Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/5/2008
Publication Date: 7/10/2008
Citation: Martinez-Reyna, J., Vogel, K.P. 2008. Heterosis in switchgras: spaced plants. Crop Science 48: 1312-1320. Interpretive Summary: Switchgrass is a potential biomass energy crop because of its high biomass yield potential and desirable conservation and agronomic attributes. To date, hybrid vigor has not been utilized by plant breeders to improve biomass yield of switchgrass by the use of hybrid cultivars. Hybrids were produced by crossing related and unrelated populations of switchgrass including plants from different ecotypes and were evaluated in multi-year field trials. The results demonstrated that heterosis or hybrid vigor exists in switchgrass for biomass yield and that hybrid cultivars could potentially be developed by using plants from the upland and lowland ecotypes as parents.
Technical Abstract: Population and specific hybrids were made between populations and genotypes of switchgrass, Panicum virgatum L., and their progeny were evaluated for heterosis in space-transplanted field trials in eastern Nebraska for a three year period. ‘Kanlow’ (lowland tetraploid) x ‘Summer’ (upland tetraploid) hybrids exhibit mid-parent heterosis for 2nd & 3rd year biomass yields for both population and individual plant hybrids. These data and previously reported molecular marker data indicate that lowland tetraploid and upland tetraploid switchgrasses represent different heterotic groups that can potentially be used to produce F1 hybrid cultivars. Hybrids produced from cultivars and experimental strains developed from upland, octaploid germplasm originating from spatially separated western and eastern regions of the original tallgrass or an adjacent forested ecoregion did not exhibit heterosis for any trait evaluated. These results suggest that the populations evaluated were from the same or closely related large germplasm pools or heterotic groups. A method for developing F1 switchgrass hybrid cultivars utilizing the gametophytic self-incompatibility mechanism of the species is described.