South Africa’s agriculture faces increasing climate challenges, particularly for vulnerable crops such as fruit. Dr Peter Johnston, a climate scientist, highlights the difficulties of adaptation, while Dr Hennie Groenewald, executive manager at Biosafety South Africa, offers hope through genome editing.
Agriculture is facing significant challenges due to climate change, and South Africa’s agricultural regions are already feeling the heat, literally. As climate change continues to intensify, farmers are forced to make critical decisions about crop selection and farming practices in the face of growing uncertainties.
In this article, Dr Peter Johnston, a climate scientist at the University of Cape Town, and Dr Hennie Groenewald, Executive Manager at Biosafety South Africa, explore how the cultivation of climate-resilient crops and the emerging field of genome editing are shaping South Africa’s agricultural future.
While crops are traditionally grown in specific climates suited to their needs, this balance is increasingly disrupted by rising temperatures and erratic rainfall patterns, says Johnston.
“Farmers know that out of every ten years, there will be about three years when the rainfall is too high and three years when it is too low, and four years are just right. This variability is something they’ve always learned to cope with, but climate change adds a new layer of unpredictability,” he states.
The unpredictable nature of rainfall and temperature spikes is particularly problematic for certain crops, he explains.
“For example, apples (and grapes) need a certain number of chill units—hours or days below 0°C in the dormant season—to thrive. As the climate warms, these chill units are decreasing, and farmers are forced to turn to expensive chemical interventions, driving up costs.”
This is a reality many fruit farmers face. The potential loss of crops due to heat stress, drought, or extreme weather events could devastate livelihoods, especially for high-value export commodities like citrus, nuts, and deciduous fruits and grapes.
Yet, Johnston emphasises that South African farmers are resilient. They have long adapted to challenging environmental conditions and will continue to do so.
“Farmers adapt to their changing environment – whether that means being more conservation minded, choosing more drought-tolerant varieties, altering planting schedules, or even reorienting their vines and orchards to reduce sun exposure.”
The vulnerability of South African crops
According to Johnston, grain farmers may be better positioned to adapt in the short term. Their crops, such as maize, have shorter growth cycles, allowing them to respond and adapt to gradual changes in weather patterns.
“Grains usually have a 90-to 120-day growth cycle, and if the conditions aren’t right, farmers can make different decisions about seed selection, fertiliser and input purchases and adapt their techniques, and salvage their crop yields from extreme weather,” he notes.
However, it is South Africa’s fruit industry that stands at the edge of a precipice.
“Fruit farmers are far more vulnerable. These crops are long-term, high-value investments, and mostly for export. A failed harvest can spell financial disaster.”
As the climate continues to shift, farmers in this sector face increasingly difficult decisions about how to protect their livelihoods. The stakes are high, not just for individual farmers, but for the entire economy and the millions of South Africans who depend on agriculture for their livelihoods.
Genome editing: A glimmer of hope?
However, let’s talk about genome editing, a technology with the potential to revolutionise agriculture by creating crops that are more resilient to climate stressors like drought, pests, and heat.
Dr Groenewald explains that genome editing encompasses a range of techniques designed to modify an organism’s genetic material. The term “genome” refers to all of an organism’s genetic material, while “editing” signifies making precise alterations, much like editing text in a document.
Groenewald further clarifies the distinction between genetic modification and genome editing.
“Genetic modifications refers to when we take a gene from a different organism and put it into crops. With genome editing, you change the existing traits in a plant versus genetic modification, where you bring something in.”
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Regulatory framework for genome-edited crops
Groenewald emphasises that regulations overseeing food products have been established for many years. South Africa enacted the GMO Act to provide specific oversight for genetically modified organisms and derived foods.
“Before a GM food crops can be planted and sold in the market, it must undergo a thorough safety assessment. This process ensures that any potential risks associated with the crop are identified and addressed, guaranteeing that the food produced is safe for consumption.”
Groenewald notes that many countries worldwide have concluded that genome editing is distinct from traditional genetic modification, opting to regulate it differently.
However, in South Africa, the regulatory authority issued a notice in October 2021 stating that, based on their interpretation of the relevant legislation, all genome-edited products are considered genetically modified organisms (GMOs).
“At the moment, we see genome editing still regulated as GMOs,” Groenewald shares.
Future prospects
Looking to the future, Groenewald believes genome editing will provide consumers with more choices.
“We can also use South African local crops and improve them. I would like to see agriculture becoming more sustainable because of the traits that we could use to reduce dependence on chemicals, for example, so it’s more sustainable, and I want to see farmers being more profitable.
“I would like to see us using genome editing as a tool that benefits everyone throughout the value chain,” he says.
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