Switchgrass Genotype Study As a Bioenergy Crop in Kansas, USA

Due to increasing fuel costs and uncertainty of fossil fuel supply on the planet, developing bioenergy crop such as switchgrass might play an important role in terms of diversifying energy sources and increasing energy sustainability. There are many potential bioenergy crops and switchgrass is one of them. Switchgrass is a native warm-season grass and once it’s established, it can last several years with low inputs and maintenance. The objectives of this study were to: 1) assess the best performing switchgrass genotype suitable for Kansas soil and climatic condition in the USA, and 2) determine the correlation between plant height or tiller numbers per plant and dry biomass of various switchgrass genotypes. Seeds of twenty accessions of switchgrass were sown in trays under greenhouse conditions and transferred into cones after emergence. Twenty two different genotypes (i.e., Alamo, Cave-in-Rock, Kanlow, SL 93 C2-1, SL 93 C2-2, SL 93 C2-3, SL 93 C2-4, NL 94 C2-1, NL 94 C2-2, NL 94 C2-3, NL 94 C2-4, NSL 2009-1, NSL 2009-2, NSL 2009-3, NSL 2009-4, SWG 2007-1, SWG 2007-2, SWG 2007-3, SWG 2007-4, SNU 98 LMBP C1-1, SNU 98 LMBP C1-2, SNU 98 EMBP C1-1) of seedlings were allowed to grow in cones for 30 days under controlled environments. Thereafter, the seedlings were transplanted into the field at the Kansas State University North Research Farm in Manhattan, Kansas, USA. The growth and yield components of various switch grass genotypes were measured. Plant height and number of tillers per plant was measured in five randomly selected plants from each replication. Single plant was harvested and dried in oven at 50°C for a week and dry weight was recorded and expressed as g plant^-1. Plants in a meter square were hand harvested and dried in oven at 50°C for a week and dry weight was recorded and expressed as g m^-2. Significant difference in plant height was observed among the genotypes. The genotypes, SL 93 C2-2 was the tallest (193.9 cm) and there was no significant difference between SL 93 C2-2 and NL 94 C2-1, NL 94 C2-2, NL 94 C2-3, NL 94 C2-4, NSL 2009-1, NSL 2009-3, NSL 2009-4, SL 93 C2-1, SL 93 C2-3 and SWG 2007-2. The genotype Cave-in-Rock was the shortest (124.2 cm) among the genotypes. Significant difference in number of tillers per plant was observed among the genotypes. The genotypes Alamo recorded the highest numbers of tiller plant^-1 (24.4) which was on par with NL 94 C2-1, NL 94 C2-4, NSL 2009-2, NSL 2009-3, SL 93 C2-1, SL 93 C2-2, SL 93 C2-3, SL 93 C2-4, SWG 2007-1 and SWG 2007-2. The genotype Cave-in-Rock had the lowest numbers of tiller plant^-1 (14.3) compared with other genotypes. The genotypes Alamo, NL 94 C2-2, NL 94 C2-3, NSL 2009-1 and NSL 2009-1 had increased above ground biomass compared with other genotypes. The genotypes SWG 2007-3, SNU 98 LMBP C1-2, SNU 98 EMBP C1-1, Cave-in-Rock and SWG 2007-4 had lower above ground biomass than other genotypes of switchgrass. The correlation study indicates that there was a significant positive correlation between number of tillers per plant and per plant dry weight (R²=0.93), number of tillers per plant and plant height (R²=0.94), and plant height and per plant dry weight (R²=0.82). This study might help bioenergy crop breeders develop certain genotypes that can have high biomass with both high number of tillers per plant and taller plant characteristics.