SOMATIC HYBRIDS BETWEEN SOLANUM-ETUBEROSUM AND DIPLOID, TUBER BEARINGSOLANUM CLONES

Electrofusion was used to obtain somatic hybrids between Solanum etube rosum (2n=2x=24) and two diploid potato lines. These hybridizations we re conducted to determine if haploidxwild species hybrids are better f usion partners than conventional S. tuberosumGp. Tuberosum haploids. R estriction fragment length polymerase (RFLP) analyses of the putative somatic hybrids confirmed that each parental genome was present. The s omatic hybrids between S. etuberosum and a haploid S. tuberosum clone, US-W730, were stunted and had curled, purple leaves. In contrast, som atic hybrids between S. etuberosum and a haploidxwild species hybrid ( US-W 730 haploidxS. berthaultii, were vigorous and generally tuberized under field conditions. These hybrids were designated as E+BT somatic hybrids. Analyses of 23 E+BT somatic hybrids revealed a statistically significant bias towards the retention of S. etuberosum chloroplasts. Stylar incompatibilities were observed when the E+BT somatic hybrids were used as pollen donors in crosses with S. tuberosum cultivars. Rec iprocal crosses did not show this incompatibility. The progeny were vi gorous and had improved tuber traits when compared to the maternal E+B T parent. RFLP analyses of three sexual progeny lines confirmed the pr esence of all 12 S. etuberosum chromosomes. In two of these lines, RFL Ps that marked each of the 24 chromosome arms of S. etuberosum were pr esent. However, RFLP markers specific for regions on chromosomes 2, 7, and 11 were missing from the third clone. Because other markers for t hese chromosomes were present in the progeny line, these results indic ated the likelihood of pairing and recombination between S. etuberosum and S. tuberosum chromosomes.