ISHS Acta Horticulturae 705: V International Walnut Symposium
STUDY ON THE NEW VEGETATIVE PROPAGATION METHOD ‘EPICOTYL GRAFTING’ IN WALNUT TREES (JUGLANS SPP.) |
| Authors: | H. Suk-In, L. Moon-Ho, J. Yong-Seok |
| Keywords: | walnut trees, epicotyl graft, scions, root stock, survival rate |
| Abstract:
In Korea the current walnut production and import is about 4,000 M/T (production: 1,300, import: 2,700) per year. According to a long time prospect for walnut demand, its consumption and demanded-amount respectively will increase and approach to about 6,000 M/T (domestic demand: 5,000, import: 1,000) on 2000’s. If we want to be produced walnuts 6,000 M/T per year, we need to planting and management for about 10,000 ha walnut trees. Grafted trees propagated from superior cultivar by asexual method must be planted. Because walnut tree is difficult to grafting and rooting, the epicotyls technique was studied. Seeds of Mandshurica walnut (Juglans mandshurica) or Persian walnut (J. regia) were sown and seedlings grafted from five to ten days after its germination. Scions which contained one or two buds were cut from 3 to 6 cm. The seedlings were cut from two to four in height from the ground, and then the center of cut section was conducted with cleft grafting method. Finally, they were fixed with plastic clamp. After grafting, each of grafts was covered with poly-vinyl envelope to protect against dry, and then kept at 25-27° C and 80~85% humidity. After about ten days, its buds started to burst. If the grafts would be grown about from three to five centi¬metres, the envelope must be removed. Finally if seedling is shown greatly growth in pots, and if it increase external temperature, the grafts must be translocated to a nursery and be managed intensively. The survival rate was shown to the range from 65% to 87.5% according to grafting time. The rate in February was greater than that in March and April. In addition, the total average rate was 78.9% and it was estimated to the high survival rate, relatively. But the rate in April was lower than the others as well as was not significant, statistically. Three varieties, 'Yongdong', 'Sinnou' and 'McKinster', were grafted each of 360 trees according to the sampled parts and varieties. The average rates within varieties were investigated in terminal and middle part, 85.5% and 78.4%, respectively, and the former part was measured to be superior to the latter. But only one scion could be sampled in the terminal part, on the other hand, several scion in the middle part. The survival rate of 'Yongdong', the new variety in Korea, was measured 76.4% and 68.9%, in terminal and middle part, respectively. In addition, the rate of 'Sinnou' was shown 90.8% and 90.3%, and the rate of 'McKinster' 89.2% and 76.1%, respectively. Therefore the 'McKinster' which has been produced variety in United States, was more excellent than the others in the survival rate | |
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