Leptinotarsa decemlineata, the Colorado potato beetle (CPB), is the primary insect defoliator of potatoes in North America. To combat this destructive pest and reduce the need for pesticides, wild tuber-bearing Solanum species with CPB resistance can be incorporated into potato breeding programs for resistant variety development. S. pinnatisectum is a Mexican diploid species that has been shown to possess high levels of CPB resistance. However, the genetic basis of its resistance is unknown, and attempts to introgress S. pinnatisectum-derived CPB resistance into cultivated lines have been unsuccessful due to the post-zygotic barriers of this 1EBN species. The research first aims to quantify the resistance of S. pinnatisectum, as well as that of sexually compatible species, including S. jamesii and S ehrenbergii. Loci associated with CPB resistance in S. pinnatisectum will be identified through crosses with a susceptible compatible parent, resulting in a diploid mapping population. Detached leaf bioassays with CPB larvae and SNP genotyping of this population will be employed to identify causative loci and genetic markers for use in breeding efforts. Thus far, detached leaf bioassays assays have confirmed high resistance in S. pinnatisectum and susceptibility in a S. jamesii clone, as well as intermediate resistance in their hybrid progeny. Additionally, other wild species have been assessed as potential sources of CPB resistance, including S. okadae, S. tarnii and S. acroglossum. Ultimately, introgression of CPB resistance into cultivated diploid germplasm will be achieved by leveraging unique lines with high interspecific compatibility.
