Climate change – arid areas need new crops

Last year’s Monsanto/BASF agreement, and the accompanying massive investment in producing drought-tolerant maize, wheat, sorghum, cotton and soya beans, show the big companies have identified drought as both the next big global crop risk, and a lucrative opportunity.
Issue date : 16 January 2009

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Last year’s Monsanto/BASF agreement, and the accompanying massive investment in producing drought-tolerant maize, wheat, sorghum, cotton and soya beans, show the big companies have identified drought as both the next big global crop risk, and a lucrative opportunity.

They have already secured vast databanks of gene and metabolic sequences as key assets in often aggressive acquisitions. These will preclude others, especially developing nations and their research agencies, from entering the marketplace.
Still, investing most of the global research funding in five or so main staple crops might be a risky strategy. Even with genetic engineering, it’s questionable if these crops will cope with the hotter and drier scenarios expected due to climate change.
And while the crop-breeding superpowers contemplate genetic modification of maize and other conventional crop species for drought tolerance, there are thousands of other African, Asian and South American plant species which show potential as food crops and which are already drought-tolerant.

The “orphan crops” solution
Studies in Africa of so-called “orphan crops” show that there are about 2 000 “undiscovered”’ food plant species, which include novel grains, vegetables and fruit, on the continent. All of these could be farmed, or at least harvested in a carefully managed way. These plants never get much of the international research funding, but South Africa should try to investigate them in a systematic and well-funded way. This could complement research on how far we can push conventional crops to new levels of drought and salinity tolerance.

South Africa has a vast botanical wealth of about 25 000 plant species, but only about 1 000 or so medically active ones have been well-researched. Not nearly enough work has been done on those species which could have food uses and could be improved for commercial production and local food security.

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The Department of Science and Technology’s Climate Change Technology Needs Assessment, published in 2007, reviews possible climate change adaptation strategies for the agricultural sector. It warns that, for the agricultural sector to cope, it will need new crop species and cultivars as well as macro-economic diversification and livelihood diversification in rural areas.

While there are many existing local efforts to diversify rural livelihoods, notably through agri-tourism, agriculture remains the main economic activity in South Africa’s arid provinces. The economy still depends on livestock farming, although there are moves towards novel niche crops such as agave, hoodia and devil’s claw, and irrigated crops like olives and sugar beet in the Eastern Cape for biofuel production. This should be pushed for wider application in areas which aren’t currently designated as arid, but may become more so with climate change.

Developing totally new cultivars and crops that are adapted to dry and hot conditions is going to be more difficult. Developing drought-tolerant crops will need both public and private research funding and it will take about 15 years to establish them.
New cultivars can be created through both conventional plant breeding and the genetic modification of existing crops. Finding the genes for genetic modification is a huge challenge – currently only simple traits such as insect resistance (the Bt gene) and herbicide resistance have been successful commercially. Work done at the University of Cape Town and the Agricultural Research Council has looked at novel, local, drought-tolerant genes which could be used to create new local crops, but it’s still at the experimental stage.

Climate change is already bringing about new opportunities in farming, even in the arid areas, in the form of carbon farming. An example is the Baviaanskloof Mega Reserve’s Clean Development Mechanism (CDM) project to restore the spekboom thickets of the Eastern Cape, and recoup international carbon money to do this. In addition to the restoration of the subtropical Thicket biome, there could be an opportunity for formal bioprospecting of these plants, either for their drought-tolerance genes or for their ability to sequester carbon under very harsh conditions – something which is obviously also genetically based.

Most existing CDM projects look at temperate or tropical agriforestry or forestry systems to grow woody plants for long-term carbon storage, but the spekboom is an arid area plant. We could consider growing it as a novel crop in other arid areas of the region where it isn’t endemic.

The challenges of novel crops
The commercialisation of novel crops and local biodiversity isn’t without its complications. Linked to the Convention on Biological Diversity is the issue of access and benefit-sharing (ABS). Often, valuable products were developed using local knowledge or biodiversity where local people gave their knowledge away inadvertently, as they didn’t realise what researchers were going to do with it. ABS is a complex issue globally and could become even more so as countries and companies start looking for the new cultivars, and crops needed to ensure agricultural production under climate change.

Fortunately, South Africa has new ABS regulations (February 2008, Department of Environmental Affairs and Tourism). Nobody – and this includes foreign and local agencies – can use local biodiversity or local knowledge of this biodiversity to develop novel products or processes without an ABS agreement. While we look for new crops, including genetically modified ones with drought-tolerance genes, these regulations should ensure that benefits accrue to South Africa from any indigenous drought-tolerant species or genes we have. – Roelof Bezuidenhout
E-mail Dr Sue Taylor [email protected].     |fw