IN-VITRO REGENERATION OF CHICKPEA (CICER-ARIETINUM L.) - STIMULATION OF DIRECT ORGANOGENESIS AND SOMATIC EMBRYOGENESIS BY THIDIAZURON

In vitro regeneration in chickpea (Cicer arietinum L.) was achieved by direct culture of mature seeds on Murashige and Skoog (MS) medium sup plemented with either N-phenyl-N'(-1,2,3-thidiazol-5-yl) urea (thidiaz uron, TDZ) or N-6-benzylaminopurine (BAP). Multiple shoots formed de n ovo without an intermediary callus phase at the cotyledonary notch reg ion of the seedlings within 2 to 3 weeks of culture initiation. TDZ wa s found to be more effective compared to BAP as an inductive signal of regeneration. The former induced multiple shoot formation at all the concentrations tested (1 mu M to 100 mu M), although, maximum morphoge nic response was observed at 10 mu M concentration. Addition of naphth aleneacetic acid (NAA) alone or in combination with BAP to the MS medi um failed to invoke a similar response. When the TDZ supplemented medi um was amended with L-proline, the resultant regenerants were mostly s omatic embryos. Histological investigations confirmed the switch in th e regeneration pathway from directly formed adventitious shoots to emb ryogenesis. For obtaining plantlets, adventitious shoots were rooted o n MS medium supplemented with 2.5 mu M NAA; somatic embryos were germi nated and established on MS medium. Normal plants were regenerated fro m both adventitious shoots and somatic embryos and transferred to soil .