Research into the importance of winter chill to fruit production is needed urgently.
Chris Atkinson, head of science at East Malling Research (EMR), is warning that this year’s harsh winter should not detract attention from climate change and global warming.
EMR is aiming to help commercial growers worldwide as they seek a more detailed understanding of the science behind the winter chill effect that triggers consistent time of blossoming, and subsequent fruit development which maximises the yield potential the following summer.
Atkinson said: “We must not fall into a false sense of security after this winter. We need to be investing in approaches that enable UK growers to adapt to the changes already apparent in winter chill, as well as the further decreases forecast to occur by the end of the century.
“Our climate records, kept since 1913, when compared to data from other UK locations, show that throughout the country the amount of winter chill has already declined. In the South East we are already experiencing a 12 per cent reduction in the number of chill hours each winter, while the number of spring frosts has declined by a much higher percentage.”
Looking at climate scenarios mapped out by scientists for the future, the amount of chill the UK receives is set to decline still further: according to worse-case examples, by as much as 50 per cent in Kent over the next 70 years. Although this winter has been closer to the UK’s experience of winters 25 years ago, winters generally will become shorter and milder.
Atkinson said: “This will impact significantly on growers. As the South East’s climate fails to deliver the period of chill and dormancy required for maximising the yield of commercial perennial crops, the traditional varieties that require larger amounts of chill will likely be disappearing or migrating north to chillier or longer winters.
“… Forward-looking growers will need advice on how to adapt to these new demands in order to sustain UK-based food production levels. This may require the use of alternative cultivars with lower chill requirements.”
According to Atkinson, growers might even need to consider completely different replacement crops with much lower chill needs.
He said: “UK grape production is increasing and this crop generally has a much lower chilling requirement than traditional tree fruits, particularly apples.”
He further warned of the impact on imported crops the UK relies upon in order to sustain overseas growers.
“With a greater fundamental understanding of how plants actually measure and respond to chilling we should be able to help growers overcome some of the negative consequences of warmer winters,” he said.
