Research Article

Abstract

Intraspecific chromosome number variation is widespread among plants, however little attention has been given to the implications of ploidy level on restoration success of particular cytotypes. We conducted a cytometric study on six big bluestem (Andropogon gerardii) populations from the Carolinas. In addition, soil data were collected and compared among the sites. Results from flow cytometry indicated the occurrence of two distinct cytotypes among the populations without evidence of populations with mixed cytotypes. The amount of nuclear DNA was consistent for hexaploids (6x) and nonaploids (9x) reported from midwestern populations of big bluestem. A cluster analysis of the distances between populations failed to detect any geographical clumping of populations by cytotype. Although the general soil characteristics across all sites exhibited a broad range of soil conditions; CEC, K, Mn, and percentage Ca and Mg (as percentage of CEC) levels were significantly higher for the 6x populations. The documentation of nonaploid populations of eastern big bluestem from this study is of potential conservation concern due to their small population sizes and the reported reduced reproductive rates for the 9x cytotype in midwestern populations. Studies from midwestern populations of big bluestem indicate reduced seed production in nonaploids compared to hexaploids. We suggest that in addition to the use of local genotypes in the restoration and conservation of eastern big bluestem populations, that cytotypic determination be made of introduced seed material into eastern remnant populations to avoid the establishment of individuals with reduced reproductive compatibility within those populations.