Heterosis for biomass yield and quality traits in a reciprocal cross population between Miscanthus sinensis and Miscanthus lutarioriparius

Heterosis plays an important role in plant breeding and has been widely used in the production of a variety of food crops. However, cross-breeding is particularly important in the breeding of new varieties of the energy crop miscanthus due to its characteristics of self-incompatibility and lack of interspecific reproductive isolation. Therefore, in the current study, 30 direct cross hybrids and 150 reciprocal cross hybrids were obtained from a cross between M. sinensis and M. lutarioriparius. These hybrids were significantly different in phenotype and were used for a detailed analysis of heterosis. The mid-parent, over-parent and over-standard heterosis of the hybrids for yield-related agronomic traits were analyzed. The results showed that the hybrids from direct and reciprocal crosses exhibited significant trait segregation and acquired dominant agronomic traits from both parents, showing mid-parent, over-parent and over-standard heterosis. Plant height, tiller number, stem node number, and stem diameter showed maternal inheritance. Principal component analysis was used to construct the linear combination relationship of yield-related agronomic traits. Excellent hybrids were screened against the commercial miscanthus variety Miscanthus × giganteus. These hybrids were superior to their two parents and M. × giganteus in terms of phenotypic yield-related agronomic traits, biomass yield, and quality. These results not only confirmed the feasibility of breeding miscanthus by remote crosses, but also provided a reference for the application, cross-breeding and breeding of new miscanthus varieties.