Genetic material from an ancient grass relative is being crossed with modern wheat varieties to produce ‘superwheat’ lines which could offer growers improved crop performance within the next decade. Wendy Short spoke to *NIAB plant breeding specialist Dr Philip Howell about the project.

THE species that is used in the research programme is wild goatgrass, which was a contributor to the emergence of wheat about 10,000 years ago. Goatgrass can still be found all over the Middle East and beyond and compared with modern wheat varieties it is ‘hugely diverse’ in terms of its genetic potential. It could offer a range of benefits, including higher yields, greater disease resistance and enhanced pest and drought tolerance, said Dr Howell.

The UK-based superwheat project was launched ten years ago by the **BBRSC and involves several research organisations, including NIAB, and is part of a wider project, he explained.

“Our programme recreates the original hybridisation activity that took place many thousands of years ago in the Middle East between an ancient wheat and goatgrass,” said Dr Howell. “This crossing provided the basis for today’s modern wheat varieties.

“The greenhouse and laboratory work that is used in the re-creation technique has produced re-synthesised wheats, which are known in general terms as superwheats and more scientifically as synthetic hexaploid wheats. They are fully crossable with modern wheats and make an ideal bridge for transferring useful genetic diversity from wild relatives to modern UK varieties.”

Scientists have produced 50 re-synthesised lines using goatgrass crossed with UK winter and spring wheats. These pre-breeding lines will be further tested, but their eventual commercialisation could help to address the issue of the yield plateau, which had peaked over the past decade at about 8 tonnes/ha, he noted.

The re-synthesised lines generally produce yields that are lower than their modern counterparts’. Most will grow too tall to hold any commercial value and are therefore also prone to lodging. Another common trait is the tendency for the husk to cling to the seed and this makes threshing difficult, leading to unacceptable losses at harvest. Some re-synthesised wheats have also been found to reach the flowering period too early in the season; a quality which would render UK-grown crops vulnerable to frost damage.

However, there is an indication that some of the pre-breeding lines may prove to be useful sources of improved disease resistance over modern varieties and there are signs of a positive response to yellow rust and septoria tritici in particular. Despite these promising indications, as with all novel resistance more testing is required before any firm conclusions can be drawn, stressed Dr Howell.

Several other positive traits have been identified in the superwheat varieties, with some showing the potential to produce adequate yields in a low-nitrogen situation. This feature could become increasingly important in the future due to environmental concerns linked to farm fertiliser inputs, he said. In addition, some possessed larger-than-average grains compared with modern types, with others displaying a higher number of grains per ear.

The UK was not the first country to produce re-synthesised wheats, Dr Howell pointed out. A programme in Mexico in the 1980s resulted in new lines being launched, with the emphasis on drought-tolerant varieties for the developing world.

He believed the UK had been slow to explore the potential benefits of the technique. The project was being undertaken in two linked parts; the Wheat Improvement Strategic Programme and its current form, Designing Future Wheat.

“The principal challenges of the superwheat programme have already been overcome and there is no doubt that goatgrass has made a valuable contribution toward diversity. Only minimal performance testing of the new varieties has been carried out and the next stage will be very exciting. Further down the line, the grain will be processed and its baking qualities, for example, will be assessed.

“The crossed wheat types have attracted considerable interest from commercial plant breeders and they are already examining a variety of options. It is expected that the next five to seven years will see selected resynthesised wheats from the programme sown in commercial trials, with the first of the new superwheat varieties expected to be launched on the open market a few years further down the line.”

Scientific method

The crossing of two species requires scientific methods to override the ‘stop’ that occurs in nature. The superwheats are being developed by crossing durum wheat, which is a tetraploid, with goatgrass, a diploid. As material passes through the programme, it is thoroughly screened by researchers and breeders to ensure that any negative characteristics are identified and eliminated. Meanwhile, NIAB is also crossing modern wheats with other close relatives, including emmer and rivet wheats, in a further quest to find alternative new genetic material.

*NIAB – National Institute of Agricultural Botany

**BBRSC – Biotechnology and Biological Sciences Research Council