Varietal impact on final soil populations of Pratylenchus thornei – Macalister, Qld 2015

2015

Research organisaton
Funding sources

Trial details

Researcher(s) Steven Simpfendorfer (NSW DPI)
Year(s) 2015
Contributor Department of Primary Industries NSW
Trial location(s) Macalister, QLD
Further information View external link
Varietal impact on final soil populations of Pratylenchus thornei – Macalister, Qld 2015 locations
Aims

To evaluate the relative resistance of each variety to Pt under field conditions. 

Key messages

KEY FINDINGS:

  • Cereal variety choice can have a large impact on Pratylenchus thornei (Pt) population build-up within paddocks, which can then affect how following crops and/or varieties perform in the rotation.
  • Significant differences were evident between varieties with an 8.9-fold difference in final Pt populations between the best (Commander) and worst (Mitch) entries.
  • Very susceptible varieties should be avoided in paddocks with known root lesion nematode (RLN) populations as they can increase the population to high risk levels in one season (e.g. 19.1-fold increase with Mitch).
  • There was no significant difference between varieties in crown rot inoculum level that developed during the season based on postharvest PreDicta B assessment.

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
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
Download the trial report to view additional trial information

Method

Crop types Cereal (Grain): Wheat Cereal (Grain): Barley
Treatment type(s)
  • Crop: Variety
  • Seed treatment: Inoculant
Trial type
Trial design

Macalister 2015 Wheat

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Fertiliser Not specified
Inoculant Not specified
Other trial notes

Treatments

  • A total of 16 winter cereal entries (one durum, two barley and 13 bread wheat; Figure 1).
  • Added (plus) or no added (minus) crown rot at sowing using sterilised durum grain colonised by at least five different isolates of Fusarium pseudograminearum (Fp).
  • All plots in the trial were cored (10 cores/plot at 0–15 cm on previous crop row) after harvest (November 2015) to determine final (Pf) Pt populations for each variety.
  • Pt populations determined in all soil samples based on PreDicta B® analysis, a DNAbased test provided by the South Australian Research and Development Institute (SARDI). Levels of residual crown rot inoculum (log Fusarium DNA) were also determined from the same samples. Note: They were non-spiked (no added stubble) soil cores as collected on the previous crop row primarily for Pt analysis.
  • Pt data transformed for analysis ln(x + 1) to determine significance with backtransformed values for Pt presented in Figure 1.

 

Results

  • This site had a medium Pt population (5.5 Pt/g soil) at sowing following a barley crop grown in 2013 and a faba bean crop in 2014.
  • The addition of Fp inoculum at sowing did not have a significant impact on final Pt numbers (P = 0.275) with no significant interaction evident in any of the entries.
  • Significant differences were evident between varieties in final Pt populations developed in the top 15 cm of soil which ranged from 11.8 Pt/g soil after the barley variety Commander up to 105.0 Pt/g soil after Mitch (Figure 1). This represents an 8.9 fold difference in final Pt populations between entries. 
  • The barley variety Commander and bread wheat variety Suntop were the only entries which maintained final Pt populations at a medium risk level (2.0 – 15.0 Pt/g soil) at harvest.
  • All other entries increased the final Pt population to within a high risk level (>15.0 Pt/g soil) for the following crop in 2016 (Figure 1).
  • Both barley varieties and the durum variety Jandaroi were generally towards the mid to lower end of final Pt populations relative to the bread wheat entries.
  • The two barley varieties appear to vary in their resistance to Pt with La Trobe leaving approximately double the Pt population of Commander.
  • In barley, Commander increased the starting Pt population around 2.1 fold while La Trobee had a 4.5 fold increase in Pt numbers over the 2015 season.
  • In bread wheat there was between a 2.5 fold (Suntop) up to 19.1 fold (Mitch) increase in the Pt population over the 2015 season.
  • The one durum entry Jandaroi resulted in a 3.8 fold increase in the Pt population over the 2015 season.
  • Crown rot risk is a sum of the DNA levels of all three Fusarium species known to cause crown rot expressed on a log scale where <0.6 is below detection, 0.6-1.4 is low, 1.4-2.0 is medium and >2.0 is high risk.
  • All entries left low inoculum levels (0.5 to 1.8) in the uninoculated plots and high levels (2.0 to 3.0) in the inoculated plots with no significant difference between entries.

