Comparison of one-cotyledon and hypocotyl-only cucurbit grafting methods over time after fatty alcohol rootstock treatment
Fatty alcohol treatment at the appearance of the first true leaf controls meristematic regrowth and increases stored carbohydrates of cucurbit rootstocks used in grafting. As a result, older, treated rootstocks contain enough stored energy to allow improved grafting success in a shorter period of time. An overview of three experiments will be presented to describe this novel approach to cucurbit grafting. First, a rate trial was conducted to determine the optimal concentration of fatty alcohol for rootstock treatment. Nine rates (0.00, 3.75, 5.00, 6.25, 7.50, 8.75, 10.00, 12.50, and 15.00%) of two commercial fatty alcohol products (Fair 85 and Off-Shoot T) were applied to interspecific hybrid and Lagenaria rootstock types. Damage and regrowth incidences were recorded, and 6.25% was found to be the optimal treatment concentration. The second experiment analyzed rootstock hypocotyl carbohydrate content at 1, 7, 14, and 21 days after fatty alcohol treatment. In interspecific hybrid rootstock hypocotyls, total soluble sugar increased significantly over 14 days after treatment, and starch levels significantly increased over 21 days after treatment. In Lagenaria rootstock hypocotyls, total soluble sugars increased significantly over 14 days after treatment. In the final experiment, the two rootstocks were grafted at 1, 7, 14, and 21 days after fatty alcohol treatment to determine the effect of fatty alcohol treatment on rootstock grafting success and the optimal grafting time after fatty alcohol treatment. Interspecific hybrid squash and Lagenaria type rootstocks showed increased graft survival at 7 and 14 days, respectively, after grafting with the one-cotyledon graft method. At 7 and 14 days after treatment, grafting with the new hypocotyl only method was successful in interspecific hybrid squash and Lagenaria rootstocks, respectively.
Hassell, R.L. and Daley, S.L. (2016). Comparison of one-cotyledon and hypocotyl-only cucurbit grafting methods over time after fatty alcohol rootstock treatment. Acta Hortic. 1123, 27-34
Citrullus lanatus, cotyledon-free graft, grafting methods, regrowth control, watermelon grafting