The Crossability and Genetic Relationship between Solanum retroflexum Dun. and S. nigrum L

Abstract

Several reciprocal cross pollinations were made between Solanum nigrum (2n=72) and S. retroflexum (2n=48); crosses were successful when the higher chromo-somal form was used as female parents; the cause for failure of its reciprocal crosses was discussed.
Cytomorphological features of the species and their F₁ hybrid were studied. The hybrid was pentaploid (2n=60). Its breakdown of meiosis and high pollen sterility seem to be primarily due to chromosomal cause. From the occurrence of as many as 24 bivalents and 12 univalents in few pollen mother cells of the hybrids, it is suspected that S. retroflexum or one of its close relatives has participated in origin of S. nigrum.