December 11, 2024
By Rosa Jauregui, Tropical Forage Plant Breeder, Urochloa spp. and Megathyrsus maximus, the Alliance of Bioversity International and CIAT
A major step in the development of resilient guinea grass – a cornerstone in The Alliance of Bioversity International and CIAT’s (The Alliance) tropical forages breeding program – has been reached with the release of the crop’s reference genome. It was sequenced by Corteva Agriscience using combined Pacbio HiFi, Bionano and Hi-C sequencing technologies and funded by Crops to End Hunger (CtEH). This reference genome will open in a new era for breeding Guinea grass, a crucial tropical forage widely used for livestock feed in the tropics, and it will also benefit other breeding and research programs for genetically related species.
Guiness grass – a key forage for livestock
Guinea grass (Megathyrsus maximus), a perennial forage crop, ranks among the world’s largest sources of livestock feed, especially in tropical and subtropical regions. In Brazil alone, over 20 million hectares are dedicated to this resilient crop, which can thrive across diverse environmental conditions. This adaptability makes Guinea grass indispensable for livestock farmers in need of reliable forage.
But despite its global value, Guinea grass remains a semi-domesticated “orphan crop,” receiving limited investment. This creates an even greater need for public breeding initiatives to unlock its potential.
In this context and as part of its tropical forage crop breeding program, The Alliance focuses on developing improved Guinea grass varieties with enhanced resilience to challenges like drought, waterlogging, and low temperatures.
The power of a reference genome
The newly released reference genome provides a blueprint for the genetic makeup of Guinea grass, allowing researchers to identify and map genes linked to desirable traits. Previously, breeders faced significant challenges in identifying key genes due to the lack of a detailed genetic map. Now, with the genome sequence available, breeders can quickly locate genes associated with critical traits, enabling them to select the best candidates for breeding.
The reference genome functions much like a highly detailed map, showing the arrangement of DNA along chromosomes, complete with markers and alleles. This unprecedented level of detail in Guinea grass will empower The Alliance and breeders worldwide to make precise, data-driven decisions and expedite breeding cycles. This breakthrough will also benefit other breeding and research programs working on related species, as breeders often use reference genomes from closely related species when one is not yet available.
This genome sequencing initiative was made possible through the support of Corteva, leveraging their world-class plant genomics and reference assembly process, and funding from the Crops to End Hunger program, with financial backing from Germany through GIZ.
With the release of the reference genome, the next phase focuses on gene annotation—determining which genes are active under various conditions and pinpointing their exact locations within the genome. For gene annotation, the team is collaborating with the Earlham Institute, demonstrating that this methodology and CtEH-funded project are yielding further collaboration.
Gene annotation will enable marker-assisted selection and genomic selection, reducing the breeding cycle time and improving accuracy. The Alliance’s tropical forage breeding team uses advanced bioinformatics tools like CGIAR Breeding Analytics Pipeline, Bioflow, to analyze these genomic datasets and implement genomic selection.
Supporting sustainable and productive livestock systems
Globally, about two-thirds of the world’s agricultural land is dedicated to livestock feed, and the annual contribution of livestock to climate change accounts for roughly 50% of agricultural emissions.
In the tropics, improved forages offer one of the most cost-effective strategies to enhance livestock production efficiency. These forages require less water and land, reduce reliance on fertilizers, and play a vital role in conserving biodiversity and mitigating climate change by reversing land degradation.
Tropical forage breeding programs aim to increase productivity, thus reducing the amount of land required for livestock production—a priority in regions like Latin America, Africa, and Asia, where the demand is high for forages with robust nutritional quality and resilience to environmental stresses.
The Alliance’s tropical forage breeding program is dedicated to developing climate-resilient, high-yield forage varieties that improve livestock productivity, enhance food security, and lower agriculture’s environmental impact. Improved forages like Guinea grass have the potential to boost livestock productivity while reducing the greenhouse gas emissions associated with livestock farming.
The release of the Guinea grass reference genome is only the start of this important work, setting the stage for continued innovations in tropical forage crops that will support livestock producers, enhance sustainability, and ultimately benefit the three-way ecosystems for fodder – farmers – and end consumers worldwide.
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Crops to End Hunger (CtEH) is a multi-funder initiative that aims to accelerate and modernize the development, delivery and wide-scale use of new crop varieties that are better adapted to climate change and that address gender equity, nutrition, food security and poverty. We extend our heartfelt appreciation to all the generous supporters of this initiative, with special recognition to GIZ. We also express our gratitude to the CGIAR research funders for their invaluable contributions to the CGIAR Trust Fund. Photo credit: The Alliance.
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