|Mitchell, Robert - Rob|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2008
Publication Date: 11/26/2008
Citation: Vogel, K.P., Mitchell, R. 2008. Heterois in Switchgrass: Biomass Yield in Swards. Crop Science 48:2159-2164. Interpretive Summary: Improving the biomass yield of switchgrass (Panicum virgatum L.) will improve its utility as a dedicated energy crop by increasing energy yield per acre. In this study, Kanlow and Summer population hybrids were grown in high-plant density plots under competitive conditions similar to that of production fields or pastures and harvested for biomass yields for two years. Biomass yields of the hybrids exceed those of the best parent of the hybrids by 30 to 38%. These results demonstrate the potential effect that the development of hybrid cultivars could have on increasing bioenergy yield of switchgrass per unit of land. Substantial additional research will be needed before commercial switchgrass hybrids will be available for use by farmers.
Technical Abstract: Improving the biomass yield of switchgrass (Panicum virgatum L.) will improve its utility as a dedicated energy crop by increasing energy yield per acre. In a previous space-transplanted study, mid-parent heterosis for biomass yield was reported for population and specific F1 hybrids of the lowland-tetraploid cultivar ‘Kanlow’ and the upland-tetraploid cultivar ‘Summer’. These two cultivars were proposed to be two different heterotic groups. The objective of this study was to determine the extent of heterosis for biomass yield in reciprocal Kanlow (K) and Summer (S) F1 population hybrids grown in simulated swards and to determine the effect of advance in generation on biomass yield. Parent populations and their F1, F2, and F3 population hybrids were grown in transplanted sward plots located near Mead, NE for a three-year period. Plant density in the simulated swards was equivalent to acceptable stands in seeded plots. Plots were not harvested the establishment year to enable them to become fully established. Biomass yields were determined for the following two years. There was significant high-parent heterosis of 30 to 38% (P<0.01) for biomass yield for both the KxS F1 and SxK F1 hybrid populations. Heterosis for biomass yield declined as expected with advance in generation. Heterosis for biomass yield in switchgrass may need the competitive conditions of swards to be fully expressed. Larger trials established with seed are needed to further verify these conclusions. These results do provide ample justification for additional research to develop switchgrass population and specific hybrids.