BREEDING OF LIME TOLERANT RHODODENRON ROOTSTOCKS
Nearly two million seedlings from seven open pollinated species and eleven crossings were screened in vitro on selection medium containing 4.8 g/l CaCl2 and 9 g/l total salt concentration. Lime tolerance of surving seedlings to be used as rootstocks was tested on clonal basis in the field on sandy loam supplemented with different amounts of CaCO3. Graftings of 60 selected rootstock clones and 20 hybrid cultivars were carried out in order to test compatibility between rootstocks and scions. 'Cunningham's White' rootstocks were used as control. Volume of root bales and plant height were determined after three years of growth on peat-free sandy loam of pH 5.8–6.0. Significantly larger root bales and increase in plant height were found in grafts of selected rootstocks and hybrid cultivars. Selected rootstocks obviously exhibit a general salt tolerance resulting in a better adaptation to ions present in calcareous soils.
Preil, W. and Ebbinghaus, R. (1994). BREEDING OF LIME TOLERANT RHODODENRON ROOTSTOCKS. Acta Hortic. 364, 61-70
In vitro selection, salt tolerance, calcium carbonate, rootstock-scion interactions