Reduced height, or semi-dwarf wheat varieties with improved drought resilience may soon be grown in fields across the globe, following an exciting scientific discovery.
Researchers at the UK’s John Innes Centre in collaboration with an international team of researchers have discovered a new height-reducing gene: Rht13.
This means that seeds can be planted deeper in the soil, giving access to moisture, without the adverse effect on seedling emergence seen with existing wheat varieties.
New gene
Varieties of wheat with the Rht13 gene could be rapidly bred into wheat varieties to enable farmers to grow reduced-height wheat in drier soil conditions.
“We have found a new mechanism that can make reduced-height wheat varieties without some of the disadvantages associated with the conventional semi-dwarfing genes,” said John Innes Centre group leader, Dr. Philippa Borrill.
“The discovery of the gene, its effects and exact location on the wheat genome, means that we can give breeders a perfect genetic marker to allow them to breed more climate-resilient wheat.”
The work undertaken to date suggests that additional agronomic benefits of the new semi-dwarfing gene may include stiffer stems, better able to withstand stormier weather.
Over the past six decades, reduced height genes have increased global wheat yields.
This is because the short-stemmed wheat they produce puts more investment into the grains rather than into the stems and has improved standing ability.
Challenges
However, this approach to wheat breeding also has a significant disadvantage – when these varieties are planted deeper to access moisture in water-limited environments, they can fail to reach the surface of the soil.
The newly discovered Rht13 dwarf gene overcomes this problem of seedling emergence because the gene acts in tissues higher up in the wheat stem.
So, the dwarfing mechanism only takes effect once the seedling has fully emerged. This gives farmers a significant advantage when planting deeper in dry conditions.
The discovery of the Rht13 dwarfing gene was made possible by recent advances in wheat genomic research.
“In dry environments, this alternative, reduced-height gene will allow farmers to sow seeds at depth and not have to gamble on the seedlings emerging,” Philippa Borrill added.
The members of the John Innes team also believe that the stiffer stems could result in less lodging.
In addition, the up-regulation of a pathogen-related, dwarfing gene may help to enhance resistance response to certain pathogens.
The next step for this research will be to test how this gene works in diverse agronomic environments from the UK to Australia.
The John Innes research team are also investigating how the mechanism works. They are exploring the theory that it may be down to molecular restrictions on the cell wall preventing elongation.
