Raising a more resilient yam in West Africa

Published 4 hours ago

Proposed by Illuminated

Originally posted on Illumina News Center

In many tropical countries, yams are known as the “queen of crops”. Around the world, these are the fourth most used root and tuber crop— after potatoes, cassava and sweet potatoes — and they feed hundreds of millions of people.

Because yams are grown in so many different regions, they are also incredibly diverse: to the tune of around 600 species, and each of these species comes in several cultivars or varieties. The world’s largest producer is the West African ‘yam belt’, which stretches from southeast Guinea to northwest Cameroon, with Nigeria contributing the highest yield. The yam not only contributes to food security and nutrition, but is also an integral socio-cultural symbol – yams often play an important role in wedding ceremonies and festivals.

But as widespread and important as yams are, they have been largely overlooked by researchers, especially compared to other root and tuber crops. When Dr. Ranjana Bhattacharjee joined the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria in 2009, knowledge of yam genomics was limited due to lack of funding. Bhattacharjee, however, recognized the nutritional and economic importance of these starchy tubers and became motivated to perform extensive genomics-assisted research on them.

Bhattacharjee is the 2022 recipient of the Illumina Agricultural Greater Good Initiative to agree. Since 2011, Illumina has recognized research proposals that will increase the sustainability and productivity of important food products and animal species. As the 2022 grant recipient, Bhattacharjee will be able to perform whole genome sequencing of approximately 1,000 Guinea yam samples on the Illumina NovaSeq™ 6000 System. This is one of the largest numbers of yam samples ever sequenced.

Bhattacharjee and his colleagues look forward to using this grant to understand the genetic relationships between different yam species (both cultivated and wild) in West Africa, and to study crop-specific genes that may confer disease resistance, resilience and higher yield. Sequencing data will be made public on IATI’s open-access platforms.

“Genomic sequencing is revolutionizing the agricultural sector right now,” she says, and she hopes that with this sequencing project, the amount of knowledge generated will change the status of this orphan crop.

When supplies of domesticated yams become scarce, yam farmers and breeders often go in search of wild varieties which they then cross with farmed or cultivated varieties.

But this process is laborious, and has not been optimized, says Dr Robert Asiedu, former yam breeder and Director Emeritus of IITA-West Africa. Although yams can grow well without fertilizers or herbicides, they should be staked, hilled and monitored regularly for weeds. Farmers and breeders have to wait about a decade to develop a new variety or hybrid. “We need modern, high-throughput tools and technologies to try to transfer targeted traits from one species to another,” says Asiedu.

Bhattacharjee hopes this partnership with Illumina will cut the time it takes to develop a new cultivar in half and help identify traits that will provide more clues to improve such an important crop through comparative genomics. “Ultimately, the goal is to make a culture more resilient,” she says.

To learn more about how genomics is enabling food security research or to apply for the Greater Good Grant 2023, click here.

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