Adjusting grape berry ripening to suit a changing climate: plant growth regulator-based solutions

Summary

Objective

To develop methodologies that can help expand the harvest window by delaying ripening from occurring during the hottest part of summer and produce fruit of enhanced quality.

Background

Global warming poses new challenges for the wine sector due to changes in berry development. In recent seasons, harvest periods have been compressed, resulting in difficulties in winery intake scheduling and processing, and ripening occurring during hotter times of the year.

Control of the initiation and progression of ripening can alleviate problems associated with increasingly narrow harvest windows and undesirable shifts in the timing of the ripening phase. This project will further develop, optimise and commercialise the use of pre-veraison plant growth regulator (PGR) applications to control ripening and improve berry quality.

Research approach

Ripening-delaying treatments using auxins such as NAA (1-naphthaleneacetic acid) and other PGRs will be fined tuned and the treatments adapted to a commercial setting. The project will further investigate the effect of ripening-delaying treatments on fruit quality parameters, focusing on a selection of flavour/aroma compounds and on the improvement of ripening synchronicity between berries/bunches. Developing mass spectrometry-based methods for the analysis of non-volatile grape metabolites will be a key part of the project. This will allow the classification of pre-veraison grapes into defined developmental stages and identify those stages most responsive to PGR treatments. These methods will allow vineyard managers to reliably predict the best time to treat the fruit for optimal effect on ripening.

Sector benefits

The capacity to manipulate harvest timing will assist in the scheduling of grape harvest and intake into wineries, will improve the composition of fruit/wine and reduce overall costs and wastage.