Determination of the Most Suitable Time and Methods of Walnut Grafting Under West Azarbaijan Climatic Conditions

Considering present problems in the production of grafted walnut trees and the role of them in the production of uniform and quality nuts, this experiment was conducted with 11 different grafting methods and times including: cleft, earth up cleft, bark, tongue, shield budding at three times (spring, summer and fall), patch budding (spring, summer and fall) and chip budding. Treatments were arranged in a randomized complete block design with four replications in 2005. Also a preliminary experiment was conducted with the abovementioned treatments systematically in 2004. Results showed that there was a significant difference among treatments on the grafting percentage. The highest grafting percentage (93.3% and 83.75%) obtained from the bark grafting operated at early May of 2004 and 2005, respectively. In the second rank, spring patch budding and earth up cleft grafting resulted in the 60% and 40 % grafting percentage, respectively. However, grafting success in the case of ordinary cleft grafting in both years was about 20%. In other methods and times of grafting the union of scion and rootstocks did not occurred successfully, although the graft union two weeks after operation was green. In conclusion the suitable time of grafting was limited to the early spring. Therefor, it could be recommended to propagate walnut by bark grafting and spring patch budding provided that scions has been stored at refrigerator.