Frequently Asked Questions

The National Variety Trials (NVT) program, established and managed by the Grains Research and Development Corporation (GRDC), is the largest independent grain crop variety evaluation program in the world. NVT is a national program including both commercially available varieties and pre-commercial breeding lines of 10 grain crop species. The program generates independent information for growers and agronomists to assist in variety selection.

NVT’s main purpose is to create enduring profitability for Australian grain growers by providing growers and their advisers with comparative information on yield performance, grain quality and disease resistance ratings of commercially available grain varieties.

This information is accurate, consistent, independent, timely and locally relevant to assist in varietal decision making.

Besides our main purpose to assist growers in commercial variety selection, NVT also has benefits for other areas of the grains industry by:

• Being a platform on which important, non-NVT grains industry research projects are based. This is achieved through the provision of resources (such as datasets, grain samples, plot access) generated as a result of standard NVT operations under the NVT Resource Sharing scheme.
• Providing single origin seed of consistent quality for researchers through the NVT Research Seed Multiplication Program.
• Contracting, administering, and managing small plot trials for a wide range of GRDC projects through the NVT Infrastructure Sharing  scheme.
• Supporting the breeding industry by offering subsidised variety testing across our extensive network of trials  and providing performance data which can be utilised by seed companies within their programs.

NVT is funded and managed by GRDC. The NVT management team consists of eight people responsible for the governance, operation and administration of the program. The team’s primary focus is the governance of the program, including its successful delivery and continuous improvement.

Many NVT services are contracted to service providers who perform the work on behalf of GRDC. These services include:

• field trial provision
• pathology testing
• statistical analysis
• grain quality testing
• seed multiplication
• extension
• results publication
• database management.

Yes, local stakeholders are involved in management decisions and provide management advice for trials in their region.

Each NVT region has an NVT Advisory Committee, comprised of local growers and advisors who are consulted for regional management advice.

To ensure management of NVT trials is tailored to deliver the best outcomes for growers, each NVT region has an NVT Advisory Committee (NACs) comprised of local growers and advisors. The NACs are an advisory and consultative mechanism established as a “growers’ voice” to provide local or regional operational advice to NVT management. The NACs are specifically aimed at getting input from growers, or those representing grower interests, to ensure trial management reflects district practice.

NAC members meet annually in late February/early March and may be contacted by the NVT team or Trial Service Providers throughout the year for ad hoc advice. The standard NAC agenda requests NAC members to:

• Review the commercial variety list to ensure all varieties tested are relevant to local growers.
• Review the germination windows to ensure that target planting times reflect the practice of local growers.
• Provide advice and support to the Trial Service Providers on agronomic issues occurring with trials.
• Assist in identification of potential trial hosts and the most suitable paddocks.

NAC members include a mix of growers and agronomic consultants from a particular region. Anyone may nominate someone for NAC participation by contacting the respective NVT Regional Manager or emailing nvt@grdc.com.au.

The NVT Regional Managers are responsible for identifying, recruiting, and contracting suitable NAC members, and for organising and running the annual NAC meetings in each region.

Suitable NAC members should:

• Be a grower or advisor that can represent the best interest of growers without a conflict of interest.
• Have a sound understanding of the NVT program, its purpose, and how it functions (although this can be learned in the role).
• Have a good understanding of local grower practice and agronomics within the region.
• Ideally have an established local network that they can tap into for advice.

Like the growers and advisors who are NAC members, Breeders who participate in NVT also contribute toward the ongoing success of the program. For example, NVT’s Participating Breeders:

• Provide advice and feedback throughout the year on the quality of NVT trials.
• Are consulted to provide input in the development of NVT Policy, Protocols, and processes.
• Annually review the list of commercial varieties tested in the program.
• In some instances, supply seed of pre-commercial and commercial cultivars for inclusion in trialling.

All commercially relevant grain varieties are included in the NVT program. Commercially relevant varieties are identified through an annual review process that involves consultation with key stakeholders, such as NACs and Participating Breeders, and considers data on variety uptake and delivery/production figures. For commercially relevant varieties, this review process also identifies the specific regions in which the variety is relevant.

