Wheat breeding for improved yields, pest and disease resistance has played an integral role in sustaining wheat production in the UK and around the world for decades. However estimated production growth rates in the UK will fall short of demand within 16 years unless scientists and breeders can come up with more resilient wheat strains.
Bristol University researcher Dr Sacha Allen said that current UK wheat yield gains of 0.5-0.7% per year would produce a 13% increase in wheat yields by 2030, but said this was well short of the projected 40-50% increase required to meet food security objectives.
“Recent yield gains since 1982 were almost entirely due to the contribution of improved varieties. The recent leveling off in wheat yields has highlighted the need to introduce new sources of wheat germplasm and genetic variation into existing wheat breeding programs,” she told Milling & Grains.
The priority? Speed…
Allen is part of a team of scientists involved in a wheat genotyping program to identify genetic sequences in different wheat varieties useful for future breeding. The research will enable targeted breeding for increased yields, pest and disease resistance and adaptability to changes in climate. The team has used modern sequencing and genetic marker technology to adapt novel sources of germplasm from wild relatives, exotic material and synthetic lines to use in modern cultivars that commercial breeders can work with.
The linchpin of the research was to speed up the sequencing process and hence the team has designed a wheat genotyping array that will only screen for previously identified sequences of potential use to breeders.
“Because the genome of wheat is so large and complicated it is impractical to sequence the entire genome of every wheat line we have to screen, so we have developed a suite of markers that will help us to identify chromosomal segments and track them through the breeding process. Essentially, we have designed an array to screen 96 samples at a time for 820,000 markers at a relatively low cost per sample,” Allen explained.
A condensed form of the genotype array (a so-called ‘breeders array’), containing 35,000 markers useful to breeders, will be used to screen hexaploid (six sets of chromosomes) wheat lines at an affordable price and enable them to introduce particular advantageous traits into new wheat breeds, for example to reduce pre-harvest sprouting as a result of too much rainfall, leading to a loose of thickening power in flour.
Large scale, global wheat array
“This is the first project, globally, to attempt to introduce such diverse germplasm into breeding programs on a large scale,” Allen said.
“The 820K wheat array is the largest wheat genotyping array developed to date. Using this array, breeders will be able to target certain traits in different varieties, but ensuring there is no decrease in yield. It should help speed up traditional breeding processes and we could see the benefits within five years.”
The research at Bristol University is linked to a broader BBSRC-funded project – the Wheat Improvement Strategic Programme – to accelerate the genetic improvement of modern UK wheat.