Activities on forest gene concervation and tree breeding in Lithuania
| Present status of gene
conservation and tree breeding
Genetic diversity, which characterises the inter- and intra-population diversity within species, aside the ecosystem diversity and species diversity is an important level of bio-diversity. Therfore the conservation of genetic diversity is considered as the key element in conservation of biodiversity and sustainable forestry. However, in Lithuania, the Law of Protected Territories, the Law of Forest, and the Law of Wild Plants, etc., for a long period have not recognised the importance of gene conservation. There were no specialised laws for protection and conservation of forest genetic resources. Botanical reserves and other types of reserves were aimed at preserving endangered species and their biotopes, but are not concerned with conserving genetic diversity as such. In Lithuania, units for conservation of forest genetic resources were not included into register of the territories protected at state level. Only in 2002, the new law on Plant national genetic resources and updated Forest law and law on Protected areas recognized the importance of conservation forest genetic resources.
Conservation of forest genetic resources is co-ordinated and financed by the Department of Forests under the Ministry of Environment of the Lithuanian Republic. The Conception Program for Forest Regeneration that was approved in 1994 includes the prospective development of a basis for conservation of genetic diversity. The Convention for Protection of Bio-diversity signed in June 1992 in Rio de Janeiro was ratified in 1995. The State Program on Lithuanian Forestry and Timber Industry Development (approved in 1996 for period up to 2003) and the Strategy and Plan for Action for Protection of Bio-diversity in Lithuanian Republic (approved in 1997) consider some aspects of forest gene conservation. However, there were no special national program concerned with the development of applied gene conservation and breeding. Just recently (in 2003) the Program for conservation of forest genetic resources was adopted for the 10 year period (2004 to 2014).
During the past 40 years a wide network of units for conventional gene conservation and tree breeding has been created in Lithuania. At present (2003 01 01), the network of forest gene conservation in situ and ex situ, and tree breeding units consists of:
Genetic reserves are designated to preserve genetic diversity of a species over environmentally heterogeneous sites on comparatively small areas (less than 30 ha) by restriction of silvicultural activities. Strict genetic reserves that were established two decade ago to preserve sustainable development of resources in communities of species in environment that is as natural as possible over a large forest area (more than 200 ha) have fail to achieve their destiny therefore recently they were transformed into genetic reserves. The main efforts were placed on Scots pine and Norway spruce. Past work in establishing conventional gene conservation network that safeguarded important populations from cutting should be considered as the first step in creating a functional gene conservation system. Now we need to proceed further in order to secure sustainable gene conservation.
|Unfavourable environmental conditions in recent years showed drawbacks in the conventional in-situ conservation system. Over half of the coniferous genetic resources and a portion of the broad-leaved genetic resources were lost due to combined action of droughts, insect outbreaks, and windfalls, or due to natural succession of tree species. In the period 2001 to 2002 huge areas of ash stands were efected by dieback all over the country. It indicates that we have already experiencing negative consequences of global climatic changes. Based on experience and on new understanding of general gene conservation objectives and principles, the shortcomings of the conventional static forest gene conservation system are outlined below.|
|Photos by Romas Barauskas|
1. In the past, the non-interference approach and management restrictions were based on preservationist conservation objectives were not adequate to the current rapidly changing environment. Therefore the:
2. Natural genetic diversity was insufficiently represented from geographical, population, ecological, and generation viewpoints. In the past:
3. Legislation, financing, and publicity were insufficient to accomplish gene conservation objectives:
These shortcomings call for the urgent development of a new system for sustainable and secure gene conservation that would be flexible enough to cope with rapid environment changes and expansion of human activities into forestlands.
|In 1994, Lithuanian Forest Research Institute in co-operation with other Lithuanian agricultural institutes and universities have started research programe "Plant genetic resources", Lithuania joined to the EUFORGEN program, Nordic gene Bank has started program for support of conservation of genetic resources in Baltic states, in 1998, the long term state research program GENOFUND have been launched. These programs have promoted the re-activating and initiating of new activities regarding forest gene conservation and tree breeding in Lithuania. One of many positive issues of these programs was that they convinced and motivated national authorities to support preparation of new legislation on gene conservation, tree breeding, seed farming, reforestation, etc.|
Participation in activities of three EUFORGEN networks has helped to increase the understanding of new approaches in forest gene conservation and to adjust to new concepts in the preparation of new national strategies, programs and recommendations. As outlined below, there has been much recent progress in forest gene conservation and tree breeding during last decade in Lithuania.
At present, the main emphasis of forest gene conservation and tree breeding in Lithuania includes:
Challenges of gene conservation and tree breeding
The prime objective of gene conservation is to ensure the continuous survival, adaptation, and evolution of a species over unlimited number of generations in a continuously changing environment. The objective of breeding of broad-leaved tree species is to improve human utility features, including: (1) quality of stem and wood, (2) growth, (3) resistance and adaptability while conserving a sufficient genetic variation for each successive cycle of long-term selection, taking into consideration future changes in breeding priorities and climate. In order to achieve these objectives, it is necessary to promote the maintenance of a broad genetic variation and to create favourable conditions for rapid adaptation of each species. One general prerequisite for successful evolution is the regeneration of the gene resource population. Thus, active measures should be taken where there is a difficulty in of maintaining the gene resource population over successive generations.
