Genetic variation in Miscanthus X giganteus and the importance of estimating genetic distance thresholds for differentiating clones

Authors

Katarzyna Glowacka, University of Illinois at Urbana-ChampaignFollow
Lindsay V. Clark, University of Illinois at Urbana-Champaign
Shivani Adhikari, University of Illinois at Urbana-Champaign
Junhua Peng, Huazhong Agricultural University
J. Ryan Stewart, Brigham Young University
Aya Nishiwaki, University of Miyazaki
Toshihiko Yamada, Hokkaido University
Uffe Jorgensen, Aarhus University
Trevor R. Hodkinson, Trinity College Dublin, Ireland
Justin Gifford, University of Illinois at Urbana-Champaign
John A. Juvik, University of Illinois at Urbana-Champaign
Erik J. Sacks, University of Illinois at Urbana-ChampaignFollow

Date of this Version

2015

Citation

GCB Bioenergy (2015) 7, 386–404

Comments

© 2013 John Wiley & Sons Ltd

doi: 10.1111/gcbb.12166

Abstract

Miscanthus x giganteus (Mxg) is an important bioenergy feedstock crop, however, genetic diversity among legacy cultivars may be severely constrained. Only one introduction from Japan to Denmark of this sterile, triploid, vegetatively propagated crop was recorded in the 1930s. We sought to determine if the Mxg cultivars in North America were all synonyms, and if they were derived from the European introduction. We used 64 nuclear and five chloroplast simple sequence repeat (SSR) markers to estimate genetic similarity for 27 Mxg accessions from North America, and compared them with six accessions from Europe, including the species’ type-specimen. A subset of accessions was also evaluated by restriction-site associated DNA sequencing (RAD-seq). In addition, we assessed the potential of new crosses to increase Mxg genetic diversity by comparing eight new triploid Mxg progeny grown from seed, along with samples of the parental species M. sacchariflorus and M. sinensis. Estimates of genotyping error rates were essential for distinguishing between experimental error and true genotypic differences among accessions. Given differences in estimated error rates and costs per marker for SSRs and RAD-seq, the former is currently more cost-effective for determining if two accessions are genetically identical. We concluded that all of the Mxg legacy cultivars were derived via vegetative propagation from a single genet. In contrast with the Mxg legacy cultivars, genetic similarity to the type-specimen of eight new triploid Mxg progeny ranged from 0.46 to 0.56. Though genetic diversity among the Mxg legacy cultivars is critically low, new crosses can provide much-needed variation to growers.