Variation in the flowering phenology of apple and pear in Australia

Bud burst and flowering dates of commercial apple and pear cultivars were monitored in three geographically and climatically distinct growing regions of Australia (Applethorpe, Queensland; Shepparton, Victoria; Manjimup, Western Australia). Whole tree field assessments were made of 5% green tip, first open flower and progression of flowering to full bloom at all sites. Initial data from 2012 and 2013 indicated significant regional and varietal variation in the timing of bud burst and flowering. Variability in the duration of the period between first open flower and full bloom among sites suggests potential effects of climate on the consistency of flowering. Relationships between phenological variability and temperature are discussed. Field measurements and temperature data are being used to develop cultivar specific models of bud burst and flowering time. These phenological models will be used in conjunction with 2030 climate forecasts to make predictions about potential impacts on the pome fruit industry in Australia. Preliminary results from the modelling analysis are presented.