EFFECT OF ROOTSTOCK AGE AND SCION SOURCE ON GRAFTING Malus doumeri, AN APPLE TREE

Grafting Malus doumeri, an apple tree, is becoming important as plantation areas are increasing in recent years. The effects of rootstock ages and scion sources on success rate, shoot number, and growth of M. doumeri were conducted in North Vietnam by using the sub-side grafting technique. The results indicated that at both three and five months of growth, the ages of rootstock significantly affected shoot number and shoot length. While at five months of growth success rate of grafting was higher in using rootstock of 2-years old. The ratio was 88.9% in 2-year-old rootstocks and that was 65.1% in the 1-year-old rootstock. At five months of growth, shoot number was 1.6, and shoot length was 55.2 cm in using 2-year-old rootstocks. Scion sources did not significantly affect the success rate at both three and five months of growth. Meanwhile, they did significantly affect shoot number and shoot length. The shoot number reduced between three and five months of growth due to competitions for light and nutrients, and ice rain. It is concluded that to graft M. doumeri trees, rootstocks of 2-years old should be used by sub-side technique. While looking for suitability between rootstock and scion source/cultivars should be taken care of for higher success rate and better growth of shoots on the scion.