Resistance of solanum species to potato viruses A, X, and Y

Abstract

Some selections ofS. tuberosum (S. andigenum) were found to possess a high level of resistance to mechanical and graft inoculation with viruses A and X. Nine of the selections proved highly resistant to inoculation with both viruses; graft inoculated plants developed no symptoms nor could either virus be recovered from them. Apparent immunity to graft inoculation with virus X was found in selections ofS. acaule, S. sucrense and 1 species hybrid. Four selections ofS. tuberosum and 1 selection ofS. maglia developed symptoms of virus X infection but were poor hosts for the virus as indicated by low titer upon subinoculating to indicator hosts. One selection ofS. cardiophyllum, 4 ofS. chacoense, 3 ofS. demissum, 2 ofS. hougasii, 1 ofS. phureja, 1 ofS. tuberosum, 8 ofS. stoloniferum and 2 species hybrids were apparently immune from mechanical inoculation with virus Y. Nine of these selections were apparently immune from graft inoculation with virus Y. Apparent immunity to graft inoculation with virus A was found in selections ofS. chacoense, S. demissum, S. hougasii, S. maglia, S. phureja, S. stoloniferum and 8 species hybrids. About half of the selections developed symptoms of virus A infection but the virus could not be recovered from them. No selection was found to be highly resistant to all three viruses.