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Molecular and other markers for establishing essential derivation in crop plants (EDV)

Essential derivation is concerned with defining the boundary of ownership around an existing plant variety. The European Union Plant Variety Rights Office implemented the full provisions of the 1991 UPNC Convention in 1994 (Council Regulation 2100/94. The concept of the dependent variety is, therefore, one of legitimate interest to EU Member States, the Commission and to the plant breeding industry within the EU. Molecular markers are ideal tools for testing essential derivation and to define a notion of minimum distance in a scientific context, and they would provide legislative bodies with a scientific model for tailoring future regulations to the needs of breeders and the public. The project proposes to study different concepts of essential derivation using several DNA markers and a few model species, and will deliver a sound statistical interpretation of these results. The project will deliver a scientific platform for future legislative efforts.

The overall objective of this project is to develop a scientifically based framework for the determination of the essential derivation of plant varieties. The concept of the dependent or essentially derived variety (EDV) arises from the 1991 revision of the UPOV Convention. The resolution of the EDV issue by scientific means is essential to the development of plant breeding and associated industries within Europe.
Essential derivation is concerned with defining the boundary of ownership around an existing variety. If a new variety was found to fall within this boundary, then it would be deemed to be essentially derived (dependent) from the first variety. If, on the other hand, a new variety exceeded the boundary, then it would be a new (independent) variety. Both types of variety are eligible for Plant Breeders' Rights (PBR), but EDVs will be subject to other licensing arrangements and agreements as well.

Progress to Date
1) A forensic approach to rose identification using a small set of highly informative micro-satellite markers has been developed. This is clearly capable of distinguishing between all true varieties and of identifying mutant derived EDV lines.
2) Information on relationships between barley varieties and between closely related barley experimental lines, on either side of the EDV threshold, will guide the decision-making process of breeders and authorities.
3) Maize hybrids and parents have been studied from molecular morphological approaches and statistical analysis performed. The boundary F2/BC1 is widely seen as crucial in EDV issues but results show this boundary is blurred at the genetic level.
4) The methodology for analysing relationships has been devised for use with a variety of data types - molecular and morphological, pedigree and field performance.

We have unequivocally established that ED can be measured using molecular markers. Moreover we have developed methods for its assessment in the three crops under examination. We have developed a number of statistical tools for use in the measurement of EDV and example sets of background data for comparison. In a more generic sense this project has established a framework for the assessment of EDVs in any crop, giving clear principles of approach to the use of various analytical techniques. It is clear that morphological measures are generally inappropriate.

The 1991 UPOV convention introduces the concept of Essentially Derived Varieties, and gives the following examples of methods by which they may be obtained: 'selection of a natural or induced mutant, or of a somaclonal variant, the selection of a variant individual from plants of the initial variety, backcrossing, or transformation by genetic engineering'. We have demonstrated that molecular markers can be used to detect the close similarities between essentially derived varieties and the donor variety in all these cases. Colour sports in roses were used to represent mutants, somaclonal variation was examined using DH barley lines, we have studied the natural variation within varieties to establish the potential for isolating natural variants from an initial variety. For backcrossing, we have looked at each generation of lines in barley up to backcross 4 and a separate population of near-isogenic lines, plus maize F2 and backcross 1 lines. Finally, we have examined transformation by genetic engineering using GM barley and GM maize.

The project has shown that independently bred rose cultivars are genetically more distant than independent barley cultivars, perhaps reflecting the outbreeding nature of rose and the convergence for a limited number of ideotypes and shared pedigree materials within barley. Maize cultivars fall between these extremes, being outbreeding but also sharing common ideotypes. Within varieties of rose there is no problem caused by genetic variation due to the vegetative propagation, whereas species reproduced by seed, like maize & barley, considerable variation within varieties exists. These factors make the detection of EDV in rose where colour mutants are derived from independent varieties considerably more straightforward than in barley and maize. ED situations involving very small genetic changes such as tissue culture, transformation, and selection from a variety are clearly detectable in maize and barley because they do not differ significantly at the genetic level, but there is more of a challenge defining the threshold in backcross situations, as there is overlap between individuals at each cross with individuals of the preceding and proceeding cross. We have paid particular attention to developing statistical tools to tackle this particular area. These observations will be relevant when considering EDV models for other species, as the choice of species for the project has been made to encompass the majority of situations likely to occur in plant breeding.


Scientist responsible for the project

Huntingdon Road
CB3 OLE Cambridge
United Kingdom (The) - GB

Phone: +44 1223 276381
Fax: +44 1223 277602


Project ID QLRT-1999-01499
Organisation NIAB (formally National Institute of Agricultural Botany)
Area 5.4
Start date 01 March 2000
Duration (months) 36
Total cost 2 277 923 €
Total EC contribution   1 364 992 €
Status Completed

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