Variability in waxiness of Eucalyptus gunnii foliage for floriculture

Eucalyptus gunnii leaves can appear as green or glaucous phenotypes with the latter more desirable for floriculture. The epicuticular wax from these two types were compared morphologically using environmental scanning electron microscopy, chemically using gas chromatography, and molecular markers were found to distinguish the two types using RAPDs and bulked segregant analysis. Both phenotypes had wax tubes, which in the glaucous type were significantly longer and thicker and the surface area was covered more densely than on the green type. When compared chemically, the glaucous wax seemed to contain a higher percentage of alkanes, alcohols and free fatty acids, but lower percentages of β-diketones and esters than the wax from the green type. The glaucous type had a greater yield of wax per unit area of leaf than the green. Seven molecular markers were found which would distinguish the green and glaucous bulks. No individual marker could totally distinguish all green individuals from all glaucous individuals but this could be achieved using combinations of markers