Somatic Hybridization Between Solanum commersonii Dun. and S. tuberosum L. (Potato)

The large and very diversified Solanum genus includes seven cultivated species and more than 200 wild tuber-bearing species with basic chromosome number x=12 and ploidy level ranging from 2x (2n=24) to 6x (2n=72). Solanum tuberosum subsp. tuberosum (2n=4x=48), derived from crossing, chromosome doubling, and diversification of some South-American species, includes the common potato crop, and is adapted to long-day conditions (Matsubayashi 1991; Hawkes 1994). Nowadays, the common potato is grown worldwide for various food and industrial purposes, and it is the most important noncereal crop (Bajaj 1987; Zuba and Binding 1989). Traditional breeding of S. tuberosum (tbr), however, is a difficult task, due to high heterozygosity, tetrasomic inheritance, self-incompatibility, and sterility in cultivated genotypes. Also because it is vegetatively propagated, its genetic variability is rather limited. Fortunately, a number of innovative breeding and biotechnological approaches proved successful in genetic manipulation of S. tuberosum to induce and preserve novel genetic variability, produce disease-free plants, manipulate ploidy, and introduce genes from wild species (Bajaj 1987; Zuba and Binding 1989; Bradshaw and Mackay 1994).