Hybridization Studies of Five Species of the Solanum Nigrum Complex Found in South Africa and two Cocktail Tomato Cultivars

Species from the Solanum nigrum complex are not as popular as potatoes and peppers but are economically important fruit or leafy vegetables in some parts of the world. The aim of this study was to look at the hybridization potential of genotypes from the Solanum nigrum complex, and two cocktail tomato cultivars, to facilitate a future breeding program. Solanum americanum Mill., S. burbankii Bitter, S. chenopodioides Lam., S. retroflexum Dun. and S. scabrum L. are some of the species found in Southern Africa. Crosses, including reciprocals, were made between these five species and two cocktail tomato cultivars. Fifty percent of the crosses made, resulted in fruit set, but only 22.5% of the produced seeds germinated to yield progeny. Cytological analyses of the chromosome numbers showed no variation from the normal euploid series. The occurrence of polyploidy between the species is probably the most efficient barrier to natural hybridization between the species.