Variability in waxiness of Eucalyptus gunnii foliage for floriculture

Eucalyptus gunnii leaves can appear as green or glaucous phenotypes with th e latter more desirable for floriculture. The epicuticular wax from these t wo types were compared morphologically using environmental scanning electro n microscopy, chemically using gas chromatography, and molecular markers we re found to distinguish the two types using RAPDs and bulked segregant anal ysis. Both phenotypes had wax tubes, which in the glaucous type were signif icantly longer and thicker and the surface area was covered more densely th an 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 beta-diketones and esters than the wax from the green type. The glaucous type had a greater yield of wax per unit area of leaf th an the green. Seven molecular markers were found which would distinguish th e,green and glaucous bulks. No individual marker could totally distinguish all green individuals from all glaucous individuals but this could be achie ved using combinations of markers. (C) 1999 Elsevier Science B.V. All right s reserved.