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A comparision of conventional and molecular methods for DUS testing of wheat. - VS0118

Newly bred varieties (cultivars) of crops have to undergo statutory testing before being marketed in the UK. Part of this testing is to determine their Distinctness, Uniformity and Stability (DUS). This is currently carried out using tests almost exclusively involving the observation of morphological characters. The main objective of the proposed research programme is to evaluate the potential of molecular markers (DNA profiling methods) in DUS testing of plant varieties and develop an optimised and efficient operational system for their use. Wheat will be used as a model crop, and a decision will be taken within the project on the additional/alternative use of barley. Sequence tagged site DNA microsatellites (simple sequence repeats, SSRs) will be the profiling method of choice. In both species, many • SSRs are either published, publicly available or can be obtained by NIAB through involvement in other research projects. Their use has been largely optimised and their value for discrimination between varieties demonstrated. This project will obtain, optimise and test a number of SSR markers for wheat, and focus on assessing the umfomaty of varieties with regard to SSRs. A `test set' of suitable primers that could be used in DUS testing will be developed and evaluated. This evaluation will be achieved by undertaking a parallel running exercise in which the results obtained from testing as carried out using the current system will be compared with those that would be obtained if the SSR test set were used. The SSRs will be analysed using an automated separation and detection system, and the efficient throughput of analysis maximised. One of the stated MAFF PVSD policy objectives is to ensure the evolution of efficient and affordable testing procedures, as well as to increase the science base underpinning statutory testing and contribute to the development of harmonised systems. Molecular markers have the potential to contribute towards an improved, efficient and cost-effective DUS testing procedure, but this potential needs to be assessed systematically. The results from this project will form a coherent assessment of the application of DNA profiling to plant variety testing and hence allow its potential to be evaluated objectively.
The overall objective of this project is to assess the uniformity of varieties of wheat with respect to DNA microsatellites, to develop test sets of primer pairs, to evaluate their application in DUS testing and to devise an efficient and optimised operational system for their use.
This will be achieved through the following series of objectives:
1. Obtain 50 SSR markers for wheat

2. Optimise PCR and analysis conditions for the separation of these SSRS

3. Design primers to facilitate maximum multiplexing of these SSRs

4. Examine the polymorphism of 10 current varieties using these SSRs

5. Assess the uniformity of 48 individuals from each of these 10 varieties, to determine the most useful SSRs in terms of both distinctness and uniformity (the test set)

6. Analyse 40 of the current National List varieties for polymorphism, using the test set

7. Analyse 40 of the current National List varieties for uniformity, using the test set

8. Examine 10 selected candidate varieties (D and U) with the test set

9. Carry out a more complete `parallel running' exercise (D and U) with the test set

10. Examine 10 selected varieties using the tests set to analyse at least 5 seed lots of each variety. 11. Devise a SSR-based testing system optimised for maximum throughput and efficiency.
Project Documents
• Final Report : final report or cereals DUS testing   (334k)
Time-Scale and Cost
From: 1999

To: 2002

Cost: £267,275
Contractor / Funded Organisations
National Institute of Agricultural Botany
Molecular Biology              
Plant Varieties and Seeds              
Plants and Animals              
Technology Transfer              
Variety Testing              
Fields of Study
Plant Varieties and Seeds