The conventional static forest gene conservation system of the past is being transformed into a dynamic one that is based on the Multiple Population Breeding System (MPBS) concept. The MPBS concept combines secure and sustainable conservation of forest genetic resources, preparation for possible eco-climatic changes, and efficient tree breeding. The corresponding MPBS scheme for conservation of Scots pine in Lithuania has already been developed (Eriksson & Pliűra 1997). Basically, the same parameters would hold for broad-leaved tree species, with some adjustments based on the results of ongoing research. Knowledge of the pattern and degree of the genetic variation of broad-leaved species that are present in a region will serve as a basis for the national forest gene conservation strategies and programs.
According to the MPBS, a gene resource conservation/breeding population should consist of 10-20 small sub-populations, each with an effective population size of 50 genetic entries. At present, it is assumed that at that size of breeding-gene conservation population (750-1100 individuals) the alleles of frequencies down to 0.01 (uncommon + common alleles) will be sampled and that will provide sufficient genetic variation for both long-term sustainable gene conservation and long-term breeding purposes. In creating breeding lines (with the 10 best families in each) alleles of frequencies up to 0.25 are involved and are sufficient to guarantee diversity and sustainability of new stands, and to provide high genetic gain. In order to capture the adaptations that already are present in different eco-climatic conditions, selecting and sampling should sufficiently cover geographical patterns of species genetic variation as well as eco-climatic conditions. The essence of dynamic gene conservation by using the MPBS concept is to promote adaptation by exposing the gene resource population to natural selection and in turn to evolution in a variety of directions (Fig. 2). Therefore, a gene conservation network of both natural in situ sub-populations as well as synthetic ones ex situ ones ought to be established over a broad array of eco-climatic conditions.
Gene conservation populations should be intensively managed to improve the adaptation of each sub-population, to increase genetic differences between them, to guarantee their sustainability during all periods of ontogenesis, to insure continuous regeneration of the population of the target species, and to protect against all types of damage. In order to minimise costs, gene conservation ought to be carried out jointly with tree breeding and genetic studies.
Recently EUFORGEN has recommended the levels (milestones) of gene conservation activities that ought to be followed on a step-by-step or parallel manner. These levels are:
In order to successfully develop these gene conservation measures and to transform the conventional national system of gene conservation and tree breeding into a dynamic multiple population joined breeding - gene conservation system, we must develop and adopt legal and policy instruments that promote and encourage forest gene conservation in state and private forests. We must:
Constructing a joint gene conservation and tree breeding program
According to occurrence, distribution, population size, social status, stage in ecosystem, and economic importance in Lithuania, tree species could be grouped into 4 groups: (1) common coniferous tree species of high economic importance , (2)common social broad-leaved tree species of moderate economic importance ; (2) for uncommon social broad-leaved tree species; and (3) for rarely occurred asocial broad-leaved tree species of minor economic importance. Some of species characteristics differ from those that species demonstrate in Nordic countries or West Europe.
Four different gene conservation and breeding programs that are based on MPBS and evolutionary approach are under preparation for these groups of broad-leaved tree species:
The networks of gene conservation sub-populations are under creation along defined eco-climatic gradients and forest eco-regions (=regions of provenances) in Lithuania .
In-situ gene conservation sub-populations are under establishment on areas that already have the most suitable conventional gene reserves (Fig. 2). In the regions that have no suitable gene and seed reserves some new sub-populations should be selected. The sub-populations should represent: (a) the forests of the main eco-regions (regions of provenance or breeding zones); (b) marginal populations; (c) populations valuable for breeding; (d) endangered populations; (e) populations that have rare or distinctive features; and (f) populations growing under specific ecological conditions.
The networks of ex-situ sub-populations are being established as regular progeny test plantations. In order to safeguard the evolutionary potential of the species and increase the efficiency of tree breeding the population size of ex-situ gene conservation-breeding sub-populations should be of 200-300 genetic entries. The genetic diversity of ex-situ sub-populations could be increased using material from neighbouring eco-regions and countries. The new generations will be created using open pollination or crossing the best 50 individuals selected within the best 50 families.
The combination of methods for mating, testing, selecting and creating production populations in constructing tree breeding-gene conservation ex-situ programs is selected based on species eco-genetic peculiarities, species economic importance and financial possibilities. Due to financial limitations there is no realistic to plan to use a high number of families from plus trees and representatives of natural sub-populations, and some very intensive methods (e.g., artificial crossing, testing of vegetative progeny, vegetative propagation, etc.) in the first cycles of breeding broad-leaved tree species. The principle scheme (with some alternatives) of multiple-population long-term breeding-gene conservation of non-rare broad-leaved tree species in Lithuania is presented in Figure