Characterization of Cell Wall Composition in Bi-Parental Population of Switchgrass.

Enhancing enzymatic hydrolysis of cellulose by minimizing the lignin content will maximize the ethanol yields from plant biomass and reduce the processing cost as well. A full-sib switchgrass mapping population consisting 251 genotypes developed from lowland AP13 and upland VS16 have been evaluated at three locations (Ardmore and Burneyville, OK and Athens, GA) since 2008. Biomass harvested after senescence in 2009 and 2010 was evaluated for lignin content and sugar release. Biomass samples harvested from all the six environments after senescence were analyzed at NREL for lignin content, S/G ratio using the molecular beam mass spectrometry (MBMS) and sugar release characteristics by co-saccharification. Significant differences were observed among the genotypes and the environments for the traits. The lignin content ranged from 19-27% of the dry biomass while the glucose and xylose release ranged from 120-313 and 123-263 mg g^-1, respectively. Regression analysis of the sugar release on the lignin content found out that a unit increase in lignin content decreases a total sugar release up to 10 mg g ^-1. Based on the results 10 genotypes with low average lignin content and above average sugar release value were selected for further evaluation and development of synthetic variety.