Synthetic seeds could help farmers break pest and disease cycle
A new project to produce synthetic seeds for cassava – one of the world’s most important food crops – could transform the way it is grown, and help protect smallholder farmers in Africa, Asia and Latin America from devastating pests and disease outbreaks.
The project by the International Center for Tropical Agriculture (CIAT) was one of the around 100 selected to receive a grant from Grand Challenges Explorations, a USD 100m initiative funded by the Bill & Melinda Gates Foundation that encourages groundbreaking global health and development research.
Cassava is the third-most important source of carbohydrate in Africa, a major industrial crop grown by smallholders in SE Asia, and a vital food crop in Latin America. Despite being recently described as a “Rambo root” for its ability to survive drought and tolerate poor soils, and therefore withstand some of the expected impacts of climate change, cassava’s Achilles heel is its vulnerability to pests and diseases. Cassava brown streak and cassava mosaic disease, together with mealybug, mite and whitefly infestations are some of the most formidable constraints on production, resulting in huge yield losses.
Cassava’s vulnerability is partly due to the way the crop is propagated – usually by the planting of stem cuttings – which often enables pests and diseases to pass from one growing season to the next. CIAT scientists believe that growing cassava from synthetic seeds produced by clean, healthy plants could help farmers break this pest and disease cycle.
Synthetic seed production is already used in the pine industries in Canada and Scandinavia to produce disease-free trees for paper, timber and fuel. These seeds are artificially induced in vitro, from the plants’ growing points – called meristems – by treating them with synthetic hormones to make them produce “somatic embryos”. These are exact genetic replicas of the parents, and have the ability to generate whole plants. They can then be given a synthetic protective coating, mimicking a normal seed cask, for ease of storage and transportation.
“Plants follow set programs for growth and reproduction, and using specific hormones enables us to make them switch from one program to another and produce somatic embryos” explained CIAT scientist and Principal Investigator for the project, Paul Chavarriaga. “We’re aiming to mimic the natural processes to make cassava plants produce seeds from meristems, instead of, for example, flowers, roots or leaves. If we start with clean plants, the new seeds will also be free from diseases or pest infestations. This could mean that farmers will no longer need to take cuttings from sick plants.
“An added advantage is that it is possible that synthetic seeds could be stored for a year or more, compared to cuttings that only last for one-to-two months,” he added.
“If you can help boost food security this way, you also provide a firm basis for the success of so many other development interventions.”
Of particular interest in the project will be the work to produce synthetic seeds for the KU50 cassava variety, widely grown by smallholders in Thailand for the starch industry. The cassava industry in Thailand and surrounding SE Asian countries is particularly vulnerable to pests and diseases, especially from new, invasive pest species; the sudden outbreak of the cassava mealybug in 2009 destroyed large swaths of Thai cassava, and now threatens neighboring Laos and Cambodia. Scientists believe the source of the outbreak was almost certainly contaminated plant cuttings brought into the country from abroad.
Proof of concept
The first phase of the project, which runs until October 2013, will attempt to prove that it is indeed possible to produce synthetic seeds from cassava varieties from Africa, Asia and Latin America. If successful, the team will be invited to apply for a second phase of funding which could see large scale seed production and the transfer of seeds to experimental stations across the tropics, and eventually, farmers’ fields.
“There is so much potential for a technology like this to help build resilience into the cassava production system and make a huge difference to the livelihoods of smallholder farmers,” continued Chavarriaga. “The first challenge is to prove that synthetic seed production from cassava can be done. After that, the sky’s the limit.”
“Grand Challenges Explorations encourages individuals worldwide to expand the pipeline of ideas where creative, unorthodox thinking is most urgently needed,” said Chris Wilson, director of Global Health Discovery and Translational Sciences at the Bill & Melinda Gates Foundation. “We’re excited to provide additional funding for select grantees so that they can continue to advance their idea towards global impact.”
About Grand Challenges Explorations
Grand Challenges Explorations is a US$100 million initiative funded by the Bill & Melinda Gates Foundation. Launched in 2008, over 600 people in 45 countries have received Grand Challenges Explorations grants. The grant program is open to anyone from any discipline and from any organization. The initiative uses an agile, accelerated grant-making process with short two-page online applications and no preliminary data required. Initial grants of US$100,000 are awarded two times a year. Successful projects have the opportunity to receive a follow-on grant of up to US$1 million.