Genotype x Environment Interaction of Lignocellulosic Characteristics of Switchgrass Grown on Marginal and Prime Soil.

Switchgrass (Panicum virgatum L.) is a native perennial, warm-season grass that is currently being utilized as a bioenergy feedstock in the United States. Limited information exists as to the performance of switchgrass cultivars on marginal soils compared to prime farmland; however, research indicates that lignocellulosic traits (i.e. cellulose, hemicellulose, and lignin) have been shown to vary across populations, years, and locations.  Therefore, a major breeding goal is to determine whether selection of switchgrass cultivars in non-target environments (prime farmland) will result in similar performance in target environments (marginal soils).  In order to achieve this goal, the objectives of this study were to (i) examine genotype by environment effects, (ii) determine broad-sense heritability estimates, and (iii) perform stability analyses on cellulose, hemicellulose, and lignin content in switchgrass clones grown on marginal and prime soils.  Thirty switchgrass clones were evaluated for cellulose, hemicellulose, and lignin content at one prime and two marginal locations in New Jersey in 2009 and 2010.  Significant genotype x environment interactions were observed for all traits evaluated, with the greatest impact of the environment detected for hemicellulose content.  There was stronger genetic control for cellulose than for hemicellulose and lignin content in switchgrass.  Interestingly, cellulose, hemicellulose, and lignin content were not stable for any of the clones across all of the environments; however, several clones consistently ranked in the top or bottom 15% for each trait across locations and years.  Overall, results support the existence of both specifically and broadly adapted switchgrass germplasm, and demonstrate the need for evaluation of switchgrass germplasm across multiple years and environments (including both prime and marginal sites) in order to develop cultivars with optimal lignocellulosic characteristics