Effects of scion properties on success and survival of walnut epicotyl grafting

This study was conducted to evaluate the effects of scion properties (number of buds on scion, presence of terminal bud on scion, and scion diameter and length) on success of epicotyl grafting and early growth of grafted walnut ‘Chandler’ at the college of Aburaihan of University of Tehran, during 2013-14. Grafting success, survival of the grafted trees, callus quality, shoot length and leaf number per tree were measured 150 days after grafting. No significant differences were found between scions containing terminal bud or lateral buds. The highest callus quality, grafting success (83.4 percent) and survival rate (72.8 percent) were obtained by using double bud scions. Using scions with 3-6 mm diameter significantly increased grafting success (73.4 percent) and survival rate (61.1 percent) of the grafted trees. The highest survival rate (56.1 percent) was found in trees grafted with 7-12 cm scions. The highest leaf numbers were found in the trees grafted with double bud scions, and 7-12 cm scions (9.1 and 8.6 leaves, respectively). The longest shoots were observed in trees grafted with scions containing two bud, and 3-6 mm diameter and 7-12 cm length (9.1, 12.7 and 12.2 cm, respectively). In conclusion, using scions containing two buds, with 3-6 mm diameter and 7-12 cm length were suggested to improve success of epicotyl grafting and quality of the grafted walnut ‘Chandler’ trees.