Evaluation of criteria to assist the selection of good quality grafted grapevines prior to their commercialisation

The production of grafted grapevine plant material is a complex process with many steps running over at least one year, from grafting to final sorting in nurseries. To reach the market France, grapevines must meet three criteria by law: resistance manual graft union test (or thumb test), minimum number roots and woody, lignified stem which has grown bud scion wood 2 cm long. This study aimed evaluate possibility using visual select good quality grapevines, without need do because therefore very subjective; depends on strength applied person who realises it. was done 22 scion/rootstock combinations different degrees success, i.e., producing proportions marketable plants after year nursery. legal currently used France as well other external measurable such length diameter, thin thick roots, rootstock diameter were measured combinations. Variation values for these observed correlations between studied. data then analysed determine visible contribute most identifying grafts. percentage grafts strongly correlated positively stem. variables highest predictive effect (other than test) large screen discussed, but no single, or combination criteria, sufficiently replace test.