ARS | Publication request: Switchgrass Genetics: Status, Future Directions, and Implications for Simulations

Submitted to: Annual International SWAT Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 2009
Publication Date: August 5, 2009
Citation: Vogel, K.P. 2009. Switchgrass Genetics: Status, Future Directions, and Implications for Simulations. In 5th International SWAT Conference Abstracts, August 5-7, 2009.

Technical Abstract: Switchgrass (Panicum virgatum L.) is a C4 polymorphic species with two ploidy levels, two major and numerous minor ecotypes adapted to different plant hardiness zones and ecoregions in its range. Switchgrasses are determinate, photoperiod sensitive, and require short days to induce flowering. Photoperiod requirements for switchgrass cultivars are based on the latitude where the parent germplasm evolved. Flowering is induced by decreasing day length during early summer. In the USA, moving northern ecotypes south provides them a shorter than normal day length during summer months and they flower early resulting in reduced biomass yield. The opposite occurs when southern ecotypes are moved north. They remain vegetative longer and produce more biomass than northern strains moved south. The photoperiod response is associated with winter survival. Southern types moved too far north will not survive winters because they stay vegetative too late in the fall or break dormancy too early. The growth and development of a switchgrass plant thus depends upon its genotype (parent germplasm origin) and the location where it is evaluated. Development including flowering depends on photoperiod and also on growing-degree-days (GDD). Other factors that determine specific adaptation is response to precipitation and the associated humidity which can be associated with increased foliar diseases. Plant breeders undoubtedly will improve biomass yield and quality of switchgrasses for use in bioenergy production systems. It is very difficult to breed for adaptation and the adaptation response of new cultivars is expected to be based on parent germplasm’s latitude or Plant Adaptation Region of origin. Modeling switchgrass growth, development and productivity will require knowledge of cultivars, their origin, and the plant adaptation region in which they will be grown.