Does omega-type graft compromise vine performance? Evaluation of five bench grafting methods across nursery, vineyard establishment, and first productive years

Grafting Vitis vinifera L. scions onto Vitis sp. rootstocks became essential in viticulture following the phylloxera crisis in the late 19th century. Among the various bench grafting methods, omega grafting became predominant due to high efficiency and compatibility with mechanization. However, concerns have been raised about its potential impact in vine performance. This study compares five bench grafting methods, omega (OM), full cleft (FC), V-shape (V), mechanical (WTm), and hand-made (WTh) whip and tongue, to evaluate implications during the nursery stage, vineyard establishment and vine performance over the first seven seasons after planting. Results suggest a three-phase trajectory in vine development following grafting: (1) a short-term nursery phase the grafting method clearly impacts performance, (2) a mid-term phase post vineyard establishment where growth and yield converge regardless of method; and (3) a long-term phase, in which structural weaknesses at the graft union may lead to delayed decline. During the nursery stage, OM consistently outperformed others in grafting success and vegetative development. In early vineyard years, OM and WTh showed a tendency to promote better vine development, although this trend faded after the third year. In contrast, differences in vine survival and training compliance emerged later. At the end of the seventh season, vine mortality reached 18 % in WTm and 7.5 % in V, whereas OM and FC maintained low losses (< 3 %). These findings contradict previous concerns about OM grafting limitations and support its continued use as a reliable method in commercial nurseries. In any case, longer-term monitoring is necessary to understand vineyard productive lifespan implications.