Effects of Basal Medium, Growth Regulators and Growth Medium on Micropropagation of Semidwarf Pear Rootstock “Pyrodwarf”

Pear rootstock Pyrodwarf as semi-dwarfing rootstock has been used because of its many advantages. To optimize in vitro propagation conditions and study the effect of basal medium, different combinations of plant growth regulators on micro propagation and rooting of Pyrodwarf rootstock, this study was conducted. In the first experiment, the effect of five basal media including: MS, 1.5MS, 2MS, WPM and B5 were studied on shootlet number and shootlet length. In the second experiment, the effect of two plant growth regulators; BAP and TDZ with four concentrations (0, 0.5, 1 and 2 mgl-1) was studied on shootlet number, shootlet length, node number, internode number and internode length. In the third experiment, the effect of two basal media MS and ½MS supplemented with two plant growth regulators: IBA and NAA with four concentrations (0, 1.5, 3 and 4.5 mgl-1) was studied under three and four days darkness for root induction. Acclimatization of rootstock was surveyed separately in coarse perlite, fine perlite, peat moss and perlite + peat moss. Results showed that the highest proliferation, 3.71 shoots per explants, was observed in B5 medium. The highest shoot number with mean of 12.44 shoots per explant were observed in concentration of 1 mgl-1 BAP. The highest rooting percentage with mean of 100% and root number with mean of 3.04 was observed in ½MS media supplemented with 4.5 mgl-1 IBA. The roots with better quality were observed in induction for three days in darkness. The highest acclimatization and survival percentage of seedlings in pyrodwarf rootstock obtained in coarse perlite growth medium .