Abstract
The heat event that occurred in many parts of Australia in 2009 was the worst on record for the past decade, with air temperatures exceeding 40°C for 14 days. Our aim was to assess the impacts of this heat event on vine performance, including ripening, yield, and gas exchange of Vitis vinifera cv. Semillon grown in a Riverina vineyard. To assess the affect of high temperatures on Semillon grapevines, the vines were covered with a protective layer to reduce radiant heating and were compared with vines exposed to ambient conditions. The heat event had major effects on ripening; reducing the rate of ripening by 50% and delaying harvest ripeness and causing a high incidence of berry shrivel and sunburn. Yield was not affected. Photosynthesis was reduced 35% by the heat event while transpiration increased nearly threefold and was accounted for by increased stomatal conductance. The conclusion of this study was that heat events delayed ripening in Semillon berries and caused a significant reduction in berry quality. Strategies to minimize the radiant load during heat events are required and this study has confirmed a protective layer can reduce canopy temperatures and enhance berry quality.
Highlights
High temperatures are a common occurrence in grape growing regions of Australia
The objective of this study was to investigate the effect of high temperatures on vine performance and berry ripening in Semillon grapevines growing in vineyard conditions
The high temperatures of the 2009 growing season were very unusual within the decade in that temperatures above 40◦C persisted for 14 days in a row
Summary
High temperatures are a common occurrence in grape growing regions of Australia. Recent high temperatures have occurred in Australia in the summers of 2006 and 2009 and in both instances the high temperatures persisted for more than 5 days (Australian Bureau of Meteorology, 2011). Such high temperatures can occur as early as the time of flowering right through to harvest (Gladstones, 1992). Crop losses can occur when high temperatures affect flowering and later in the season can slow growth of berries and impede sugar accumulation (Greer and Weston, 2010) and delay harvest, reduce yields, and compromise berry composition. There appears to be varietal differences in the response of vines to high temperatures and radiation intensity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
