A comparison of mechanical characteristics among Setaria viridis var. minor, Setaria italica, and Setaria × pycnocoma species of the family Poaceae

Abstract Setaria viridis var. minor and Setaria × pycnocoma occur sympatrically in various places in Japan, despite their different morphological and mechanical traits. Morphological and mechanical analyses were performed to determine whether the putative hybrid S. × pycnocoma possessed the morphological and mechanical characteristics of its ancestral species, S. viridis var. minor and Setaria italica . Our results indicated that S. italica had the highest panicle weight and longest culm with the lowest culm mechanical strength and S. viridis var. minor had the lightest panicle weight and shortest culm with the highest culm mechanical strength. S . × pycnocoma had a wide range of culm strengths, including mechanical properties of both ancestral species, which suggested that the intermediate mechanical characteristics of this species had been gained by repeated introgression within themselves.