SARDI demonstrated that wild barley species Hordeum bulbosum possesses new sources of genes which may provide agronomically-valuable traits such as resistance to leaf rust, scald and net form net blotch and tolerance to boron, salt and moisture stress.
- Test unique barley genetic resources previously generated in SAGIT-funded project S0107R for agronomically valuable characteristics. These included resistance to leaf rust, net form net blotch, scald, crown rot and root lesion nematode,
and tolerance to boron, frost, salt and moisture stress.
- Advance the backcross material to a stage suitable for crossing into the University of Adelaide Barley Breeding Program.
In The Field
During this project, the bulbosum parents were tested for resistance to scald, net form net blotch and leaf rust. Very good sources of resistance were found.
Tests for crown rot, root lesion nematode and frost tolerance could not be conducted because of difficulties in producing backcross lines from the bulbosum accessions.
New scald, net form net blotch and leaf rust resistance genes were crossed back into Commander barley plants.
Specifically, this project has delivered to the barley breeding program third generation backcross lines of bulbosum leaf rust resistance in Commander plants and germplasm with potential boron tolerance. Germplasm from eight new bulbosum accessions was crossed with Commander to provide a potential source of many new traits for barley breeders.
DISEASE AND TRAIT TESTING
Specific test results include:
Barley x bulbosum hybrids were tested to determine whether their scald resistance mechanism was different to the natural resistance already present in the barley variety Osiris. A different mechanism of resistance would contribute to a more robust strategy for breeding for scald resistance.
The exact mechanism of resistance in the hybrids was unclear and more analysis is required.
Net form net blotch
Majority of bulbosum lines tested were moderately resistant to resistant to net form net blotch.
Leaf rust resistant germplasm was backcrossed into Commander plants and is undergoing further analysis and evaluation for breeding potential through the barley breeding program.
Hydroponic experiments indicate there may be useful sources of salt tolerance in bulbosum. It appears to have physiological tolerance to sodium accumulation, which is different to the mechanism in some salt tolerant breeding lines which exclude sodium. More research on genetics and physiology of this trait may provide alternative sources of salt tolerance for barley breeding.
Water stress tolerance
Preliminary experiments on water stress tolerance found bulbosum may have genes which allow barley to better recover after water stress events. Commander and bulbosum crosses produced higher biomass and better rates of survival after water stress than Commander itself.
It is possible that Hordeum bulbosum has higher levels of boron tolerance than cultivated barley. While lab tests were inconclusive, field and glasshouse tests are ongoing.
The next step is to further develop this genetic material to allow rapid backcrossing of these specific traits. However, this will require a new project using the new ‘genotyping by sequencing’ technology to quickly minimise the quantity of bulbosum DNA in the hybrids.
SARDI: Dr Phil Davies, Dr Parminder Sidhu and Dr Hugh Wallwork with Dr Klaus Oldach and Dr Katherine Linsell
University of Adelaide: Dr Jason Eglinton and Dr Stewart Coventry
ACPFG: Prof Mark Tester and Dr Yuri Shavrukov
The lack of availability of new resistance sources of scald, leaf rust and net form net blotch, and boron, salt and moisture stress tolerance is impacting on profitable barley production, particularly in more marginal cropping country in South Australia.
Building on SAGIT project S0107R, Hordeum bulbosum parents were tested for resistance to scald, net form net blotch and leaf rust.
Dr Phil Davies, SARDI Senior Research Scientist
T: 08 8313 9494
E: [email protected]
Value for Growers
- New resistance sources for scald, leaf rust and net form net blotch will provide greater insurance against these diseases by providing a more diverse array of genetic defences in varieties.
- Boron, salt and moisture stress tolerance willenable more profitable barley production throughout South Australia.