F.R. Bach
Frans Richard Bach is currently Forest Officer with the National Forest and Nature Agency, Hørscholm, Denmark. He was previously an Associate Professional Officer with the Forest Resources Development Branch, Forest Resources Division, FAO.
Following up an analysis published in Unasylva, 33(133) (Palmberg, 1981), this article focuses on the progress of a long term FAO Project on Genetic Resources of Arid/Semiarid Zone Arboreal Species for the Improvement of Rural Living. The project is an example of a systematic approach to the conservation of forest genetic resources.
Arid area in the western part of Haryana, India. Annual rainfall in the area is 250 mm
The gene pool of tree species in semi-arid lands is being threatened by increasing pressure progressive desertification. This is occurring at a time when genetic diversity in arid and semi-arid tree species is needed more than ever. Availability of appropriate genetic materials, combined with an increased knowledge on intraspecific variation in tree species, is a prerequisite for the optimal utilization of such species - i.e. matching provenance with site and end-use (FAO, 1981; Palmberg, 1981).
In collaboration with national institutes in developing countries, the FAO Forestry Department is active in promoting the exploration, conservation and improved utilization of genetic resources of tree species in arid and semi-arid zones. Components of such activities are also integrated into FAO field projects where appropriate. For example, the project Development of Genetic Resources of Multipurpose Trees in Sudano - Sahelian Africa is providing technical assistance to 17 countries of western and eastern Africa in collaboration with national governments, the Permanent Interstate Committee for Drought Control in the Sahel (CILSS) and the Intergovernmental Authority on Drought and Development (IGADD). The project has prepared or assisted in the preparation of project documents for genetic improvement programmes in the region; organized meetings and workshops in order to develop network activities; and prepared technical guides and manuals on genetic conservation and seed collection and handling (de Framond, 1990). The FAO/UNEP Project on In Situ Conservation of Forest Genetic Resources, operational from 1985 to 1989, developed pilot activities in a number of countries and regions.
In the early 1970s, the prevailing viewpoint with regard to the fuelwood crisis in the developing world was that the best potential for its resolution lay in the establishment of large-scale plantations of fast-growing species. However, the limitations of this approach soon became apparent, and as early as its third and fourth sessions, held in 1974 and 1977, respectively, the FAO Panel of Experts on Forest Gene Resources called for urgent attention to be paid to slower growing arboreal species that are cultivated for multiple uses such as fuel, food, fodder, soil stabilization, shade, shelter and agroforestry. The Panel recommended concentration on species in arid and semiarid zones, where the fragility of the environment and increasing population pressure were creating the greatest risk of degradation of the resource base and depletion of the genetic resource pool.
Based on the Panel's recommendations, the project on Genetic Resources of Arid/ Semi-arid Zone Arboreal Species for the Improvement of Rural Living was initiated in 1979 (FAO, 1974; FAO, 1977; Palmberg, 1981). Financial assistance was obtained from the International Board on Plant Genetic Resources (IBPGR) between 1979 and 1985, and the project was continued beyond 1985 using FAO Regular Programme funding.
The overall objective of the project is to gather information and genetic material for the conservation, evaluation and characterization of arid and semi-arid zone species that are of vital importance to local rural communities whose only source of fodder, fuelwood and construction timber may be hardy arboreal species. The final goal is a better and more rational utilization of genetic resources on a sustained basis. In addition, the project should help in creating a self supporting network of centres concerned with conservation and seed collection of the species in question (FAO, 1981; Palmberg, 1983; 1984).
The initial phase of project activity, which took place from 1979-1980, was an on-the-ground survey of the needs and possibilities for a cooperative programme in the conservation of tree gene resources in arid and semi-arid areas of Latin America, Africa, India and southwestern Asia. Nine countries - Australia (collection and conservation only), Chile, India, Israel, Mexico, Peru, Senegal, the Sudan and Yemen - were selected as the initial core of participants (they are still actively participating in the project and have been joined by 19 others).
