Rachael Sheridan

Doctor of Philosophy, (Plant Biology)
Study Completed: 2019
College of Sciences


Thesis Title
Environmental and Genetic Influences on Growth, Flowering, and Nectar Production in Mānuka (Leptospermum scoparium J.R. Forst. & G. Forst.)

Read article at Massey Research Online: MRO icon

To help drive the international success of the NZ honey industry, it is key to further optimise both nectar and dihydroxyacetone (the compound in nectar responsible for the bioactivity of manuka honey) production in Mānuka. Selecting varieties to maximise nectar potential requires an understanding of how environment and plant factors interact at a whole-plant level. Ms Sheridan used controlled environments to study the relative performances of genetic clones with varying levels of nectar dihydroxyacetone and characterized the response at growth, flowering, and nectar production level. One significant finding was that nectar quantities were little affected by differences in air temperature, but both temperature and light quality were major determinants of the quality of those nectars (ratios of dihydroxyacetone to total sugars). Overall, her results indicated that genetics, environment and their interactions contributed significantly to the quality of the Mānuka nectars and potentially the quality of the honey derived from that nectar.

Dr Huub Kerckhoffs
Dr Jonathan Stephens
Professor Cory Matthew
Professor Jason Wargent