Likewise, exogenously applied ABA in in vitro culture also resulted in decrease in shoot regeneration frequency from the cotyledonary explants ascertaining the differential level of endogenous ABA is one of the determinants of differential regeneration response of Cot and Cot E under in vitro cultural condition. Cytokinin antagonized inhibitory effect of ABA mediated by cytokinin responsive proteins, such proteins are up regulated differentially in Cot E has recently shown us through proteomic study confirming further the role of ABA.