an optimized protocol for in vitro propagation of pyrus communis and pyrus syriaca using apical-bud microcuttings

Purpose: in tunisia, pear cultivars are widely threatened by the attack of fire blight disease. cultivation of tolerant cultivars is an effective control strategy for disease control. for this purpose, a reliable protocol was established for micropropagation of local pyrus communis and pyrus syriaca l. and for largescale production of highquality plantlets. research method: using apical explants, different media and hormones were tested to establish a micropropagation procedure for local tunisian pyrus communis cultivars ‘arbi’, ʻmaltiʼ, ʻmahdia 6ʼ and ʻmoknine 10ʼ and for pyrus syriaca. disinfection with 4% hgcl2 treatment for 20 minutes showed the highest percentage of plant survival. successful initiation of the cultures was achieved on ms basal medium supplemented with 0.25 mg l^-1 ba. findings: during the proliferation stage, optimal shoot multiplication was obtained on ms medium with a half concentration of nh4no3 and kno3 supplemented with 0.1 mg l^-1 iba and 2 mg l^-1 ba, but for maximum shoot length the ba concentration needed to be lowered to 1 mg l^-1. a rooting rate of 100% and the highest root length and root number were attained on cheng medium supplemented with 1.0 mg l^-1 iba. pear vitroplants were successfully acclimatized on s2 substrate, composed by peat moss. research limitations: vitroplants acclimatization step needs to be well studied for the improvement of theacclimatized vitroplant survival rates by reducing the symptoms of crown rot. originality/value: this efficient optimized in vitro protocol will be successfully applied for large multiplication of high quality of tunisian pyrus vitroplants and cultivars.