Preserving the 'ancestors' of the rice plant.

CAN THO - Amidst the Lung Ngoc Hoang wetland, a population of wild rice plants is quietly thriving, preserving valuable genetic resources for research, conservation, and rice breeding.

Valuable genetic material for rice cultivation.

Reviewing records and research documents on wild rice, Dr. Nguyen The Cuong – Head of the Agronomy Department (Mekong Delta Rice Institute) – stated that wild rice is the "ancestor" of cultivated rice and appeared in the evolutionary process approximately 14-15 million years ago.

To date, scientists worldwide have discovered approximately 22 species of wild rice, of which Vietnam has 4 species. Notably, two of these species, Oryza rufipogon and Oryza officinalis , are found in the Mekong Delta region.

Two wild rice species with valuable genetic resources have been discovered in the Mekong Delta. If effectively exploited, they could create a breakthrough in rice breeding. Photo: Kim Anh.

According to Dr. Cuong, the wild rice species Oryza officinalis provides a very valuable genetic resource and has been used as hybridization material to introduce genes conferring resistance to brown planthopper into cultivated rice varieties. The wild rice species Oryza rufipogon is considered particularly valuable due to its ability to tolerate salinity and flooding, and its good adaptation to rising temperatures in the context of climate change, as well as to phosphorus-deficient soil environments. These are essential traits in the development of new rice varieties.

However, in recent years, the use of wild rice to exploit genes carrying valuable traits for breeding purposes has been quite limited, despite the existence of methods for introducing valuable genes from wild rice (gene cloning) into cultivated rice and mapping QTLs (Quantitative trait loci) to identify the locations of genes or chromosomal regions related to complex traits.

If valuable genes from wild rice are effectively exploited, it could lead to breakthroughs in the breeding of sustainable rice varieties that are better adapted to rapidly changing and harsh environments and climates.

Unlike cultivated rice, wild rice has unique ecological and biological characteristics: its stem can flatten when on land or float in water; the grains are small, easily shed, and have a dark husk; and its high dormancy slows down germination. Many wild rice species are sensitive to day length, have smaller grains than cultivated rice, and exhibit high yield variation. These "unusual" characteristics have allowed wild rice to survive, adapt, and continuously evolve in nature for millions of years.

Wild rice possesses ecological and biological characteristics that are highly valuable in the breeding of new rice varieties. Photo: Kim Anh.

Another notable characteristic is that the genome of wild rice is more stable than that of cultivated rice during evolution because there has been no human intervention through domestication. Therefore, it has a greater capacity to preserve its natural genome, providing valuable genetic material for cultivated rice. Furthermore, in its natural environment, it will continue to evolve, and its genetic diversity will increase.

In Vietnam, while wild rice conservation is receiving attention, there are no large-scale programs in place. Some wild rice conservation models have been implemented in Tram Chim National Park ( Dong Thap province) through the preservation of seed gene banks under low-temperature conditions (at -70°C or -10°C to -20°C). This helps preserve wild rice for many years without losing its genetic diversity.

Therefore, the optimal conservation method is "dynamic" conservation in nature. Wild rice grows in its natural environment, continues to evolve, and maintains its genetic diversity.

Today, many countries consider wild rice as a particularly rare national resource. China has discovered more than 10 species of wild rice, which are strictly protected in biological reserves. Some areas are even completely off-limits to humans to avoid disrupting their natural growth.

In Thailand, the government also maintains wild rice gene conservation areas as part of its national food security strategy.

Preserving a "living gene bank"

Lung Ngoc Hoang Nature Reserve (Phuong Binh commune, Can Tho city) is a rare place that still preserves many wild rice populations with great scientific and economic value.

According to Mr. Le Thanh Son, Deputy Director in charge of the Conservation Area, wild rice is scattered under the forest canopy or along canals, growing in small but widespread patches, making it impossible to determine the exact area.

In areas with good water exchange, wild rice grows lush and healthy. Along canals where tides and alluvial deposits accumulate, rice thrives more due to less biological competition.

Staff from the Wetland Science and Conservation Department (Lung Ngoc Hoang Nature Reserve) inspect the growth of wild rice plants. Photo: Kim Anh.

Recognizing wild rice as a valuable genetic resource contributing to ecological balance, the Lung Ngoc Hoang Nature Reserve Management Board has proposed to the Can Tho City People's Committee a plan to coordinate with scientists to determine the distribution area and assess the growth status of these rice varieties. Simultaneously, they will research suitable ecological conditions, develop and test models for sustainable restoration and development, and devise long-term management and conservation solutions for wild rice.

Mr. Tran Be Em, Head of the Wetland Science and Conservation Department (Lung Ngoc Hoang Nature Reserve), said that from 2015 to the present, the Reserve has added 981 plant species to the list, building a biodiversity database. Among them, wild rice has been identified as a key research subject.

Currently, the unit is focusing on investigating the distribution, conducting field surveys, and creating maps of wild rice distribution. The main focus is on selecting 1-2 hectares in the ecological restoration zone to carry out long-term restoration and conservation. The steps include clearing weeds, cleaning the area, replanting, monitoring growth, and collecting data to build a scientific basis for long-term conservation efforts.

According to Mr. Bé Em, the life cycle of wild rice begins in April each year when the rainy season arrives. Wild rice seeds germinate, the stem grows tall, the leaves become large, and the roots are capable of neutralizing acidic substances and absorbing nutrients from the soil.

From August to December, the rice plants grow tall and flower. The rice panicles are large and straight, but the grains are small and sparse. When ripe, the grains fall off naturally, are carried away by the water, and grow into new plants.

"Wild rice only ripens once a year and has good genetic resistance to brown planthoppers and white-backed planthoppers. The rice flowers in October and ripens sporadically from November to December, not all at once like cultivated rice," Mr. Bé Em said.

Preserving wild rice contributes to safeguarding the pristine values ​​of nature. Photo: Kim Anh.

From the perspective of a research institution, Dr. Nguyen Thuy Kieu Tien - Deputy Director of the Mekong Delta Rice Research Institute - assessed that Lung Ngoc Hoang has a long history of the existence and development of wild rice with a rich and diverse genetic resource. However, the area of ​​wild rice is shrinking due to the impact of agricultural cultivation and aquaculture, leading to the gradual loss of this valuable genetic resource.

In addition to research, the Lung Ngoc Hoang Nature Reserve Management Board has built a biodiversity database to serve information storage, research, and breeding. Simultaneously, it focuses on conserving native habitats, preserving rare species, and monitoring invasive alien species. This work helps protect the integrity of the ecosystem and prevent the risk of encroachment that could lead to the decline of wild rice populations.

These efforts will contribute to maintaining ecological balance, preserving valuable genetic resources in nature, and laying the groundwork for research on breeding high-quality rice varieties that are adaptable to climate change. Above all, the conservation of wild rice has profound humanitarian significance, preserving the pristine values ​​of nature and serving as a bridge between scientific knowledge and the indigenous ecosystem.

“Wild rice is an important genetic resource for new breeding programs. Not only can scientists exploit the diverse variations from cross-breeding between wild rice and high-yield rice, but they can also utilize valuable characteristics to create well-adapted rice varieties. Therefore, preserving wild rice in Lung Ngoc Hoang is urgent and strategic,” emphasized Dr. Kieu Tien.

Source: https://nongnghiepmoitruong.vn/luu-giu-to-tien-cua-cay-lua-d780375.html