Geographic patterns of genetic variation in Cordyline australis; does fingerprinting recover phenotypic and phenological patterns?

Abstract

The genetic variation of 28 populations of Cordyline australis (cabbage tree, tī kōuka) grown from wild-collected seed from across New Zealand was assessed using amplified fragment length polymorphism (AFLP). There was strong geographical structure in the data, with the main differentiation being between plants from the northern North Island and those from the central North Island and further south; a split that was not concurrent with any obvious physical barriers. Further smaller genetic divisions were evident in the data, with eight groups found across the range of C. australis, while genetic variation was found to decrease markedly with latitude. We compare the patterns of genetic variation with earlier studies looking at morphological variation across the range of C. australis, as well as the relative survival of plants from different latitudes in three common garden replicates.