مرکز منطقه ای اطلاع رساني علوم و فناوري - The effects of cutting times of the rootstock s top and rootstock’s stem thickness on graft success in walnut for topworking graft

Abstract :

One of the important problem in walnut production is establishing orchards with unfruitfulness trees and using cultivars that doesn’t suitable for this area. In recent years walnut cultivation is began to be done with high lateral bearing capacity cultivars. For this aim, in unfruitfulness orchards topworking studies has begun with these cultivars. Grafting methods and periods, ecology, the cutting time of the rootstock’s top before grafting and the applications made after grafting affect the graft success on walnut. In this study, the effects the cutting times of the rootstock’s top before grafting on graft success and shoot growth were examined. Also the effect of the rootstocks thickness to graft success and shoot growth were examined. For this aim rootstocks were divided into three groups and their top were cut in two periods (60 and 20 days before graft). Graft success was determined one month after grafting as sprouting ratio. On the other hand, length and diameter of graft scion shoots, number of internodes per shoot, the distances of internodes, sugar, starch and carbohydrate (mg L^-1) contents of shoots were investigated after vegetation period. The cutting time of the rootstock’s top affected the graft success, the distance of internodes, sugar, starch and carbohydrate (mg L^-1) contents of sprouts statistically. In the study, highest graft sprouting ratio was 92.7% on thick rootstocks which cut off in early period (60 days before grafting).Rootstock’s diameter didn’t affect the scion’s starch, sugar and carbohydrate level statistically. According to the study, we can advise that bark grafting on walnut should be made on thick rootstocks and rootstock’s top should be cut before leaf appearance.