Geographic variation in seedling morphology of Chukrasia species

Abstract

Seed collected from 23 native provenances of Chukrasia A.Juss. and one Australian land race was used to study geographic variation in seedling morphology under temperature-controlled glasshouse conditions. Twenty-four variates were measured for each seedling and the resultant data subjected to univariate and multivariate analyses. The multivariate analyses effectively separated the Chukrasia genus into three different groups or eco-geographical clusters. The most important characteristics that separated the groups were bark structure, leaf type and midrib colour. The first group, provenances from China, Laos, Malaysia, Vietnam and the Australian land race, is characterised by smooth bark, pinnate or intermediate leaves and reddish-green to greenish-red midrib. The second group, provenances from Myanmar and Thailand, is characterised by rough bark, mainly bipinnate leaves and green midrib. The third group, provenances from Sri Lanka, is characterised by rough bark, bipinnate leaves and red midrib. The study clearly shows Chukrasia to be a polymorphic species comprising at least three ecotypes or possibly three ecospecies. A study of allozyme variation may better reveal the systematics within the genus.