Screening for resistance against Myzus persicae and Macrosiphum euphorbiae among wild Solanum

As a consequence of selection for productive traits, the genetic diversity of Solanum tuberosum cultivars has been drastically reduced. With the goal to develop aphid-resistant potato cultivars, our objective was to quantify the resistance of 14 accessions belonging to five wild potato species (Solanum chomatophilum, Solanum stoloniferum stoloniferum, Solanum bukasovii, Solanum marinasense and Solanum medians) against two aphid pests, Myzus persicae and Macrosiphum euphorbiae. Aphids were reared under controlled conditions in microcages clipped on the abaxial face of mature leaves of the Solanum species. The five wild Solanum species induced more than 90% of nymph mortality in M. persicae. The mortality rate of Ma. euphorbiae was also >90% on all S. chomatophilum, S. stoloniferum and S. medians accessions and on S. bukasovii-PI 414155. When enough adult aphids emerged, that is for Ma. euphorbiae on three S. bukasovii and three S. marinasense accessions, the prereproductive period, the adult survival and fecundity were assessed. These parameters allowed us to calculate the intrinsic rate of natural increase (rm), the finite rate of increase and the population doubling time (DT). The rm and the finite rate of increase were significantly reduced, whereas the population's DT was significantly enhanced for most (five out of six) wild Solanum accessions. All accessions of S. chomatophilum, S. stoloniferum and S. medians and S. bukasovii-PI 414155 were highly resistant to both M. persicae and Ma. euphorbiae. In conclusion, S. chomatophilum-PI 310943 and -PI 310990, and S. stoloniferum-PI 195167, -PI 201855 and -PI 275248, can be amenable for potato breeding programmes. © 2007 Association of Applied Biologists.