Effects of Growth Media and Fe Source on Micropropagation and Rooting of Semi-Dwarf Pear Rootstocks, Pyrodwarf and OH×F87

The current research was conducted to set a protocol for mass propagation of two semi-dwarfing pear rootstocks Pyrodwarf and OH × F87 in vitro condition. Three subsequent experiments were carried out for evaluation of the effects of growth media، iron source and rooting potential of plant materials. At the first experiment، effects of five growth media including MS، modified MS، DKW، QL and modified QL with different ratios of nitrate to ammonium، calcium and chloride were tested on proliferation and growth of shootlets. The results showed advantages of modified QL and QL، respectively for Pyrodwarf and OH×F87. Compared ratios of critical ions showed susceptibility of pears to high ratios of ammonium/nitrate and presence of chloride in the media، in which negative effects of these ions appeared as reduced proliferation of the rootstocks. Evaluation of iron source، conducted by using Fe-EDTA and Fe-EDDHA chelates and results demonstrated slight reduction of proliferation and higher quality of shootlets on Fe-EDDHA medium. In order to test the rooting potential of pear rootstocks، the micro-cuttings were more suitable exposed to 0 (control)، 0. 5 and 1 mgl-1 IBA in two MS and QL media. Rooting was observed in all micro-cuttings، but MS media enriched by 1 mgl-1 IBA caused higher number of roots per explants and length of rootlets in both rootstocks.