| An effective regeneration of Pyrus .pyrifolia 'Cuiguan' and agrobacterium-mediated transformation system were developed in this study. Ferritin was introduced into 'Cuiguan', and a new transgenetic pear germplasm was obtained. The result were as follow:1. The browning of explants was effectively inhibited when VC was added at 0.1 g·L-1 on early culture and the medium was altered there times in nine days.2. In order to found an effective propagation in vitro system for 'Cuiguan', effect of medium was compared. Result shows that shoots propagated better on medium AS with BA 1.0 mg·L-1 and NAA 0.1 mg·L-1 than other mediums.3. Factors that effect percent of regeneration of 'Cuiguan' were studied, including type of basic medium, type and content of honnone, time of darkness treatment, node position of leaf, way of leaf deposition. The regeneration system which had the highest regeneration rate at 88% was chosen. The process was that culture leaf separated from second to fourth node was on put MS medium containing TDZ 1.5 mg-L-1 and IAA 0.3 mg·L-1, and cultured in darkness for 21 days, then light subculture was continued.4. Factors that influence percentage of transformation including time of dipping and co-culture, type and content of antibiotic, day of delayed selection culture, intension of selection were studied. The effective transformation system of 'Cuiguan' was developed as follow: Leaves were dipped into agrobacterium suspension for three minutes, then were co-cultured in darkness on NN69 medium with TDZ 1.5 mg·L-1 and IAA 0.3 mg·L-1 for three days, and then cultured in darkness on NN69 medium with TDZ 1.5 mg·L-1 IAA 0.3 mg·L-1 and Cef 250 mg·L-1 Selection culture was carried out also in darkness on NN69 medium with TDZ 1.5 mg·L-1 IAA 0.3 mg·L-1 Km 7.5 mg·L-1 till resistance tissue were formed. Resistance tissue were light subcultured with light for one or two times, then resistance shoots were obtained, and was propagated through continued subculture.5. In this study, we obtained transformation plants in 'Cuiguan' carrying Ferritin gene. These plants is detected positive to GUS dyeing were also obtained, and detection experiments were expected to be continued.
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