CULTIVAR EFFECT ON ADVENTITIOUS ROOT DEVELOPMENT OF CLONAL APPLE ROOTSTOCKS

Spur ''Redchief'' and ''Granspur'' and non-spur ''Imperial Double Red Delicious'' and ''Granny Smith'' applies (Malus domestica Borkh.) on MM 106 and MM 111 cootstocks were field-set 18 cm deeper than in the nursery row using two planting methods. Trees were drug and root systems evaluated at the end of one growing season. Planting method resulted in differential scion growth, but no differences in adventitious root development on the buried rootstock shank. Rootstock did not affect incidence of shank rooting, although the MM 111 stock had a tendency to produce more roots per rooting site. Cultivar type significantly affected shank root development, with non-spur cultivars having an increased percentage of shanks rooting and a significantly increased number of burrknots with developing roots produced on each rootstock shank.