June: Discovery of wheat | News and features

The international study appearing in Nature reveals that at least 60% of the genetic diversity found in a historic collection of wheat is untapped, providing an unprecedented opportunity to improve modern wheat and sustainably feed a growing global population.

Researchers at the University of Bristol have helped develop a new genotyping chip that will allow breeders to track these new genetic variants as they cross them into UK varieties in the future. This speeds up the breeding process as seedlings can be screened as soon as they emerge to select those with the desired traits, rather than waiting a whole season for them to grow to maturity before testing for resistance to diseases, for example.

Dr Gary Barker, from Bristol’s School of Biological Sciences, explained: “This decade-long study analyzed the genome sequences of more than 1,000 wheat varieties from around the world and identified untapped genetic variation that was not present in the collection of varieties we are currently breeding. From Great Britain.

“It gives UK wheat farmers a new source of natural genetic variation which will help increase our wheat’s resistance to disease and climate change for decades to come.”

An inter-institutional collaboration led by Dr Simon Griffiths, at the John Innes Center and Professor Shifeng Cheng from the Shenzhen Institute of Agricultural Genomics, Chinese Academy of Agricultural Sciences (CAAS), studied the AE Watkins Landrace Collection, a historic collection of landraces. of wheat that is no longer grown anywhere in the world and compared this to modern wheat.

The achievement is the result of a joint effort of the consortium. Professor Cheng said: “We have built a collaborative and complementary consortium with full openness, making resources in germplasm, genomic and phenotypic datasets publicly available through the Watkins Worldwide Wheat Genomics to Breeding portal. Our effort has facilitated and accelerated many existing projects in both basic research and reproductive practices.”

One of the key factors contributing to the success is in-depth phenotyping, covering experimental stations in the UK (three sites) and field evaluation (five sites) from northern to southern China. In total, 137 traits were surveyed in this study. This work was supported in particular by Rothamsted Research, which worked as a phenotyping center to better understand the qualities and characteristics of wheat, to connect the crop to the genetic sequence.

The team constructed a map of wheat genomic variation, a haplotype-phenotype association map. The race-cultivar comparison showed that modern wheat cultivars use only 40% of the genetic diversity found in the Watkins Collection.

The remaining diversity represents a gold mine with the potential to improve modern wheat, explained Dr Griffiths, group leader at the John Innes Center and author of the paper. “This 60% found in this study is full of the beneficial genes we need to sustainably feed humans,” he said. “Over the past ten thousand years we have tended to select for traits that increase yield and improve disease resistance.

“We have found that the Watkins landraces are full of useful variation that is simply missing in modern wheat, and it is imperative that we implement this in modern breeding. What’s exciting is that genes and traits are already being discovered using the data and tools developed over the past decade.”

The AE Watkins Collection of Bread Wheat (Watkins Collection) assembled in the 1920s and 1930s from 32 countries, represents the most complete collection of historic wheat in the entire world.

The collection provides a snapshot of the diversity of cultivated wheat before the advent of modern, systematic plant breeding, and shows how genetic variation is dispersed in groups, or ancestral groups, around the world. “We can regain the new, functional and beneficial diversity that was lost in modern wheat after the ‘Green Revolution’ of the 1920s.^th century and have the opportunity to add them back into the elites in breeding programs,” said Professor Cheng.

Genomic and bioinformatics analysis completed by researchers at the Shenzhen Institute of Agricultural Genomics allowed the consortium to see where modern wheat came from. They found that globally, wheat varieties originated in central and western Europe, with only two of the seven ancestral groups in the Watkins collection being used in modern plant breeding.

Using three complementary association genetic approaches (QTL mapping, GWAS and NAM GWAS), the team discovered hundreds of unique Watkins haplotypes that can confer superior traits to modern wheat, informing breeders which accessions carry which genetic loci or alleles useful in their breeding. programs.

Key traits already found in this untapped diversity include nitrogen use efficiency, slug resistance, and pest and disease resistance.

Dr Griffiths added: “There are genes that will allow plant breeders to increase the efficiency of nitrogen use in wheat, if we can introduce them into modern varieties that farmers can grow, they will need to apply less fertiliser, saving money and reducing the emissions. “

Fertilizer use in agriculture is expensive and contributes to greenhouse gas emissions, reducing its use could help agriculture move towards net zero. Increasing the efficiency of nitrogen use in crops and reducing the nitrogen footprint of agriculture is currently a big challenge globally, especially for countries like China.

To accomplish this unprecedented research feat, the team developed a core set of 119 landraces that represented the breadth of genetic variation within the Watkins collection. This set of diversity was then crossed and crossed back into modern wheat to make a collection of 12,000 wheat lines that are now stored in the Germplasm Resource Unit at the John Innes Centre.

This means that for the first time in 100 years, these lost traits have been incorporated into modern wheat, and the data and tools are already being used to improve crops.

This research establishes a framework for whole genome engineering of wheat, connecting genomics to the phenomenon and practice of breeding. “We have implemented a pre-breeding strategy to decode, discover, design and advance breeding,” said Dr Griffiths. “Indeed, the genomic revolution leads to the genetic revolution and a reproductive revolution,” concluded Shifeng Cheng. “This study was truly a collaborative, long-term effort and could not have been completed without international cooperation and long-term funding.”

In collaboration with commercial plant breeders in the UK, the team created the freely available Breeding Toolkit, a set of online resources that are open source and globally accessible for anyone to use. The toolkit provides an integrated set of tools for the research and breeding communities, enabling others to access and use new and beneficial diversity to provide sustainable and resilient wheat now and in the future. These germplasms, resources and toolkits developed in this study are still under further investigation in various experimental stations in China.

Paper:

“Exploiting local species diversity empowers wheat breeding” by Shifeng Cheng et al. in Nature.