Breeding for Resistance in Cabbage and Cauliflower to Cabbage Looper, Imported Cabbageworm, and Diamondback Moth1

Abstract Resistance to Trichoplusia ni (Hubner), Pieris rapae (L.), and Plutella xylostella (L.) in cabbage [ Brassica oleracea L. (Capitata group)] and cauliflower ( B. oleracea , Botrytis group) was studied using a 5-parent diallel. Resistance was quantitatively inherited without undesirable linkages. When Plant Introduction (PI) 234599 (a glossy-leaved cauliflower) was used as a parent, narrow sense heritabilities of 22-47% were obtained for resistance. This resistance was maintained irrespective of plant age or presence or absence of alternate oviposition hosts. Plants with moderate tolerance only express it at maturity. The highest levels of resistance were transferred with difficulty into desirable type cauliflower and cabbage with slight bloom.