The survey included information on participating institutions; status of conservation and exploration of the priority species (mainly Acacia and Prosopis, as defined by the Panel of Experts on Forest Gene Resources and the participating countries); the need for further conservation and exploration; research on species-specific utilization, country-capacity in seed storage and handling; and type and amount of outside assistance needed (FAO, 1980).
Exploration and collection
The operational phase of project activities was initiated in January 1981, with the exploration and collection of reproductive materials of the tree species/provenances identified in the first phase. The areas considered for action were those receiving less than 500 mm precipitation per year as well as areas of seasonally dry tropical regions that experienced, on average, six or more rainless months per year (Palmberg, 1981).
The exploration component resulted in taxonomy publications on Acacia and Prosopis spp. (FAO, 1983a; 1983b), and the gathering of basic information needed for the seed collection phase. This information was further supplemented during seed collection.
Seed collection of Acacia and Prosopis species from selected natural or naturalized stands was carried out by all countries, while additional seed of Cercidium and Chilopsis spp. was collected in Mexico. All seed lots were collected in accordance with FAO guidelines and were carefully documented in a standard format (see Table 1). The guidelines recommended that collections be made from a minimum of 20 well spaced trees per provenance to avoid genetic relatedness of the mother trees. (Palmberg, 1983; FAO, 1988).. Seed collection was carried out by local institutes in the countries; in some cases (Australia, West Africa, Central America) assistance was also obtained from the Commonwealth Scientific and Industrial Research Organization (CSIRO), the Centre technique forestier tropical (CTFT) and the Commonwealth Forestry Institute (CFI) in Oxford. By the end of 1987, a total of 1600 kg of well documented seed from 281 provenances of 43 species was collected (see Table 1).
The collected seed lots were stored at the DANIDA Forest Seed Centre (DFSC), Denmark. In addition, the CSIRO collected and stored seeds of Acacia aneura from 12 locations in Australia as well as provenances of A. cowleana and A. holosericea, and made these seeds available to the project (Midgley and Gunn, 1985).
Establishment of trials
Distribution of the collected seed lots to a wide range of institutes, including universities, national forest services and research institutes, FAO and bilateral field projects as well as some NGOs, for the establishment of trials in the eight other participating countries was initiated in 1983. Selection of planting sites and of the specific provenances to be tested was based on comparison of the conditions at the site of origin and at the trial site, and the proposed end-use of the plantations. Although in most cases a combination of exotic provenances were tested, local provenances or species were always included as well, following the principle that introduced species should only be given priority in planting programmes if they prove notably superior to local species or provenances grown under the same conditions for all specified end uses (Palmberg, 1981).
