THE RESPONSE OF APPLE ROOTSTOCKS P.22, M.9 AND M.26, AND APPLE TREE CULTIVARS ‘JONAGOLD’ AND ‘GALA’ TO SOIL ACIDIFICATION

Acidification of Polish soils is a big problem in respect to large area of soils recognized as very acidic or acidic (60% of total area under cultivation). Considering the very unfavourable effects of strong acidification on soil and plant growth, studies were aimed at determining the level of tolerance of apple rootstocks and apple tree cultivars to soil acidification.
Soil acidification, down to pH 3.6 (in KCl), strongly reduced growth of apple rootstocks in comparison with pH 4.6 and 6.0. Among the examined apple rootstocks, P.22 was the most tolerant to strong soil acidification.
A lower level of tolerance was shown by the rootstock M.9 and the lowest by M.26. At pH 3.6, M.26 rootstock had the highest concentrations of Al and Mn in the roots and shoots.
The leaves of apple rootstocks grown in the most acidic soil contained the highest concentrations of Al and Mn when compared to rootstocks grown at pH 6.0. Both ‘Jonagold’ and ‘Gala’ grafted on P.22 rootstock had the highest number of flowers and fruitlets, with less on M.9 and the fewest on M.26.

XXVI International Horticultural Congress: Key Processes in the Growth and Cropping of Deciduous Fruit and Nut Trees

L. Sas Paszt, S. Mercik

apple, scion cultivars, rootstocks, growth, mineral content, pH levels

https://doi.org/10.17660/ActaHortic.2004.636.20