The effects of an altered glucosinolate profile, on the invertebrates within a Brassica napus crop (PhD)

Summary

In this study double haploid (DH) Brassica napus plants containing novell allelles from wild Brassica species (1) were grown in a series of field trials, with the comercial B. napus cultivar Recital. The Glucosinolate (GSL) content and profile of the two plant types and volatiles produced from damaged tissue, were monitored throughout the growing. The effect of breeding for a novel GSL profile on yield and the effect of the altered GSL profile on the insect community of the crop were assessed.

The GSL profile and volatile signature of the DH plants was found to be distinct from that of the Recital plants. There was no indication that breeding for an altered GSL profile had affected yield. Regular sampling of the insect fauna of the crop using sweep netting and sticky traps showed that the early flowering DH plants were initially more attractive than Recital to several pest and beneficial species suggesting that it may function as a temporal trap crop. However, Meligethes aeneus (Pollen beetle) continued to be attracted to the DH plants throughout the season, suggesting an attraction to the GSL profile of the DH plants. Sampling also showed that DH plots contained higher numbers of non pest individuals and for much of the growing season higher levels of species richness than Recital plots.

The attractiveness of the DH to important pests such as Ceutorhynchus assimilis (the cabbage seed pod weevil) and Meligethes aeneus coupled with a yield comparable to many commercial cultivars suggests that the DH plants may make an excellent trap crop for winter OSR.