TABLE 1. Seed collection 1981-1987*
*Seed stored by DANIDA Forest Seed Centre.
|
Species |
Supplying country |
||||||||||||
|
Number of seedlots collected |
Number of provenances collected |
ARGENTINA |
CHILE |
INDIA |
ISRAEL |
MEXICO |
NIGER |
PAKISTAN |
PERU |
SENEGAL |
SUDAN |
YEMEN |
|
|
Total |
357 |
281 |
3 |
52 |
53 |
4 |
38 |
13 |
21 |
38 |
29 |
24 |
6 |
|
Acacia albida |
12 |
6 |
|
|
|
2 |
|
|
|
|
4 |
|
|
|
A. berlandieri |
8 |
5 |
|
|
|
|
5 |
|
|
|
|
|
|
|
A. caven |
6 |
4 |
|
6 |
|
|
|
|
|
|
|
|
|
|
A. ehrenbergiana |
2 |
2 |
|
|
|
|
|
2 |
|
|
|
|
|
|
A. farnesiana |
16 |
12 |
|
|
|
|
12 |
|
|
|
|
|
|
|
A. nilotica |
10 |
9 |
|
|
|
|
|
1 |
7 |
|
|
|
1 |
|
A. nilotica var. adansonii |
2 |
1 |
|
|
|
|
|
|
|
|
1 |
|
|
|
A. nilotica adstringens |
2 |
2 |
|
|
|
|
|
|
|
|
|
2 |
|
|
A. nilotica indica |
15 |
13 |
|
|
13 |
|
|
|
|
|
|
|
|
|
A. nilotica indica cupressiformis |
8 |
7 |
|
|
7 |
|
|
|
|
|
|
|
|
|
A. nilotica indica jacquemontii |
12 |
12 |
|
|
11 |
|
|
|
1 |
|
|
|
|
|
A nilotica indica var. vediana |
7 |
6 |
|
|
6 |
|
|
|
|
|
|
|
|
|
A. nilotica nilotica |
5 |
4 |
|
|
|
|
|
|
|
|
|
4 |
|
|
A. nilotica ssp. tomentosa |
16 |
10 |
|
|
|
|
|
|
|
|
4 |
6 |
|
|
A polyacantha |
1 |
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
A raddiana |
14 |
7 |
|
|
|
1 |
|
1 |
|
|
5 |
|
|
|
A senegal |
43 |
27 |
|
|
5 |
|
|
4 |
4 |
|
10 |
3 |
1 |
|
A. tortilis |
8 |
5 |
|
|
3 |
1 |
|
|
|
|
|
|
1 |
|
A. tortilis raddiana |
7 |
7 |
|
|
|
|
|
|
|
|
1 |
6 |
|
|
A tortilis ssp. spirocarpa |
5 |
3 |
|
|
|
|
|
|
|
|
|
3 |
|
|
Atriplex repanda |
9 |
9 |
|
9 |
|
|
|
|
|
|
|
|
|
|
Balanites aegyptica |
6 |
6 |
|
|
|
|
|
|
|
|
4 |
|
2 |
|
Bauhinia rufescens |
1 |
1 |
|
|
|
|
|
|
|
|
|
|
|
|
Cercidium microphyllum |
1 |
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
Cercidium praecox |
1 |
1 |
|
|
|
|
1 |
|
|
|
|
|
|
|
Ficus salicifolia |
1 |
1 |
|
|
|
|
1 |
|
|
|
|
|
|
|
Molluga nudicaulum |
1 |
1 |
|
|
|
|
|
1 |
|
|
|
|
|
|
Prosopis sp. |
9 |
8 |
|
1 |
|
|
|
1 |
|
|
|
|
|
|
P. affinis |
1 |
1 |
|
|
|
|
7 |
|
|
1 |
|
|
|
|
P. alba |
7 |
7 |
2 |
5 |
|
|
|
|
|
|
|
|
|
|
P. alba var. panta |
1 |
1 |
1 |
|
|
|
|
|
|
|
|
|
|
|
P. chilensis |
9 |
9 |
|
9 |
|
|
|
|
|
|
|
|
|
|
P cineraria |
23 |
18 |
|
|
8 |
|
|
|
9 |
|
|
|
1 |
|
P flexuosa |
7 |
6 |
|
6 |
|
|
|
|
|
|
|
|
|
|
P. glandulosa juliflora |
1 |
1 |
|
|
|
|
1 |
|
|
|
|
|
|
|
P. glandulosa van torreyana |
12 |
10 |
|
|
|
|
10 |
|
|
|
|
|
|
|
P. juliflora |
1 |
1 |
|
|
|
|
1 |
|
|
|
|
|
|
|
P. Iampa |
1 |
1 |
|
1 |
|
|
|
|
|
|
|
|
|
|
P. pallida |
43 |
36 |
|
|
|
|
|
|
|
36 |
|
|
|
|
P pallida var. armata |
2 |
1 |
|
|
|
|
|
|
|
1 |
|
|
|
|
P siliquastrum |
7 |
7 |
|
7 |
|
|
|
|
|
|
|
|
|
|
P. tamarugo |
13 |
10 |
|
10 |
|
|
|
|
|
|
|
|
|
|
Ziziphus mauritiana |
1 |
1 |
|
|
|
|
|
1 |
|
|
|
|
|
Source: FAO, 1985; 1988
TABLE 2. Seed distribution 1983-1989*
*Seed stored by DANIDA Forest Seed Centre.
