Regeneration and transformation via Agrobacterium tumefaciens of the strawberry cultivar Chandler

The effects of growth regulator balance and culture conditions on the morphogenetic response of leaf disks from greenhouse grown plants of the strawberry cultivar Chandler, have been studied. Best results were obtained in the presence of 2.46 mu M IBA and 8.88 mu M BA, where 47% of the cultures regenerated after 16 weeks with 2.9 shoot colonies per regenerating leaf disk. Optimum incubation conditions included two weeks in the dark with subsequent transfer to light (40 mu mol m(-2) s(-1), 16 h). The regeneration protocol was also valuable when leaf disks from in vitro grown plants were used as explants. Transformation was attempted using Agrobacterium tumefaciens carrying the plasmid pBI121. Leaf disks from in vitro cultures proliferating in the presence of 2.21 mu M kinetin were best explants for transformation. A 4.22% of inoculated explants showed kanamycin resistance after 16 weeks in a medium containing 25 mg l(-1) of this antibiotic. The transgenic nature of several shoots was also confirmed by the GUS assay and PCR analysis.