Genetic architecture of genes from the wild potato plant (Solanum pinnatisectum) showing resistance to the Colorado potato beetle

The Mexican wild potato species Solanum pinnatisectum is an important gene source for resistance to Colorado potato beetle and late blight. Diploid progenies segregating for resistance genes to Colorado potato beetle were developed by crossing S. pinnatisectum with S. cardiophyllum. The hybrid lines were resistant to Colorado potato beetle. A resistant hybrid line from this cross was selected and backcrossed as a female to S. cardiophyllum to generate a backcross progeny. This backcross progeny was tested for genetic architecture of the Colorado potato beetle resistance gene. Resistance percentage of the test lines over the control was determined for statistical analysis. The Chi square test result showed a significant 1: 3 ( resistance: susceptible) ratio in this backcrossing population, indicating that resistance in S. pinnatisectum to Colorado potato beetle may be controlled by two independently segregating major genes having two respective loci, acting in a complementary epistatic manner. The availability of Colorado potato beetle resistance genes, along with late blight resistance genes in S. pinnatisectum may enable breeders and geneticists to develop a single cultivar through the gene pyramiding method.