Scientists from the Institut National de la Recherche Agronomique in Clermont-Ferrand, France, said they had constructed a map of the largest wheat chromosome, chromosome 3B, and demonstrated it should be possible to sequence the plant's entire genetic code. In the past, the wheat genome has been viewed as all but impossible to sequence because of its sheer size. It comprises 17bn base pairs of the chemicals that make up DNA - five times more than the human genome. The 3B chromosome alone is more than twice the size of the entire genome of rice, which was the first major food crop to be sequenced six years ago.

Once the whole wheat genome is sequenced, researchers say it will be much easier to identify genes that can be used either in conventional plant breeding programs or to develop genetically modified crop varieties. Scientists, meanwhile, are already using the genetic data collected so far by the French team, with a team in Australia homing in on a gene involved in resistance to an alarming new form of stem rust.