Abstract:
Genetic variation and interpopulation structure were assessed in 20 populations of the New Zealand coastal tree Metrosideros excelsa (pohutukawa) using allozyme markers. Average levels of polymorphism (P = 58%) and allelic richness (Na = 1.69) were typical of long-lived trees and higher than has been previously observed for other New Zealand tree species, which have generally been found to be genetically depauperate. Observed heterozygosity was low (mean Ho = 0.12) and consistently less than expected under Hardy-Weinberg equilibrium (Fis = 0.26), suggesting significant inbreeding. Interpopulation genetic differentiation was moderate (Fst = 0.20, mean D = 0.053) and this was correlated with low interpopulation gene flow estimates (Nm = 1.15). These results suggest that revegetation programmes should source seed locally and avoid taking material from small populations in which selfed seed may make up a significant portion of the seed crop.
