Cytogenetical Relationships among Three Species of Chili Peppers, Capsicum chinense, C.frutescens and C.baccatum

Abstract

In order to elucidate cytogenetical relationships among three Capsicum species, C. chinense, C, frutescens and C.baccatum, intra- and inter-specific hybrids were examined cytologically. In intraspecific hybrids of C.baccatum and C, frutescens, chromosome pairing at MI of PMCS was regular with 12 bivalents, and their pollen stainability was high. For the interspecific hybrids between C. chinense and C.frutescens, meiotic chromosome pairing was also very regular with 12 bivalents. The average was 0.06 univalents and 11.97 bivalents (9.81 rings and 2.16 rods). Their pollen stainability was relatively high. Therefore, it was suggested that C.chinense and C.frutescens are not two distinct specles but a single species involving two different varieties as seen in C.baccatum. For the interspecific hybrids of C.baccatum × C.frutescens, few univalents were observed at MI, and the average meiotic chromosome pairing was 0.87 univalents, 10.22 bivalents, 0.31 trivalents, 0.34 quadrivalents and 0.06 hexavalents. Considering the present results and the geographical distribution of wild progenitors, it can be concluded that C.baccatum and C.chinese/C.frutescens complex were originally derived from a common ancestral species monophyletically, and that their geographical distribution occurred subsequently, resulting in reproductive isolation among them.