Time after Scion Harvest and Grafting Method Influence Graft Success Rate for Purple-fruited Pitanga (Eugenia unifloraL.)
The pitanga (Eugenia unifloraL., family Myrtaceae) is a large shrub or small tree native to South America. It has considerable commercial potential, but clonal propagation is challenging. Propagation by seed is easy, but the seedlings are highly variable; the desirable, purple-fruited varieties do not come true from seed. Propagation by cuttings, air layerage, or other methods that require the formation of adventitious roots usually fails. Grafting has been successful for some propagators, but it is not common. The goals of this project were to discover a grafting method that would give an acceptably high rate of success, and to test the effect of storing budwood for several days before grafting. Scion wood of the superior, purple-fruited ‘Zill Dark’ cultivar was harvested in Lakeland, FL, and carried in hand luggage to Honolulu, HI, where veneer grafts and chip buds were made at the University of Hawai’i at Manoa and at the Kona Experiment Station at Kealakekua. The scion wood was stored in polyethylene bags, slightly damp, at ambient temperature (21 to 28 °C, 70 to 82 °F) until grafted. At the Manoa site, 87% of the first-day ‘Zill Dark’ veneer grafts were successful, whereas only 5% of chip buds survived and grew. Of second-day grafts, 50% of veneer grafts and 6% of chip buds survived and grew. At the Kona site, only 15% of third-day veneer grafts of ‘Zill Dark’ and no chip buds survived. It appears that the veneer graft method has the potential to give reasonably high rates of graft success for E. uniflora.