Articles
THE INTERNATIONAL PLANTING SYSTEMS TRIAL AT BOLOGNA
It involves two cultivars, Golden Delicious and Gloster 69, on two rootstocks, M.9 and M.27, at densities from about 1800 to 9000 trees/ha.
Several training systems are being tested – free palmette, slender spindle in single and double rows, North Holland spindle in three rows, and on M.27, minibush and slender spindle in six-row beds.
Up to the seventh leaf, the plots at Bologna have shown an interaction between rootstock and cultivar.
The Golden Delicious trees have grown larger at lower densities, but this has not been the case with Gloster 69. With this more vigorous cultivar the size of the trees has not been influenced so much by planting density as by the rootstock, with smaller trees on M.27.
Overall, the performance of the palmette and the single row slender spindle appears superior among the training systems on M.9. Productivity and fruit quality have been either lower in the double row slender spindle and in the North Holland spindle triple rows, or at best comparable to that of the two former systems.
The productivity per hectare of Golden Delicious has been affected by density; the plots on M.27 with 8889 trees/ha have outcropped all those on M.9. For Gloster 69, the highest yield per hectare was produced by the North Holland spindle in three row beds.
The trees on M.27, although planted at twice the tree density, performed poorly in terms of yield, revealing a lack of adaptation of this variety to the M.27 rootstock.
The high productivity of Golden Delicious on M.27 resulted in smaller fruit size, while no negative effects of density and/or rootstock have emerged for Gloster 69. Tree efficiency was highest for Golden Delicious and lowest for Gloster 69 on M.27.