|
Species |
Receiving country |
|||||||||||||||||||||||||||
|
Number of provenances received |
Argentina |
Brazil |
Bolivia |
Burkina Faso |
Cape Verde |
Chile |
Denmark |
El Salvador |
France |
India |
Israel |
Jordan |
Kenya |
Mali |
Mexico |
Niger |
Pakistan |
Peru |
Portugal |
Senegal |
Sierra Leone |
Sudan |
Sweden |
Thailand |
Tunisia |
United Kingdom |
Yemen |
|
|
Total |
834 |
36 |
21 |
7 |
44 |
2 |
49 |
24 |
1 |
47 |
81 |
7 |
3 |
49 |
20 |
48 |
7 |
118 |
16 |
16 |
39 |
1 |
31 |
2 |
1 |
35 |
101 |
28 |
|
Acacia albida |
22 |
|
1 |
|
3 |
|
|
1 |
|
|
4 |
|
|
|
|
3 |
|
3 |
1 |
|
|
1 |
1 |
1 |
|
|
1 |
2 |
|
A. berlandieri |
7 |
|
1 |
1 |
|
|
1 |
|
|
|
1 |
|
|
|
|
|
|
2 |
|
|
|
|
|
|
|
|
1 |
|
|
A. farnesiana |
18 |
1 |
1 |
1 |
|
|
2 |
2 |
|
|
|
|
|
7 |
|
|
|
2 |
|
|
|
|
|
|
|
|
2 |
|
|
A. nilotica |
45 |
3 |
1 |
|
|
|
5 |
|
|
3 |
7 |
|
|
|
|
3 |
|
8 |
|
|
1 |
|
1 |
|
|
3 |
8 |
2 |
|
A. nilotica adstringens |
9 |
|
1 |
|
|
|
|
1 |
|
1 |
|
|
|
|
1 |
|
2 |
|
|
|
|
|
|
|
1 |
2 |
|
|
|
A. nilotica indica |
24 |
|
|
|
|
|
1 |
|
|
3 |
|
|
|
|
|
|
3 |
|
6 |
|
|
|
|
|
|
2 |
9 |
|
|
A. nilotica indica cupressiformis |
24 |
|
1 |
|
|
|
|
|
|
2 |
3 |
|
|
|
|
|
|
5 |
|
|
2 |
|
|
|
|
2 |
7 |
2 |
|
A. nilotica indica jacquemontii |
44 |
1 |
2 |
|
|
|
1 |
3 |
|
5 |
2 |
|
|
4 |
|
1 |
|
4 |
2 |
|
3 |
|
2 |
|
|
2 |
12 |
|
|
A nilotica indica var. vediana |
19 |
|
1 |
|
|
|
|
|
|
3 |
2 |
|
|
|
|
|
|
3 |
1 |
|
1 |
|
|
|
|
2 |
6 |
|
|
A. nilotica nilotica |
11 |
1 |
|
|
|
|
|
1 |
|
1 |
1 |
|
|
|
|
|
|
3 |
|
|
|
|
|
|
|
2 |
2 |
|
|
A. nilotica ssp. tomentosa |
36 |
1 |
1 |
|
|
|
2 |
3 |
|
1 |
3 |
|
|
3 |
|
3 |
|
3 |
2 |
|
2 |
|
2 |
|
|
4 |
6 |
|
|
A. raddiana |
25 |
1 |
1 |
|
|
|
1 |
1 |
|
1 |
3 |
|
|
2 |
|
2 |
|
2 |
2 |
|
1 |
3 |
|
|
|
|
4 |
1 |
|
A. senegal |
99 |
3 |
1 |
|
17 |
|
12 |
2 |
|
7 |
8 |
|
|
|
|
5 |
|
19 |
1 |
1 |
1 |
|
|
|
5 |
12 |
5 |
|
|
A. tortilis |
37 |
2 |
|
|
5 |
|
3 |
1 |
|
3 |
|
|
|
|
|
4 |
|
4 |
2 |
|
4 |
|
4 |
|
|
|
4 |
1 |
|
A. tortilis raddiana |
29 |
1 |
1 |
1 |
4 |
|
|
3 |
|
1 |
4 |
|
|
2 |
|
1 |
|
4 |
|
|
1 |
|
|
|
|
|
4 |
2 |
|
A tortilis ssp. spirocarpa |
16 |
1 |
1 |
|
2 |
|
|
|
|
1 |
2 |
|
|
|
|
1 |
|
2 |
|
|
1 |
|
|
|
|
2 |
2 |
1 |
|
Atriplex repanda |
27 |
2 |
|
1 |
|
|
|
|
|
|
1 |
|
|
|
|
4 |
|
1 |
1 |
3 |
7 |
|
4 |
|
|
|
|
3 |
|
Balanites aegyptica |
3 |
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2 |
|
|
|
|
|
|
|
|
|
Cercidium microphyllum |
2 |
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
Cercidium praecox |
3 |
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
1 |
|
Prosopis sp. |
20 |
|
|
|
3 |
|
8 |
|
|
|
4 |
|
|
|
|
|
2 |
3 |
|
|
|
|
|
|
|
|
|
|
|
P. alba |
5 |
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
2 |
|
|
2 |
|
|
|
|
|
|
|
|
P. alba var. panta |
