Quantitative Genetics of Eucalyptus globulus: Affinities of land race and native stand localities

Genetic variation was examined in a Eucalyptus globulus base population collection comprising 276 seed lots from 12 Australian localities and four land races developed in Europe and South America. Thirty variables collected over a 4-year period from four field trials in Argentina representing growth, relative bark thickness, tree form, transition to adult foliage and pilodyn penetration were used to determine the quantitative genetic affinities of the populations. The patterns of quantitative genetic differentiation were summarised using canonical discriminant and cluster analyses. Tasmanian and Victorian native stand localities were clearly genetically different. Land race samples were variable but generally had closer affinities to native stand localities from southern Tasmania. Portuguese selected full sibs families were the fastest growing, even faster than OP progeny with the same parents presumably due to inbreeding depression after partial selfing. Many native stand localities were superior in growth to land race material. The only consistent genetic difference found between land race and native stand material was in tree form at two sites. The generally better form of land race samples is most likely due to artificial selection. Large gains in both growth and wood density can be simply achieved by using material from appropriate native provenances.