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Model behaviour - the race to conserve crop wild relatives

Paraguay's Chaco region where scientists located their search for wild peanuts (Ilosuna)
Paraguay's Chaco region where scientists located their search for wild peanuts
Ilosuna

The peanut - or groundnut - originated thousands of years ago from the fortuitous crossing of three wild plant species on the border of Argentina, Paraguay and Bolivia. The resulting hybrid contained a combination of desirable traits: it was easy to grow and provided high levels of energy and protein. Over recent centuries, this leguminous hybrid (Arachis hypogaea) has been adopted by farmers in other regions and is now consumed worldwide.

But, with wild peanut relatives under-represented in gene banks and under threat from the expansion of industrial agriculture, a team of scientists from the International Center for Tropical Agriculture (CIAT) and Bioversity International traveled to the remote plains of Paraguay's Chaco region to determine whether they could locate the wild relatives of domestic peanut.

Pinpointing the peanut

Searching for crop wild relatives (CWRs) in situ is a daunting task. "It can be like looking for a needle in a haystack," says Andy Jarvis of CIAT's Decision and Policy Analysis program. "We needed a quick way of pinpointing where exactly the peanut relatives might be, so we ran a series of models to predict possible locations."

The models, based on data from sites with known presence of species, combined with a range of bioclimatic variables to help identify potential sites, indicated some very specific regions in the Chaco that were previously unexplored for wild peanuts. Sure enough, when the team arrived, armed only with a GPS* device and their set of predictions, they found that in 70 per cent of cases, the models located wild peanut populations, and in total, the team found 20 previously unknown populations of wild peanut relatives, and even to discover a new species. Seed samples were taken for analysis and conservation at the national gene bank in Asuncion, Paraguay's capital city, as well as the United States Department of Agriculture gene bank in Fort Collins.

Wild peanut relatives are under-represented in gene banks and under threat from the expansion of industrial agriculture (CIAT/Neil Palmer)
Wild peanut relatives are under-represented in gene banks and under threat from the expansion of industrial agriculture
CIAT/Neil Palmer

All domesticated crops have - or had - wild relatives, which often provide valuable genetic material to plant breeders in developing varieties with improved traits, such as disease resistance, or drought tolerance. While many of these ancestor plants continue to grow in the wild, others are on the verge of extinction. Encouraged by their success, Jarvis and the team ran further successful models in Paraguay to find wild relatives of Physalis (cape gooseberry), potato and chilli peppers.

Building on success

In recognition of the innovative use of computer technology in biodiversity research, Jarvis received the GBIF* Ebbe Nielsen Award for Bioinformatics in 2009 and has continued to champion the importance of conserving CWRs. "It is chilling to think that genetic resources of such importance to humanity, that have taken millions of years to evolve, can be completely obliterated in a matter of decades - or less - and lost forever," he says.

With almost 70,000 unique accessions, all painstakingly documented, CIAT's gene bank is one of the largest collections of plant genetic material in the world. But there are gaps in the collection, especially with respect to the CWRs. Consequently, Jarvis and his team are fine-tuning their approach, focusing on "Gap Analysis" - the combined use of models to highlight the missing material with models to predict the locations of wild species to plug the gaps.

"Without these models, searching for just one CWR could take a lifetime," says Jarvis. "With the models we can pinpoint where they are most likely to be - and Gap Analysis ensures we are collecting precisely the right material. CIAT scientists have even collected material from locations that are now built-up city areas."

Plugging the gaps

With natural resistance to pests and diseases, the conservation of CWRs is vital (CIAT/Neil Palmer)
With natural resistance to pests and diseases, the conservation of CWRs is vital
CIAT/Neil Palmer

For Jarvis, protecting this biological heritage is essential, but he believes that CWRs are also a crucial piece in a much bigger puzzle: "If we are to have agricultural systems capable of providing enough food and nutrition for a rapidly growing world population that is also facing challenges like climate change, the conservation of CWRs is vital."

"But it's not just about food production." He adds, "These plants can help provide the firm foundations for eco-efficient agriculture - sustainable farming systems. With natural resistance to pests and diseases we can reduce the needs for pesticides and fungicides, and thanks to the hardiness of these species we can produce more food with less land."

CIAT and Bioversity International are working with the Global Crop Diversity Trust to identify further gaps in gene bank collections around the world, including national gene banks. The task of filling in the gaps across the globe is daunting, and so dozens of scientists from developing and developed countries alike have been trained to prioritise their collecting and pinpoint the wild populations quickly. "We've developed robust models and software which can help scientists from national institutions use these new technologies to get out into the field and collect CWRs before it's too late", says Jarvis.

*Global Positioning System
*Global Biodiversity Information Facility

Written by: Neil Palmer

Date published: March 2010

 

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The efforts of the CGIAR scientists in locating wild relativ... (posted by: Kskarnic)

 

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