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
P. chilensis |
53 |
2 |
1 |
|
7 |
2 |
|
1 |
|
|
5 |
2 |
|
7 |
6 |
2 |
2 |
7 |
1 |
|
2 |
|
2 |
1 |
|
|
3 |
|
|
P. cineraria |
118 |
4 |
1 |
|
|
|
7 |
1 |
|
13 |
11 |
|
|
11 |
6 |
6 |
2 |
14 |
2 |
4 |
6 |
|
8 |
|
1 |
3 |
13 |
5 |
|
P flexuosa |
11 |
2 |
1 |
|
|
|
|
|
|
|
1 |
|
|
|
|
2 |
1 |
3 |
|
|
|
|
|
|
|
1 |
|
|
|
P glandulosa juliflora |
4 |
1 |
1 |
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
P glandulosa var. torreyana |
13 |
2 |
1 |
1 |
|
|
|
|
|
|
3 |
|
|
1 |
2 |
|
|
2 |
|
|
|
|
|
|
|
1 |
|
|
|
P. juliflora |
8 |
1 |
1 |
|
1 |
|
|
1 |
|
|
|
|
|
|
|
|
|
1 |
|
1 |
|
|
|
|
|
1 |
1 |
|
|
P. Iampa |
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
P. pallida |
57 |
4 |
1 |
1 |
|
|
4 |
2 |
|
2 |
11 |
|
|
12 |
6 |
5 |
|
4 |
|
3 |
|
|
|
|
|
|
2 |
|
|
P. siliquastrum |
4 |
|
|
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
3 |
|
|
|
|
|
|
|
|
|
|
|
P tamarugo |
38 |
3 |
|
|
|
|
|
1 |
1 |
|
5 |
5 |
2 |
2 |
|
|
4 |
1 |
4 |
1 |
|
4 |
|
|
3 |
|
2 |
|
|
Ziziphus mauritiana |
1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
Source: FAO, 1988 (updated)
Guidelines for establishment of the trials, elaborated by FAO, proposed a randomized complete block design, comprising plots of 36 trees (6x6), spacing 3 x 3 m and four replications. The advantages of this design are its suitability for a wide variety of experimental situations and the ease of analysis and interpretation of test results, even in the case of failure of one or more populations (Burley and Wood, 1976). In order to limit environmental variation within the trials, very large trials were avoided and the number of provenances was kept to a maximum of 25 per trial. Standardized forms were prepared by FAO for documenting the establishment of the trials (FAO, 1982).
From 1985 on, as it became apparent that the amount of seed collected was more than adequate for testing in the eight original countries (excluding the ninth, Australia), distribution of seeds was extended to an additional 19 countries for trials and four developed countries for laboratory research and transmittal to bilateral projects (see Table 2). For example, some of the seeds sent to the United Kingdom were used for field trials in Nigeria; another despatch to the same country was used by a student at the University of Bangor for laboratory research. Seed is still available for testing and conservation purposes for other interested countries and institutes.
Senegal and India are important contributors of seeds for the project, and both have also received substantial amounts of seed for the establishment of field trials. A description of their efforts, as representative examples of the work being carried out by participating countries, is presented below.
