Crop wild relative species under threat

Many of the wild plants that will be the building blocks for future global food supply are missing from the world’s genebanks, according to new research by the International Center for Tropical Agriculture (CIAT) in coordination with the Global Crop Diversity Trust (Crop Trust) and the Royal Botanic Gardens (RBG), Kew.
These so-called crop wild relatives (CWR) – distant cousins of well-known food crops like rice, potato maize and wheat – are widely recognised as one of the most important resources available to plant breeders in the fight against climate change. But many have not been collected and conserved in genebanks, meaning breeders are unable to use them. In addition, many of their habitats are under threat from urbanisation, pollution, deforestation, climate change and war.

CWR possess valuable genetic diversity that can be used to develop crops capable of adapting and thriving under the impacts of climate change, including higher temperatures, increased soil salinity due to rising sea levels, and more frequent and severe pest and disease outbreaks.

The research has been carried out as part of the Project “Adapting Agriculture to Climate Change: Collecting, Protecting and Preparing Crop Wild Relatives”, which is funded by the Government of Norway.  More than thousand CWR of the world’s 81 most important crops have been mapped. The research revealed significant gaps in the world’s genebanks, both in terms of species and regions.
Key findings include:

• 29 per cent of the total, or 313 wild relative plant species analysed, are completely missing from the world’s genebanks
• A further 257 (23.9%) of species are represented by fewer than ten samples having been collected for each, leaving out a substantial amount of potentially important plant diversity.
• Over 70 per cent of the total crop wild relative species are in urgent need of collection and conservation to improve their representation in genebanks
• Over 95 per cent are insufficiently represented in regard to the full range of geographic and ecological variation in their native distributions.
• The most critical collecting gaps occur in the Mediterranean and Near East; western and southern Europe; Southeast and East Asia; and South America.

The research study has been published in March in the journal Nature Plants . It compared predicted CWR distributions with records from the world’s genebanks to produce what is believed to be the most comprehensive list of gaps in collections of crop wild relatives to date.

The authors found that the wild relatives of important food security crops like banana and plantain, cassava, sorghum and sweetpotato are all in urgent need of collection and conservation, along with those of pineapple, carrot, spinach, and many other fruits and vegetables. Even for the wild relatives of vital staples like rice, wheat, potato, and maize – which tend to be better represented in genebanks – there are still significant gaps in the collections.
In addition, they flagged the fact that some of the CWR marked as high priorities for collection and conservation are under threat, from war and civil strife in places like Syria and Afghanistan and from changes in land use, such as deforestation, in southeast Asia.

The study also revealed some areas where CWR are relatively well collected, for instance for wheat, chickpea, tomato, soybean, and rice.  These samples have already proved valuable in past plant breeding efforts. For instance, genes from a wild rice species Oryza nivara were instrumental in helping to develop rice varieties resistant to the grassy stunt virus, a disease that caused hundreds of millions of dollars of damage to Asian farmers in the 1970s, while a single wild tomato species provided genes boosting solids content by 2.4 per cent, estimated to be worth about 250 million USD a year to the global tomato industry.

(CIAT/wi)

More information

To access the Nature Plants article

The Adapting Agriculture to Climate Change Project