High copper levels in the medium improves shoot bud differentiation and elongation from the cultured cotyledons of Capsicum annuum L.

The effect of copper sulphate on differentiation and elongation of shoot buds from cotyledonary explants of Capsicum annuum L. cv X-235 was investigated. Shoot buds were induced on medium supplemented with 22.2 mu M BAP and 14.7 mu M PAA. Elongation of shoot buds was obtained on MS medium containing 13.3 mu M BAP + 0.58 mu M GA(3). Both shoot induction and elongation media were supplemented with different levels of CuSO4 (0-5 mu M). The levels of CuSO4 in the induction as well as elongation medium highly influenced the shoot bud formation and their subsequent elongation. Highest number of shoot buds per explant was obtained when the concentration of CuSO4 was increased 30 times to the normal MS level. Shoot buds formation frequency i.e., the number of shoots formed per explant was increased two fold as compared to those formed on control. Elongation both in terms of percentage and length of shoots was better than that on control. Healthy elongated shoots were rooted on MS medium supplemented with 5.7 mu M IAA. Rooted plantlets were transferred to field conditions.