An ancient wild rice may hold genetic secrets for climate-resilient farming – if Vietnam can save it from vanishing and neglect
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Wild rice seeds of the Oryza officinalis variety are grown in the net house of the Mekong Delta Rice Research Institute in Cần Thơ, Vietnam. Expert says that their remarkable genetic diversity make them ideal for breeding climate-resilient rice (Image: Nam Phong / Mekong Eye)
“It’s been so long I can barely remember. It’s delicious, fragrant, soft but not sticky,” says Trần Văn Lựa, 53, a farmer from Đồng Tháp province, south-west Vietnam, recalling the taste of wild rice. As a child, he would harvest the grain during flood season, when wild rice flowers. Today, however, it is a rare sight.
Wild rice, known locally as “ghost rice” (lúa ma), is the common name for Oryza rufipogon, a perennial native to Vietnam’s Mekong Delta and the ancestor of modern Asian rice (Oryza sativa). It carries genes that confer resistance to pests like rice leaf folder moths, stem-boring insects and viral diseases like rice grassy stunt and ragged stunt – traits lost in modern varieties. Its high genetic diversity is a rich resource for scientists to develop new genes that are adaptive to drought, flooding, heat and acidic soils.
As climate pressures mount, these qualities are proving more important than ever. Yet Vietnam, one of the species’ last global refuges, is struggling to preserve it.
A lifeline during flood season
In the 1970s, wild rice was a lifeline during wartime and food shortages. It thrived in the floodplains of the Đồng Tháp Mười region, where seasonal inundation submerged fields for months. A sack of wild rice, locals say, would fetch three times the price of regular rice.
Once abundant, it has since become a rarity, often mistaken for “weedy rice” (Oryza spontanea), an aggressive weed that produces fewer grains, which shed early, causing mass crop failures. The perception of wild rice as a weed has persisted even among international scientific circles, with the North American Plant Protection Organization and several US states classifying it as such.
Vietnam is home to four of the world’s roughly 20 known wild rice species: Oryza rufipogon, Oryza nivara, Oryza officinalis and Oryza granulata. Only rufipogon and officinalis are still found in the Mekong Delta; nivara was last seen in the Delta’s Tràm Chim National Park in 1980, and is now still present in Hồ Lắk, a lake in central Đắk Lắk province.
A rare cluster of Oryza rufipogon, or “ghost” rice, in Tràm Chim National Park, Vietnam. Once abundant and a crucial food source during shortages, it has since become a rarity, often mistaken for “weedy rice” (Image: Nam Phong / Mekong Eye)
Bùi Chí Bửu is the former director of the Institute of Agricultural Science for Southern Vietnam and one of the few Vietnamese scientists studying wild rice. He says its remarkable genetic diversity makes it ideal for breeding climate-resilient rice.
Wild rice grows low across wetland plains and can survive months of inundation. Its seeds can lie dormant for years, germinating only when conditions align.
Harvesting it requires precision: wild rice sheds grains at the slightest breeze, so farmers often go out on their boats before dawn – when winds are calm – spreading blankets across their boats and tapping the stalks with bamboo poles to catch the falling grains.
This ghostly shedding is what earned it the name lúa ma – ghost rice.
It is valued for its genes. “Wild rice possesses a highly diverse genetic foundation,” Bửu says. “The species contains rare genes that cultivated and native rice varieties have lost over the evolutionary pathway”. These include alleles – specific gene variants – that were largely lost during the domestication of rice and modern breeding efforts, which narrowed the gene pool by selecting only for traits like high yield or uniformity. Many of these lost genes are now recognised as critical for tolerance to climate stress and toxic metals in acidic soils.
Bùi Chí Bửu, one of the few Vietnamese scientists studying wild rice, tends to Oryza officinalis in his garden in Cần Thơ. He says that the species contains rare genes that cultivated and native rice varieties have lost over the evolutionary pathway (Image: Nam Phong / Mekong Eye)
Research by Bửu’s team found that while cultivated rice in Vietnam has a low genetic diversity index (0.2), wild rice in the Mekong Delta ranges from 0.4 to 0.6, sometimes higher. “For a country with weak genetic diversity [of rice] like Vietnam, preserving species with rich genetic foundations is essential,” he says.
Meanwhile, despite resembling cultivated rice, weedy rice is genetically unstable due to crossbreeding with genetically dissimilar strains. It sheds all its grains at maturity, causing up to 60% crop loss, and spreads rapidly. Its similarity to farmed rice renders it resistant to herbicides, making it especially difficult to control.
Tracking a vanishing gene bank
In his home garden in Cần Thơ, a city by the Mekong Delta, Bửu tends to several wild rice species collected from across southern Vietnam.
Wild rice is remarkably resilient, but not invincible. To keep them alive, he must propagate the plants every few years. “Even as a perennial, if left alone, they will exhaust themselves and die,” he explains.
On-farm conservation – where plants are cultivated and selected in open fields rather than labs – is a low-cost method used in Vietnam and parts of Africa, but it comes with risks. Plants are vulnerable to cross-pollination and small gene pools can collapse with a single failed generation.
A more secure backup lies at the Mekong Delta Rice Research Institute (MDRRI), also in Cần Thơ, where hundreds of pots of wild rice are maintained alongside a small seed bank. The institute stores 600 samples of Oryza rufipogon and Oryza officinalis in cold storage and net houses – screened structures that regulate sunlight and pest exposure. To preserve viability, seeds are periodically revived, grown and re-stored to prevent the gradual loss of germination.
