Report from Year One (Summary)
01.02.2002 - 31 .01.2002
An assessment of the genetic diversity and potential of European ash is being made by taking measurements and growth data from existing provenance trials and by using molecular marker analysis. Morphological and growth data has been collected and the first analyses have shown significant variation among provenances.
Evaluation of existing provenance trials of ash Fraxinus excelsior
A scheme for grading ash forking
Furthermore, within the best performing provenances, plus trees have been selected and propagated by grafting. First results have shown significant differences between provenances for height and circumference data and genotypic heritability varied between 0.32* and 0.76*** on the two sites examined. The coefficient of phenotypic variation decreased with time; it ranged from 15-19% for data collected in 1990 to 5-6% for data collected in 2000. The analysis of data on stem form and crown form showed very highly significant differences among provenances and heritability was characterised as medium to very low (from 0.68 **** to 0.26 NS). Provenance effects were also very highly significant for frost damage at two sites and genotypic heritability was good (from 0.60 *** to 0.72***). The genotypic hertabilities and gains were computed after a multi site analysis of all characters measured. This showed that provenance effect was highly significant for height growth but not for height increment and stem girth. Height heritabilites were 0.78*** from 1990 growth data, decreasing to 0.53** for 2000 data. Provenance effect was at least, significant for crown and stem form giving genotypic heritabilities from 0.44* to 0.77***.
Ash seeds have being collected, distributed and stratified by the 7 partners who will establish the European provenance trial. Each partner will test a core collection of 30 provenances collected in diverse geographic regions within the natural European of ash.
An assessment of nuclear and chloroplast DNA markers was made for the studies on genetic diversity, gene flow and hybridisation. Five microsatellite markers were agreed as useful. The first estimates of genetic diversity using theses markers showed a high level of diversity within populations. However, more detailed analyses showed a deficiency in heterogyosity in some populations which may indicate a higher level of inbreeding than previously expected.
Plus trees were identified among the trees in provenance trials. They were characterised and conserved in the nursery by collecting and grafting scions from them onto ash rootstocks. The best trees in the best provenances have been conserved in this way. This material is then used to establish shoot cultures and to develop an effective system for large scale micropropagation. Established shoot cultures from selected trees were successfully distributed to five institutional and commercial partners for bulking up and for experimentation.
However, the presence of endogenous bacteria was detected and their presence reduced the efficiency in propagation. Methods for sterilising buds and for establishing cultures were investigated. It was easier to establish sterile and viable cultures from seedlings than from grafted selected trees.
Shoot cultures of selected ash trees in the micropropagation phase
Rooting of selected ash trees in the micropropagation phase
Methods were developed to improve the success in sterilising buds and in establishing viable cultures. These included using a heat treatment to break the dormancy in winter buds and a new formulation of the growth medium. Once the cultures were established in vitro, they could be micropropagated by using apical or axillary buds as explants. Rooting occurred spontaneously and plants were weaned to the glasshouse. Somatic embryogenesis was also demonstrated in ash for the first time and further development of this system of propagation has much potential. Experiments were set up to induce flowering in ash trees in the nursery by applying different regimes of drought stresses. First measurements indicated a decrease in stomatal conductance in accordance with the level of the applied drought stress.
Methods to survey the end users of ash were determined in the context of identifying the key players who will affect the adoption of any new technologies (or germplasm) in relation to ash. The existing state of the art in adoption models has been reviewed. Based on this, the methods were developed to conduct the survey in relation to this project. The participants who will constitute the Consultation Panel of end users have been identified among the European partners in this project. They will act as an important source of information in the market for ash as well as on other aspects related to ash improvement.
Benefits and Beneficiaries
European users of ash include nurseries, foresters, landowners, foresters, local communities, craftworkers, furniture makers, saw mills and environmental groups. The benefits from the project will be to:
- Obtain a genetic evaluation of the ash tree, how it breeds, reproduces and how its growth potential and performance varies depending on its region of origin. This will lead to defining guidelines on how to manage ash woodlands for their multi functional purposes of maintaining biodiversity as well as for producing high quality timber at economic prices.
- Provide a scientifically sound method for genetically improving/breeding ash while at the same time, ensuring the conservation of genetic diversity in further generations of trees. This will be facilitated by the establishment of the European Provenance trial for ash. Planting ash material from over 30 different geographic regions, in 8 different European sites, in a fully replicated trial will provide a very useful resource for establishing the range of growth potentials in ash and the limits for its genetic improvement.
- Provide alternative strategies to genetically improve ash. On the one hand a low intensity programme can be employed by selecting at the provenance level. On the other hand a more intensive approach is possible by using controlled crosses and vegetative propagation. The development of efficient methods for large scale vegetative propagation and for manipulating flowering will greatly facilitate this process. Results from this project will offer alternative strategies to improve and manage the genetic resource of ash.
- Identification of the factors which influence the decisions of farmers/foresters to grow ash trees will be beneficial to those involved in producing genetically improved materials. The important needs and expectations of end users will be identified as well as a general view of the market situation for ash in Europe.
