Abstract: Miscanthus is a tall, perennial plant of the grass family, with highly efficient C₄ photosynthesis and therefore has potential to become an important bioenergy crop. Tiller number is one of important agronomic traits of Miscanthus and plays an extremely important role in yield regulation. We used two established interspecific genetic linkage maps of Miscanthus floridulus and M. sacchariflorus for quantitative trait locus (QTL) analysis of tiller number, together with the tiller number phenotype data from Tai'an in 2014, 2015 and Dongping in 2015. Results showed that the frequency of the tiller number phenotype followed the normal distribution of continuous variation, according with the hereditary characteristics of quantitative traits. A total of sixteen QTLs were identified for tiller number using a multiple-QTL model. The single QTLs explained 11.4%-21.5% of the phenotypic variation and the logarithm of odds (LOD) values of these QTLs ranged from 3.06 to 6.09. Three of the QTLs were detected repeatedly 3 times: qmfTI-2 explained 12.7%, 12% and 15.5% of the phenotypic variation, qmsTI-1 explained 12%, 12.1% and 19.8% of the phenotypic variation and qmsTI-2 explained 21.5%, 20.2% and 13.4% of the phenotypic variation. Three of the QTLs were detected twice, of which qmfTI-1, qmfTI-3 and qmsTI-4 explained, respectively, 12.4% and 11.4%, 13.8% and 13.2%, and 12.1% and 14.3% of the phenotypic variation. Through the QTL analysis of tiller number of Miscanthus, our study provides a good foundation for molecular marker-assisted breeding and improvement of Miscanthus germplasm resources.

Key words: Miscanthus, genetic population, tiller trait, QTL mapping