DISEASE RESISTANCE IN SOLANUM-PHUREJA AND DIPLOID AND TETRAPLOID SOLANUM-TUBEROSUM X SOLANUM-PHUREJA HYBRIDS

Diploid Solanum phureja, diploid and tetraploid S. tuberosum x S. phureja hybrid, and tetraploid S. tuberosum backcross clones were assessed for resistance to commercially important diseases. There was a reduction in the expression of S. phureja characteristics with increasing dosage of S. tuberosum genetic material. The generally high resistance of the S. phureja group to common scab, potato leafroll virus and potato virus Y decreased, while resistance to gangrene, foliage and tuber blight tended to increase. Resistance genes were probably well dispersed throughout the S. phureja genotype so that many were lost on hybridisation, but S. phureja could be a useful source of scab and virus resistance in the production of S. tuberosum cultivars.