An efficient protocol for the regeneration of whole plants of chickpea (Cicer arietinum L.) by using axillary meristem explants derived from in vitro-germinated seedlings

An efficient and reproducible protocol for the regeneration of shoots at high frequency was developed by using explants derived from the axillary meristems from the cotyledonary nodes of in vitro-germinated seedlings of chickpea (Cicer arietinum L.). Culture conditions for various stages of adventitious shoot regeneration including the induction, elongation, and rooting of the elongated shoots were optimized. The medium for synchronous induction of multiple shoot buds consisted of Murashige and Skoog basal medium (MS) with low concentrations of thidiazuron (TDZ), 2-isopentenyladenine (2-iP), and kinetin. Exclusion of TDZ and lowering the concentration of 2-iP and kinetin in the elongation medium resulted in faster and enhanced frequency of elongated shoots. Cultivation of the stunted shoots on MS with giberellic acid (GA(3)) increased the number of elongated shoots from the responding explants. pH of the medium played a very crucial role in the regeneration of multiple shoot buds from the explants derived from cotyledonary nodes. A novel rooting system was developed by placing the elongated shoot on a filter paper bridge immersed in liquid rooting medium that resulted in rooting frequency of up to 90%. A comprehensive protocol for successful transplantation of the in vitro-produced plants is reported. This method will be very useful for the genetic manipulation of chickpea for its agronomic improvement.