Genetic variation and structure of remnant stands of pohutukawa (Metrosideros excelsa, Myrtaceae)

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 (N_a = 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 H_o = 0.12) and consistently less than expected under Hardy‐Weinberg equilibrium (F _is = 0.26), suggesting significant inbreeding. Interpopulation genetic differentiation was moderate (F _st = 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.

Keywords:

• Metrosideros excelsa
• pohutukawa
• allozyme analysis
• genetic variation

Notes

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