The program also includes pre-commercial lines that are not commercially available to growers. These lines are entered into the program and into specific regions by Breeders through an annual nomination process.

There are more than 650 NVT trials across Australia each year. These trials are broken down into crop type and, within some crop types, are further divided into distinct trial series. Separate trials for crops allow for more appropriate sowing dates and in-season management for varieties tested in the program, ensuring that varietal differences in yield performance aren’t masked by other factors.

The NVT program has a number of trial series, tailored to manage differences in:

• Species type e.g. NVT has desi and kabuli trial series for chickpea
• Maturity and appropriate sowing date e.g. NVT has main and long season trial series for barley
• Herbicide tolerance e.g. NVT has imidazoline and main season trial series for lentil
• Rainfall zone e.g. NVT has low-medium and medium-high rainfall zone trial series for canola.

NVT trials include varieties that are suitable for testing in that trial series and region. Suitability is based on information supplied by variety owners and observations of in-field performance, and as well as from information in the NVT Protocols on which maturities would be suitable for testing in specific trial series. If any unsuitable varieties are entered into a trial, they are identified prior to trial harvest and removed by the NVT team.

Independent information on newly commercialised varieties is incredibly important to growers. Therefore, NVT includes pre-commercial lines to ensure we provide growers with independent results for these lines at the point of commercialisation. To reduce the risk of growers selecting poor-performing varieties whilst simultaneously accelerating the adoption of superior varieties, growers are encouraged to only commit to new lines once NVT results are available on newly commercialised lines.

Additionally, by submitting pre-commercial lines, breeders can gauge performance of their varieties against pre-commercial lines from other companies. This helps breeders in decision making on variety commercialisation, avoiding the release of inferior varieties.

GRDC does not fund testing of pre-commercial lines as there is no guarantee these lines will become commercially available to growers. In fact, 72% of lines tested in NVT are never commercialised. To address this, Breeders pay a subsidised cost to purchase NVT testing of their pre-commercial lines.

When a pre-commercial line becomes commercially available to growers, GRDC retroactively compensates the Breeder for up to two years of pre-commercial testing. Compensation is in the form of Commercialisation Credits, each of which can be used for free pre-commercial line entry into an NVT trial.

NVT field trials are managed by regionally contracted Trial Service Providers who sow, maintain and harvest trials. Trials are managed in accordance with the NVT Protocols to provide consistent quality across the nation.

Regionally and at site level, trials are managed according to district best practice, including sowing dates, nutrition, and chemical application. Trials are managed to remove disease, weed and fertiliser constraints so genetic performance can be accurately compared across the different environments.

NVT trials are not gross margin trials, agronomy trials, or trials to create variety specific management packages.

Acceptable germination windows are clearly defined for all trials within a crop and region. Varieties included in trials are entered based on their maturity to fit within the germination windows to avoid frosting and other issues that can impact if varieties are not suitable for the germination window.

Germination windows are constantly reviewed by the NVT Advisory Committee (NAC) to reflect district practice. Over the 20 years of NVT these windows have advanced significantly with most main season trials now sown 3-4 weeks ahead of those sown 20 years ago.

Trials are sown to germinate at dates reflecting district practice and trial managers generally aim to sow at the same time as the grower for the paddock used or within days to avoid issues such as complications of emerging crops and subsequent chemical drift.

Disease control through fungicide application is a common practice for growers as part of their integrated disease management strategy. As NVT trials contain a range of maturities, multiple fungicide applications may be required to adequately protect all varieties trialled. Removing the impact of disease in NVT trials allows variety performance to be accurately measured without differences in variety disease/pest resistance/susceptibility affecting yield performance and grain quality. The NVT program runs an additional pathology program that produces the NVT Variety Disease Resistance Ratings.

NVT trials are managed using better than local best practise to minimise the impact of disease on varietal performance, however in high disease pressure seasons a certain level of disease occurrence is unavoidable.  Susceptible varieties do suffer in a high disease pressure season, but if a trial had appropriate fungicide application(s) at appropriate times, then the trial results are released. It is important to publish yield information in such disease conducive years, as it is reflective of the real-world grower experience in those seasons.

