Effect of Seed Preconditioning and Culture under Different Light Intensities on Callus Induction and Regeneration in Excised Cotyledon Cultures of Mungbean (Vigna radiata (L.) Wilczek)

Different seed preconditioning treatments and light intensities were tested for their effect on the callus induction and regeneration in cotyledon cultures of mungbean ( Vigna radiata (L.) Wilczek). There were six preconditioning treatments evaluated including imbibition in sterile distilled water, inoculation in plain agar, and inoculation in 6-benzyladenine (6-BA) supplemented media over a varing period of time. The cultures were incubated in two light intensity conditions; namely, full light (50 μmol m-2 sec-1) and minimum light (8.5 μmol m-2 sec-1). Results of the study showed that (1) plain imbibition of seeds in sterile distilled water for 16 hours was more favorable for regeneration than preconditioning with 6-BA enriched media, and (2) preconditioning of callus formation and better callus growth. Other important observation. was the differential response to plantlet regeneration under different regeneration media. Plantlet regeneration in B5 basal medium supplemented with 1.0 μM NAA and 9.0 μM 6-BA was relatively higher than the other regeneration media under full light intensity while Murashigc and Skoog (MS) basal medium and MS basal medium supplemented with 1.0 μM NAA and 9.0 μM 6-BA had highter plantlet regeneration under minimum light intensity.