In Senegal the project is being implemented by the Institut sénégelais de recherches agricoles and the Direction des recherches sur les productions forestières (ISRA/DRPF). Seed collection was carried out primarily in the northern half of the country, in an area stretching from Thies to various parts of the Fleuve du Senegal area (see Map).
Location of seed collection sites and trial sites in Senegal
ISRA/DRPF have established trials using both introduced and indigenous species and provenances in Bandia, southeast of Dakar (1984); Keur Mactar, at Kaolack (1987); Port Drame, at Kaffrine, near the border with the Gambia (1986); and Podor/Nianga, along the Fleuve du Sénégal near the border with Mauritania (1984). The field trials cover a wide range of site conditions with an annual rainfall of 300 to 500 mm in Bandia, for example, and of 150 to 300 mm at Podor (ISRA/DRPF, 1988; 1989).
The largest of the trials is the Bandia trial, where Acacia and Prosopis species of the following origins are being tested:
· Acacia nilotica (India, Senegal)
· A. raddiana (Israel, Senegal)
· A. senegal (Yemen)
· A. tortilis (India, Israel, the Sudan, Yemen)
· A. aneura (Australia)
· A. holosericea (Australia)
· A. cowleana (Australia)
· Prosopis chilensis (Chile)
· P. cineraria (India)
· P. juliflora (Senegal)
An evaluation carried out by ISRA/DRPF in 1988 and field observations from 1990 seem to indicate that local provenances and/or Indian provenances of the species tried are superior in terms of production volume, health, straightness of stems, etc. On the other hand, Australian acacias and P. chilensis are not doing well at this site; although some of these provenances showed good growth in the first years, they now appear unhealthy and have a high mortality rate. Provenances from Israel and Yemen are very bushy and slow growing, but the rate of survival is high. However, it should be noted that these results must be considered as indicative only, given the young age of the trials.
In India the project is being implemented by the Forest Research Institute (FRI) in Dehra Dun, with the active participation of the Central Arid Zone Research Institute (CAZRI); the Institute of Arid Zone Forestry Research (IAZFR) in Jodhpur, Rajasthan; and the Central Soil and Water Conservation Research and Training Institute (CSWCRTI) in Dehra Dun. The FRI has also distributed seeds to a number of state forest services in the country, including those in Punjab, Haryana, Uttar Pradesh, Rajasthan, Gujarat, Maharashtra, Andhra Pradesh, Karnataka and Tamil Nadu. The Tamil Nadu Agricultural University: and a private research institute in Maharashtra have also received seeds for trials.
Seed collections of Indian species and provenances took place in all: the states listed. Collections and trials thus cover a wide range of conditions in the arid and zones of India, in areas with an annual rainfall ranging from only 200 mm (in parts of Rajasthan) to nearly 1000 mm (in parts of Tamil Nadu) (FRI, 1990). It is noteworthy that at some of the sites in southern India, precipitation has been lower than usual over the past years; for example, at a site in Karnataka, which receives an annual average of some 650 mm, less than 300 mm were recorded in 1990.
Showing similar results to those obtained in Senegal, Acacia provenances from Israel and Yemen are small and bushy but hardy. Some provenances from the Sudan also showed this growth pattern; however, Sudanese Acacia tortilis and A. tortilis raddiana seem to be producing straighter stems and higher volumes in a trial in Tamil Nadu. A. holosericea is doing very well at a site in Tamil Nadu, while A. aneura seems less successful in southern India. Again, results must be considered indicative.
Additional seedlots have been despatched to India recently, and complementary trials are being established.
Assessment
As the trials in the participating countries move ahead, the next important stage in the project is the development of an assessment methodology for overall comparison of the results. This "global" assessment will provide results on which to base identification of priority provenances for use in future conservation efforts. It will also facilitate appropriate matching of provenance, site and end-use through increased knowledge of the variation of each species, and the adaptability of specific provenances to a range of environmental conditions.