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Two wild rice varieties, Oryza officinalis and Oryza rufipogon, are currently stored in the gene bank of the Mekong Delta Rice Research Institute, but funding has become a problem (Image: Nam Phong / Mekong Eye)
However, institutional seed banks face funding challenges.
“In the past, funding for our gene bank came entirely from the Plant Resources Center, which supported cold storage and seed rejuvenation,” says Trần Ngọc Thạch, the institute’s director. “But now, we fund the cold storage ourselves, so preservation is less than ideal.”
There are two main strategies for conserving wild rice: ex-situ, through storage in seed banks, and in-situ, conserving the plants in their natural habitats. While gene banks safeguard genetic material, they halt natural evolution. In-situ conservation, on the other hand, allows species to continue adapting to changing conditions.
Elsewhere, wild rice remains a low priority. The Indigenous Rice Gene Bank at Cần Thơ University is among the few better-funded preservation facilities in the country, with around 5,000 samples. But its focus is on seasonal, lowland and rain-fed varieties from the Mekong Delta – none of them wild.
“Wild rice seeds require special regeneration conditions, which we are not prioritising due to limited funding and manpower,” says Nguyễn Thành Tâm, head of agricultural development at the MDRRI.
In-situ conservation is widely regarded as the best way to protect and evolve the species. But it, too, is under pressure: farmers prefer high-yield hybrids, and wetland habitats are shrinking or degraded.
Tràm Chim National Park, in Đồng Tháp province near Vietnam’s border with Cambodia, is the country’s largest in-situ wild rice conservation site and has drawn international interest for its biodiversity. The park, along with the larger province, is home to Oryza rufipogon populations with the highest recorded genetic diversity in the Mekong Delta.
Before 2015, Tràm Chim’s wild rice fields covered nearly 1,000 hectares, thriving alongside wetland species like Eleocharis dulcis (water chestnut or năn ống), Eleocharis atropurpurea (purple spikerush or năn kim) and several types of native grasses.
Today, park officials estimate only 520 hectares remain – half the area seen a decade ago. Pure wild rice fields, which totalled just 33 hectares in 2015, have continued to shrink. “Wild rice is now scattered across many areas rather than concentrated in one place,” says Đoàn Văn Nhanh, deputy director of the park’s Center for Conservation and International Cooperation.
Cruising through Tràm Chim’s waterways in early January, the usual blooming season for wild rice, there was little sign of the plant – only stretches of water chestnut. A few clumps of wild rice clung to levees.
Each year, wild rice sprouts tall as Mekong floodwaters rise, flowering at peak inundation, but patterns are changing. “It seems that this year, the flood surged and retreated unusually fast, leaving barely any wild rice,” says Trần Văn Lựa, a local farmer.
Nhanh agrees. He believes erratic floods have disrupted the plant’s natural cycle. Roaming cattle, often released into the park, graze on what little remains.
Rebuilding a habitat
Covering just over 7,300 hectares, the national park shelters 130 plant species, 130 freshwater fish and 231 bird species – many of them endemic. But years of mismanaged hydrology have disrupted this delicate balance. A 10-year restoration project, backed by over VND 184 billion (USD 7 million) from the Đồng Tháp Provincial People’s Committee, is now underway. The Sarus Crane Conservation and Development Project combines ecological restoration, captive breeding and organic agriculture to restore crane populations and protect the park’s biodiversity.
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A flock of sarus crane in Tràm Chim National Park. The endangered species uses ghost rice fields as feeding and resting grounds and are now a rare sight in the area (Image: Tang A Pau)
“At Tràm Chim, we are restoring and rehabilitating the ecosystems, with a focus on Eleocharis atropurpurea [purple spikerush], the main food source for cranes,” says Nhanh. The cranes are an indicator of wetland health, he adds.
To prevent forest fires, park managers introduced canals and levees to maintain higher water levels year-round, altering the natural six-month cycle. Wild rice, unable to regenerate without dry periods and decomposed surface nutrients, began disappearing, including from its former stronghold on the park’s eastern side.
Wild rice plays a critical ecological role in the Delta. Its roots, stems, leaves and seeds are a major food source for birds and fish during stressful periods like deep flooding or drought, explains Dương Văn Ni, a biodiversity expert at Can Tho University. When wild rice disappears, the food chain unravels. Species that depend on it decline – and eventually vanish.
“Water flow into the Mekong Delta no longer follows its usual patterns,” says Nhanh. “With unpredictable climate and hydrological factors, we must remain flexible in how we manage the park to avoid significant losses.” Water levels, he adds, are now adjusted in response to shifting rainfall patterns.
Efforts to reverse the damage are underway. Controlled burning of grasslands was reintroduced and park staff are restoring native grasses critical to crane habitats, alongside wild rice. A five-hectare pilot plot of wild rice has shown tentative signs of recovery. A new ecological rice farming initiative, dubbed “Rice calls the cranes back”, has also been launched to align organic cultivation with habitat restoration. The broad goal is to convert 200 hectares to this model by 2028.
But as Mekong flood patterns grow more erratic – driven by climate change and upstream hydropower – the long-term outlook of species like wild rice remains uncertain. Their loss would not only threaten local biodiversity, but erase genetic resources for climate-resilient agriculture across the region.
“Each species has its own adaptation limits, and wild rice is no exception,” says Dương. “Maintaining a healthy natural ecosystem, therefore, creates the best conditions for many species. Ongoing, updated research will be essential to sustain the ecosystem as a living being.”
This article was originally published on Dialogue Earth under the Creative Commons BY NC ND licence. Read the original article.
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