Resistance to cabbage seedpod weevil among selected Brassicaceae germplasm

Abstract

AbstractBrassicaceae germplasm (Brassica napus L., Brassica rapa L., Brassica juncea (L.) Czern., Brassica carinata A. Braun, Sinapis alba L., Camelina sativa (L.) Crantz, Crambe species) with cultivar development potential for the prairies was evaluated for resistance to cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae)) infestation under field conditions in southern Alberta from 2001 to 2005. Relative susceptibilities were as follows: B. rapa and B. napus > B. juncea = B. carinata > S. alba. Although some of the germplasm evaluated varied within species in terms of glucosinolate profile, erucic acid level, oil content, and plant height, none of these factors appeared to influence the degree of C. obstrictus damage. A subset of this germplasm was also evaluated in the greenhouse. Although the canola species B. rapa sustained the highest level of damage in the field tests, it was similar to other Brassica genotypes in the greenhouse. All lines of S. alba were virtually immune to weevil attack in both field and greenhouse tests, regardless of glucosinolate profile, suggesting that other factors confer resistance in this species. Synchrony of crop development with weevil activity in the field explains some of the variability in damage observed among genotypes and illustrates the importance of combining field and greenhouse studies when assessing resistance.