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Grain the advantage

Innovations in plant variety testing in Europe are laying the foundation for more sustainable agriculture. breeding better crop varieties is an essential component in the development of sustainable agricultural production systems.

Advances in plant variety testing can help breed better resilience traits to preserve crop yields

Innovations in plant variety testing in Europe are laying the foundation for more sustainable agriculture. Breeding better crop varieties is an essential component in the development of sustainable agricultural production systems. Plant breeding has a demonstrated track record of success in driving agricultural productivity and profitability. However, increased agricultural productivity needs to be balanced against sustainability challenges.

Plant breeding develops innovative new products (varieties), and needs an intellectual property framework that fuels continued progress by enabling seed companies to profit from their sale.

Distinctive strains

“New varieties are protected by a grant of plant breeders rights (PBR), similar to a patent, granting exclusivity to the breeder or their licensees for a period of 25-30 years, after which seed of the variety may be produced by anyone,” explains Senior Research Officer Dan Milbourne. “To acquire PBR, new varieties undergo a testing process that establishes that they are sufficiently different to all other previously registered varieties of the same species, and have stable and consistent features.” This process is called distinctness, uniformity and stability (DUS) testing. In the EU, breeders can submit their variety to any of a number of recognised examination offices (EOs), where they will be placed in multi-year comparative trials with all existing varieties and other new entrants. Depending on the species, numerous morphological and developmental characteristics are measured in the new candidates, continues Dan. “Essentially, the new variety must be measurably different in at least one way to all other varieties (distinctness) and must exhibit all measured characters consistently across the planted variety (uniformity) every time it is sown (stability). Once these conditions are met, the new variety is given a grant of PBR and placed on the EU Common Catalogue of Plant Varieties.”

Value propositions

DUS benefits the breeder, and creates the impetus for novel variety development, but doesn’t generally address performance. To ensure this, plant varieties undergo a second process called value for cultivation and use (VCU) testing. In the EU, VCU testing is carried out on a country-by-country basis; new varieties are subjected again to multi-year comparative trials to test whether they offer value in the specific environment and production system of that country.

Dan explains: “VCU evaluates varieties on the basis of characteristics such as yield, disease resistance and quality, and new varieties must represent advances in some or all of these characteristics. Successful completion of VCU trials allows a variety to be placed on the National List, which is a prerequisite for the sale of seed of that variety in the country.”

INVITE the comparison

Official variety testing acts as the ‘gatekeeper’, directing the types of varieties that can reach the marketplace.  Teagasc is part of an EU Horizon Research and Innovation project called INVITE (Innovations in Plant Variety Testing in Europe). The project started in 2019, involves 29 partner organisations from 13 countries and works on ten major species that represent crop categories for which there is significant use and breeding activity in the EU.

The goal, explains Dan, is to “foster the introduction of new varieties with high resilience to biotic and abiotic stresses, high adaptation to sustainable management practices and high resource use efficiency by advancing the state of both DUS and VCU testing.” To achieve this, continues Dan, “INVITE is identifying bioindicators associated with plant resource use efficiency, sustainability and resilience. Further, the project is developing new phenotyping and genotyping tools to measure these bioindicators, and developing statistical tools to predict variety performance under a range of environments and crop management practices”. The tools and methods will be made available for examination offices and post-registration organisations to improve efficiency and accuracy of DUS and variety performance testing. The aim is to better integrate sustainability criteria in these processes and to act as a driver for the development of sustainable varieties.

Spaced perennial ryegrass plants under evaluation

Split the difference

Within INVITE, Teagasc is responsible for tasks in two crop species important to Ireland: wheat and perennial ryegrass (PRG). For PRG, Teagasc is addressing an emerging problem in the scale of trials associated with DUS testing, explains Dan. “New PRG varieties have to be tested against all of the varieties already on the common catalogue. DUS for PRG is based on about 20 individual morphological and developmental characteristics that have to be scored on 60 individual plants for each of the hundreds of established and candidate varieties. Managing and phenotyping these extensive trials is increasingly difficult because of the size of the trials and number of detailed measurements to be taken.”

One potential solution is to identify subsets of established varieties in the common catalogue that would be suitable for comparison with new candidate varieties, reducing the total number of varieties that need to be planted in each round of testing. Teagasc and collaborators at the James Hutton Institute (Scotland) and INRAE (France) have combined DUS data from over a decade of trials with tens of thousands of genetic markers to begin the development of such approaches. They are also developing robust, cost-effective  genotyping assays for routine use by EOs.

Developing resilience

Teagasc is also involved in developing resilience bioindicators for use in VCU testing, through work being led by Ewen Mullins, Head of Crop Science at Teagasc. Septoria tritici blotch (STB) is caused by the fungal pathogen Zymoseptoria tritici, and is the most prevalent disease for wheat production in Western Europe. Currently, there is no wheat variety available with durable resistance to STB, meaning farmers rely heavily on the use of fungicide to preserve yield. “Prior to the appearance of visual STB symptoms,” Ewen explains, “there is a symptomless latent period of up to 30 days, during which STB advances unchecked through the host plant, followed by rapid spore production.”

Previous work at Teagasc showed that a longer latent phase is a desirable trait to define quantitative and durable resistance of wheat against STB. In INVITE, Teagasc is developing molecular diagnostics tools to measure this phenomenon by tracking STB build-up in the latent phase. This could be used in both breeding and in VCU testing to identify STB-resistant varieties. Other highlights in INVITE include development of the use of genetic markers to directly identify genes conferring disease resistance traits; advances in drone and ground-based image analysis using hyperspectral and visible wavelengths to improve data capture of traits in large-scale trials; development of statistical methods allowing testing networks across Europe to share data more readily; and the development of variety-choosing tools for growers, based on economic and sustainability criteria.

Dan concludes: “Improvements to variety testing driven by the participation of research organisations, breeders and variety testers in INVITE will help underpin the development of the next generation of varieties for a more sustainable European agricultural system.” 


The authors would like to acknowledge the contributions of Stephen Byrne and Manfred Klaas in carrying out the work described in wheat and PRG at Teagasc. 


The INVITE project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 817970.


Dan Milbourne
Senior Research Officer, Crops Research Centre, Teagasc Oak Park.

Ewen Mullins

Head of Crop Science, 

Teagasc Oak Park.


[pic credits] Teagasc