Sowing outside of the recommended windows will compromise variety performance and result in invalid data unsuitable for inclusion in the Multi Environment Trial (MET) analysis. Therefore, it is important that trials are sown within the recommended germination windows and that trials are abandoned prior to sowing if this is not possible.

Pre-watering is sometimes required to avoid sowing trials outside their recommended germination window. Additionally, early break wheat trials are designed to inform growers what varieties perform best when an unseasonal rainfall event occurs prior to the normal main season break. These events do not occur regularly, and in most seasons supplementary watering is required to replicate an early break. This ensures that germination occurs within the suitable window for the varieties sown.

In rare instances, supplementary watering of trials may also be considered to ensure trials survive where severe post-emergent drought is threatening plant survival.

To provide transparency and accuracy in interpreting results, supplementary watering volumes are reported with the rainfall data.

It is recognised that the environmental conditions between seasons can change considerably at a given location, and we never expect the conditions experienced in one year will occur in following years.

The purpose of NVT is to provide information to growers that assists in varietal choice for their location. Due to seasonal variation, this choice should not be based on a single year’s conditions; rather, performance of a variety in a location over time provides more accurate indicators of future performance at that location.

It is recognised that supplementary watering does create conditions that are different to those experienced in that location in that year. However, given the environmental variation between seasons, watering of trials can be required to avoid trial failure and still produces valuable data for variety selection.

It is important to note that the supplementary watering is measured, recorded and available in NVT reporting to accurately reflect the environmental and management conditions the trial was subjected to.

NVT trials are managed for accurate variety comparisons in the absence of external limitations. As such, nutrition should not be a factor limiting variety performance, which means fertiliser rates may exceed common commercial practice.

Fertiliser rates are calculated using nitrogen budgets considering soil fertility, moisture and yield potential, and are adjusted to suit each trial’s needs. All trial sites are comprehensively soil tested up to one metre depth prior to sowing, which aids fertiliser application decisions.

Dry sowing is not routine practice for NVT trials as dry sown trials may not receive timely and effective germinating rains to enable the trial to germinate within its optimal germination window. Additionally, dry sown trials have an increased risk of staggered emergence leading to patchy establishment. Trials with patchy establishment have a high chance of being compromised due to plot variability and an increased abandonment risk.

NVT trials are designed to reflect district best practice, with regards to germination of the crop. This means in seasons with a late break NVT operations are timed in way that sowing may not coincide with commercial crops in the region, but germination will.

Differences in seed size, seed origin/source and seed nutrient content are variables that can influence yield and thus obscure genetically driven differences in variety yield performance.

In order to remove these variables from the program, each year NVT produces premium quality seed for over 242 commercially available varieties at a single location, which is graded to ensure uniformity. Genetic testing and periodic renewal of seed occurs to ensure varietal purity and avoid contamination.

Seed is produced for all commercial lines included in the NVT program except hybrids (canola and sorghum), which require specialised production systems managed by breeding programs. Seed of pre-commercial lines is supplied by breeding programs.

Trial locations are chosen following extensive consultation with stakeholder groups including:

• Growers & Grower Advisors
• NVT Advisory Committees
• GRDC regional grower panellists
• NVT Participating Breeders
• Statisticians
• Market production intelligence.

Our key considerations when determining trial locations are to ensure trials are distributed in a way that:

• Reflects representation and prevalence of existing crops
• Reflects representation of environments within a region
• Avoids clustering of trials resulting in duplication and obsolete trials
• And most importantly, ensures growers have access to local trial results that are relevant to them leading to increased confidence in the results.

NVT’s site selection aims to ensure adequate representation of all environments and conditions for established crop species within regions.

Representation of crop types in NVT in a region broadly correlates to the popularity of those crop types in the region. NVT trials are not feasible in areas where there are few variety options available and agronomic crop practices are not well established.

