Domesticated 3,000 years ago, African rice looks to the agriculture of the future

The analysis of genetic data of African rice, domesticated 3,000 years ago in Mali, opens "tracks for the agriculture of tomorrow facing the challenge of global warming, say researchers.

Thanks to the sequencing of 246 wild and cultivated African rice genomes, researchers from the Research Institute for Development (IRD) and AfricaRice Africa Rice Center, with support from the Office of the Commissioner for Atomic Energy (CEA) showed that human domestication of rice cultivation in Africa occurred three millennia ago in the interior delta of the Niger River in northern Mali, according to Current Biology an article published Thursday and confirming research published in 2014.

"The Sahara 6-7,000 years ago was a large, wet savannah populated by hunter-gatherers who started keeping seeds from one year to the next when the area started to dry up and Wild rice has started to dwindle, "says AFP François Sabot, genomic scientist at the IRD in Montpellier, one of the authors of the article.

Subsequent to the domestication of rice in Asia, which dates back 10,000 years and was completed "6 to 7,000 years ago" according to the researcher, the domestication of rice in Africa was concomitant with the emergence of the agriculture in the Fertile Crescent (Iraq, Syria …) then in the West, he adds.

– Huge production potential –

With data collected from 163 domestic varieties and 83 wild species harvested in the Sahel and East Africa, researchers from IRD, CEA and AfricaRice generated the largest genomic database on rice available to date, indicate the three agencies.

"We have proved in a method that is not open to interpretation that domestication in Africa has taken place in Mali, confirming archaeological discoveries on amphorae carrying traces of rice in this region," says Mr. Sabot.

Some studies had speculated that this domestication took place further west, towards present-day Senegal. In 2014, a team of researchers, who had first sequenced the genome of "African rice", had already located domestication along the Niger Delta 3,000 years ago, according to an article by Nature Genetics.

While the emergence of a crop form of rice in Africa is a result of climate change that took place thousands of years ago, it is now possible that the genetic traits of African rice, resistant to water stress and certain pathogens, can help the plant adapt to the new climate changes that are emerging, add the researchers.

"The African rice species, Oryza Glaberrima, has never been mass cultured in Africa, but we are starting to rediscover it on its resistance to pathogens, drought, iron toxicity and weeds. the only problem is that this variety is not very productive, "says Sabot.

"All our discoveries will be transferred to AfricaRice, which aims to improve rice cultivation and trade in Africa," he explains.

The organization created in 1971 to stimulate the rice sector through research and the creation of new varieties, has already created a variety for the African continent, the "Nerica".

According to the researcher, Africa "has the potential to become the largest rice producer in the world" because there is still a lot of land available for cultivation.

Nerica currently covers 1.7 million hectares and has lifted 8 million people out of poverty in 16 African countries. But the continent still spends more than $ 7 billion a year on rice imports, according to AfricaRice.

As for importing resistant seeds from Africa into Asia, the researcher doubts: "For Asian countries, rice is cultural, several countries are fighting over the origin of domestication, it seems unthinkable in the short term that an African rice is accepted in Asia, even to fight against the effects of the warming ".

However, he believes, "the introduction of some resistance factors from African strains is possible, there is already work in progress."