Wild potato species are an immense source of genetic variability which has been relatively little used. Many diploid and tetraploid wild species are compatible with diploid clones of Solanum phureja cultivated on the Andes of South America. The resulting hybrids can have various levels of ploidy:

1. a) diploid, 2n = 24 (wild diploid x cultivated diploid)

2. b) triploid, 2n = 36 (wild tetraploid x cultivated diploid)

3. c) tetraploid, 2n = 48 (wild tetraploid x cultivated diploid producing 2n gametes.

Gene transfer from wild to cultivated clones in the case of a) diploid and b) triploid hybrids is assured by utilizing them as male parents, which may produce 2n pollen grains by First division restitution or Second division restitution in the meiotic process, in order to fertilize tetraploid cultivars or clones of S. tuberosum ssp. tuberosum or spp. andigena. In the case c), in which the hybrids produced are tetraploid, gene transfer is more simple since the hybrids can be used either as males or females in backcrosses to tuberosum or andigena tetraploid clones.

By this method, hybrids were obtained from crosses between S. phureja clones and 12 species (S. acaule, S. andreanum, S. boliviense, S. bulbocastanum, S. chacoense, S. Colombianum, S. microdontum, S. sanctaerosae, S. sogarandinum, S. stoloniferum, S. toralapanum and S. vernei) belonging to seven taxonomic series (Figure 1).