Climate change deniers or those that think ‘yippee climate change will allow us to bask in hot summers’  – think again – climate change does not work that way and it is happening right now in our own time.

We may moan about our weather in Scotland but cold and frosty winters play an important role in how plants and crops recover in the Spring.

A research group based at the James Hutton Institute has told a meeting of the British Ecological Society in Birmingham of their investigations on the effect of warmer winters on Blackcurrants.  Milder winters may cause blackcurrant crops to flower later in the year, produce fewer fruit, and over repeated years and have a reduced plant lifespan.

Dr Katharine Preedy from Biomathematics and Statistics Scotland said:

“Blackcurrants have particularly high chill requirements and so are already seeing the effects of milder winters”.

A key crop worth about £10 million a year to the UK economy, blackcurrants are primarily processed as an ingredient and juice for major brands like Ribena (brand value at £140 million).

Understanding how different blackcurrant varieties may respond to climate change is critical to farmers. About 35% of the crop currently grown is known to require 1,800 hours of chilling below 7°C. Some varieties, however, need far lower temperatures and others can tolerate warmer temperatures as long as the chilling lasts longer.

Many farmers coordinate processing with apple producers in shared facilities, hence, a delayed blackcurrant season may force them to harvest unripe fruit of poorer quality or they might miss the chance to process the fruit at all.

Dr Preedy said:

“Blackcurrants are like the canary in the mine. If we can understand what they need in a changing climate, we can apply our knowledge to similar crops like blueberries, cherries, apples and plums”

To explore the relationship between chilling period and bud opening, the ecologists carried out controlled temperature experiments (at temperatures ranging from -4 to +8°C for up to 150 days) on 20 different blackcurrant varieties. The findings were then compared with blackcurrant cuttings sent in from farmers across the UK and temperature data obtained from local met office stations.

They found that each blackcurrant variety preferred different levels of chilling. In addition, some were able to compensate for warmer winter temperatures if they were chilled for long enough, whilst for other more sensitive varieties, longer chilling periods did not compensate for being less cold, causing erratic bud break.

The differences lie in the genetics, as some varieties have evolved in different climatic regions or are the result of selective breeding over the years.

Professor Hamlyn Jones from the University of Dundee said:

“If we can understand this, farmers can carefully select varieties based on the climate and conditions in which they are going to be planted, and breeders can develop varieties that are more resilient to both warmer winters or periods of extreme cold”.

Dr Katharine Preedy will present the group’s work on Monday 17 December 2018 at the British Ecological Society annual meeting. The conference will bring together 1,200 ecologists from more than 40 countries to discuss the latest research.

Dr Preedy said:

“In the future, we hope to identify genetic markers associated with the ability to withstand variable winters, so we can rapidly breed new varieties of blackcurrants”.

The study is funded by the UK’s innovation agency, Innovate UK, and the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS) division.