CIMMYT, USask contribute to decode genetic maps of 15 wheat varieties
In a landmark discovery for global wheat production, an international team led by the University of Saskatchewan (USask) and scientists from the International Maize and Wheat Improvement Center (CIMMYT) have sequenced genomes for 15 wheat varieties representing breeding programs around the world, enabling scientists and breeders to much more quickly identify influential genes for improved yield, pest resistance and other important crop traits.
The research results, just published in Nature, provide the most comprehensive atlas of wheat genome sequences ever reported, say separate releases issued yesterday by USask and CGIAR, the Washington-based global federating body of food security research institutions.
Wheat scientists at home and abroad told Dhaka Tribune that the new knowledge gained through these latest sequencings would, among other things, help develop traits to fight fungal disease wheat blast that has damaged hectares of wheat crops in South America since 1985 and also attacked wheat fields in Bangladesh in recent years.
With more than 215 million hectares planted annually, wheat is the most widely cultivated cereal in the world. Annual global wheat trade is higher than that of maize and rice combined. Wheat is also the most important source of protein and provides around 20% of human caloric intake globally. With a growing population, wheat production needs to increase by around 60% in the next 40 years to meet demands. Therefore, the challenges for wheat breeders and growers are tremendous.
Bangladesh grows only a seventh of its yearly wheat requirements and depends largely on an annual import of over six million tons to meet domestic demand.
About the latest breakthrough, project leader Curtis Pozniak, a wheat breeder and director of the USask Crop Development Centre (CDC), said “It’s like finding the missing pieces for your favorite puzzle that you have been working on for decades. By having many complete gene assemblies available, we can now help solve the huge puzzle that is the massive wheat pan-genome and usher in a new era for wheat discovery and breeding.”
“These discoveries pave the way to identifying genes responsible for traits wheat farmers in our partner countries are demanding, such as high yield, tolerance to heat and drought, and resistance to diseases and pests, including wheat blast,” said Ravi Singh, head of global wheat improvement at the Mexico-based CIMMYT and a study co-author.
Nearly a hundred scientists from universities and institutes in Canada, Switzerland, Germany, Japan, the U.K., Saudi Arabia, Mexico, Israel, Australia, and the U.S. are involved in ‘The 10+ Genome Project’ – which is a global partnership that leverages collaborative expertise and funding with the aim to characterize the wheat ‘pan genome’.
The study findings build on the first complete wheat genome reference map published by the International Wheat Genome Sequencing Consortium in 2018, increasing the number of wheat genome sequences almost 10-fold, and allowing scientists to identify genetic differences between wheat varieties.
The research team was also able to track the unique DNA signatures of genetic material incorporated into modern cultivars from wild wheat relatives over years of breeding.
“With partners at Kansas State University, we are very excited to leverage these genomic resources for genomics-assisted wheat breeding at CIMMYT” said Philomin Juliana, CIMMYT wheat breeder and study co-author.
“This study has also provided the complete assembly of a wheat chromosomal segment called Vpm-1, which is derived from a wild wheat relative and has been consistently associated with high grain yield in the CIMMYT germplasm. This is a key milestone, given that this chromosomal segment is now present in more than 90% of the elite spring wheat lines distributed internationally by CIMMYT.”
The team also used the genome sequences to isolate an insect-resistant gene (called Sm1) that enables wheat plants to withstand the orange wheat blossom midge, a pest which causes millions of dollars in losses to wheat producers each year.
“Understanding a causal gene like this is a game-changer for breeding because you can select for pest resistance more efficiently by using a simple DNA test than by manual field testing,” Curtis Pozniak said.
When Bangladesh's wheat fields were struck by blast in 2016, in the deadly fungal disease's first emergence in Asia, the country was hit hard and government had to go for a “wheat holiday” program – discouraging farmers in blast-affected districts from growing wheat with neighbouring India, putting up stringent quarantine in place as precaution to possible cross-border blast spread.
Two years later, Bangladesh's wheat scientists managed developing a resistant variety – Bari Gom 33 – which can now moderately withstand the wheat blast.