Introducing a Simple and Efficient Procedure for Topworking Persian Walnut Trees

Abstract

To find the most suitable procedure for improving the quality and productivity of Persian walnut trees ( Juglans regiaL.) through topworking, different grafting methods were compared from 2001 to 2006. The effect of cultivar (scion) on grafting success was also assessed in a separate trial with the most successful method of grafting in 2004. Modified bark grafting of scaffolds performed in mid-April resulted in the highest graft take (100%) and survival (> 85%). Grafting success differed (0 to 100%) depending on the cultivar used as the scion. Other grafting (whip and cleft) or budding (chip, patch and I-shaped) methods on scaffolds produced poor results and/or no survival. The number of nuts, color and weight of kernels was superior in the topworked trees compared to the non-topworked ones (P ≤ 0.01). The modified bark grafting method represents a simple and effective technique to convert inferior walnut trees to desirable cultivars. This technique included delaying grafting date for two weeks after rootstocks were cut back and temporarily covering the graft union with moist sawdust. After about three weeks, the sawdust cover was removed and the graft union was covered with grafting wax.