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Keywords:

  • bioenergy crop;
  • micropropagation;
  • Miscanthus;
  • somaclonal variation;
  • somatic embryogenesis;
  • tissue culture

Abstract

The perennial rhizomatous grass, Miscanthus×giganteus is an ideal biomass crop due to its rapid vegetative growth and high biomass yield potential. As a naturally occurring sterile hybrid, M. ×giganteus must be propagated vegetatively by mechanically divided rhizomes or from micropropagated plantlets. Plant regeneration through somatic embryogenesis is a viable approach to achieve large-scale production of plantlets in tissue culture. Effect of the callus types, ages and culture methods on the regeneration competence was studied to improve regeneration efficiency and shorten the period of tissue culture in M. ×giganteus. Shoot-forming calli having a yellow or white compact callus with light-green shoot-like structures showed the highest regeneration frequency. Percentage of shoot-forming callus induction from immature inflorescence explants was 41% on callus induction medium containing 13.6 μM 2,4-d and 0.44 μM benzyladenine (BA). The use of a regeneration medium containing 1.3 μM NAA and 22 μM BA was effective at shortening the incubation period required for plantlet regeneration, with 69% of total regenerated plantlets obtained within 1 month of incubation on regeneration medium. Embryogenic-like callus morphotype could maintain regeneration competency for up to 1 year as suspension cultures. Field grown regenerated plants showed normal phenotypic development with DNA content and plant heights comparable to rhizome propagated plants. Winter survival rates of the regenerated plants planted in 2006 and 2007 at the University of Illinois South Farm, Urbana-Champaign, Illinois, were 78% and 56%, respectively.