By Sharon Atieno

More than 70 wild relatives of some of the world’s most important crops which provide genetic resources necessary to breed crops with greater resilience to climate change, pests and diseases, as well as improve yields, are threatened with extinction, a study reveals.

The study co-authored by the International Union for Conservation of Nature (IUCN) published in the journal Plants, people, Planet, analyzed 224 plants closely related to maize, potato, bean , squash, chilli pepper, vanilla, avocado, husk tomato and cotton crops.

According to the findings, 35% of these plants are threatened with extinction as a result of conversion of wild habitats for human use, shifting from traditional agricultural systems to mechanization, widespread use of herbicides and pesticides, invasive species and pests, contamination from genetically-modified crops, over-collection and logging.

Photo credits: INIFAP

The wild plant groups at highest risk of extinction are Vanilla with all eight species in the region listed as Endangered or Critically Endangered on The IUCN Red List of Threatened Species TM, followed by  92% of cotton (Gossypium) and 60% of avocado (Persea) species found to be threatened. Two groups related to maize, Zea and Tripsacum, are 44% and 33% threatened respectively. Thirty-one per cent of bean species, one out of four chilli pepper species, 23% of potato species, 12% of husk tomato species, and 9% of squash species are further threatened with extinction.

To date, at least sixteen crop wild relatives included in this study have been used to breed food crops that are more resilient to the changing climate, extreme weather and other threats. These include breeding squashes to withstand cold, maize capable of producing higher yields and potatoes resistant to drought as well as to late blight disease, which historically devastated potato crops in Europe.

“In today’s fast-changing world, genetic diversity is crucial to making our crops resilient to climate change. We need biodiversity to ensure sustainable livelihoods and food security for the world’s growing population, as this study shows,” said IUCN Director General Dr Bruno Oberle in a statement.

“These results also highlight the urgent need for a strong global biodiversity conservation framework that sets measurable, science-based goals, to ensure a resilient future.”

Photo credits: INIFAP

According to Dr Bárbara Goettsch, Chair of the IUCN SSC Cactus and Succulent Plant Specialist Group and lead author of this Darwin Initiative-funded study, these findings have potentially critical implications for livelihoods and food security.

“It is imperative that conservation and agricultural sectors work together to safeguard Mesoamerica’s crop wild relatives, while supporting rural economies and livelihoods. These species must be protected on the ground through sustainable and diverse agricultural production. At the same time, the genetic diversity of crop wild relatives must be better represented in gene banks,”Dr. Goettsch said.

The wild species are natives to Mexico, Guatemala, El Salvador and Honduras.

“Given Mesoamerica is a centre of origin and domestication of major crops, it is of worldwide importance in the context of global warming that we preserve the region’s crop wild relatives and their genetic diversity, as these plants have evolved in varied environmental conditions,” said Dr José Sarukhán, National Coordinator of Mexico’s National Commission for the Knowledge and Use of Biodiversity (CONABIO).

“Local people traditionally use these diverse species as food and medicine, and numerous cultural groups have key roles to play in their preservation. Understanding the extinction risk of crop wild relatives is fundamental to develop local, national and regional conservation strategies.”

Photo credits: INIFAP

This study is the result of a collaboration between IUCN and seven partners, including CONABIO, Instituto Nacional de Investigaciones Agrícolas y Pecuarias (INIFAP), Instituto de Ciencia y Tecnología Agrícolas (ICTA), Centro Nacional de Tecnología Agropecuaria y Forestal “Enrique Álvarez Córdova” (CENTA) and the University of Birmingham. All 224 crop wild relatives assessed in the study are now published on the IUCN Red List of Threatened SpeciesTM.

The results reported here are not limited to the region. Other wild relatives of food crops such as banana, apple, prunes and ginger are also threatened, according to the IUCN Red List.

Through its partnership with Toyota since 2016, IUCN has assessed over 2,000 crop wild relatives globally of which 32% are estimated to be threatened. These include the wild relatives of apple, prune, sweet pea, coffee and ginger, among others.