For the Swiss apple-production there are available several suitable rootstocks. Practically all widespread rootstocks are susceptible to fire-blight and to replant-diseases. Therefore a comprehensive analysis of rootstocks that possibly are robust to the above-mentioned diseases and that can compete with the properties of the standard rootstock M9 T337 is required.
Possible rootstock alternatives to M9 are the rootstocks CG 11, B9, J-TE-E and Supporter 4. These rootstocks have been tested at two research sites in Güttingen and Wädenswil in combination with the varieties Milwa, La Flamboyante, Gala Galaxy and Braeburn according to yield, fruit-quality, robustness to fire-blight and root suckering.
The positive effect of fire-blight robust rootstocks works best with even robust varieties. Regarding fruit quality no effects have been identified in relation with the rootstock. The yield with the rootstock CG 11 was higher than that of other rootstocks. It can be a good alternative to M9 in the future, especially in combination with varieties with low vigour or at problematic sites.
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