The Pachytene Chromosomes ofSolanum Clarum

Abstract

The pachytene karyotype of Solanum clarum (clr) is described and shown to differ with respect to five chromosomes from that described in S. tuberosum L. (Group Andigena) and other tuberous Solanum species. In S. clarum, chromosomes II and VI have a pronounced interstitial chromatic chromomere in their long arms and chromosome V and X have characteristically large telochromomeres in their long arms. Also chromosome IV has a completely chromatic short arm. These differences between the karyotype morphology of S. clarum and that of other tuberous Solanum species are sufficiently distinct to suggest a polyphyletic origin for tuberizing ability in species within sub-section Tuberarium of the genus Solanum.