Cytogenetical relationships among three species of chili peppers, Capsicum chinense, C. frutescens and C. baccatum.

Abstract

In order to elucidate cytogenetic relationships among 3 Capsicum spp., 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 PMC [pollen mother cell] 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. C. chinense and C. frutescens are apparently not 2 distinct species but a single species involving 2 different varieties as seen in C. baccatum. For the interspecific hybrids of C. baccatum .times. C. frutescens, few univalents were observed at MI, and the averge meiotic chromosome pairing was 0.87 univalents, 10.22 bivalents, 0.31 tivalents, 0.34 quadrivalents and 0.06 hexavalents. Considering the present results and the geographical distribution of wild progenitors, C. baccatum and C. chinense/C. frutescens complex were originally derived from a common ancestral species monophyletically, and their geographical distribution occurred subsequently, resulting in reproductive isolation among them.