Milling oats an option for paddocks with crown rot
Milling oats may be a more profitable option than wheat in paddocks with a high level of fusarium crown rot, according to recent research.
The Department of Primary Industries and Regional Development’s (DPIRD) two-year Grain Flagship project found milling oats are more tolerant to crown rot than wheat and barley, but are unsuitable as a break crop to reduce the risk of the fungal disease.
Crown rot costs WA wheat and barley growers an estimated $7 million per annum, however, relatively little was known about its impact on milling oats.
The disease is widespread across the WA grainbelt, particularly in low to medium rainfall areas, where oats have not typically been grown.
With competitive prices for milling oats, growers in low rainfall areas have become more interested in sowing the crop, prompting the need to investigate variety susceptibility to crown rot.
All seven oat varieties tested were more tolerant to crown rot than the two benchmark wheat varieties, suggesting oats could be a cereal alternative for paddocks where there was a disease risk.
Average yield losses for milling oats to the predominant crown rot pathogen, Fusarium pseudograminearum, was four per cent, which is about four times lower than that measured in wheat.
The trials showed no oat varietal differences in yield responses to crown rot.
The results highlight milling oats as a more tolerant cereal crop option for use in rotations where crown rot is a problem, to limit the extent of yield loss.
The field trials tested the milling oats varieties Bannister, Carrolup, Durack, Kojonup, Mitika, Williams, and Yallara, and two benchmark wheat varieties, Mace and Emu Rock, in inoculated versus uninoculated replicated plot trials at Merredin and Pingelly in 2016, and Merredin and Muresk in 2017.
At both sites, the pre-sowing inoculum levels in 2017 following the oat trials the previous year were not different among wheat and oats, or between varieties sown in 2016.
This means that oats cannot be used as a break crop for wheat and barley crops, which are known to increase crown rot inoculum levels, as both trials had similar levels of inoculum in 2017.
The trials showed there was no difference in disease levels in the 2017 Mace wheat crop following the different oat and wheat varieties.
If the management strategy is to reduce the level of crown rot in a paddock, a non-cereal crop, like canola or lupins, would be preferable to optimise profitability and provide good grass weed control.
An economic analysis suggested milling oats was the most profitable crop for paddocks where crown rot was a problem, provided the price of oats was above $270 per tonne.
In GRDC-funded trials, wheat and barley varieties were found to vary significantly in relative yield losses due to crown rot, as documented in the current crop variety guides.
Growers with paddocks that have a high risk of crown rot are urged to select the most appropriate cereal crop, based on the forecast for the season, and yield potential.
The outcomes from the department’s research will be included in the next edition of the Oat Variety Guide, while the new findings will be updated in the soon-to-be-released GRDC Crown rot Tips & Tactics publication.