OPTIMIZATION OF HORMONAL COMPOSITIONS OF MEDIA IN INVITRO PROPAGATION OF APPLE(Malus domestica Borkh) CULTIVARS FROM NODAL SEGMENTS

Abstract

Apple (Malus × domestica Borkh.) is the fourth most important fruit crop in the world. Apple has wider consumer acceptability in Ethiopia both as a fresh table fruit and value added processed products. The present study was planned to investigate invitro propagation of apple (Malus domestica borkh) cultivars from nodal segments. The nodal segment explants were collected from apple cultivars. The MS medium supplemented with sucrose and different concentrations of growth regulators were used for shoot proliferation and root induction. The optimum compositions of growth regulators in MS medium were assessed. Comparison of full and half strength MS media on root induction was investigated. The result effects of MS medium supplemented with various concentrations of indole-3-acetic acid (IAA) and kinetin on shoot proliferation rate, shoot number per explant, shoot length, leaf number indicated that significantly the highest shoot response was recorded for princess cultivar with maximum shoot proliferation rate (65.25%), shoot number per explant (2.57), shoot length (7.28cm), leaf number per explants (6.15) after four weeks of culture. The root inductions of microshoots regenerated for three apple cultivars demonstrated that root induction was observed after 20 days of culturing. Significant rooting rate, root number and root length were observed for all treatments. Among the cultivars, significantly the highest rooting rate (48.30%), root number (6.25), and root length (4.15cm) were recorded for princess apple cultivar with full strength MS medium. The comparison of full and half strength MS medium on root induction at 1.5mg/L IAA demonstrated significant differences (P<0.05 based on chi square (ᵡ2) in rooting rate among the three apple cultivars. However, there was no significant difference in root number and root length per microshoot among the apple cultivars.