Regeneration of peanut (Arachis hypogaea) plantlets by in vitro culture of immature leaves

Abstract

The in vitro regeneration of buds, shoots and roots from immature leaves of 3-5 day old peanut (A. hypogaea L. cv. Colorado Manfredi) seedlings was studied under defined nutritional, hormonal and environmental conditions. The first 2 leaves (2-5 mm in length) removed from aseptically germinated seeds were cultured on Murashige and Skoog medium containing vitamins as in B5 medium and 0.8% agar, supplemented with 12 combinations of naphthaleneacetic acid (NAA) (0.01- 4 mg/l and benzyladenine (BA) (1 and 3 mg/l). Bud regeneration occurred in all hormone combinations but the maximum with 2-5 mm long leaflets, some success was also obtained with leaflets 8-13 mm long. No buds were regenerated when fully expanded leaflets were cultured. Development of buds into shoots was readily achieved by transferring regenerated buds into fresh medium containing 0.01 mg/l NAA and 1 mg/l BA. A few roots were induced to grow when callus with buds was also transferred to medium devoid of hormones. Bud regeneration from immature leaves was induced in vitro in 5 of the 10 cultivars tested.