Abstract
Callus was initiated from mature seeds without the rinds of barnyard grass, Echinochloa oryzicola Vasing, on a modified Murashige and Skoog (MS) medium containing 2.0∼20.0 mgl-1 2, 4-D. The rate of callus formation was greatly improved with the addition of 4 mgl-1 tryptophan. Upon transfer to MS medium containing 6.0 mgl-1 of 2, 4-D, the calli were sustained in subcultures. The plantlets were regenerated under light on MS medium involving various hormone combinations of 2, 4-D and cytokinins. In the regenerated plantlets 55% were normal plants and 45% abnormal plants including albinos. The processes of plantlet regeneration were observed after the plantlets were embedded in paraffin. The ratio of embryogenesis to organogenesis was found to be 25 : 75 and this ratio could not be effectively controlled by media using varying concentration of 2, 4-D, BA, kinetin, and zeatin.
