A SELECTION OF OILSEED RAPE, BRASSICA-RAPA L, WITH RESISTANCE TO FLEABEETLES, PHYLLOTRETA-CRUCIFERAE (GOEZE) (COLEOPTERA, CHRYSOMELIDAE)

Five cycles of single-plant and progeny-row selection in lines derived from Brassica rapa L. ''Tobin'' were used to identify plants with inc omplete resistance to flea beetles, Phyllotreta cruciferae (Goeze). Th is line, called C8711, had higher survival, grew larger, and yielded m ore seed than Tobin when the two lines were compared in field plots at Glenlea, Manitoba, unprotected by insecticide. C8711 without insectic ide yielded more seed than Tobin treated with a lindane seed dressing, but less than Tobin treated with carbofuran granules. With carbofuran , which prevents most flea beetle damage, the yield of C8711 was 35% h igher than for Tobin. At Saskatoon, Saskatchewan, the differences betw een C8711 and Tobin were not statistically significant, although the t rends were similar to those at Glenlea. C8711 was late maturing, produ ced small seed, and was not of canola quality. The resistance in C8711 is attributed to a low level of antixenosis, rapid growth at the coty ledon stage, and tolerance to damage during the first 3-4 weeks of gro wth.