PROPAGATION OF APPLE ROOTSTOCKS IN THAILAND: PROPAGATION BY CUTTINGS AS RELATED TO SEASONAL CHANGES, GROWTH REGULATORS, AND ROOTING MEDIA

Three experiments were conducted to determine a suitable method for improving the propagation of 3 varieties of apple rootstocks (MM106, Marubakaido N-1 and Indonesian) by using leafy terminal stem cuttings, under intermittent mist and full sunlight.

Terminal leafy stem cuttings of Marubakaido N-1 rooted quite readily from June to October. It was found that 97.5 percent of them rooted within 1 month. Cuttings rooted poorly, during November to January. 'Indonesian' and 'MM106' rooted very poorly in all months.

Marubakaido N-1 cuttings were treated with 3 concentrations of each of 4 root promoting chemicals (IAA, IBA, NAA and 2, 4, 5-T). IBA gave significantly better rooting than either the control or other chemicals. Treating the base of 'MM106' and 'Indonesian' cuttings with the same chemicals did not give significant improvement in rooting. However, treatment of Marubakaido N-1 cuttings with IBA significantly increased percent rooting and the quality of roots formed.

Burned rice hull and fine sand in the ratio of 1:1 (by volume) has been found to be the best rooting medium for Marubakaido N-1 compared with burned rice hull, fine sand, coir-dust, and coir-dust-sand media. However, no significant differences were observed for the other rootstocks.