Influence Of Drought Stress On Bioenergy Traits In Sorghum.

Sorghum is a multipurpose crop with high biomass yields, sugary sap similar to sugarcane, and starch-containing grain. This versatility gives growers options to use sorghum for sugar or livestock feed production as well as a bioenergy crop. Additionally, sorghum is genetically diverse, with many drought tolerant varieties and good adaptability to various locations in the United States as well as around the world. Investigation of sorghum variety traits under limited water availability is especially important with changing climate and predicted increases in drought frequency and severity. Three studies (greenhouse limited irrigation, drydown root evaluation, irrigated and dryland field trials) were conducted on 20 varieties to evaluate sorghum traits related to drought tolerance.  Morphological traits were measured including leaf area, plant height, and stem diameter as well as physiological traits such as photosynthetic rate, stomatal conductance, and water use efficiency. Combining these studies, we compared above and below ground biomasses, plant physiology, genetic and environmental components under irrigated and dry treatments as well as assessed how these traits covary.  Forage varieties CHR-FS4, HP95BMR, HP85BMR, HP99BMR and a sweet sorghum variety (Sweet Six BMR) demonstrated high yield characteristics across the three studies and under both irrigated and dry treatments. Correlation analysis from the greenhouse study showed tiller diameter and plant height were negatively correlated under irrigated conditions and total leaf area and tiller diameter were positively correlated under dry conditions.