Genes found for increased flour yield
GroundCover™ Issue: 138 January - February 2019 | Author: Dr Gio Braidotti
More flour can be extracted from the same amount of grain following the identification of two genes that play a critical role in determining the flour yield of wheat varieties
The recovery of flour from the dry milling of wheat grain is a trait that has proven difficult to improve by selective breeding. Now, however, research has found that reducing expression of two particular genes can increase the amount of flour extractable from grain, including the grain produced by high-yielding, feed-grade wheat varieties.
The discovery was made following extensive comparisons at the molecular level of 30 wheat varieties that are genetically programmed to produce grain with different milling properties. The research team was led by Professor Robert Henry of the Queensland Alliance for Agriculture and Food Innovation (QAAFI).
The genomic analysis identified two genes that determine the flour yield (the amount of flour that can be extracted from grain).
These genes belong to a larger family that encode fasciclin-like arabinogalactan proteins (FLAs).
Professor Henry says that the two genes implicated in flour yield play a structural role that affects the rigidity of the interface between endosperm and bran.
“We showed that when expressed at low levels, the resulting grain breaks up more easily during milling, resulting in more flour,” he says. “That means we can select for higher flour yield by breeding wheat that is genetically programmed to express the two targeted FLAs at low levels in the grain.”
The finding has important implications. Currently, recovery of flour from dry milling usually ranges between 70 and 80 per cent of the wheat grain, which is below the theoretical maximum of 85 per cent. Existing testing techniques have made it extremely difficult for wheat breeders to target greater flour yield.
The new insight into the two FLA genes now allows the development of DNA markers to easily, cheaply and quickly compare hundreds, even thousands, of breeding lines for their potential flour yield.
Also this kind of DNA marker-assisted screening technology can be used on minute amounts of plant material, sourced even from seedlings. This bypasses the need to produce large quantities of grain for a milling-based test to estimate flour yield.
The potential knock-on effect could considerably improve the general productivity of the wheat industry via several pathways. The first involves an expedited pathway for screening breeding material for high flour yield.
Another option exists, however, that fascinates Professor Henry. He explains it is already possible to breed wheat that produces extremely high quantities of grain, but the grain is usually unsuited to milling and is consequently used as feed for livestock.
“We now have the option to silence FLA gene expression in high-yielding, but feed-grade wheat, using gene-editing techniques,” he says. “Adding milling quality to the genetics of what are currently feed wheats would increase the amount of premium-grade grain reaching mills and allow a jump to ultra-high flour yields.”
Combining all the potential applications of this new selective breeding capability could quickly provide one of the yield ‘quantum leaps’ needed to meet growing international demand for wheat, he adds.
Particularly attractive to Professor Henry is the potential to add more flour into the supply chain without the need to cultivate more land or use more water, soil nutrients or fertiliser.
Was this page helpful?