Resistance to Aphids, Late Blight and Viruses in Somatic Fusions and Crosses of Solanum tuberosum L. and Solanum bulbocastanum Dun

Solanum bulbocastanum Dun. is a wild potato species resistant to late blight, Phytophthora infestans (Mont.) de Bary, green peach aphid, Myzus persicae (Sulzer), and potato aphid, Macrosiphum euphorbiae (Thomas). Because of its reproductive incompatibility with S. tuberosum, S. bulbocastanum aphid resistance has been under-realized in potato breeding. Solanum tuberosum + S. bulbocastanum somatic fusions created for introgression of late blight resistance and subsequently backcrossed to cultivated potato were screened to determine if aphid resistance, virus resistance, and late blight resistance could be concurrently incorporated. Among the 63 lines screened, nine expressed resistance to green peach aphid and five lines expressed resistance to potato aphid. Virus resistance field screenings over 4 years indicated 29 lines were resistant to PVY and five were resistant to PLRV. Of those, two were resistant to both PVY and PLRV. Lines were tested with markers linked to R genes for resistance to PVY as well as the marker for late blight resistance. Line K7G-319 has pyramided M. persicae, M. euphorbiae, and PVY resistance and line K7G-329 has pyramided M. persicae, M. euphorbiae, PVY and late blight resistance into one clone, which can now be used as a breeding source for multiple resistance factors. This study has shown that somatic hybridization can be used to introgress aphid resistance from wild potato species that are sexually incompatible with S. tuberosum.