Effect of Age and Size of Hypocotyl Explant on in vitro Shoot Regeneration in Eggplant

In the present study, effect of size and age of hypocotyl explant on in vitro organogenetic responses was assessed in eggplant cv. Manjarigota. Size and age did not affect callus-initiation response, but showed marked influence on shoot regeneration response. Hypocotyl explants 1.5cm long showed highest shoot regeneration response (77.4%); either increase or decrease in size resulted in reduced response. Five to 15 day old hypocotyl explants showed direct shoot regeneration from cut ends, whereas 20-30 day old hypocotyl explants showed indirect shoot regeneration from callus produced on cut ends. Five day old explants were most responsive, with highest (91.23%) and thirty day old explants least responsive with reference to shoot regeneration response (20.85%). Shoot regeneration frequency decreased with increasing age, whereas shoot regeneration efficiency increased with increasing age of hypocotyl explants.