Exploration, identification and description/documentation of neem seed sources in its natural distribution and among land races are the first activities to be undertaken in any neem selection and improvement programme.
Several schools of thought exist regarding the definition of the term "provenance". Further, the term "origin" is used by the OECD to refer to natural populations only. To avoid confusion the term "seed source" is used in this document initially to mean the exact location where seeds have been collected, with no genetical implication. When trials are established, the term "provenance" will have to be used to refer to the plants in the nurseries and trials.
The present guidelines, based on a proposal by the DANIDA Forest Seed Centre, Denmark, were discussed and approved for implementation by the International Neem Network in the Second Consultation on Neem Improvement, Jodhpur, India, 28 February - 4 March 1994.
The objective of these guidelines is to provide a common procedure for seed source exploration, identification and description. A common procedure is necessary
These guidelines should be implemented by all the Network collaborators.
They may also be useful to any other neem selection and improvement programme.
The objective is to identify and describe/document seed sources to represent the ecoclimatic and presumed biological variation of neem in the country.
Neem may occur in discontinuous stands in very varying ecological conditions, generally scattered over large areas of fairly uniform ecological conditions, or as roadside/avenue trees, or in small or large stands, etc. Geographical factors that could cause variation in tree species would be for example: north-south due to day length, or temperature changes, altitude due to temperature, dry-moist, and topography, aspect, and soil. North-south, altitude, dry-moist may give rise to a continuous type of variation, whereas the others could cause a discontinuous form of variation. It is generally assumed that the patterns of genetic variation would reflect the ecoclimatic and geographic variation.
Within each country major ecoclimatic zones should be defined based on latitude, altitude, climate, forest or vegetation types, topography, etc. A minimum of one seed source of neem should then be identified to represent each zone. If the total number of seed sources are considered "too large" some ecoclimatic zones may be combined for the first sampling.
The total number of seed sources to represent the variation of neem in one country will of course depend on the extent of the species range and the diversity of the eco-geographical zones in which it is found. To give an order of idea, 60 seed sources were identified in 8 ecoclimatic zones in India, and 40 seed sources in 4 ecoclimatic zones in Thailand.
The seed sources proposed for inclusion in the international trials will be selected among all the seed sources which will be identified and documented in all the participating countries, to represent a good sample of geographical and ecoclimatic variation.
Natural tree stands will first of all be considered for sampling.
Man-made plantings originating from, and located in the vicinity of, natural tree stands may be included.
Seed sources from a number of countries in Africa, Latin America, and
South East Asia with no natural neem, will also be included. These are
often called "land-races", ie. populations that have been through 1 or
more generations of adaptation in the country.
The area must be sufficiently large to ensure possible future bulk collection, regular in shape, and of reasonable uniform conditions in respect of climate, aspect, topography, and major soils. In Thailand, for example the areas of the seed sources defined vary between 30 and 900 hectares with an average around 200 hectares. The number of trees per hectare varies greatly, but will often be less than one. The estimated number of fruit that may be produced varies between 12,000 and 3,600,000.
The boundaries must be clearly defined and observable, or easily established,
in the field. Typical boundaries may be roads, rivers, mountain ranges,
ravines, lakes, forests, and of course international frontiers. In some
cases when a stand extends for miles in all directions, with no obvious
boundary in one or more directions, it may be necessary to define an arbital
boundary. This may be a compass direction from a well known and easily
observable fix-point, viz a road junction or a temple.
Ultimately a careful description of each identified seed source must be made. The purpose is to ensure that any additional collection can be made in the same area. The description will include information of administrative regions (state county, province, municipality, nearest town, village), locality name, boundaries, latitude, longitude, altitude, climate and forest/vegetation type, size of area, seed production potential, as well as average best seed collection period.
The information must include three types of maps: i) country map showing approximate location in country, ii) smaller-scale map showing enough details to locate seed source in relation to a widely known town, mountain, locality, and finally iii) a map in scale 1:20,000-1:50,000 where the exact boundaries of the seed source are clearly seen. The boundaries shown on the map must be on clearly identifiable also in the field. When detailed maps are not available, a hand-drawn map of the seed source boundaries will be established.
It is recommended that, for each country, all identified seed sources are mapped, super-imposed on ecoclimatic zones.
Appendix A gives the standard form to be used in the Network for the description/documentation of the seed sources (completed for a Thai seed source as an example).
It may however be impossible to obtain all the required information at a time. In a first time, as soon as possible, a minimum set of information should be made available for each seed identified.
The minimum set of information on seed sources includes:
Appendix B gives an example a listing of minimum information for some of the neem seed sources in Thailand.
SEED SOURCE NAME: Ball Ko Saliam
LOCAL SEED SOURCE CODE:
SPECIES (botanical): Azadirachta indica var. siamensis Val., Azadirachta
indica A. Juss. (delete what is not appropriate)
(vernacular): Neem, Nim, Nimba, Limbo, Margosa, Mai Sadaw, Mai
Saliam,
Map ref.: Thailand 1 :50,000, ed. 1- RTSD, 1969, series 1301 sheet 4846 III. Thailand Highway Map, 1: 1,000,000, Roads Assoc. of Thailand, 1988. World (S.E. Asia) 1:1,000,000, Series 1301, Ed. 7-AMS, sheet NE 47, 1971. Refer to annex A I-A3 for maps.
Latitude: 18º 42' North
Longitude: 99º08' East.
Altitude: 300 m.a.m.s.l.
Country: Thailand.
Province: Changwat Chiangmai
Adm. unit: Amphoe Meuang
Tambun: San Kampaeng.
