Fig. 3
Principal component analysis biplot of morphological and physiological traits of 49 switchgrass genotypes under well-watered and drought stress conditions after 30 days of treatment. The seven physiological parameters (Pn, Ci, g s, Tr, RWC, WUE and EL) allow to separate 49 switchgrass genotypes that were either grown under well-watered (circled) or drought treatment (box) conditions. Arrows represent physiological traits with various length based on the impact of each trait on the separation of genotypes. RWC relative water content, EL electrolyte leakage, Pn photosynthetic rate, g s stomatal conductance, Tr transpiration rate, Ci intercellular CO2 concentration, WUE water use efficiency, LL leaf length, LW leaf width, SL leaf sheath length