TRANSFORMATION OF PECAN AND REGENERATION OF TRANSGENIC PLANTS

A gene transfer system developed for walnut (Juglans regia L.) was suc cessfully applied to pecan (Carya illinoensis [Wang] K. Koch). Repetit ively embryogenic somatic embryos derived from open-pollinated seed of 'Elliott', 'Wichita', and 'Schley' were co-cultivated with Agrobacten ium strain EHA 101/pCGN 7001, which contains marker genes for beta-glu curonidase activity and resistance to kanamycin. Several modifications of the standard walnut transformation techniques were tested, includi ng a lower concentration of kanamycin and a modified induction medium, but these treatments had no measurable effect on efficiency of transf ormation. Nineteen of the 764 viable inoculated embryos produced trans genic subclones; 13 of these were from the line 'Elliott'6, 3 from 'Sc hley'5/3, and 3 from 'Wichita'9. Transgenic embryos of 'Wichita'9 germ inated most readily and three subclones were successfully micropropaga ted. Three transgenic plants of one of these subclones were obtained b y grafting the tissue cultured shoots to seedling pecan rootstock in t he greenhouse. Gene insertion, initially detected by GUS activity, was confirmed by detection of integrated T-DNA sequences using Southern a nalysis.