C. annuum L. var. Ôjishi (P1, capsaicin content 0.05%) and var. Fushimi-amanaga (P2, 0.05%) were used as the non-pungent parents, and var. Yatsubusa (P3, 0.25%), var. Takanotsume (P4, 0.30%) and C. frutescens L. Ac 1443 (P5, 1.00%) served as the pungent parents. 2. Determinations of capsaicin content in dry matter were made by a new method combining paper-chromatography with the taste threshold stimulus method (Tab. 1). 3. No metaxenia was observed in fruits obtained from crosses non-pungent (♀)×pungent (♂) (Tab. 2). 4. In crosses between non-pungent and pungent, a similarity between the reciprocal crosses was observed for many characters, e.g. pungency, fruit shape and fruiting position (Figs. 1 & 2). F1 hybrids showed about the same capsaicin content as their pungent parent varying within a narrow range (Tabs. 3 & 4). In F2 various degrees of pungency were segregated from non-pungent to more pungent than the pungent parent. The frequency distribution shows a bimodal curve (Figs. 3 & 5). In BF1, bimodal wide variation was observed as in F2. 5. In a cross pungent×more pungent, an interspecific hybrid (for morphological characters see Ohta 1961a), the F1 plants showed about the same capsaicin content as their more pungent parent. The F2-segregation of various pungency degrees showed a continuous variation, from non-pungent to more pungent than the more pungent parent (Tab. 5 and Fig. 6). BF1 and BF2 showed also a wide variation. © 1962, The Genetics Society of Japan. All rights reserved.