The pear (Pyrus spp.) is one of the most important temperate fruit crops. A complete protocol for adventitious shoot regeneration was developed from the leaves of four pear varieties grown in vitro: Abbe Fetel, Yali, Packham's Triumph and Aikansui, and the Chinese rootstock variety Dull. Shoot explants were collected from the field and cultured in vitro in Murashige and acid (IBA). After four weeks, leaf explants of all 5 varieties grown in vitro were excised and cultured in MS cultures were maintained in darkness for 21 days for shoot induction in the shoot induction medium (IM), then transferred to the shoot expression medium (EM) in room at (25±2)℃ under a 16/8 h light/dark photoperiod regime for 8 weeks. Finally, the shoots were transferred to the MS shoot elongation medium (SEM) supplemented gibberellic acid (GA3). A combination of TDZ and NAA had a significant effect on the number of shoot regenera-tions in all 5 tested varieties. The maximum mean number of shoots and maximum number of shoots per leaf obtained from Yali variety were 11.8 (P≤0.001) and 22, followed by Aikansui with 6.6 (P≤0.001) and 4.6, and Duff with 8 (P≤0.001) and 12, all arising from the For Packham's Triumph and Abbe Fetel, the maximum mean number of shoots and maximum number of shoots per leaf were 5.6 (P≤0.001), 4.8 and 8 (P≤0.001), and 11, which produced significantly higher adventitious shoots problems associated with shoot proliferation and regenera-tion were also observed and discussed in this paper.
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