Assessment of phenology, growth characteristics and berry composition in a hot Australian climate to identify wine cultivars adapted to climate change

Background and Aims

The phenology, growth traits and fruit composition of cultivars in the CSIRO germplasm collection, located in a hot Australian region, were assessed to identify those adapted to climate change.

Methods and Results

The study involved 465 cultivars assessed over four seasons. Differences in key traits included a 5-week range in budburst; a 4-month harvest window; a twofold difference in the growth period from budburst to harvest; a fivefold difference in fruitfulness and in leaf area index; a 15-fold difference in berry mass; and a five- to 15-fold difference in berry mineral ion concentration and large differences in fruit composition. The latter included pH (range 3.48–4.95), titratable acidity (1.60–9.07 g/L), tartaric acid (2.20–7.95 g/L), malic acid (0.80–7.74 g/L), yeast assimilable nitrogen (70–505 mg/L) and, in red wine cultivars, total anthocyanins (0.04–5.79 mg/g) and phenolic compounds (0.55–3.60 a.u.).

Conclusions

Cultivars grown under hot conditions with late budburst to minimise frost risks; short growth periods and small canopies to improve water use efficiency; and early and late ripening to extend the season have been identified. Early ripening cultivars had better fruit composition than late ripening cultivars.

Significance

Opportunities to broaden genetic diversity will enhance the capability of the wine industry to meet challenges associated with climate change. Poor fruit composition, however, associated with high pH is a limiting factor under hot conditions.