Guidance

DUS trials – information for trial operators

Published 11 December 2024

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This publication is available at https://www.gov.uk/government/publications/vcu-and-dus-trials-procedures-for-trial-inspection-and-validation/bbec1049-7025-4586-83e3-a87949a00fc5

These procedures set out how to conduct official measures for distinctness, uniformity and stability (DUS) trials under Regulation 9 of the Seeds (National Lists of Varieties) Regulations 2001 (as amended). 

1. Introduction to DUS trials 

An agricultural plant variety is accepted by the national authorities on to the Great Britain (GB) and Northern Ireland (NI) variety lists in accordance with the provisions of the Seeds (National List of Varieties) Regulations 2001 and the Seeds (Variety Lists) Regulations (Northern Ireland) 2020. 

It is a condition of acceptance, under Regulation 5(3) (b) of the Seeds (National List of Varieties) Regulations 2001 and Regulation 5(5) (b) of Seeds (Variety Lists) Regulations (Northern Ireland) 2020, that the variety is stable and sufficiently uniform as described in paragraphs 2 and 3 of Part 1 of Schedule 2. 

Distinctness, uniformity and stability (DUS) is assessed by tests and growing trials in accordance with the appropriate protocols and procedures. 

2. Purpose 

The requirements for conducting inspection, technical and official supervision of growing trials, tests, and assessments in relation to official examinations of DUS of varieties of agricultural crops entered for variety list trials are set out in these protocols. 

3. Scope 

These procedures apply to all species of agricultural crops, vegetables, potatoes and herbage entered for GB and NI variety list trials. 

4. Responsibilities 

The trial design and data handling of growing trials, tests, and assessments outlined in these procedures are carried out under the responsibility of the national authorities.  

Regarding Great Britain, this is overseen by the: 

  • Secretary of State for Environment, Food and Rural Affairs 

  • Scottish Ministers 

  • Welsh Ministers 

Regarding Northern Ireland, this is overseen by, the Minister for Agriculture, Environment and Rural Affairs in Northern Ireland. 

The trials are supervised by officials of the national authorities:  

  • Animal and Plant Health Agency (APHA)  

  • Scottish Government 

  • Department of Agriculture, Environment and Rural Affairs for Northern Ireland 

The procedures are authorised by the national list and seeds committee (NLSC). They cannot be amended without its approval. Requests and suggestions for amendments to DUS procedures should be put in writing to APHA.  

Read more about official supervision audits 

These procedures are administered by: 

Plant Varieties and Seeds   
Animal and Plant Health Agency (APHA) 
Eastbrook 
Shaftesbury Road, 
Cambridge  
CB2 8DR 

Email: pvs.helpdesk@apha.gov.uk

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