IN VITRO MORPHOGENESIS OF SHOOTS FROM LEAF EXPLANTS OF CUCUMBER (CUCUMIS SATIVUS L.)

Abstract

Organogenic callus induction and adventitious shoot formation were achieved from leaf explants of cucumber cv. Poinsett 76. About 92.4% of leaf explants derived from 20-d-old in vitro seedlings produced green compact nodular organogenic calluses in Murashige and Skoog medium containing 2.69 μM α-naphthalene acetic acid (NAA) and 4.44 μM 6-benzyladenine (BA) after two successive transfers at 15 days interval. Adventitious buds were produced from these calluses after two weeks when they were transferred to MS medium supplemented with 1.34 μM NAA, 8.88 μM BA, 0.45 μM thidiazuron (TDZ), and 0.034 μM L-glutamine with the shoot induction frequency of 81.4%. Shoot proliferation occurred when callus explants with emerging shoot buds were subjected to two successive transfers at an interval of 15-d each in the same medium. Shoots with a length of 1 cm were excised from callus and were elongated in MS medium fortified with 4.44 M BA and 1.44 μM Gibberellic Acid (GA 3 ). Elongated shoots were rooted in BA (4.44 μM) and 2.46 μM IBA, acclimatized in greenhouse and subsequently established in soil with a survival rate of 65%. TDZ has been exploited to produce shoots from leaf calluses for the first time in cucumber. This protocol yielded an average of 35 shoots/leaf explant in a culture duration of 4 months.