COLORADO POTATO BEETLE RESISTANT SOMATIC HYBRID POTATO PLANTS PRODUCED VIA PROTOPLAST ELECTROFUSION

摘要

Leptines are natural glycoalkaloids found only in certain selections of the wild potato species Solanum chacoense. These rare glycoalkaloids have been identified to be phytochemical defensive agents against insect herbivores such as the Colorado potato beetle (CPB). In an attempt to introduce this CPB resistance into the cultivated potato S. tuberosum, interspecific somatic hybrid plants were developed between a dihaploid of S. tuberosum and a high leptine-producing germplasm selection of S. chacoense. The somatic hybrid was fused using protoplast electrofusion and regeneration techniques. Selection of interspecies fusion cell lines was based on hybrid vigor in protoplast-callus (p-callus) growth, on shoot regeneration from p-calli, and on characteristic appearance of anthocyanin pigment. This selection system was highly efficient and 12 of 13 fully regenerated plants were identified as somatic interspecies hybrids, as determined by the analyses of morphologic biochemical, and isozyme markers. In vitro insect bioassays demonstrated that the hybrids averaged a threefold reduction in leaf consumption by the CPB when compared to cultivated potatoes.