In 1989, 42 institutes and projects in 26 countries that had established trials from 1984 to 1988 were approached by FAO regarding their willingness to participate in an overall global assessment of the project. Thirty-nine of the institutes approached have indicated their readiness to collaborate over the next two or three years and have generally indicated that there will be a suitable number of successful trials to permit an overall assessment. The DANIDA Forest Seed Centre has agreed to provide technical and financial assistance for the assessment of the trials, which is to be carried out in collaboration with institutes in the countries and FAO.
As indicated by the title of the project, its main objective is the "improvement of rural living". Consequently the tree species included are all of socio-economic value and most have multiple actual or potential end-uses. Therefore, assessment of productivity must also consider various outputs; for example, the production of woody biomass for fuelwood (kg per year per hectare and calorific value); and fodder from leaves and pods as well as its nutritional value and timing of fodder production. Timing is particularly important as tree species and provenances that produce a large volume of high quality fodder during the rainy season, when other fodder sources are readily available, will be less valuable than those that produce a smaller volume of lower quality fodder in the dry season (when other sources are scarce). Other important considerations are potential for utilization as live fencing and wind-breaks; gum production (mainly in Acacia senegal); production of poles for construction and fencing; and suitability for use in soil improvement (primarily in terms of nitrogen fixation). These considerations were included in the original evaluation guidelines distributed by FAO to the participating countries (FAO, 1982).
Assessment methodologies of other ongoing schemes must also be borne in mind, for example, those used in the international trials of Central American dry zone hardwood species, coordinated by the CFI (Stewart, 1989).
Development of the assessment methodology is being done through pilot assessment activities in collaboration with participating institutes in three countries, Senegal, India and Pakistan, where comprehensive and well-maintained trials are available. The pilot assessments in Senegal and India are briefly described below (Bach, Graudal and Moestrup, 1991).
Pilot assessment in Senegal. The Bandia trial, November-December 1990. Three basic assessments have been made at this trial:
· A phenological study covering observations of the stage and conditions of leaves, flowers and fruits.· Measurement covering vertical height; length of the longest stem; diameter at 0.3 m of the three largest stems; number of stems at 0.3 m and 1 m (to reflect how bushy the tree is and thus how useful it is for live fencing); and straightness (number of stems appropriate for use as construction wood).
· Analysis of the fodder value of pods. Pod samples were collected and forwarded to the ISRA livestock section for analysis of the content of dry matter; organic matter; total nitrogen; lignin; calcium; phosphorus; and total digestible nutrient and residual portions. Additionally, the in vitro nutrient value will be estimated by the in sacco method (pod and leaf samples are inserted into the rumen of a living cow and degradation of the fodder is monitored regularly).
Pilot assessment in India. The Jodhpur trial (Rajasthan), March 1991. This trial was established in 1984 by CAZRI and comprises eight provenances of Acacia nilotica, three provenances of A. raddiana, two provenances of A. senegal and three provenances of Prosopis cineraria. The pilot assessment at Jodhpur is focused on the establishment of a biomass regression, i.e. biomass in terms of dry weight of the trees as a function of traits measured directly in the field; for example, height and diameter (Stewart, 1989). Measurements of diameter, vertical height and crown width have been carried out and a count made of the number of stems.
The pilot assessments have, as expected, revealed some difficulties. For example, some of the trees were very bushy and thorny, making traditional measurements such as height and diameter impossible, or at least irrelevant. This was particularly the case with Acacia senegal provenances from the Near East. Given that gum production will probably be the main objective for this species, it will be necessary to develop a technique for monitoring this trait.
In the case of the Indian assessment, the development of the biomass regression necessitated some destructive sampling in this case, i.e. some trees had to be felled, cut up and measured to establish the exact amount of biomass. In the future, based on the results of this test, it may be possible to develop a formula relating biomass to other traits, thus permitting field measurements without felling the trees.
Based on the pilot assessments in Senegal, India and Pakistan, a methodology for overall assessment of the trials established within the framework of the project is currently being developed and will be applied over the coming two or three years.
