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Our tropical fruits are vulnerable to climate change. Can we make them resilient in time?


Plants provide almost every calorie of food we eat. Grains such as rice, wheat and maize make civilization possible. For thousands of years, farmers have cultivated grains, fruit and vegetable varieties to obtain larger crops and plants that are more resistant to different climates.

But climate change will cause massive disruption to the plants we rely on. A hotter world. Drier in some places. Wetter in others. Intensified droughts. More fire. Sudden torrential rain.

We need plants with even greater resilience. But is it possible?

We believe so. Our team has been working on climate-proofing five popular fruits: banana, the most purchased product in supermarkets, as well as pineapple, passion fruit, custard apple and pawpaw. We’ve already done this with chickpeas to produce new, more resilient varieties.

Pineapple plants like tropical conditions. Their genomes may hold the secrets of climate resilience, but they have limits.
Author provided

What does climate change mean for horticulture?

Australia, the driest inhabited continent, has already seen weather patterns change. Droughts have become more severe, heat waves and fires have intensified, and heavy rainfall and flooding have become more frequent. In some areas, there is less rainfall in the winter and the ocean temperature rises.

Fruit and vegetable production is one of Australia’s most important agricultural sectors, with an annual production value (excluding wine grapes) exceed A$11 billion in 2021–2022.

But this could change. The warping climate and increased instability make it harder for fruit growers to plan.

The Australian fruit sector has already experienced large-scale losses of young fruit trees, or seasonal fruit develops badly.

As winters get warmer, we may see lower apple, pear, cherry and nut yields. That’s because these trees usually go into hibernation during cold spells. If the weather is not cold enough, they will not grow and develop normally.

Read more: Farms are adapting well to climate change, but there’s work to be done

What can we do?

Fruit growers have a long game to play. It takes years for saplings of apple trees planted today to begin to bear marketable fruit.

This long time to a payout can make it difficult to respond quickly to climate challenges.

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Custard apples are a popular tropical fruit.
Author provided

But there are new methods we are trying. Modern tools such as whole genome sequencing and allele mining allow us to better understand how vital traits are encoded in the genome of a tree. This, in turn, can help us address traits like drought and heat tolerance, which will be valuable in the future. With this knowledge, we can manipulate these genes to get stronger effects, or transfer them to other plants using modern breeding techniques.

We have already used these techniques to find genes in chickpeas encoding better drought resistance. Plants with these genes can survive temperatures up to 38℃ and also produce better yields. After we isolated these genes, breeders in India and African countries made use of this knowledge to produce new, more drought tolerant varieties.

You might think drought tolerance is about better water retention. Not necessary. In these new and improved varieties we see deeper roots, stronger growth and better leaf growth. This strength secures their yields during drought stress.

chickpea plant
New chickpea varieties are more resistant to heat and drought.

Now we are using these techniques to extract the genomes of popular tropical fruits such as bananas and pineapples. We want to do the same thing we did for chickpeas: create climate-resistant cultivars.

What worked for chickpeas may not work for papaya and other fruits. What we want is to find characteristics that increase survivability under extreme conditions.

What would make these fruit trees and plants resilient to climate change? A high tolerance for stress is essential. If you’re a gardener, you know that some plants can take a beating, while others are finicky and can die easily. It will help to find genes that promote robustness.

But there are other genes we’re looking for – those that code for improved yields and better fruit quality.

We are also working on accurate predictions of climate resilience characteristics against the predicted climate changes in our fruit growing regions. We can map out the utility of these traits for specific regions by statistically testing correlations between different genes and measuring plant traits.

Once we are better able to predict crop performance reliably, we avoid the long time it takes to repeatedly grow and test new cultivars under field conditions and wait for the intense conditions needed to test how they respond.

The climate is changing, fast. We need to adapt our food sources just as quickly.

Read more: From field to store to fork, our farmers are increasingly concerned about climate change

We are grateful to Vanika Garg, Anu Chitikineni, Robert Henry, Natalie Dillon, David Innes, Rebecca Ford, Parwinder Kaur and Ben Callaghan for their collaboration and support

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