Glucosinolate profile variation of growth stages of wild radish (Raphanus raphanistrum).

Wild radish (Raphanus raphanistrum L.) produces glucosinolates (GSL), which are important for its use as a biofumigation or allelopathic plant for weed management. Total GSL concentrations and individual GSLs were quantified in different plant parts at different developmental stages. Eight GSLs were found in various plant tissues but glucoerucin, glucoraphenin, and glucotropaeolin comprised >90% of the total GSLs. All three are degraded to isothiocyanates, which are associated with weed suppression. Maximum GSL concentration (1942.2 micromol/plant) occurred at 50% flowering stage prior to the time of maximum biomass production, when GSL concentration was 1246.65 mumol/plant. Roots contributed <15% of the total GSL. The highest concentration of GSLs was in flowers at flowering stage, but due to the low biomass they contributed only 11.83% to the total GSL. On the basis of these results, wild radish should be incorporated into soil at 50% flowering to provide the most GSLs for weed suppression.