QTL Mapping for Biomass Yield and Yield Components in a Miscanthus sacchariflorus x M. sinensis Population

Miscanthus is a promising bioenergy crop. An understanding of the genetics behind yield of Miscanthus is critical to the crop’s improvement. In this study, a mapping population of 281 F1 progeny was developed from a cross between M. sacchariflorus ‘Robustus’ (♀) and M. sinensis var. condensatus ‘Cosmopolitan’ (♂). High density genetic maps were constructed using single nucleotide polymorphisms (SNPs), which were generated using restriction site-associated DNA sequencing. The female map spanned 2,102 cM, with 1632 SNPs distributed on 19 linkage groups (LGs), and the male map spanned 1,838 cM, with 2352 SNPs distributed on 19 LGs. Comparative genomic analysis confirmed a whole genome duplication in M. sacchariflorus relative to Sorghum bicolor, which had previously been described in M. sinensis. Moderate to high correlations were found between yield components (flowering time, height, compressed circumference, basal circumference, compressed circumference to basal circumference ratio) and yield per plant and yield per area. All yield components were positively correlated with yield except for flowering time. QTL analysis for seven traits across two years identified 12 QTLs on the female map and 14 on the male map. Two major multi-trait QTL clusters were identified on LGs 10 and 19 of the female map, and one on LG 10 of the male map, which might be the result of natural selection for co-adapted traits, pleiotropy, tightly linked genes, or a bias due to differences in recombination rates.