Studies on the genetic basis of resistance to potato leaf roll virus, potato virus Y and potato virus X in Solanum brevidens using somatic hybrids of Solanum brevidens and Solanum tuberosum

Amongst tetrapoid somatic hybrids of Solanum tuberosum and Solanum brevidens, the expression of resistance to potato virus X (PVX), potato virus Y (PVY) and potato leaf roll virus (PLRV) ranged between that of the fusion parents. Genotypes with general morphology resembling S. brevidens generally were more resistant to virus infection. In contrast, hexaploid hybrids could be divided into high and low resistance groups, resistance being associated with two doses of the S. brevidens nuclear genome, but again genotypes with general morphology resembling S. brevidens were more resistance. Correlation of resistance to the different viruses was observed in aneuploid hybrids lacking parental chromosomes. This observation suggests that resistance/susceptibility is associated with the loss of individual S. brevidens or S. tuberosum chromosomes.