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Apeldoorn, Netherlands

Eilmann B.,Wageningen University | de Vries S.M.G.,Center for Genetic Resources | den Ouden J.,Wageningen University | Mohren G.M.J.,Wageningen University | And 2 more authors.
Forest Ecology and Management

Forests of the future should be resistant to exacerbating climatic conditions, especially to increasing drought, but at the same time provide a sufficient amount and quality of timber. In this context coastal Douglas-fir (Pseudotsuga menziesii (Mirb.)) is a promising species since it remains productive even under chronic drought. By choosing suitable provenances within the range of Douglas-fir (P. menziesii (Mirb.)) for a given site we can further optimise tree fitness under dry conditions or even increase timber yield.Eighteen coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) var. menziesii) provenances were tested for seedling survival, yield, wood quality, and drought tolerance by taking advantage of a Dutch provenance trial, established in 1971 within the framework of the 1966/1967 IUFRO seed collection program. The site of the Dutch trial is representative for many sites in Central Europe and is characterised by a moderate precipitation and temperature regime. Measurements on height and diameter growth were combined with a dendrochronological study on growth response to drought years.We found a clear latitudinal trend indicating that Douglas-fir provenances from the northern part of the species-distribution range are generally more productive than provenances from the south. In contrast, drought tolerance increased towards the south. This suggests that it is impossible to identify provenances combining maximum productivity with lowest susceptibility towards drought. However, based on the results from the trial we can give recommendations on suitable provenances that are expected to perform best under future conditions in Central Europe. On sites where severe drought events are unlikely to occur in future, fast growing provenances from the north, like Nimkish, should be planted. These provenances respond plastically to drought years, but the strong reduction of tree growth in the drought year itself indicates that these provenances will be harmed by an increasing frequency of drought events. However, on sites where water availability is likely to decrease, provenances from the Olympic Peninsula like Forks and Matlock are very promising since they showed still relatively high yield in combination with a high potential to cope with drought.If summer drought increases in frequency and severity as expected, the latewood/earlywood ratio will be drastically reduced with negative consequences for wood quality and cavitation resistance. However, some provenances, like Marblemount or Matlock, might compensate for the negative effect of summer drought on latewood/earlywood ratio by the contribution of photosynthesis in winter to whole-year carbon stock. © 2013 Elsevier B.V. Source

Odong T.L.,Wageningen University | van Heerwaarden J.,University of California at Davis | Jansen J.,Wageningen University | van Hintum T.J.L.,Center for Genetic Resources | van Eeuwijk F.A.,Wageningen University
Crop Science

Exploitation of the available genetic resources around the world requires information about the relationships and genetic diversity present among genebank collections. These relations can be established by defining for each crop a small but informative set of accessions, together with a small set of reliable molecular markers, that can be used as reference material. In this study, various strategies to arrive at small but informative reference sets are discussed. For selection of accessions, we proposed genetic distance optimization (GDOpt) method, which selects a subset of accessions that optimally represent the accessions not included in the core collection. The performance of GDOpt was compared with Core Hunter, an advanced stochastic local search algorithm for selecting core subsets. For the selection of molecular markers, we evaluated (i) the backward elimination (BE) method and (ii) methods based on principal component analysis (PCA). We examined the performance of the proposed methodologies using five real datasets. Relative to average distance between an accession and the nearest selected accession (representativeness), GDOpt outperformed Core Hunter. However, Core Hunter outperformed GDOpt with respect to allelic richness. The BE performed much better than other methods in selecting subsets of markers. Methods based on PCA showed that, for practical purposes, the inclusion of the first few (two or three) principal components (PCs) was often sufficient. To obtain robust and highquality reference sets of accessions and markers we advise a combination of GDOpt (for accessions) and BE or methods based on PCA using a few PCs (for subsets of markers). © Crop Science Society of America. Source

Maurice-Van Eijndhoven M.H.T.,Wageningen UR Livestock Research | Maurice-Van Eijndhoven M.H.T.,Wageningen University | Hiemstra S.J.,Wageningen UR Livestock Research | Hiemstra S.J.,Center for Genetic Resources | Calus M.P.L.,Wageningen UR Livestock Research
Journal of Dairy Science

Milk fatty acid (FA) composition was compared among 4 cattle breeds in the Netherlands: Dutch Friesian (DF; 47 animals/3 farms), Meuse-Rhine-Yssel (MRY; 52/3), Groningen White Headed (GWH; 45/3), and Jersey (JER; 46/3). Each cow was sampled once between December 2008 and March 2009 during the indoor housing season, and samples were analyzed using gas chromatography. Significant breed differences were found for all traits including fat and protein contents, 13 major individual FA, 9 groups of FA, and 5 indices. The saturated fatty acid proportion, which is supposed to be unfavorable for human health, was smaller for GWH (68.9%) compared with DF (74.1%), MRY (72.3%), and JER (74.3%) breeds. The proportion of conjugated linoleic acid and the unsaturation index, which are associated positively with human health, were both highest for GWH. Differences in milk fat composition can be used in strategies to breed for milk with a FA profile more favorable for human health. Our results support the relevance of safeguarding the local Dutch breeds. © 2011 American Dairy Science Association. Source

Odong T.L.,Wageningen University | Jansen J.,Wageningen University | van Eeuwijk F.A.,Wageningen University | van Hintum T.J.L.,Center for Genetic Resources
Theoretical and Applied Genetics

Definition of clear criteria for evaluation of the quality of core collections is a prerequisite for selecting high-quality cores. However, a critical examination of the different methods used in literature, for evaluating the quality of core collections, shows that there are no clear guidelines on the choices of quality evaluation criteria and as a result, inappropriate analyses are sometimes made leading to false conclusions being drawn regarding the quality of core collections and the methods to select such core collections. The choice of criteria for evaluating core collections appears to be based mainly on the fact that those criteria have been used in earlier publications rather than on the actual objectives of the core collection. In this study, we provide insight into different criteria used for evaluating core collections. We also discussed different types of core collections and related each type of core collection to their respective evaluation criteria. Two new criteria based on genetic distance are introduced. The consequences of the different evaluation criteria are illustrated using simulated and experimental data. We strongly recommend the use of the distance-based criteria since they not only allow the simultaneous evaluation of all variables describing the accessions, but they also provide intuitive and interpretable criteria, as compared with the univariate criteria generally used for the evaluation of core collections. Our findings will provide genebank curators and researchers with possibilities to make informed choices when creating, comparing and using core collections. © 2012 The Author(s). Source

Agency: Narcis | Branch: Project | Program: Completed | Phase: Agriculture | Award Amount: | Year: 2007

The overall objective of the Trust is ¿to ensure the long-term conservation and availability of plant genetic resources for food and agriculture with a view to achieving global food security and sustainable agriculture.¿ In particular, the Trust shall: Endeavour to safeguard collections of unique and valuable plant genetic resources held ex situ, with priority given to the Treaty¿s Annex I and Article 15.1(b) collections; Promote an efficient goal-oriented, economical and sustainable global system in accordance with the International Treaty and the FAO Global Plan of Action; Promote regeneration, characterization, documentation and evaluation of crop genetic resources, and exchange of related information; Promote the availability of plant genetic resources; And, promote national and regional capacity building, including training, as it relates to the above. This project porvides technical support to facilitate the implementation of the Trust¿s crop strategies and regional strategies.

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