Characterization of Somatic Hybrids Solanum bulbocastanum plus dihaploid Solanum tuberosum

A total of 45 somatic hybrids of S. bulbocastanum 8003 (2n=2x=24, cytoplasmic type W gamma; blb 8003) and dihaploid S. tuberosum 243 (2n=2x=24, cytoplasmic type T beta gamma.; tbr dh 243) generated by protoplast fusion were acclimatised and 36 recovered. Most of the somatic hybrids exhibited morphological abnormalities and a reduced growth stature. Five hybrids were intermediately dwarfed and two were tbr like. Eight somatic hybrids initiated flowering but only three generated the complete flower structure. The flowers produced less pollen with 10% fertility. The female fertility was strongly reduced. The vegetative growth phase was delayed and tubers yield was reduced. Three somatic hybrids had good tuber productivity but still lower than the tbr parent. A laboratory test with Phytophthora infestans infection showed that 33 lines were as resistant as parent blb 8003. An effect of the cytoplasm composition on the resistance level was not detected. Hybrids with different cytoplasm composition (T beta gamma, W beta gamma, WT beta gamma) showed a similar response to P. infestans infection. On the basis of the evaluation, seven perspective somatic hybrids were selected as suitable for potato breeding programme. The protoplast fusion turned out to be a suitable tool for creation of new breeding materials of Solanum genera.