An international team of scientists led by researchers at the University of California, Riverside have reached a milestone in their work to sequence the barley genome, which they say will make crop breeders’ work easier.

The work of mapping the barley genome began 15 years ago; cereal crops have very long, complex genomes and researchers working on the project have now sequenced portions of the genome that together contain nearly two-thirds of all barley genes.

Although the work is not yet complete, UCR researchers said that the new information published this week will not only expand geneticists' knowledge of barley's DNA but also help in their understanding, at the genetic level, of wheat and other food and feed crops. The breakthrough will also have applications in plant breeding, by increasing the precision of markers for traits such as malting quality or stem rust.

"What we have now is much finer resolution of genetic information throughout the barley genome," said UC Riverside professor Timothy J. Close. Prof Close said that researchers’ work has created "An improved resource used throughout the world,” and identified areas of the genome that appear to counter long-held views on the distribution of genes in the genomes of barley, wheat and their relatives.

Prof Close said that the new knowledge relates to recombination - which is the natural formation of new combinations of genes. He said the new knowledge unearthed will be of use to plant breeders, who rely on recombination to produce favourable genes for malting quality, stem rust or any number of traits for cultivated barley varieties.

He explained, "For example, a breeder might succeed in adding a favorable allele [gene] for stem rust resistance from a wild barley, but along with that gene drag along another gene that causes shattering of the mature head. Now the breeder would have a stem rust resistant plant, but the seeds would all fall to the ground rather than remain on the plant until harvest.

“So, if a gene lies within a gene-dense, low-recombination region, then this means that a much larger number of progeny [plants] must be examined to find those that derive from rare recombinational events that separate the desired new allele from undesirable forms of neighboring genes. Knowing the location of gene-dense low-recombination regions helps with decisions about which genes to pursue for variety improvement."

Close and his colleague Stefano Lonardi, a professor of computer science and engineering at UCR, revealed that the amount of genome sequences the researchers released is about four times the size of the entire rice genome. They have shared the new information with the International Barley Sequencing Consortium.