Using AFLP markers to inform population management of the endemic Chatham Island toetoe, Austroderia turbaria (Poaceae).

Abstract

Austroderia turbaria Connor is a threatened grass endemic to the Chatham Islands. Although formerly more widespread, remaining natural populations consist of highly fragmented remnants and/or individuals. Population genetic analysis of seed-raised progeny from six of the extant natural populations on Chatham and Pitt islands, using amplified fragment length polymorphisms (AFLPs) and microsatellite markers, shows that there are very low levels of variation (expected estimated heterozygosity He 0.023–0.030, no. of effective alleles Na 1.039–1.053), and no significant differentiation within or between populations on the two islands. Flow cytometric analysis of endosperm to embryo ratios suggests a sexual breeding system. This lack of population variation and no discernable differences between the two islands suggest that management practices such as the establishment of new populations can be carried out irrespective of the location of source material. One caveat to this is the possibility of Fusarium wilt occurring on the islands, in which case measures should be taken to best prevent spread across the range of the species.