N. Bas

Genetic diversity in perennial ryegrass and white clover among old Dutch grasslands as compared to cultivars and nature reserves

To support conservation policies for old Dutch grasslands that are still in agricultural use, morphological variation and AFLP‐based (amplified fragment length polymorphism‐based) genetic diversity was studied in perennial ryegrass and white clover populations and compared with the diversity in reference varieties. In addition, AFLP variation was also studied in grasslands located in nature reserves. From principal component analysis (PCA), it appeared that date of ear emergence in perennial ryegrass and characters related to plant vigour in white clover were the main morphological characters separating the reference varieties from the old Dutch grassland populations, and some of the grassland populations from each other. In both species, intrapopulation variation was lower for the reference varieties. Lower heterogeneity within the reference varieties was also found in the AFLP analysis. All common AFLPs observed in old Dutch grasslands could also be found in the reference varieties and nature reserves. Only a small number of low‐frequency alleles found in old Dutch grasslands were absent from the other two groups. However, band frequencies of markers could vary considerably between populations, which may have been caused by selection. Analysis of the AFLP data by PCA distinguished the majority of reference varieties from the old Dutch grasslands, and showed genetic differentiation only between some grasslands. Comparison of old Dutch grasslands with grasslands in nature reserves indicated that basically the same range of genetic variation is covered by the two groups. Our study indicates that the Netherlands harbour a more or less continuous population for major parts of the diversity of perennial ryegrass and white clover. It was concluded that no specific conservation measures are presently needed to maintain genetic diversity of perennial ryegrass and white clover occurring in old Dutch grasslands.

Improved method for fibre content and quality analysis and their application to flax genetic diversity investigations

Abstract Evaluation for fibre content and quality in a breeding selection program is time consuming and costly. Therefore, this study aims to develop a method for fast and reproducible fibre content analysis on small flax straw samples. A protocol has been developed and verified with fibre screening methods used commonly in flax breeding. A large number of different accessions of mostly fibre flax and some linseed, present in the core collection of CGN, were grown under comparable conditions and were analysed for their bast fibre contents by warm water retting and green decortication methods. From the core collection, a selection was made of a number of high, medium and low fibre yielding flax accessions with extremes in stem length, branching or fibre bundle appearance. These were analysed with the novel fibre extraction procedure utilising short autoclave treatment in 0.05 M EDTA as calcium complexing agent. Since 1999, cultivars selected for the core were grown around Wageningen on sandy soils. The fibre content was determined by different methods and a correlation was found between the values obtained by warm water retting and the autoclave procedure. However, the data obtained by green decortication show up to 20% and on average 15% higher fibre content values. This higher value roughly corresponds to the weight of the cuticula and remaining xylem tissue that is more efficiently removed by retting and autoclave treatments. The reproducibility of this fibre content determination method for small straw sample analysis (25 g) is a promising tool for accelerated breeding protocols.

MORE EFFICIENT CONSERVATION AND USE OF VEGETABLE GENETIC RESOURCES IN EUROPE: ECPGR ACHIEVEMENTS AND PERSPECTIVES

The European Cooperative Programme for Plant Genetic Resources (ECPGR) is a regional network funded by the European countries and coordinated by Bioversity International. The Vegetables Network with representatives of 42 countries, is one of the crop specific ECPGR networks (http://www.ecpgr.cgiar.org/ networks/vegetables.html). It consists of six Working Groups (WGs), i.e., on Allium, Brassica, Cucurbits, Leafy Vegetables, Solanaceae and Umbellifer Crops. Sharing responsibilities for the ex situ conservation of European vegetable crops genetic resources is the highest priority of the Vegetables Network. It is foreseen that the rationalization of the collections will lead to higher cost-efficiency, and improvement of plant genetic resources documentation and quality. These efforts will be continued within the framework of the AEGIS initiative (A European Genebank Integrated System) (http://www.aegis.cgiar.org/). Challenges for the Vegetables Network include the identification of the so-called Most Appropriate Accessions (MAA) for each crop for their inclusion in the decentrally managed European Collection, and the development of agreed crop specific technical standards for conservation. Achievements of the Network in recent years include the development of European Central Crop Databases (ECCDBs), quality standards for collection man-agement of seed-propagated crops and cryopreserved material, safety duplication improvement and definition of minimum characterization descriptors. Several EU-funded projects have initiated and accelerated the activities of the WGs. Apart from further improvements within the framework of AEGIS, the Network is planning a number of other initiatives, such as improving collaboration at the global level (Allium), developing molecular characterization protocols (lettuce), filling the gaps in the conservation of wild relatives (Brassica and Umbellifer Crops), and improving the Network’s communication with the scientific community and the public at large.