Detailed description of location: North of the road passing south through the villages Bank Ko Saliam and Ban Rong Gong Khao. Ban Ko Saliam is situated ca. 6 km south of San Kampaeng. Starting just north of Wat Ko Saliam (and a factory) proceed southeast along track to Ban Nong Niang and Ban Mae Hat Luang. In this village turn west to Ban Rong Gong Khao, then north until Ban Ko Saliam.
The total area is estimated at 115 hectares.
The trees arise from natural regeneration and are likely to be remnants of Neem occurring naturally, and have been slowly moving into the area (see "Neem in Thailand" by Lauridsen et al., Forest Genetic Resources Information No.19, FAO, Rome, 1991).
The site is flat. The area is located on a plain (paddy fields). The soil are stiff, alluvial, podzolic soils, which are fertile but poorly drained. Typically the neem trees are located on termite mounds, which may have a higher calcium content and pH than the other soils, or on dykes framing the individual rice fields.
The rainfall is 1271 mm per year, with a pronounced dry season during the months of Nov-April. The climate is affected by the mountains surrounding the plain. A detailed description of the climatic conditions is attached as annex B. Nearest weather station is at Chiangmai.
The neem trees are found in scattered groups or as single trees. A survey by two lines 1000 x 2 x 15 and 1200 x 2 x 15 meters in the northern, respective the southern, end gave the following statistics:
Northern line (representing 60% of area): 12 groups of trees, corresponding to 4 groups per hectare, or 6 trees per hectare. Average spacing 47 x 47 m, varying from 28 to 300 m. Mean tree height is 10.3 m +/- SE 1.4 m, diameter 26.7 cm +/- SE 1.2 cm. The trees have been repeatedly coppiced, but are healthy and vigorous.
Southern line (representing 30% of area): 5 large trees, or 1.4 tree per hectare.
The total number or trees in area may then be estimated at some 478, i.e. around 4 trees, or groups of trees, per hectare.
The area is farmland, mainly paddy fields. The potential tree association is dry, mixed deciduous forest with teak. Only few species associated with this type are occurring in the farmland, viz Morinda citrifolia and Combretum quadrangulare.
The western boundary is well defined being the road between the villages Ban Ko Saliam and Ban Rong Kong Khao. Similarly the road from Ban Rong Kong Khao to Ban Mae Hat Luan forms the southern boundary. The north-eastern boundary is not well defined in the field.
The population of neem in this area is well isolated from other neem; there is none to the west, north and east and for many kilometers to the south.
Neem (Azadirachta indica): The seed production is influenced by the cutting of the flower infloresences for sale. The type has predominantly flowers of bitter taste which is sold nevertheless, where normally only the "sweet" type is sold. The statistics of fruit production (counting estimates) are 445 (+/- SE 73) fruits per tree, or 1850 fruits per hectare. This fruit production would be up to 10 times larger if villagers left the infloresences intact. The weighted figure for total seed production in the area would be 213,000 +/- 42,000 fruits per year. This would be sufficient for around 70 hectares of plantation per year.
Flowering is in Late-March, and the seeds ripen during April. The best seed collection period has not been established.
The area is easily accessible by all-weather roads.
Available in nearby villages; but not examined
The land is private farmland, but the Royal Forest Department, Silvicultural Research Sub-Division, Bangkhen, Bangkok 10900, should be contacted whenever seed collection is planned.
Measures need to be taken for the conservation of the neem in this area. It is strange that this population is still existing at all in the area.
It will be possible to extend the seed collection area around 1 km to the west and to the north of the 1 km2 selected area as well as to the north-east about 5 km until the foot of the mountain range Doi Na Ngum. The ecological conditions appear similar to the above described. Tree density to the west and north is 0.5-1.0 tree per hectare with very large trees, 10 meter height and 80 cm diameter for the largest. The extension to the north-east is interrupted by villages and treeless areas. There is an estimated 1-2 trees (or group of trees) per hectare. The total area of the extension is 1200-1500 hectares. The seed production in the extension may be estimated at around 1000 fruits per tree or in average 1000 fruits per hectare.
Chief,
Thung Salaeng Luang
Forest Tree Improvement Station,
Pitsanulok,
Silvicultural Research Sub-Division ,
Royal Forest Department,
Thailand.
(some Thai seed sources given as example)
SEED SOURCE NAME: Tung Luang Railway Station
No. on map: 1
Latitude: 9 º 09' North,
Longitude: 99 º 07' East.
Altitude: 4 m.a. m.s.l.
Country: Thailand.
Province: Surat Thani
The total area is estimated at 100 hectares.
Rainfall is 1755 mm per year
10 trees per hectare each producing 1000 to 2000 seeds. Thus about 1-2 million fruits may be obtained per year in the area.
Collection months: Early April suggested but not verified.
SEED SOURCE NAME: Khao Pip
No. on map: 2
Latitude: 10º 08' North,
Longitude: 99 º 07' East.
Altitude: 10 m.a.m.s.l.
Country: Thailand.
Province: Chumporn
The total area is estimated at 1200 hectares.
Rainfall is 2070 mm per year
About 80 larger trees each giving about 500 seeds, i.e. a total of 40,000 fruits may be obtained in the area.
Collection months: Early April suggested, but not verified.
SEED SOURCE NAME: Ban Bon-Don (Bang Sapan Yai)
No. on map: 3
Latitude: 11º 16' North,
Longitude: 99º 27' East
Altitude: 100 m.a.m.s.l.
Country: Thailand.
Province: Prachuap Khirikhan
The total area is estimated at 100 hectares.
Rainfall is about 1200 mm per year .
10 trees/ha, in all 2000 trees each giving 500 seeds; total 500,000 seeds per year in area.
Collection months: Early April suggested, but not verified .
