Factors influencing grafting success and compatibility of grape rootstocks

- Weather conditions had a higher influence on callusing than rootstocks.
- The root system was less developed on the Börner rootstock.
- Welschriesling had good compatibility with all rootstocks.

The aim of this work was to examine the compatibility of different rootstocks with various wine grape varieties. In the first trial, Vitis vinifera L. cvs. Furmint, Regent, Riesling, Sauvignon Blanc, and Welschriesling were grafted onto Börner, 5BB and SO4 rootstocks. In the second trial Welschriesling was grafted on 12 rootstocks. Their growth during the first year in the vineyard was measured. As an index of compatibility, the percentage of first grade grafted vines as well as dry weight of mature shoots (canes) and roots was determined. After the grafts went through the first phase of healing often called callusing (2-3 weeks of moist warm conditions), the differences in callus formation were greater between years than among rootstocks, which were the most obvious with Furmint as a scion. No good callus formation occurred when cane (rootstock, scion) maturity is not adequate. Such was the case in 2005, there were 24% fewer grafts with fully developed callus than those in 2006. The dry weight of roots was higher on 5BB than on Börner and SO4. Börner rootstock had fewer roots, and the roots were thinner. Welschriesling had good compatibility with all rootstocks (the average grafts success was 67%), but that of 5BB, G251, and G103 (above 80%) was greater than the average. The G103 rootstock had the highest dry weight of roots. Shoot growth in vineyards was above the average with 5BB, SO4, Binova, Börner, and M V rootstocks. All Georgikon rootstocks had a lower cane dry weight per vine than the others.