New pear cultivars have been introduced in Brazil as the 'Abate Fetel'. Seedling production with higher quality of this cultivar is needed, and this can be obtained by use of micropropagation techniques. The objective of the present study was to evaluate different sucrose concentrations and types of closure flasks on micropropagation of 'Abate Fetel' pears. Nodal segments with two to three axillary buds, about 1 cm in length, from plants pre-established in vitro, were inoculated on 'QL' culture medium supplemented with myo-inositol (100mg L-1), sucrose (0, 15, 30, 45g L-1), BAP (1mg L-1), IBA (0.1mg L-1) solidified with 6.5g L-1 agar and pH adjusted to 5.7. The flasks were closured with cotton, aluminum or PVC plastic film and kept in a growth chamber at 25±2°C, light intensity of 42µmoles m-2 s-1 and 16h of photoperiod. The flasks closured with cotton showed the highest number of leaves formed in the absence of sucrose and it was not observed effect of sucrose concentration in the culture medium of shoots number and number of leaves formed. The average shoot length and the total fresh weight did not differ between the types of closure flasks used, but there was a significant increase of these variables against the sucrose increase in the culture medium. The closure flasks with PVC film showed the highest number of shoots per explant, when high sucrose concentrations was used.
Pyrus communis; flasks closure; sucrose; explants
