Trials

Our program assists Australian grain growers in varietal decision making by providing comparative information of commercially available grain varieties, including:

  • yield performance
  • disease resistance ratings
  • grain quality.

We have more than 650 trials sown at over 300 locations, for 10 crop species, across Australia each year. Our database includes more than 1.5 million plot points and is the largest independent co-ordinated trial network in the world.

Our trials are managed in accordance with the NVT Protocols to provide consistent quality across the nation.

Site locations

Our program is not a yield potential trial, but a comparative performance trial. Sites are chosen following consultation with stakeholders including:

  • agronomists
  • growers
  • NAC Committees (NVT Advisory Committee)
  • GRDC Regional Panels
  • breeder groups
  • statisticians
  • market production intelligence.

Some key considerations in trial site selection include:

  • suitability of soil type
  • representation and prevalence of existing crops
  • representation of environments within a region
  • avoidance of clustering of trials resulting in duplication and obsolete trials.

We select sites to ensure there’s adequate representation of all environments and conditions. This provides consistency over several years to allow for accurate comparison of varieties and increase the reliability of the MET analysis.

Regions with large uniform environments covering vast areas may have a smaller trial density compared to regions with less uniform environments. To make best use of resources, our program is careful to avoid clustering of trials in locations where environments are similar, resulting in data that does not provide additional value of the data set.

Trials can move between neighbouring properties from year-to-year and a 25-kilometre shift is allowed. However, trials are more likely to be successful if they’re in the same environment, due to factors such as pre-trial planning issues and reliable and well understood trial manager/property owner relationships.

Soil

Trials are contained in paddocks with a soil type which is widely representative of the district and region. We include enough trials in all environment types to provide accurate performance information.

Better performing sites with better soils are not necessarily selected, but rather, sites are selected based on uniformity and ability to deliver consistency across all trial plots. Uniform sites reduce error and better detect small variations in variety performance.

Trials with soil variability, producing variable replicated data will mask any variety yield differences resulting in trial failure which is not a good investment.

Areas such as shallow rocky outcrops, tree lines, water courses or compaction are also avoided, as it causes undesirable variation between plots. Differing locations is also necessary to avoid concerns such as frost risk, spray drift and pests.

We don’t grow all crop types at the same location to compare profitability, as different crop rotations are required for optimal performance. Our program is designed to show the genetic potential not limited by external factors, such as rotation.

Pest management also becomes difficult where different crop types are sown in close proximity. Comparison between trials at one location is not valid statistically.

Management

Our trials are managed by contracted providers who sow, maintain and harvest the trials in accordance with the NVT Protocols. This ensures our trials are delivered to high standards and there are no limiting factors like nutrition or disease, as this gives us an accurate indication of genetic varietal performance.

Every four years we go to tender for new trial provider management. Despite COVID-19, our first-year service providers recorded quality trials in 2020 and the lowest quarantined numbers in years.

Variety inclusion

Cultivars are nominated annually by commercial and private genetic breeding programs for inclusion in our program.

To be accepted, cultivars need to meet our acceptance criteria (within our NVT Protocols) and be reviewed by our team to ensure the criteria is met.

Each of the varieties entered, whether commercially available or advanced genetic lines, are subjected to a rigorous nomination process for inclusion. We work with the breeders each year to ensure all lines are included.

Varieties within two years of release

For inclusion, varieties must be “available to growers to purchase on commercial scale” within two years from the first year of inclusion in trials.

This ensures:

  • varieties included have a high probability of release
  • only relevant varieties are tested
  • our program isn’t misused as a screening/breeding/validation program.

Each variety will have two years of independent data before it is available to growers. If a variety is released, it will remain in the trial longer, depending on its adoption by growers in that area.

Commercial varieties are selected depending on:

  • uptake
  • timing of release
  • delivery percentages across a state
  • feedback from the NVT Advisory Committees.

Unreleased varieties

Unreleased varieties are trialled for two years to collect data based on multiple years and environments and provide confidence in its long-term performance. Unreleased varieties are still trialled, so growers have accurate performance information from the moment of release.

Data on unreleased varieties may be influenced by a single season’s conditions, like drought.