Abstract

The phytohormone auxin plays an important role in growth, developmental and physiological processes. The effect of auxins, 2,4-D, NAA, IAA, Dicamba and picloram, was tested for somatic embryogenesis in groundnut. Among the different auxins tested 2,4-D favored the best response of somatic embryogenesis with induction of 18.3 somatic embryos per explant that were big, healthy, succulent and green in color. Immature zygotic embryos axes cultured on MS medium with 4 mg/l TIBA (Auxin polar transport inhibitor) did not respond for somatic embryogenesis but when cultured on medium supplemented with TIBA (2 mg/l and 4 mg/l) and 2,4-D (4 mg/l) showed the induction of somatic embryogenesis. When the concentration of TIBA was increased (6 mg/l) keeping the level of 2, 4-D (4 mg/l l) constant, it resulted in browning of explants within a week of culture. These observations demonstrate the requirement of 2,4-D for induction of somatic embryogenesis and that addition of TIBA (2 mg/l and 4 mg/l) decreases the response of somatic embryogenesis and further higher levels (6 mg/l) being inhibitory for somatic embryogenesis.

Key words: Auxin polar transport inhibitor, somatic embryogenesis.