IMPROVING ALFALFA AND OTHER FORAGE CROPS FOR BIOENERGY, LIVESTOCK PRODUCTION, AND ENVIRONMENTAL PROTECTION
Location: Plant Science Research
Title: Potential for Simultaneous Improvement of Corn Grain Yield and Stover Quality for Cellulosic Ethanol
| Lewis, Magan - |
| Lorenzana, Robenzon - |
| Jung, Hans Joachim |
| Bernardo, Rex - |
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 16, 2009
Publication Date: March 1, 2010
Citation: Lewis, M.F., Lorenzana, R.E., Jung, H.G., Bernardo, R. 2010. Potential for Simultaneous Improvement of Corn Grain Yield and Stover Quality for Cellulosic Ethanol. Crop Science. 50(2):516-523.
Interpretive Summary: Production of ethanol from corn stover and other cellulosic crops such as switchgrass will play a central role in meeting the U.S. goal of replacing 30% of our oil-derived energy by the year 2030. How much ethanol can be produced from a ton of cellulosic biomass is a function of the chemical composition of the biomass. Corn stover is the single most abundant resource for cellulosic ethanol production. While there has been decades of breeding effort to increase corn grain yield, there has been no breeding effort to improving the potential to produce ethanol from corn stover. This study investigated whether the germplasm that is the basis for most modern corn hybrids contains useful genetic variation for the major chemical traits that will determine ethanol production potential of corn stover and if selection for improved stover quality would negatively impact future breeding for grain yield. Hybrid testcrosses of 223 lines derived from the mating of B73 and Mo17 (the two parents ancestral to modern commercial hybrids) showed significant variation for cellulose and lignin (an inhibitor of ethanol production) concentrations and efficiency of cellulose conversion to ethanol. These traits were all moderately heritable and were not negatively related to grain yield or other important agronomic traits of corn. These results indicate that it should be possible to simultaneously breed corn for both greater grain yield and improved ethanol production from stover. This information will be of interest to corn breeders developing new hybrids for greater cellulosic ethanol efficiency.
Corn (Zea mays L.) stover, the residue left after harvest, is an abundant biomass source for producing cellulosic ethanol in the U.S. Corn has been bred for increased grain yield but not for stover quality for cellulosic ethanol production. Our objective in this study was to assess the feasibility of breeding corn for grain yield and agronomic traits as well as stover quality traits for cellulosic ethanol production. Testcrosses of 223 B73 x Mo17 recombinant inbreds were evaluated at four Minnesota locations in 2007. Three stover-quality traits were measured: concentration of cell wall glucose in dry stover ("Glucose"); cell wall glucose released from the stover by thermochemical pretreatment and enzymatic saccharification ("Glucose Release"); and concentration of lignin on a cell-wall basis ("Lignin"). Genetic variances were significant for grain yield, moisture, stalk and root lodging, plant height, and all three stover-quality traits. Heritabilities of the stover quality traits were 0.57 for Glucose, 0.63 for Glucose Release, and 0.68 for Lignin. Phenotypic and genetic correlations were favorable or neutral among grain yield, agronomic traits, Glucose, Glucose Release, and Lignin. Lines selected with a multiple-trait index for grain yield, agronomic traits, and stover-quality traits had improved means for each trait in the index. Current corn-breeding programs should be able to incorporate stover quality for cellulosic ethanol as a breeding objective without having to use unadapted or exotic germplasm and without adversely affecting genetic gains for grain yield and agronomic traits.