Scientists on the Norwich Research Park, working with colleagues in China, have developed new techniques that will aid the application of genomics to breeding the improved varieties of crop needed to ensure food security in the future. By dissecting the complicated genome of oilseed rape they have been able to produce maps of the genome that are needed for predictive breeding.

The study was funded by the BBSRC, Defra and the China National Basic Research and Development Program.The results have been published in Nature Biotechnology.

The scientists showed how, instead of using traditional breeding, which involves crossing two varieties almost at random and selecting the best performing among the progeny, more promising results can be gained from predictive breeding; a more advanced technique where specific parts of the genome most likely to contain beneficial genes can be identified.

Genomic sequencing and the availability of genetic linkage maps can play a major part in predictive breeding efforts by linking beneficial traits to specific parts of the genome. Researchers and breeders use genetic markers to construct linkage maps, which help to identify useful genes. They are also vital to marker-assisted crop breeding, where the maps and markers can greatly accelerate the breeding in of new improved traits.

However, for key crops such as bread wheat and oilseed rape, the use of this kind of genomics-based predictive crop breeding is severely hampered due to the complicated genomes that these species possess. Many important crop plants are polyploid, possessing several sets of chromosomes. Bread wheat, for example, contains three pairs of chromosomes derived from multiple hybridisation events that occurred between two other wheat species relatively recently in its ancestry. To try to overcome this problem, a team from the John Innes Centre and The Genome Analysis Centre (TGAC), which are strategically supported by the BBSRC, combined sequence data from different sources to construct genetic linkage maps.

The team led by Professor Ian Bancroft worked on oilseed rape, which as well as being an important oil crop also plays a key role in crop rotation strategies. The strategy adopted by the group involved integrating the available sequence data for oilseed rape with that of its ancestral progenitors, and also that of a more distantly-related species for which high-quality genome sequence data is available.

The researchers were able to construct genetic linkage maps in oilseed rape, eventually identifying over 23,000 markers. This allowed them to align the oilseed rape genome with that of its relative (Arabidopsis thaliana) and also to sequence data from oilseed rape's two progenitor species.

The researchers hope this method of dissecting the genome, which has worked for crops in the oilseed rape family will also be applicable to others such as bread wheat. Professor Bancroft said, "Dissecting the genome of oilseed rape like this opens up the possibility of using predictive breeding techniques that will really help with the production of improved varieties."