High Transformation Freqtuncy of Brassica Crops with Agrobacterium rhizogenes

Genetic transformation by Agrobacterium rhizogenes was carried out using hypocotyl segments of cabbage, cauliflower, Brussels sprouts and oilseed rape. Among these plant genotypes, cauliflower exhibited the highest root induction frequency whereas cabbage showed the highest transformation frequency. Bacterial strain LBA 9402 induced more roots than strains LBA 9365 and LBA 8490. The culture of sequential segments along the full length of the hypocotyl showed that there was a gradient of increasing root induction frequency from cotyledons to the root.Transformation frequency was remarkably raised when 1-2 mm top parts of segments with all roots still attached were transferred onto the solid medium before individual roots on segments were transferred.