Identification and evaluation of flea beetle (Phyllotreta cruciferae) resistance within Brassicaceae

Abstract

All currently registered varieties of canola/oilseed rape, Brassica napus and B. rapa, are susceptible to attack by flea beetles, although to varying degrees. The development of resistant cultivars would be an environmentally acceptable means to reduce the damage caused by flea beetles. Seedlings from 10 species of Brassicaceae were evaluated for levels of antixenosis resistance to flea beetles in the laboratory, along with 308 Sinapis alba/B. napus hybrids. Thlaspi arvense and 11 cultivars of S. alba were resistant to feeding by flea beetles. In addition, 34 S. alba/B. napus hybrids were resistant to feeding by flea beetle in at least one test, although many of these failed to demonstrate resistance with repeated testing. One hybrid line was resistant to feeding by flea beetles each of the four times it was tested, while another was resistant in three out of four tests. These data indicate that resistance to flea beetles within the Brassicaceae is a genetic trait and can be transferred by interspecific hybridization. This information is the first step towards introgression of genetic sources of flea beetle resistance from resistant relatives into canola varieties. Key words: Flea beetles, Phyllotreta cruciferae, Brassica, resistance, antixenosis, introgression