In vitro Drought Tolerant of Rootstock Apple (Malus domestica Borkh.) and Pear (Pyrus calleryana)

Gharbia H. Danial, Diaa A. Ibrahim, Belan M. Khalil and Vyan M. Musa
Dept. Scientific Research, Faculty of Science, University of Duhok

The apple and pear explants were cultured in MS multiplication media supplemented
with different concentrations of polyethylene glycol (6000), (0.0, 2%, 4%, and 6%). The
results revealed that PEG at 6% was more effective than 2% and 4% by producing
significantly lower average number of branches per explants (3.58) in apple and (3.62) in
pear as compared to the highest average number of branches (6.06) in apple and (9.04) in
pear achieved by control treatment. On the other hand, the shoot length and leaves
number were reduced in both apple and pear at all PEG levels. After then, the plantlets
were rooted in MS media supplemented with 1.0 mg/l NAA, and acclimatized in
greenhouse. Under in vitro conditions callus induction from apple, the response of calli to
elevated levels of PEG was recorded as fresh weight. These results indicated that increased
levels of PEG were used to create water stress. There was a reduction in callus induction
ability with increasing levels of PEG. And the control was superior compared to all other

KEYWORDS: In vitro, Drought tolerant, Apple, Pear, Polyethylene glycol.


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