Effect of Transplanting Rootstocks Before Grafting on Xylem Exudation and Graft Success in Walnut

Abstract

The effect of transplanting seedlings before grafting on xylem exudation of seedlings and graft success was studied in early spring grafts of walnut under uncontrolled conditions. Scions of 'Yalova-1' walnut were grafted by the whip and tongue method on one- and two-year-old walnut (J. regia L) seedlings on two dates (15 March and 15 April). Transplanting seedlings did not affect either the amount of xylem exudate or the graft survival on the earlier date (March 15), but decreased the xylem exudation and increased graft survival of two-year-old rootstocks on the later date (April 15). On this date, graft survival percentage of two-year-old rootstocks was increased 20% in 2000 and 25% in 2001 by transplanting seedlings. Xylem sap exudate of two-year-old seedlings - regarded as one of the negative factors for graft success in walnuts, was decreased 2.0 ml in 2000 and 1.3 ml in 2001 by transplanting seedlings before grafting.