IN VITRO REGENERATION RESPONSE OF OKRA (ABELMOSCHUS ESCULENTUS L.) UNDER THE EFFECT OF PHYTOHORMONES

In vitro multiplication of okra is known to be delicate due to its recalcitrant nature. The current study was conducted to investigate the potential applications of thidiazuron (TDZ) on okra's in vitro regeneration. Cotyledonary leaves, hypocotyls and apices were taken from 15-day old in vitro grown seedlings, they were then inoculated on Gamborg (B5) medium containing different plant growth regulators. Maximum callus formation (100%) was obtained from cotyledonary leaves and hypocotyls on B5 without hormones also by adding 0.5 mgL-1 TDZ and 1 mgL-1 BAP for cotyledonary leaves followed by B5 containing 1 mgL-1 TDZ and 1 mgL-1 BAP with 95.83% of calli formed from hypocotyls. B5 supplemented with 1 mgL-1 of TDZ gave the highest rate (100%) of direct regeneration from apices followed by Gamborg medium without PGRs and B5 containing an equimolar concentration of TDZ and BAP with 66.66% of shoot formation. This regeneration system can be used to produce healthy plantlets with a low risk of genetic instability and somaclonal variants.