FACTORS INFLUENCING TRANSFORMATION FREQUENCY OF TOMATO (LYCOPERSICON-ESCULENTUM)

We developed an efficient procedure for transformation and regeneratio n of L. esculentum cv. Moneymaker from cotyledon explants. The effect of two parameters on the transformation frequency was investigated in detail. The use of feeder layers during cocultivation proved to be cri tical. In addition, it was found that Agrobacterium strains harbouring a L,L-succinamopine type helper plasmid yielded significantly higher transformation frequencies than those with octopine or nopaline type h elper plasmids. The-optimized protocol was used to obtain transformati on frequencies averaging 9%. Of the plants produced approximately 80% proved to be diploid, of which 67% contained the transgene(s) on a sin gle locus.