Accession Number 184

16 April 2024

A forage powerhouse unveiled.

On one of the numerous shelves in the cold store of the CIAT (International Center for Tropical Agriculture) genebank, nestled among a haystack of genetic diversity, lies a needle that has caught the eye of many researchers. Accession number 184, a population of the forage species Stylosanthes guianensis, has been making waves across various publications for its remarkable properties.

Here we spotlight this unique genetic resource, expanding on why it stands out for agricultural researchers, forage farmers, and biodiversity enthusiasts worldwide.

Biological diversity as a source of resilience is a well-known concept, yet few stories illustrate it better than CIAT’s forage accession 184. In a world increasingly affected by climate change, food security is a top priority and this plant has some incredible qualities that make it perfect for sustainable farming.

Since the collection of Accession 184 near Cali, Colombia in 1973, more precisely at the entrance to a restaurant at 960 meters above sea level,  it has made journeys to elsewhere in Colombia, but also to China, Costa Rica, Cuba, Ecuador, Ethiopia and beyond. It has shown remarkable adaptability, particularly in tropical conditions. According to Juan José González, the curator of the forage collection at CIAT, this stylo population has been distributed over 170 times, to all corners of the world.

The evaluation process of this forage was spearheaded by RIEPT in the 1980s and 1990s, when it showed significant promise in diverse regions, including North Argentina, Colombia, Brazil, Peru and several African countries, such as Benin, Cameroon, Guinea, the Democratic Republic of Congo, and Madagascar. RIEPT was the Red Internacional de Evaluación de Pastos Tropicales, or the lnternational Tropical Pastures Evaluation Network, since 1978 the main way that CIAT assessed the value of its forages collection.

Advanced breeding lines were developed and selected from the accession, for example: Reyan No. 5, which is resistant to anthracnose and tolerant to cold; Reyan No. 20,  resistant to diseases and tolerant to acid soils, drought and shade; and Reyan No. 2,  tolerant to low temperature and drought. The last two were developed through the propagation of mutations induced by space flights!  Twenty-six mutants were obtained from Reyan No. 2 seeds that were carried into outer space by a recoverable satellite in 1996. The genetic diversity of the 26 mutant lines was assessed using DNA analysis, and promising variants with different resistances to biotic and abiotic factors were identified in subsequent years.

What makes Accession 184 even more special is its application across various agricultural practices. It has been used not only as a forage to feed beef cattle, but also for goats and pigs. Farmers have found that a feeding proportion of 25% Accession 184 and 75% Brachiaria hybrid Mulato 1 offers a sustainable model for animal feeding, especially when seeds are stored for later use in dry seasons.

Reyan No. 2 has also proven immensely promising for intercropping with crops like coffee, cassava, rubber,  oil palm, coconut   and rice--even fruits like mango, orange, and lemon. With 4 million hectares planted in China today, it's not an understatement to say that Accession 184 is revolutionizing the fodder scene there.

It also offers a great solution for land restoration and degradation. It's often the starting point in land restoration due to its ability to contribute a significant amount of nitrogen to the soil. This, combined with impressive resistance to dry conditions, heat, and diseases, positions Accession 184 as a frontrunner in climate change resistance measures.

Accession 184 not only adds value to the land on which it is planted, but it also demonstrates environmental benefits through effective carbon capturing. With governments worldwide turning their attention to climate issues, this ability is more crucial than ever.

Over the years, this hardy forage has demonstrated good biomass and yield production, even in challenging environments. It is resistant to common pathogens and capable of thriving in soils low in nitrogen and high in aluminum. Despite initially being suspected of being a weed, this exceptional forage now stands as a beacon of hope for sustainable farming and food security, a stunning example of the value of biological diversity.

At the Crop Trust, we celebrate the achievements of Accession 184 and recognize its role in inspiring a new generation of agricultural research and practice. We invite our community of researchers, conservationists, and farmers to engage with this resource, exploring the possibilities it -- and others like it -- holds for advancing food security and environmental sustainability. Together, we can harness the power of genetic diversity to face the challenges of tomorrow.

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