ARS | Publication request: Insect resistance of a full sib family of tetraploid switchgrass with varying lignin levels

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 23, 2012
Publication Date: July 30, 2012
Citation: Dowd, P.F., Sarath, G., Mitchell, R., Saathoff, A.J., Vogel, K.P. 2012. Insect resistance of a full sib family of tetraploid switchgrass with varying lignin levels. Genetic Resources and Crop Evolution. 60(1):975-984.

Interpretive Summary: United States dependence on foreign oil causes economic hardships to consumers, businesses, and manufacturing. Biomass energy crops such as switchgrass may help alleviate this dependence, but high-lignin levels (which may be important in insect resistance) interfere with the production of ethanol. Field-grown leaves from lines developed at the ARS location in Lincoln, Nebraska, were tested for resistance against fall armyworms in a three-year study at the ARS location in Peoria, Illinois. A couple of the low-lignin lines were as resistant as the high-lignin lines. This information will help guide the development of sustainable lines of switchgrass for bioenergy use, thereby reducing the dependence on foreign oil and thus reducing costs to U.S. citizens by billions of dollars.

Technical Abstract: Lignin is a plant resistance mechanism against insects. Reduction of lignin in biomass grasses in order to increase the efficiency of fermentation may result in increased susceptibility to insect feeding, interfering with sustainable production. Field grown leaves of high- and low-lignin parent and progeny switchgrass (Panicum virgatum) were tested for resistance to feeding by the fall armyworm (Spodoptera frugiperda), a grass-feeding insect pest. Although the stage of the plant affected resistance relative to parent lines, two low-lignin progeny lines generally remained resistant to fall armyworm feeding. Additionally, mechanical damaging of plants increased resistance to fall armyworm feeding in several lines. These results indicate it is possible to produce low-lignin switchgrass lines through breeding while retaining insect resistance.