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Researcher(s) |
Steven Simpfendorfer (NSW DPI) |
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Year(s) | 2015 |
Contributor | Department of Primary Industries NSW |
Trial location(s) |
Macalister, QLD
|
Further information | View external link |
To evaluate the relative resistance of each variety to Pt under field conditions.
KEY FINDINGS:
Conclusions
Cereal variety choice can have a significant impact on the build-up of Pt populations within paddocks with an 8.9 fold difference in final populations between the best and worst variety at this site in 2015. Starting Pt populations of below 2.0 Pt/ g soil are considered low risk, populations between 2.0 and 15.0 Pt/g soil are considered medium risk and above 15.0 Pt/g soil are considered high risk for yield loss in intolerant crops or varieties in the northern region. This could have serious consequences for the production of following Pt intolerant crops and/or varieties within the rotation with all but two entries (Commander and Suntop) increasing the Pt population from a medium to a high risk level in one season or with one variety (Mitch) increasing the Pt population as high as 105.0 Pt/g soil at this site in 2015. Recent NSW DPI research has also demonstrated that significant yield loss still occurred in the moderately tolerant wheat variety EGA Gregory with high risk (>15.0 Pt/g) populations in the top 30 cm of soil at sowing. Very susceptible varieties should be avoided in paddocks with known RLN populations as they can blowout the population to high risk levels in one season.
Although varieties appear to significantly differ in their yield in the presence of crown rot infection, differences in the levels of partial resistance, which limits the rate of spread of the crown rot fungus through the plant during the season, do not appear to result in significant variation in inoculum levels at harvest. Partial resistance does not actually prevent the plant from being infected but rather slows the rate of fungal growth in the plant arguably delaying expression of the disease which can translate into a yield and grain quality (reduced screenings) benefit. However, the crown rot fungus, while being a pathogen when the winter cereal plant is alive, is also an effective saprophyte once the plant matures and dies. This saprophytic colonisation of infected tillers late in the season as the crop matures is the likely reason why limited practical differences in residual inoculum levels are created between varieties and winter cereal crop types.
Further research across sites is required to confirm differences in resistance of barley and wheat varieties to Pt as this can have significant implications for the build-up of Pt populations within a paddock and hence following rotational choices. For instance, while it appears that Mitch has a useful level of tolerance to crown rot (average 0.54 t/ha higher yielding than EGA Gregory in 2015), its increased susceptibility to Pt resulted in it taking nematode populations from a medium risk level at sowing to an extremely high risk level by harvest at Macalister in 2015 (Figure 1). Hence, Mitch should only be considered for production in paddocks known to be free of Pt as its increased susceptibility to Pt is likely to override the yield gain in the presence of crown rot when considering the whole rotational sequence.
Lead research organisation |
Department of Primary Industries NSW |
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Host research organisation | N/A |
Trial funding source | GRDC DAV00128 |
Trial funding source | DPI NSW DAV00128 |
Related program |
National nematode epidemiology and management program |
Acknowledgments |
This research was co-funded by NSW DPI and GRDC under project DAV00128: National nematode epidemiology and management program. Thanks to the Rob Taylor and family for providing the trial site and to Douglas Lush (QDAF mobile trials unit) for sowing, maintaining and harvesting the trial. Assistance provided by Robyn Shapland, Patrick Mortell, Rachel Bannister, Carla Lombardo and Jason McCulloch (NSW DPI) in coring plots is greatly appreciated. Soil samples were assessed for RLN populations using PreDicta B® analysis by Dr Alan McKay and his team at SARDI in Adelaide. |
Other trial partners | Co-operator: Rob Taylor |
Crop types | Cereal (Grain): Wheat Cereal (Grain): Barley |
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Treatment type(s) |
|
Trial type | |
Trial design |
Sow date | Not specified |
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Harvest date | Not specified |
Plot size | Not specified |
Plot replication | Not specified |
Fertiliser | Not specified |
Inoculant | Not specified |
Other trial notes |
Treatments
Results
|
Sow date | 1 June 2015 |
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Harvest date | 2 November 2015 |
Plot size | Not specified |
Plot replication | Not specified |
Fertiliser |
250 kg/ha urea and 40 kg/ha Granulock® 12Z at sowing |
Inoculant | • Added (plus) or no added (minus) crown rot at sowing using sterilised durum grain colonised by at least five different isolates of Fp. |
Other trial notes |
Treatments
Results
|
Rainfall avg ann (mm) | 611.5mm |
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Rainfall trial gsr (mm) | 121mm |
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.