Scientists from China have mapped a key genetic code for bread wheat, a discovery that will help improve the crop's productivity and ability to withstand extreme conditions. 

Researchers present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the genome of wheat T. urartu, the donor of the A genome. 

They also completed the whole genome sequencing, assembly and analysis of the D genome donor species Aegilops tauschii. They discovered a number of A and D genome-specific genes and new RNA molecules, and identified a group of genes that control important agronomic traits. 

The identification is expected to help provide a valuable resource for accelerating deeper genomic breeding studies and offer a new foundation for the study of wheat evolution, domestication and genetic improvement. 

The research, launched by a team from the Institute of Genetics and Development Biology under the Chinese Academy of Sciences, was also jointly conducted by Shenzhen-based BGI, and the Chinese Academy of Agricultural Sciences. 

Bread wheat (Triticum aestivum) is one of the most widely cultivated and consumed food crops in the world. It feeds about 40 percent of the world's population and provides 20 percent of a human's daily recommended amounts of calories and protein. Major efforts are underway around the world to increase the crop's yield and quality by boosting genetic diversity and resistance to cold, drought and disease. 

The widely grown common wheat is an allohexaploid, including three genomes A, B and D. Its genome is large (17,000 Mb, about 40 times that of the rice genome) and complex, with more than 85% sequences repetitive, making genome sequencing research rather difficult. This has become a bottleneck restricting further development of basic and applied research on wheat.

Results of the studies were published in Nature entitled "Draft genome of the wheat A-genome progenitor Triticum urartu" and "Aegilops tauschii draft genome sequence reveals a gene repertoire for wheat adaptation" in March, 2013.