Mass-production of papaya (Carica papaya L.) saplings using shoot-tip culture for commercial use

Culture conditions for shoot tips, excised from mature papaya trees, were investigated to develop shoot tip culture system. The aim was to proliferate saplings of newly developed cultivars for commercial use in association with a breeding program. Shoot tips of 'Wonder Blight' were grown on initiation medium consisting of MS (1962) basal components with 0.1M sucrose. Addition of 5-20μM 6BA and NAA was effective for multiplication of the shoots. Afterwards, the shoots were transferred to a medium with 2-ip for further development. Addition of 10-20μM 2-1p was effective for shoot development. Developed shoots from subculture were further examined for rooting with high (10mM) and low (10μM) concentrations of IBA for 5 sec and 10 days treatments, respectively. The shoots were then put into 'Oasis (LC-1-288: 5554)' growing medium filled with tap water for rooting. The treatment with 10μM IBA for 10 days showed higher rooting rates, though the 10mM IBA for 5sec treatment was cost effective. Rooting was also affected by size of the shoots; well developed ones showed higher rooting and faster recovery than weak ones. More than 85% of the plantlets developed roots and 80% of those recovered after acclimatization.