chokri bayoudh

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 large-scale production of high-quality plantlets. Research 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. 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.

Tunisian garlic is widely threatened by the attack of several viruses genus. For this purpose, a reliable protocol was established for rapid in vitro propagation of local garlic (Allium sativum L.) cultivars for large-scale production of virus-free plants and high quality bulblets.

Well disinfected shoot-tips of 1 mm were used as explants and cultivated on MS basal solid media enriched with various growth regulators: 6-Benzylaminopurine, α-Naphthaleneacetic acid, Kinetin, Indole-3-butyric acid and 2-isopentenyladenine for assessment of shoot formation, shoot proliferation and bulb formation.

Among the different phytohormone concentrations and combinations, MS basal medium without any growth regulators (M0) was found optimal for shoot-tip initiation (96% explants development) and plantlets elongation (56.26 mm). For shoot proliferation, the M1 culture medium containing 1 mg L-1 BAP and 0.25 mg L-1 NAA was the best, giving a multiplication rate of 1.7 plantlets/explant. Shoots on M0 culture medium formed bulblets earlier. Multiple bulblets per explants were obtained on medium M22 containing 2 mg L-1 Kin and 0.1 mg L-1 NAA. Separated bulblets were transferred individually on bulbification media. Non-dividable bulblet was developed in various sizes.

Bulblet acclimatization step needs to be well studied for high quality cloves production.

This efficient optimized in vitro protocol will be successfully applied for large multiplication of virus-free garlic cultivars.