Study on in vitro propagation of some asian pear (pyrus serotina rehd.) Cultivars

Experiments were conducted to study the in vitro propagation of nine improved Asian pear cultivars namely "KS6", "KS7", "KS8", "KS9", "KS10", "KS11", "KS12", "KS13" and "KS14" and the effects o("culture media and plant growth regulators on the micropropagation. Single-node explants, harvested from current season"s growth shoots, were disinfected and cultured on three basal media, murashige and Skoog (MS), halfstrength MS salts (1/2 MS) and woody plant medium (WPM)," supplemented with 1 mg 1-1 benzylaminopurine (BAP). Growth and proliferation of Asian pear explants at the stablishment phase were obtained only in five cultivars ("KS7", "KS8", "KS12", "KS13" and "KS14"), and WPM was the best medium for their growth. In the multiplication phase, shoots obtained from in vitro conditions were subcultured four times, each with one-month interval, on the fresh media, supplemented with various concentrations of BAP (0, 1 and 2 mg 1-1 The highest shoot proliferation rate was obtained at 2 mg 1-1 BAP. Meanwhile, with increase of BAP concentration in this stage, proliferated shoots height was decreased and vitrified shoots percentage, increased. The best medium for proliferation of "KS7" shoots was WPM, but there was not any significant difference among the various media for the other cultivars (excepting "KS14", proliferated in WPM better than 1/2 MS). Moreover, with increase of subculture number, proliferation rate was increased, too. For rooting, 1/2 MS medium with different concentrations of indolebutyric acid (IBA) were used. Shoots were transferred on mentioned medium for different durations before transfering on the hormone-free MS medium. Micro propagated shoots failed to produce roots in all cultivars, after two months.