An artificial, fertile breeding line was obtained by crossing S. acaule, Bitter to S. phureja Juz et Buk. It has 2n = 48 chromosomes and was formed by fertilization of S. acaule eggs (n = 24) and S. phureja pollen grains (2n = 24). It possesses valuable characters of S. acaule and S. phureja combined, and is highly male and female fertile, producing abundant seed by selfing or by crossing to tetraploid, cultivated potato clones. Since it is tetraploid and easy to cross, it is expected to be more efficient for transferring valuable genes from S. acaule to cultivars than the natural, well known, hybridogenic species S. ×juzepczukii (2n = 36) and S. ×curtilobum (2n = 60). © 1984 Springer.