A new method for rapid in vitro propagation of apple and pear

Improved in vitro clonal propagation methods are valuable tools for nurseri es and growers, and are essential for manipulation and improvement of tree fruit germplasm using the tools and techniques of biotechnology. We have de veloped a rapid shoot multiplication procedure for clonal propagation of ap ple, Malus xdomestica cv. Gale Gala and pear, Pyrus communis L. cv. Bartlet t. Rapid clonal multiplication was achieved after the following series of s teps: pre-conditioning of micropropagated shoots, sectioning pre-treated st ems into thin slices, placing slices onto shoot induction medium and incuba ting directly under cool-white fluorescent lights or after a brief dark inc ubation. Multiple induction of shoots recovered from stem slice explants wi thin three weeks of culture. A maximum of 37 % of cultured apple stem slice s, and 97 % of pear stein slices, showed induction of shoots. More shoots w ere recovered on phytagel solidified shoot induction medium than on agar. C ultured stem slices of both apple and pear showed maximum recovery of shoot s from shoot induction medium supplemented with thidiazuron (TDZ) compared to medium supplemented with BAP and kinetin. Under ideal conditions, pear s tems generated four times the shoots as the same quantity or length of appl e shoots. Micropropagated shoots were rooted and transferred to the greenho use and field nursery for further evaluation. Chemical names used: N-phenyl -N'-1,2,3-thidiazol-5-ylurea (thidiazuron or TDZ); 6-benzylaminopurine (BAP ).