Genotypic variability and mode of action of Colorado potato beetle (Coleoptera : Chrysomelidae) resistance in seven Solanum species

Accessions from seven wild Solanum species were evaluated in the field for resistance to the Colorado potato beetle, Leptinotarsa decemlineata (Say). The multivariate insect population density data were analyzed using factor analysis. Tile factors extracted corresponded to relevant phases of the ins ect's life cycle and provided information oil the mode of resistance (antix enosis and antibiosis) of the plant species. S. berthaultii, S. capsicibacc atum, S. jamesii, S. pinnatisectum, and S. trifidum demonstrated both antix enosis and antibiosis but expressed different levels of resistance. The mod e of resistance of S. polyadenium seemed to be antibiosis and that of S. ta rijense antixenosis. Genetic variability and heritability of insect resista nce traits within accessions was trivial or inconsistent for all Solanum sp ecies studied.