OPTIMIZATION OF MEDIA IN INVITRO PROPAGATION OF SWEET ORANGE CULTIVARS USING WASHINGTON, VALENCIA AND TANGELO ORANGE

The present study was undertaken to investigate optimization of media in vitro propagation of sweet orange cultivar from Washington, Valencia and tanjelo orange explants. The explants were collected from three sweet orange cultivars. The result indicated the highest shoot response from Washington orange cultivar with maximum shoot proliferation rate (99.75%), shoot number per explant (3.10), shoot length (10.70cm), leaf number per explants (12.50) after three weeks of culture. In all experiments no growth was observed for basal MS medium. The root induction was observed after 15 days of culturing. Significant rooting rate, root number and root length were observed for all treatments. Among the cultivars, significantly the highest rooting rate (81.255), root number (4.95), and root length (2.95cm) were recorded for Washington orange cultivar. The least rooting rate (48.45%), root number (3.55) and rootlength (2.26cm) were observed from Valencia cultivar. The effect of MS medium supplemented with NAA on root response rate, root number and root length of microshoot generated from nodal segment explants of three sweet orange cultivars indicated that microshoots from Washington orange cultivar has demonstrated significantly the highest rooting rate (84.90%), root number per microshoot (5.20) and root length (3.05cm) for MS medium supplemented with 1.5mg/L NAA. The comparison of different concentrations of IAA and NAA on root induction of microshoots from sweet orange cultivars demonstrated NAA as the more effective hormone than IAA. Phytohormones combinations of IAA (1.2mg/L) and kinetin (2.0mg/L) was found to be the best for shoot proliferations