Influence of Two Callusing Methods on Benchgrafting Success of 12 Vitis Vinifera L. Combinations in Pennsylvania

Abstract

To investigate benchgrafting success with Vitis vinifera L. in Pennsylvania, replicated randomized complete-block experiments with split-plot treatment arrangements were conducted for three years. Twelve combinations of three scion cultivars were used: White Riesling, Gewürztraminer, and Gamay with each of four rootstocks — Kober 5BB, Teleki Selection Oppenheim Number 4, Couderc 3309, and Aramon x Rupestris Ganzin Number 1. The treatments were a covering or noncovering during the callusing period of the graft unions with dry sawdust and the scions with a wet peat-vermiculite-sand mixture.

The noncovered treatment produced a significantly higher percent total yield for six combinations in the first year and three combinations in the second year. In the third year, one combination was significantly better with the covered treatment. There appeared to be no advantage in covering the grafted plants in the callusing boxes with the wet medium.

White Riesling and Gewürztraminer grafted onto Couderc 3309 seemed to be the best-suited combinations, giving consistent high percentages of total yield with either covering treatment. Gamay in combination with each of the rootstocks showed lower percentages of total yield, a result of dormant scion wood of poorer quality.

The benchgrafting and callusing method described seem commercially feasible since many of the combinations, regardless of covering treatment, produced greater than 50% total yield.