Effects of Pluronic F-68 on regeneration and rooting of two pear cultivars (Pyrus communis cvs Dar Gazi and Bartlett)

ABSTRACT: The promontory effects of the non-ionic surfactant, Pluronic F-68 (PL) were studied on shoot regeneration and rooting of leaf explants of two pear cultivars (Pyrus communis L., cvs. Dar Gazi and Bartlett) in three separate experiments. In the first experiment, effects of various concentrations of Pluronic F-68 (0, 0.5, 1.0, 1.5 and 2.0% w/v) supplemented in two basal culture media, Quoirin and Lepoivre (QL) and Nitsch & Nitsch (NN) were evaluated on shoot regeneration of pear cultivars. The results showed that for Bartlett, a concentration of 1% (w/v) PL was the most effective in both QL and NN medium and for Dar Gazi, 2% (w/v) PL supplemented into NN medium was the most influential concentration. Generally, QL gave lower regeneration rates than NN (20.4% vs 28.5%) and regeneration of Dar Gazi cultivar (15%) was significantly lower than Bartlett (33.95%). In QL, 5.2% of Dar Gazi and 33.5% of Bartlett leaves were regenerated while in NN the regeneration was 15.8% for Dar Gazi and 31.2% for Bartlett leaves. In the second experiment, the regeneration rates from leaf explants of the two cultivars were evaluated, when cultured on the same basal culture media containing two optimized regenerative concentrations of Thidiazuron (TDZ) in the presence or absence of 1% (w/v) PL. Results showed that the presence of Pluronic and TDZ in the culture media increased regeneration rates of both Dar Gazi and Bartlett cultivars significantly. In the third experiment, effects of 1% (w/v) PL added in the same basal culture media supplemented with 1µmol NAA were evaluated on rooting of the cultivars. According to the results, no significant effect was observed from PL application on root regeneration. Root regeneration was significantly higher in NN medium regardless of PL application.