Budding and Grafting of the Walnut (Juglans regia L.) and their Effectiveness in Bulgaria (Review)

摘要

The high biological value of the walnut kernel makes it an indispensable food product and that is why the walnut is on the FAO priority plants list. Therefore, only varieties with proven high nutritive value and good agro-economical indexes have to bepropagated. Walnut (Juglans regia L.) propagation is more difficult, compared to most fruit species, that is why along with the work on new methods for the production of inoculate planting material, old and reliable propagation technologies are being improved worldwide. We compiled a review of the propagation methods, techniques and technologies in the major countries with developed walnut production and analyzed their efficiency in view of climatic and other specific conditions. The most popular inoculation methods for the production of walnut transplants were presented -budding and grafting as well as the techniques used, such as patch budding, chip budding, bench grafting, whip, whip-tongue, cleft and omega. We emphasized on the new methods for theproduction of inoculated walnut trees, two of which -hot callus e hypocotyl grafting were tested and adapted in Bulgaria. Heating techniques were described as well - local heating on the graft union with hot water and hot callusing cable. According to the results of the most recent studies on hypocotyl grafting in temperature controlled greenhouses in Bulgaria, the method is 83% successful and can be implemented in the production of grafted young walnut trees.