SOME METHODOLOGICAL ASPECTS OF APPLE TRANSFORMATION BY AGROBACTERIUM

Leaf explants of apple cvs Gala and Golden Delicious were infected wit h the Agrobacterium tumefaciens strain AGL0(pMOG410). The effects of a 2 d preculture of the explants before infection and the addition of 5 -azacytidine to the selection medium were studied. The percentages of GUS-positive explants after 5 w did not significantly alter due to the se treatments. One of the 'Gala' shoots, which was removed from a leaf explant cultured for 8 w on selection medium, proved to be GUS-positi ve and will be analyzed further. In general, however, it should be con cluded that regeneration of transgenic shoots directly from leaf tissu e was not very effective.