TRANSFORMATION OF THE APPLE ROOTSTOCK M26 WITH THE ROLA GENE AND ITS INFLUENCE ON GROWTH

In vitro produced leaves of the apple rootstock M26 were infected with Agrobacterium tumefaciens strain GV3 101 containing a binary vector c arrying the nptII gene and the rolA gene on the T-DNA. Four transforme d clones were obtained from 433 infected leaves. Two of the transforme d clones had a single copy and Two had double copies of the T-DNA inte grated. In all the four transformed clones the T-DNA was integrated at different positions in the plant chromosomal DNA. All transformed pla nts exhibited reduced stem growth compared to untransformed control pl ants. Three of the clones also showed reduced internode length and two of these exhibited reduced leaf area, shoot dry weight, root dry weig ht and plant dry weight compared to the control plants. No correlation between copy number and plant phenotype was shown. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.