Overwinter variation in glucosinolate content of green tissue of rape (Brassica napus) in response to grazing by wild rabbit (Oryctolagus cuniculus)

The effects of different rabbit grazing regimes on the concentration and relative amounts of individual glucosinolates were studied overwinter in the green tissue of two oilseed rape cultivars (Bienvenu, a single-low type, and Ariana, a double-low type) and two forage rape cultivars (Hobson and Bonar). Grazing significantly increased total glucosinolate content. Within this general increase, the proportion of aliphiatic glucosinolates was reduced whereas the proportion of both indole and phenylethyl glucosinolates increased. Possible reasons for such changes are discussed.