Genetic Resistances to potato leafroll virus, potato virus Y, and green peach aphid in progeny of Solanum etuberosum

Increasing prevalence of potato leafroll virus (PLRV) and potato virus Y (PVY) has been reported in seed and commercial potato production, resulting in the rejection of potatoes for certification and processing. Host plant resistance to PLRV and PVY and their primary vector, green peach aphid, Myzus persicae, could limit the spread of these viruses. Host plant resistance to PLRV, PVY, and green peach aphid has been identified in non-tuber-bearing Solanum etuberosum (PI 245939) and in its backcross 2 (BC(2)) progeny. Resistance to green peach aphid involved a reduction in fecundity and adult aphid size. In addition, one BC2 individual was identified as possessing a genetic factor that was detrimental to nymph survival. PVY resistance was identified in all five BC2 progenies evaluated in a field screening under intense virus pressure. PLRV resistance was identified in two of the five BC2 progeny. This resistance was stable in field and cage evaluations with large populations of viruliferous aphids. Based on the segregation of virus resistances in the BC2, PVY and PLRV resistances appear to result from the action of independent genetic mechanisms that reduce the levels of primary and secondary virus infection. Two BC2 individuals, Etb 6-21-3 and Etb 6-21-5 were identified as having multiple resistances to PLRV, PVY, and green peach aphid derived from S. etuberosum. This germplasm could prove useful to potato breeders in the development of virus-resistant cultivars.