Development of Bt Collard as a Trap Crop for Cabbage
Project Leader: Elizabeth Earle (Dept. of Plant Breeding, Cornell University, Ithaca, NY)
Mark Farnham (USDA-ARS-U.S. Vegetable Laboratory, Charleston, SC)
Brian Nault (Dept. of Entomology, NYSAES-Geneva)
Anu Rangarajan (Dept. of Horticulture, Cornell University, Ithaca NY)
Tony Shelton (Dept. of Entomology, NYSAES)
Type of Grant: Pest-resistant crops; Biological control and pest biology
Project location: Wherever cabbage is grown. The general principle being tested (Bt-trap crops) is relevant nationally and internationally.
This work seeks to protect crops from insect pests by combining approaches from biological control and biotechnology. More specifically, it aims to protect cabbage from diamondback moths (DBM) through use of a collard trap crop expressing insect-resistance genes from Bacillus thuringiensis (Bt). Previous reports indicated that DBM laid more eggs on collard plants than on cabbage; however, the larvae that hatch from these eggs survive to damage crucifer crops. Bt-transgenic collard plants would attract DBM egg-laying and would also kill the hatched larvae, providing more effective insect control in a mixed field of cabbage and collard. We have introduced two different Bt genes (cry1Aand cry1C) into the collard varieties “Champion” (non-glossy leaves) and “McCormackÕs Green Glaze” (glossy leaves). Lines that are highly toxic to DBM larvae have been identified. Seeds have been recovered from self-pollination of these plants. We have also obtained progeny from crosses between cry1Aand cry1C plants in order to pyramid the two Bt genes. Seeds recovered from pollination of cytoplasmic male sterile (CMS) cabbage with pollen from cry1C plants are a first step toward production of CMS Bt-collard, which would eliminate problems of transgenic pollen flow. Initial tests of DBM egg-laying on the Bt plants and control plants indicate that the glossy collards are more attractive to the moths than non-glossy collards. The seeds already in hand and others currently being produced provide the material needed for greenhouse and field tests of the effectiveness of Bt trap crops. In addition we have produced Bt Indian mustard (Brassica juncea“Green Wave”) as an additional possible Bt-trap crop.