Comparison of formulae used in determination of graft compatibility in different grape- American grape rootstock combinations

Vitis vinifera L. cultivars have to be grafted on American grape rootstocks due to phylloxera and nematode damages, which makes it obligatory to determine their graft compatibility in a vineyard. For this purpose, any of four formulae developed by Perraudine, Branas, Spiegel-Roy & Lavee and Onaran was inconclusive to reliably determine the compatibility of a scion/stock combination. Therefore, it is needed to compare these results with values of pruning weight, yield and quality analyses obtained from a long-term grape growing. In addition, they have to be supported by histological and biochemical analyses