Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

Arvid Boe


Switchgrass (Panicum virgatum L.) is a major component of the tallgrass prairie and has been proposed as a model species for biomass fuel production. To better manage switchgrass, information on the phenology and development morphology would be useful for selecting cultivars for specific purposes and identifying breeding material for development of new cul ti vars with desired morphological characteristics. My objectives were to: 1) describe biomass production and gross aerial morphology of several switchgrass cul ti vars; 2) identify sites of tiller origin in 'Cave-In-Rock' and 'Dacotah'; 3) determine genetic and environmental effects on distribution of tillers among sites of origin; and 4) determine effect of site of origin on tiller growth and development. Data were collected from eight cultivars of switchgrass in northeastern and central SD. Differences among cultivars for aerial morphological traits were consistent across spatial and temporal environments, indicating strong genetic influences on their expression. Potential biomass production was related to latitude of cultivar origin. The stem component of biomass production was relatively consistent across environments, across cultivars, and between years. There was no discernible effect of site of origin on tiller development in the early growing season. However, by stem elongation, site of origin had a significant effect. For two genetically different cultivars, tillers originated from 3-4 axillary buds on the proaxis and the first two aerial phytomers, indicating both regions were important for tiller recruitment. Frequency of tiller occurrence varied among sites of origin and distribution of tillers among sites of origin was not independent of environment but similar for the two cultivars. It should be possible, through selection, to develop switchgrass germplasm with increased forage quality, biomass production, erosion control capability and desired morphological characteristics such as high tiller density or high vegetative-to-reproductive tiller ratio.

Library of Congress Subject Headings

Panicum -- Morphology.
Panicum -- Varieties.
Grasses -- Morphology.


South Dakota State University



Rights Statement

In Copyright