REGENERATION OF PIGEONPEA (CAJANUS-CAJAN) FROM COTYLEDONARY NODE VIA MULTIPLE SHOOT FORMATION

Plant regeneration, which is the major limiting factor for transformat ion of Cajanus cajan, has been obtained via multiple shoot formation f rom the cotyledonary node region of seedlings germinated on MS medium containing 2 mgl(-1) 6-benzylaminopurine. A mass of multiple shoot-ini tials formed at the axillary bud region of the cotyledonary node of th e seedlings within two weeks. The cotyledonary node along with the mas s of shoot-initials excised from the seedling, continued to form new s hoot-initials on MS medium containing 6-benzylaminopurine (2 mgl(-1)) and supplemented topically with indole-3-acetic acid. The formation of new shoot-initials was also observed from the cotyledonary nodal expl ant, after cutting off its surface layers to completely remove the pre -existing shoot-initials and culturing it on 6-benzylaminopurine (2 mg l(-1)) containing medium. The shoots elongated rapidly on basal MS med ium and rooted efficiently in MS medium supplemented with indole-3-but yric acid (0.5 mgl(-1)). The procedure described is efficient, and hig hly reproducible and a common response was observed for all the six Va rieties tested.