Kinnetz, E. R. 2017. Intraspecific differences in belowground associations and seedling root morphology for the biofuel crop, Panicum virgatum. Thesis, University of Louisville, Louisville, KY.
The perennial C4 grass Panicum virgatum (switchgrass) is a promising bioenergy feedstock. Switchgrass is symbiotic with arbuscular mycorrhizal fungi (AMF). I examined 12 varieties of switchgrass grouped into 2 ecotypes (upland, lowland) to see if they differed in AMF abundance and root colonization using the GLBRC Variety Trials experiment. There was higher root colonization of lowland ecotype. A greenhouse experiment evaluated the role of live soil organisms in seedling establishment of 11 varieties. Live soil increased seedling survival, growth and influenced root morphology. Ecotypes differed in root architecture. Lowland developed a higher specific root length (SRL), a trait associated with productivity. The field experiment provided evidence that lowland ecotypes had higher root colonization, while the greenhouse study found no differences in dependence on live soil microbiota. The greenhouse study does, however support the idea that AMF could be important in the seedling establishment stage.
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