Additionally, to make best use of resources, the NVT program is careful to avoid clustering of trials in locations where environments are similar as more valuable data can be gathered from trials in environmentally distinct regions. This means that regions with large areas of uniform environments may have a smaller density of NVT trials than regions with less uniform environments.

The purpose of NVT is to provide independent data on commercially available varieties to support growers’ varietal choices. NVT is not used as a demonstration program to encourage uptake of new crop types or maturities.

In emerging or potential regions for a crop species, the use of NVT to validate suitability of new crops does not provide acceptable return on investment. For growers to derive maximum benefit from GRDC’s investment in the NVT program the distribution of NVT trials is designed to reflect local crop presence. This means NVT trials are located in established cropping regions with areas of significant production of that crop or maturity rather than in areas of ‘potential uptake’.

There are other potential GRDC investments that are suited to the purpose of demonstration and development of crops.

Different crop rotations are required for optimal performance of various crops. NVT is designed to show genetic comparison not limited by external factors, such as rotation.

Pest management becomes extremely difficult where different crop types are sown in close proximity and potential herbicide drift can also be a major concern.

Crop profitability is best determined from trials specifically designed and managed to achieve this goal. Comparison between NVT trials at one location is not statistically valid for this purpose.

For more information, see Trial results question: 'Should we compare variety performance across different trials  (e.g., canola herbicide groups, or between species)?

Site uniformity is key to good trials and detecting useful differences between varieties in NVT. As such, site selection is based on uniformity and ability to deliver a consistent trial across all plots.

Trials with soil variability produce variable data which obscures variety yield differences, resulting in trial failure which is not a good investment. As such, areas with shallow rocky outcrops, tree lines, water courses, variable compaction, salinity issues, toxicity/deficiencies, etc. are avoided as these factors would cause undesirable non-genetic variation between plots.

Low, medium and high yielding environments are all included in NVT, which has locations all around the country to best represent the full range of conditions growers experience.

The NVT is not a yield potential trial, but a variety comparison trial. Trials are located in paddocks with a soil type widely representative of the district and region.

Best soils are not selected but rather, site selection is based on soil uniformity and ability to deliver a consistent trial across all plots. NVT includes enough trials in all environment types to provide accurate variety performance data for all environments.

Trials can move between neighbouring properties from year-to-year provided the trial is within a 25-kilometre radius of the locality (allocated site name). A consistent location over several years allows more accurate comparison of varieties across years and increases the reliability of the MET analysis. Additionally, trials are more likely to be successful if retained on one representative property, as this reduces risk of pre-trial planning issues and allows productive relationships and communication to be established between trial managers and property owners.

Multi Environment Trial: The Multi Environment Trial (MET) analysis is very useful for predictive purposes. It produces the most accurate and reliable prediction of future variety performance. MET analysis results are presented at an individual trial level but with the robustness of a massive dataset.

The MET analysis is conducted on a five-year dataset and includes trials from multiple environments. For some varieties, the analysis is conducted on more than 660 plots to gain an accurate and reliable result.

The strength of the MET analysis is that it analyses trials from a wide range of seasonal and environmental conditions. This ensures varieties are identified to enable selection of consistently high performing varieties for a given location.

Single Site Analysis: The Single Site Analysis (SSA) is very useful for descriptive purposes. It is less accurate and less reliable than the MET analysis for predictive performance but provides a good description of performance in that trial for that particular season only. SSA data is available sooner than MET data after a trial is harvested.

The SSA is conducted on a single trial at a single location in a given year, e.g., 2019 Horsham wheat. The analysis is conducted on a limited dataset, usually three plots for each variety.

The SSA is descriptive of the environmental conditions at that trial, e.g., how the varieties performed with an early break or dry spring.

The weakness of the SSA is that it has a low reliability to be able to repeat its results, i.e., if the environmental conditions changed so would the variety rankings.

Single Site Analysis: Many steps occur following the harvest of a trial, including data upload to the database, data analysis by biometricians, data review by breeders and NVT management prior to general public release.

