EFFECT OF PLANT GENOTYPE ON THE TRANSFORMATION OF CULTIVATED ALFALFA (MEDICAGO-SATIVA) BY AGROBACTERIUM-TUMEFACIENS

The trait for somatic embryogenesis is being introduced sexually into alfalfa (Medicago sativa) breeding populations to facilitate genetic t ransformation of this crop. Cocultivation experiments were conducted w ith an agronomically-improved embryogenic clone from one such populati on as well as with two other embryogenic clones, one of which was the source of the embryogenic trait in the breeding populations. Transgeni c plants were produced from the agronomically-improved clone whereas n one were produced from the other two clones. Among the 16 transgenic p lants analyzed there was a range in both copy number and number of int egration sites for the NPT-II gene; those plants regenerated after a p rolonged selection phase in vitro generally had the highest numbers in both respects. There was no evidence of sectoral chimerism of the tra nsgene in a subsample of transgenic plants analyzed by PCR.