Comparison of Grafting and Budding Propagation Techniques for Cultivars of the North American Pawpaw

Abstract

Pawpaw (Asimina triloba) is a fruit-bearing tree native to North America, and nurseries have a strong public demand for grafted trees. Most nurseries currently propagate pawpaw cultivars clonally through chip budding and whip-and-tongue grafting, both onto pawpaw seedling rootstock. Flexibility in successful grafting and budding techniques can optimize the type and quality of available scionwood while using the available labor. In an initial experiment, a range of pawpaw selections were subjected to grafting and budding techniques that indicated candidate cultivars and advanced selections for further examination. Therefore, the objective of this study was to determine the optimal method of propagating the pawpaw cultivars, KSU-Atwood™, KSU-Chappell™, and the advanced selection Hi7-1 using chip budding, whip and tongue, T-budding, and a cleft grafting tool. Additional trees, each of KSU-Atwood™ and KSU-Chappell™, were also subjected to green budding in the summer with the current season’s scionwood. Whip and tongue grafting was the most successful method, with a scion survival rate (SSR) of 95.8%, followed by the cleft grafting tool (SSR = 66.7%) and chip budding (SSR = 50.0%), then T-bud grafting (SSR = 25.0%), and lastly green bud grafting (SSR = 0.0%). There were no cultivar differences for the grafting techniques used. The whip-and-tongue method had the highest scion survival rate; however, cleft grafting and chip budding can be effective propagation methods for nurseries if scionwood quality does not support the whip-and-tongue grafting technique. In addition to whip-and-tongue grafting, the cleft grafting tool is a viable option for grafting pawpaw for use by personnel with less grafting experience or skill.