Macalister 2015 Barley

Sow date 1 June 2015
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

  • A total of 16 winter cereal entries (one durum, two barley and 13 bread wheat; Figure 1).
  • Added (plus) or no added (minus) crown rot at sowing using sterilised durum grain colonised by at least five different isolates of Fusarium pseudograminearum (Fp).
  • All plots in the trial were cored (10 cores/plot at 0–15 cm on previous crop row) after harvest (November 2015) to determine final (Pf) Pt populations for each variety.
  • Pt populations determined in all soil samples based on PreDicta B® analysis, a DNAbased test provided by the South Australian Research and Development Institute (SARDI). Levels of residual crown rot inoculum (log Fusarium DNA) were also determined from the same samples. Note: They were non-spiked (no added stubble) soil cores as collected on the previous crop row primarily for Pt analysis.
  • Pt data transformed for analysis ln(x + 1) to determine significance with backtransformed values for Pt presented in Figure 1.

 

Results

  • This site had a medium Pt population (5.5 Pt/g soil) at sowing following a barley crop grown in 2013 and a faba bean crop in 2014.
  • The addition of Fp inoculum at sowing did not have a significant impact on final Pt numbers (P = 0.275) with no significant interaction evident in any of the entries.
  • Significant differences were evident between varieties in final Pt populations developed in the top 15 cm of soil which ranged from 11.8 Pt/g soil after the barley variety Commander up to 105.0 Pt/g soil after Mitch (Figure 1). This represents an 8.9 fold difference in final Pt populations between entries. 
  • The barley variety Commander and bread wheat variety Suntop were the only entries which maintained final Pt populations at a medium risk level (2.0 – 15.0 Pt/g soil) at harvest.
  • All other entries increased the final Pt population to within a high risk level (>15.0 Pt/g soil) for the following crop in 2016 (Figure 1).
  • Both barley varieties and the durum variety Jandaroi were generally towards the mid to lower end of final Pt populations relative to the bread wheat entries.
  • The two barley varieties appear to vary in their resistance to Pt with La Trobe leaving approximately double the Pt population of Commander.
  • In barley, Commander increased the starting Pt population around 2.1 fold while La Trobee had a 4.5 fold increase in Pt numbers over the 2015 season.
  • In bread wheat there was between a 2.5 fold (Suntop) up to 19.1 fold (Mitch) increase in the Pt population over the 2015 season.
  • The one durum entry Jandaroi resulted in a 3.8 fold increase in the Pt population over the 2015 season.
  • Crown rot risk is a sum of the DNA levels of all three Fusarium species known to cause crown rot expressed on a log scale where <0.6 is below detection, 0.6-1.4 is low, 1.4-2.0 is medium and >2.0 is high risk.
  • All entries left low inoculum levels (0.5 to 1.8) in the uninoculated plots and high levels (2.0 to 3.0) in the inoculated plots with no significant difference between entries.
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Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Site Depth Type pH EC P K N A OC CAT
Macalister, QLD 0 - 60cm 126.00
Soil conditions
Trial site Soil texture
Macalister, QLD Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Macalister, QLD Vertosol
Soil Moisture Source: BOM/ANU
Average amount of water stored in the soil profile during the year, estimated by the OzWALD model-data fusion system.
Year Macalister QLD
2015 306.7mm
2014 288.7mm
2013 283.3mm
2012 290.9mm
2011 308.7mm
2010 323.5mm
2009 328.4mm
2008 342.8mm
2007 375.8mm
2006 341.8mm
2005 396.0mm
2004 428.5mm
2003 511.2mm
2002 521.3mm
2001 569.3mm
2000 571.4mm
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

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Climate

Macalister QLD 2015


Observed climate information

Rainfall avg ann (mm) 611.5mm
Rainfall trial gsr (mm) 121mm

Derived climate information

Macalister QLD

NOTE: Exact trial site locality unknown - Climate data may not be accurate
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Some data on this site is sourced from the Bureau of Meteorology

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.

Trial report and links

2015 trial report



Trial last modified: 23-09-2019 14:28pm AEST