Bioethanol potential of switchgrass cultivars for rainfed and irrigated conditions in marginal lands

Bioethanol is a climate-friendly alternative to conventional energy sources. This study was conducted to determine bioenergy potential of switchgrass cultivation in Central Anatolia where water scarcity limits the agricultural production. Field trials were conducted in a randomized blocks design with three replications under irrigated and rainfed conditions for three growing seasons (2019, 2020 and 2021). Biomass yield (BY), theoretical cellulosic ethanol yield (TEY), theoretical ethanol potential (TEP) with several quality parameters of 10 switchgrass cultivars were evaluated. Highest BY averages were obtained from Boomaster cultivar with 5.28 (rainfed) and 18.45 t ha-1 (irrigated) when Dacotah had the lowest BY averages of 1.55 (rainfed) and 5.29 t ha-1 (irrigated). ANOVA and Genotype Trait Biplot results revealed higher BY, TEY and TEP with lower ADF, NDF and ADL of lowland ecotype cultivars. Lowland ecotypes provided superior results in both rainfed and irrigated conditions with a higher response to irrigation. TEY of switchgrass were found as positively associated with BY, plant height and stem weight which could be used as indicators of TEY for genotype selection. In conclusion, lowland ecotype cultivars of switchgrass were recommended for bioethanol production in water limited environments.