Callus initiation and regeneration in a minor tuber crop 'Rizga' (Plectranthus esculentus N. BR.)

Abstract

Calli were initiated from tuber cuttings, internodes and leaf disc explants of P.esculentus. From tuber cutting, calli were formed when explants were cultured on MS basal salts supplemented with differing regimes of either 2, 4-D and NAA separately or in combination with 0.5mgl-1 BAP. Initiation of callus was best when cultures were incubated on 2, 4-D containing media. 2, 4-D at a concentration of 1mgl-1 and culture condition of total darkness/25oC gave maximum calli fresh weight of 541.5 ± 43.9mg. In the case of internodes, maximum callus (82.3 ± 18.4mg) was obtained when explants were incubated on MS medium supplemented with 50gl-1 sucrose and 1mg-1 2, 4-D. Leaf disc explants gave maximum calli fresh weights of 2,462.8 ± 279.7 and 1,688.8 ± 350.9 mg at sucrose concentration of 50 and 60gl-1, respectively. Histological assessment of calli initiated from explants cultured on MS basal salts supplemented with 50gl-1 sucrose and 1mgl-1 2, 4-D and CP -a cytokinin, suggested caulogenesis and somatic embryogenesis might have occurred on CP and 2, 4-D containing media, respectively.


Key words: Callus, regeneration, tuber, Plectrantus esculentus

[Global Jnl Agric Sci Vol.1(1) 2002: 55-62]