The results of the comprehensive provenance trials will be of little value, however, if the proven provenances have disappeared by the time the assessment is completed. To reduce this possibility, the collaborating countries were requested to give high priority to conservation by:
· collecting as much reproductive materials as possible from stands likely to be lost or severely depleted in the near future (for conservation ex situ);· safeguarding and managing those stands from which provenance collections were made, at least until such a time when variation patterns and the potential value of the various provenances are known (conservation in situ).
The species and provenance trials, to some extent, can also be considered as conservation stands; however, the relatively small number of genotypes will limit such use. Moreover, potential interspecies and interprovenance hybridization will preclude seed collection in the trials. Therefore, once the best provenances have been identified in each country, it is recommended that additional seeds (currently in storage) be procured for locally established seed-stands as ex situ conservation stands. These stands will need to be limited to one provenance each; be large enough (8 to 10 ha) to contain a broad genetic base; and be isolated from pollen contamination of other hybridizing species and provenances (FAO, 1988).
When the results of the assessment become available, the next step will be their application. This will include the establishment of in situ and ex situ conservation stands of valuable provenances and, ultimately, larger-scale utilization of appropriate provenances.
The assessment is likely to call for additional research activities. Given that a multipurpose tree stand can be managed for fodder, fuelwood and/or other uses, priorities must be defined when species and provenances are selected. Management regimes will have to be specified according to species' characteristics as well as end-uses. Results from the present trials may help to identify provenances that merit testing under more specialized management regimes in new trials.
Seeds are still being distributed by DFSC within the framework of the project. The seeds will be used for ex situ conservation stands, in situ seed-stands or more specialized trials as discussed above. Establishment of trials in accordance with the original guidelines (FAO, 1982) is also an ongoing activity in areas where additional information on performance of the various species and provenances is needed.
The species covered under this project are only a fraction of those that merit urgent attention, and the number of countries and institutions that are directly collaborating in the effort is undoubtedly small. However, the project continues to act as a catalyst, focusing action and attention on the importance of gathering genetic materials and information on arid and semi-arid zone woody species. The project also demonstrates one concrete way of meeting a broader challenge: the conservation of our heritage of genetic resources and the utilization of these resources for the betterment of life, particularly in rural communities.
Bach, F.R., Graudal, L. & Moestrup, S. The FAO Project on Genetic Resources of Arid/Semi-arid Zone Arboreal Species for the Improvement of Rural Living, a brief outline paper presented at the Winrock - F/FRED Workshop on MPTS Assessment Methods, Nakorn Pathom, Thailand, 12-17 May 1991. (unpubl.)
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FAO. 1983d. Collection, handling, storage and pre-treatment of Prosopis seeds in Latin America. Rome, FAO.
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FAO. 1983f. Seed insects of Prosopis species. Rome, FAO.
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FAO. 1988. Final statement on the FAO/IBPGR/UNEP Project on Genetic Resources of Arid/Semi-arid Zone Arboreal Species for the Improvement of Rural Living, 1979-1987. Forest Genet. Resour. Inf., 16: 2-8.
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ISRA/DRPF. 1988. Evaluation des résultats obtenus à Bandia en 1987- comportement de différentes espèces et provenances d'Acacia sp. et Prosopis sp. au Sénégal. Dakar, Sénégal.
ISRA/DRPF. 1989. Essai comparatif de quatre provenances d'Acacia nilotica a la station irriguée de Nianga/Podor Vallée de Fleuve Sénégal. Dakar, Sénégal.
Midgley, S.J. & Gunn, B.V. 1985. Acacia aneura seed collections for international provenance trials. Forest Genet. Resour. Inf., 13: 21-29.
Palmberg, C. 1981. A vital fuelwood gene pool is in danger. Unasylva, 33(133). 22-30.
Palmberg, C. 1983. The FAO Project on Genetic Resources of Arid and Semi-arid Zone Arboreal Species for the Improvement of Rural Living (progress report). Forest Genet. Resour. Inf., 12: 32-35.
Palmberg, C. 1984. Genetic resources of arboreal fuelwood species for the improvement of rural living. In J.H.W. Holden and J.T. Williams, eds. Crop genetic resources: conservation & evaluation. London, George Allen & Unwin Ltd.
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