Genotypic variation among sites within eleven Australian native grasses

Abstract

Eleven species of native grass were collected from 51 sites throughout western New South Wales and south-west Queensland. Approximately 10 whole plants of each species were collected from a site but not all species were collected from each site. Plants were grown in a common environment at Trangie in central western New South Wales and plant morphological and floristic characteristics measured. Data reported here are for observations made in the third year, by which time differences between populations were likely to be more genetic than environmental. Principal component and discriminant analyses revealed a strong relationship between site of origin and plant morphological characteristics, which explained between 61% and 93% of the variation within species. For all but one species, site was significantly correlated with these morphological characteristics. Site could be predicted from morphological characters with a success rate usually greater than 80%. These morphological characteristics must reflect genotypic differences among the collection from the different sites. We were unable to relate this variation to any of a range of site characteristics. Distance between sites could not be used as an indicator of morphological differences between populations. The implications of these findings are discussed in terms of providing strong evidence for the existence of ecotypes and for obtaining appropriate seed sources for revegetation/restoration programs.