Kiwi scientists trying to breed new apple varieties to handle warmer climate

New Zealand's billion-dollar apple industry is at risk because warmer winters could stop the trees from flowering - and therefore producing fruit.   

But a team of scientists is working on a solution - breeding new apple tree varieties that can withstand a warming climate.  

The industry is on track to be worth $2 billion by 2030 but the warming world could change that. 

"[It's a] big risk for regions of industry if we don't get enough chilling hours. It would limit growing apples here," said Gary Wellwood, VentureFruit's new variety manager. 

Most apple trees need between 600 and 800 "chilling hours" at temperatures below 7C in winter, during their endodormancy stage. 

Otherwise, they won't get "bud break" - which leads to flowering and fruit development.  

Scientific modelling shows by 2100, it might be too warm for bud break to occur - which could wipe out the apple industry.   

"There's a high risk it would collapse the industry in an extreme case," said Vincent Bus, the science group leader at Plant and Food Research.

The researchers collected and grew more than 100,000 samples of different apple varieties, hoping to find the best ones suited to a warmer climate.
The researchers collected more than 100,000 samples of different apple varieties, hoping to find the best ones suited to a warmer climate. Photo credit: Newshub.

To stop that happening, they've collected more than 100,000 samples from different apple tree varieties to test them in warmer conditions and see how they respond. 

"We have recorded what the bud break date is for each variety in orchards in 2020 and 2021," said Moon Chen, a scientist at Plant and Food Research. 

And they found several varieties had early bud break and low chilling requirements - ideal for breeding. 

But creating a new climate-resilient apple variety is a tricky balancing act. 

"We want to reduce the need for chilling but we want to increase the heat requirements for flowering time, to make sure that happens outside the frost risk," Bus told Newshub. 

It's a project the apple industry is keeping a close eye on. 

"It should allow us to keep growing apples in the regions we are already in," Wellwood said. 

Newshub asked if he's already seen climate change's impacts. 

"We're struggling to colour fruit in hotter conditions. Apples rely on diurnal temperature differences - warm days, cool nights," he added. 

The apple industry has several ongoing climate change projects, with the longest running being a breeding programme in Spain that began in 2022. 

That project has already launched its first commercial apple variety.