Diverse eastern gamagrass ecotypes: General characteristics, ploidy levels, and biogeography

Abstract

AbstractEastern gamagrass (EG), Tripsacum dactyloides, is a diverse warm‐season, perennial bunchgrass that is widespread in the eastern half of the United States. The objectives of this study were to obtain a large assortment of ecotypes, measure and quantify some of their morphological aspects, and determine ploidy level for many of these ecotypes. Nearly 300 ecotypes were collected from 10 states and planted in a common garden in Temple, TX. Plants were measured throughout the growing season and ploidy was determined using flow cytometry. Plant morphology measurements were variable, though none were statistically significantly correlated when compared pairwise to ploidy levels, origin, landform, precipitation, or temperature. However, multivariate analyses showed that ploidy was significantly correlated with plant volume, plant height, and leaf width. Diploids were more narrowly restricted to drier habitats, while the tetraploids were widespread. Tetraploids have also a higher volume than diploids. Likewise, mean annual precipitation was correlated with plant height and leaf width. Landform (wet vs. dry) for collection sites was significantly correlated with plant volume in the multivariate analysis. Though not statistically significant, the southernmost populations start growing earlier than plants collected further north. This new insight into EG ecology via the collected data is useful to better answer producer questions about climate and management operations as they differ among ecotypes.