Genetic stability of Australian Phalaris (Phalaris tuberosa L.) under domestication

Abstract

Thirty isolates of the Australian cultivar of phalaris (Phalaris tubevosa), sampled over the range of its distribution in south-eastern Australia, were evaluated as seeds and seedlings in controlled environments and as spaced plants and swards in the field. The variation found within and between the populations for a number of morphological, developmental, chemical, and agronomic characters indicates that the species has undergone little, if any, ecotypic differentiation during almost 90 years of cultivation in Australia. The results also indicate that the cultivar was derived from a single ancestral population of P. tuberosa and are consistent with the earlier claims that this population was of Italian origin. The evolutionary conservatism and the apparent lack of ecological adaptation in the cultivar are not due to a lack of genetic variability, but rather to the longevity and adaptability of individual plants, and the absence of natural regeneration in established stands, all of which have reduced the scope of natural selection.