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Why has the ARC formed a partnership with the University of the Western Cape (UWC)?
The ARC’s partnership with the UWC stretches over many years, whereas collaborations between the ARC’s soil and water division and the UWC’s biotechnology department started more recently.
The ARC’s mandate is to promote efficiencies in agriculture and related sectors through research, development and technology transfer.
Through this collaboration, we aim to drive excellence in agricultural-biotechnology research and enhance student training and knowledge acquisition on modern biotechnological and sustainable agricultural practices.
What were some of the highlights of the mini symposium?
The potential impact of climate change on agricultural production and food security was highlighted.
However, farmers cannot do much about climate change, so discussions centred on research findings on novel biotechnology techniques and strategies that would help to improve crop resilience, hence quality and yield, under these changing conditions.
How would biotechnology help improve climate resilience?
Biotechnology can help us to better understand plant response mechanisms associated with biotic stressors, such as pathogens, and abiotic stressors, such as high and low temperatures, droughts, salinity and heavy metals.
These findings help with the identification and selection of plant genotypes with unique traits and increased tolerance to stressors. We are not talking about genetic modification here, but merely the molecular breeding of plants that are more resilient by looking for specific markers in their genetic make-up.
Tell us more about the research.
Most UWC-related projects are investigating different ways to improve plant growth under salinity and drought.
These projects range from the identification and characterisation of stress-responsive genes to the evaluation of the role of small signalling molecules, such as calcium, chitosan, carbon monoxide and cyclic guanosine monophosphate, in plant stress responses towards increasing crop quality and yield.
The UWC and ARC also work together to develop new pome fruit varieties with desirable traits for local as well as export markets using marker-assisted breeding.
About 10 years ago, the ARC released the first low-chill apple variety in South Africa, and is now analysing a first-generation cross between Bon Rouge and Packham’s Triumph pears.
There are also various projects looking at the potential of promoting the cultivation and daily consumption of indigenous crops, such as sorghum, amaranths and rooibos, to reduce climate change and food-related disease risks.
Tell us more about these indigenous crops.
With modern diets, people have stopped eating some traditional crops in favour of crops that might not grow naturally in their areas, such as wheat, maize and rice. While wheat, maize and rice might provide adequate calories, they do not satisfy all the nutritional needs of consumers. Only eating these staples also neglects the need for dietary diversity.
There are thousands of different indigenous food species in Africa, with most of these poorly researched and understood. Even so, we know that many of them have a higher nutrient density than these new staples, and they are generally also more climate resilient as they are naturally adapted to the production environment.
Are you evaluating the nutritional value and resilience of other crops?
Yes, we are looking at the water use and drought tolerance of pomegranates. So far, we know that they are well suited to dryland production, although yields will be higher when produced under irrigation.
People think it might not be lucrative to grow pomegranates without irrigation because of the lower yields, but forget to take into consideration the cost of water, irrigation infrastructure and pumping costs. During dry spells, the dryland orchards will also perform better than the irrigated orchards.
On the other hand, amaranth, a leafy vegetable and grain crop that has very high nutritional content, achieves high yields under low irrigation.
This crop is tolerant to drought, and the ARC and UWC are analysing multiple genotypes under drought conditions, with a goal to identify highly drought tolerant genotypes that will later be distributed to homeowners and smallholder farmers.
Why was soil salinity on the agenda at the symposium?
Population growth is causing increased competition for land and water, which along with climate change is exacerbating pollution problems.
A bigger population would require more food to eat, and therefore the use of different strategies to improve crop yield and quality is necessary to produce this food, whereas shorter supplies of water will leave us with less water to dilute or wash away salts and other pollutants.
We need to look at crops that are more salt tolerant if we want to stay food secure. So far, we have uncovered that sorghum is relatively salt and drought tolerant.
The ARC is also evaluating the salt tolerance traits of rootstocks that can be used for various fruit species.
When will these rootstocks become commercially available?
We are in the final stages of evaluations. The drought-resistant rootstocks for deciduous fruit production will probably be commercially available in a few years.
What has been the market response to the low-chill apple varieties?
The low-chill apple varieties do not require as many cold units as traditional apple varieties, making them ideal for warmer areas in the country and a possible alternative in traditional apple-growing areas that might become warmer because of climate change.
So far, most of the low-chill apples have been planted in Limpopo, with a lot of the apples being sold across the border. Various projects have also been started to plant low-chill apples in KwaZulu-Natal and the Eastern Cape.
Why is new research on cover crops essential for the table grape and citrus industries?
The ARC has been doing trials on the use of cover crops in wine grape vineyards for over 20 years and have gained valuable insights that have been widely adapted in the industry over this time.
Citrus production in the Western Cape has increased significantly over the past decade. Some of the results on wine grapes would probably also be applicable to citrus, and more so to table grape production. But we need to be sure, as what works for one crop does not always work for another.
With the cover crops research in wine grape production, we specifically looked at winter cover crops, whereas we might have to look at winter and summer cover crops, or perennial crops, in citrus productio
What advice do you have for farmers on choosing which cover crops to plant?
Look at the cost and what you want to achieve with the cover crops. A low-cost option, for instance, might be to use the natural vegetation as a cover crop or to accommodate it in the planted cover crops. A big benefit of natural vegetation is that it will be well adapted to the environment.
It might also be more cost-effective to plant only one type of cover crop instead of a mixture and rotate it with other cover crops.
In terms of goals, specific crops bring specific benefits to the system. Crops like legumes, for instance, can fix nitrogen, whereas other crops, such as oats, are more aggressive growers and help to bring bulk to the system, which in turn will break down into organic matter.
Email Nomkhosi Ngcobo, public relations officer at the ARC, at [email protected].
