Questioning DUS to Better Adapt to Population Varieties

European regulations are now allowing new types of plant reproductive material to be marketed for organic agriculture, characterized by their high diversity, which poses challenges for DUS (Distinctness, Uniformity, and Stability) testing. 

Victor Nelaton, a trainee at GEVES from March to August 2024 as part of the MOBIDIV research project, explored this issue by collaborating with various teams in the Variety Study Department and the biostatistics team. His internship aimed to clarify the motivations behind the adaptations to European regulations, gather insights from research and breeding stakeholders regarding these changes, and identify methods for adapting DUS examinations for highly diverse varieties without significantly increasing costs, according to a press release.

European Regulation 2018/848 introduces two new categories: Organic Heterogeneous Material (OHM) and Biological Varieties Adapted for Organic Production (VBAPB). OHMs can be marketed with simple notification and do not require DUS testing. They consist of highly diversified and partially evolving populations resulting from the crossing or co-cultivation of varied components, representing a broad genetic base. VBAPBs include both varieties and populations that benefit from relaxed DUS requirements for uniformity, along with a VSCU (Variety Specific Control Unit) tailored to organic agriculture conditions for the relevant species. Additionally, a new European regulation on Plant Reproductive Material is under discussion, which could further open the market to new heterogeneous materials. Therefore, it is essential to investigate these developments.

Discussions with colleagues from the Variety Study Department (SEV) and those involved in organic agriculture reveal that the adoption of MHBs (Multipurpose Heterogeneous Breeds) is still ongoing. The reasons for developing and using MHBs include basic material needs, curiosity trials, innovations, and rapid adaptation. However, commercial risks associated with their broad definition and reduced controls may hinder their observation until a potential boom occurs. Future notifications regarding MHBs, currently confidential with only one wheat MHB reported in France, require careful monitoring.

DUS management of VBAPB (Biological Varieties Adapted for Organic Production) can leverage existing experience with various populations, including vegetables, hemp, and recently sunflower and maize. The main tests studied—homogeneity and distinctness—can be assessed through expert evaluation or statistical analysis. This research has identified approaches to handle heterogeneous populations by adapting tests based on specific traits.

The internship also highlighted the need for expert mobilization to extend beyond testing methods to better understand DUS implications and acceptable varietal standards for these materials. Additionally, it fostered dialogue between variety and biometry experts, facilitating cooperation and clarifying expectations in organic breeding. Ongoing discussions among examination offices, operators, and UPOV methodological groups could lead to a broader selection of methods for conducting DUS trials, allowing for better adaptation to the nature of the varieties studied.

The post Questioning DUS to Better Adapt to Population Varieties appeared first on Seed World.

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