The effects of genotype, inflorescence developmental stage and induction medium on callus induction and plant regeneration in two Miscanthus species

Several grass species of the genus Miscanthus are considered to be outstanding candidates for a sustainable production of biomass to generate renewable energy. The purpose of this study was to investigate the effects of genotype, the developmental stage of the explant donor inflorescence and the induction medium on the success rate of micropropagation. The experiments were conducted on three genotypes of M. sinensis and one of M. x giganteus. Explants from the youngest inflorescences (0.1-2.5 cm in length) showed a significantly higher callus induction rate than those from more developed inflorescences (2.6-5 cm in length). In addition, cultures initiated from explants from the youngest inflorescences showed significantly the highest rates of callus regeneration and the highest shoot regeneration rate. Three out of the four genotypes tested showed the best shoot regeneration from calli initiated from the youngest inflorescences when cultured on the Murashige and Skoog basal medium (MS) with 5 mg l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.1 mg l(-1) 6-benzyladenine (BA). The percentages of calli from those genotypes showing regeneration ranged from 45 to 76.7%, and the corresponding shoot regeneration rates ranged from 1.85 to 6.33 shoots/callus. This demonstrates that, with some adjustments, efficient micropropagation of Miscanthus sp. is feasible.