STUDIES ON ACCUMATIZATfON OF TISSUE. CULTURE COMMUNtS PEAR ROOTSTOCK

Abstract

This investigation was conducted in the Tissue Culture Laboratory, Department of Horticulture, Faculty of Agriculture Moshtohor, Zagazig University, during the period from 1997 to 2000. in vitro commums pear (Pyrus communis L.) rootstock plantlets cultured on Murashige and Skoog medium supplemented with O.lmg/L BAP (6- benzlaminopurine), l.Omg/L IBA (lndole-3-butyric acid), 30g/L sucrose and 7g/L Dificio-Bacto agar were USt!d during rooting stage. Acclimatization stage was conducted through three phases i.e. laboratory, greenhouse, und nursery phases. Meanwhile, during laboratory phase both in vitro and in v1vo procedures were used. Different experiments on this investigation were carried out in the laboratory (laboratory phase). On this concern, in vitro were plantlets prepared for acclimatization by using modification in some micronutrient elements by diluting their strength to one-half and duplication of their strength to two told of the original strength ofthe Murashige and Skoog basal medium. Adding of growth retardants (coumarin and paclnbutrazol) (at 0.0, 1.0, 2.0, 4.0 and 8.0 mg/L) level to the culture medium subjecting the in vitro plantlets to different light intensities (1 000, 2000, 3000 Lux) as well as diHerent photoperiods (continuous light, 16 hrs light and 8hrs dark,