This process ensures the data achieves the high standards in NVT Protocols. Each step provides a period of review or enactment, and this results in a minimum of 10 days between day of harvest and public release of results. The average time for the release of single site analysis of a trial is 14 days.

Multi Environment Trial: MET analyses cannot commence until all trials within the dataset have been harvested and undergone single site analysis. Not all trials in a particular dataset are harvested at the same time.

MET analyses are reviewed by NVT management and other stakeholders for accuracy prior to public release. These analyses generally occur during late December through to late January before release on the NVT website.

NVT have a vast network or trials covering all major grain crops and all grain producing environments in Australia. NVT’s online trial results map allows you to see where all trials are located.

You can use your knowledge on equivalent grain production environments (regionally or even nationally) to your situation to select remote trials which may be relevant to your environmental situation.

It is not statistically valid to compare results between trials even if co-located. This is because different trials at a location are:

• Spatially separated creating increased site variability,
• Managed differently according to the herbicide system, maturity group, and species, e.g., canola herbicide tolerance trials, bread wheat vs durum wheat trials, barley vs wheat,
• Statistically managed as separate experiments, including in their design and analysis.

The NVT program is a completely independent program funded and managed by GRDC to provide growers with reliable information to assist in variety choice. All strategic, operational, and management decisions are made by GRDC to ensure the best outcome for the Australian grains industry and Australian growers.

Collaboration between the NVT and Plant Breeding Programs is integral to the success of NVT, this collaboration provides NVT with:

• Ability to produce independent information on the latest release commercial varieties through NVT early access to pre-commercial breeder lines
• Valuable real-time feedback on trial quality to assist in monitoring the nationwide trial program
• Expert knowledge and experience on varietal performance so NVT management can assess the credibility of trials and trial results prior to general publication.

Plant breeders or their associates do not decide on the release of trials to the public, but their views are one of many considered by NVT management. NVT management welcomes feedback and any queries about the integrity of a trial which instigates an independent investigation by the NVT team.

All varieties in an NVT trial are sown at the same time of sowing. Therefore, varieties in the NVT will vary in flowering date, maturity etc., making it difficult to separate the confounding effects of stage of development and timing of the compromising event, for example, frost/shattering/pre-harvest sprouting etc.

We do record measurements from our trials. However, the purpose of recording these is to determine if there are agronomic factors that could mask genetic differences in yield performance outcomes. The purpose is not to report these measurements, as trials are not designed and managed to provide accurate comparisons on different agronomic characteristics. Agronomic data suitable for comparison between varieties should be collected from trials designed to specifically capture that data without bias.

However, our agronomic measurements are available to researchers under the NVT Resource Sharing scheme .

To accurately compare performance between varieties, NVT trials only have a single time of sowing for all varieties within a trial.

Frost events are random and will coincide with different growth stages for different varieties sown at the same time. Frosts will have differing levels of impact on yield and quality dependent on maturity of variety at the time of the frost event.

If varieties are frosted, comparative yield performance measurements are inaccurate for predicting variety performance, which is the purpose of NVT. Frosted trial information does not add value to the long-term Multi Environment Trial (MET) data set and could potentially skew the results. The information is therefore ‘quarantined’ to protect the larger NVT data set.

Frosted trial results are reported in the ‘Quarantine Trial Reports’  published on the NVT website for transparency and for local growers. However, these results should not be relied on to make variety choice decisions. Information from frosted NVT trials is not a representation of varietal frost tolerance due to the differing maturity stages of varieties when a frost event occurs.

Quarantining of results occurs for any adverse events that affect trials resulting in comparative varietal performance being biased (terminal heat stress, livestock damage, etc).

NVT recognises stressed trials can provide valuable insights into variety performance, and invests time, money, and resources to extract maximum value from trials affected by stresses (e.g. heat, drought, waterlogging, wind damage, frost etc).

When stress has occurred at a trial, the trial managers assess and score any effects on plots. The statisticians will assess these measurements to determine their significance in improving variety performance in the analysis.

Only trials that are so poor that they can't be used to adequately compare genetics are not released, however, information on these trials can be found in the quarantined trial results.