1. Nursery Phase
by Working Group on Trial Design¹
(March 1995)

Guidelines for nursery and field operations in connection with establishment of the Neem provenance trials have originally been prepared by a working group during the first international consultation on Neem genetical improvement held in Bangkok from 18th till 22nd January 1993. The guidelines have been published as follows:

• Guidelines for managing international Neem provenance trials. Report of Working Group One. In: Genetic Improvement of Neem: Strategies for the future; Proceedings of the International Consultation on Neem Improvement: Kasetsart University, Bangkok, Thailand: Publ.: Winrock, F/FRED, 1993.
• Guidelines for establishing and managing international Neem provenance trials. Report of Working Group of the International Consultation on Neem Improvement: Regional Community Forestry Training Center, Faculty of Forestry, Kasetsart University, Bangkok, Thailand, 1993 (green manual).

  A number of factors and assumptions of importance for such operations have changed since the preparation of the initial first guidelines. Therefore a new working group has been formed to revise the guidelines. The final procedures are presented below.

  The Neem-Network has decided to use stumps (see section 5 below). The following manual on nursery procedures aims at providing participants with the method of producing stump plants. The present manual - along with a manual on principles and methods of trial establishment, and a manual on assessment and evaluation procedures and methods to be issued by July 1995 - will supersede previously issued guidelines.

  The nursery procedures as below are based on the experience with stump plants of Neem from Nigeria and India. If a well adapted and safe method of producing stump plants of Neem has been experienced locally, then such a method should be used.
  
  

Under the Neem Network, seeds will be exchanged internationally over a 5-month period, March-September, 1995, to be sown immediately upon receipt. When notification of the receipt of the seeds is given to FAO and dispatcher, then please also notify any missing information or faults. Each participant will - for each trial to be established - receive around 0.5 kilograms surface-dry stones per seed source, corresponding to approximately 1000 stones for the seed sources with the largest seeds. The necessary steps to take in connection with seed receipt are described in: "Neem Network - Procedures for seed collection and exchange", FAO/DFSC, 1995.

Upon receipt of seeds, each host country may provide the seedlots with their own identity number when registering the seed in their systems. However, it is stressed that in the present international scheme seedlot identity must be maintained throughout the nursery and field trial stages using the names Provided and printed with bold type in annex A of 'Neem Network - Procedures for seed collection and exchange'. This will facilitate the later coordinated evaluation of the data obtained through the assessment of the individual trials, and it will ensure that no confusion will arise.

In addition to seedlots received through the Neem Network, trial host countries may wish to include seed from one or more of their own neem stands.

No seed provided for the field trial will be used for specific germination or moisture testing. All the seeds received must be sown immediately In the nursery for production of planting stock. Seed testing will be done through a specific research component of the scheme.

However, the trial hosts are requested to estimate the total number of seeds sown, together with the number of usable plants obtained of each seed source (see section 7).

All seeds must as previously stated be sown soonest after they have been received. For planning purposes the table in annex A of the 'Neem Network - Procedures for seed collection and exchange' gives the expected time of collection (and dispatch) of each seed source. The first seedlots are expected in March 1995, the last ones in September 1995. Stump production will take a minimum of 10 months, and since the last seedlots are expected around 5 months after the first, stump age will vary from 10-15 or more months at the time of planting in the field (during the year of 1996).

As mentioned above, it has been decided to use stumps as the planting stock!

The reason for this decision is as follows:

• Due to the length of time from the first and until the last seedlots have been sown - at the time of planting in the field trials - there will be differences in plant size between the different seed sources. Stumps would be the type of planting stock that would be best suited under these conditions. (In containers the tap-roots of seedlings would suffer if the plants were left for extended periods, or the containers would deteriorate or be damaged. Large seedlings would survive poorly if transplanted).
• Stumps will also confer some benefits regarding the evaluation of the trials, because the initial plant growth in the field would be reasonably independent on the size of the stumps. In contrast to this the size of seedlings raised in containers would have a more pronounced effect on the initial growth after transplanting to the field.
  
  

Our main concern is to obtain a sufficient number of plants. Methods of broadcasting seeds, or line sowing, as normally used in several countries cannot be used, because of the limited amount of viable seeds that may be available.

Recapitulation of open bed preparation;

• Establish beds if possible 3-4 weeks in advance of sowing or pricking out.
• Establish on loamy - loamy-sandy soil.
• Work the soil by digging or ploughing to a depth of 30-40 cm.
• Form the beds max. 1-1.2 meter wide (for ease of tending), and raised 10-20 cm, preferably with support on the sides.
• Provide with adequate drainage facilities. Where irrigation is by temporary flooding, irrigation channels are provided.
• Apply manure (only if well seasoned), or a compound fertilizer, as required (not essential to germination beds or containers).
• After preparation, keep the beds irrigated to allow for weed seeds to germinate; make frequent weedings and gentle rakings of the surface to allow as many seeds as possible to be exposed to best germination conditions.

General on sowing:

• Sow as mentioned immediately upon receipt of the seeds!
• Seeds are sown as intact "stones", i.e. the hard shell (endocarp) must not be removed!
• Place the seeds horizontally, i.e. do not point either end of the seeds upwards or downwards, unless you know for certain which is preferable.

General on shading and irrigation:

• Shading of the sowing beds is not mentioned in the literature for Neem. However, considering that the natural regeneration of Neem occurs most profusely where there is a canopy cover, a light shade - around 40-50% coverage - may be beneficial for the germination result if the weather is very hot.
• Shading of the transplant beds may be beneficial when the weather is hot, and in any case immediately after transplanting. Any shade must be reduced slowly, because the shaded seedling would suffer if exposed suddenly to direct sunlight. During the rainy season shading should be used with care because of the danger of damping off.
• Irrigation is required if sowing takes place before or after the rains. Irrigation during the rains is done as deemed necessary. Use water sparingly.
• Irrigation of the transplant beds is essential if transplanting is done during the dry season or during dry spells in the rainy season. For reasons of safety, it may be advisable to irrigate the transplants for at least 3 months after transplanting has been completed. Irrigation during the rains is to be done as necessary. The extent to which irrigation is to be continued during the dry season would depend on the severity and length of the season at each locality, and it is left to local experience to judge the need. However, irrigation should be kept at a minimum.

Alternative 1 - Sowing directly in the open root bed:

• Sow directly in open beds in lines spaced at 15-20 cm, and with 5 cm between seeds.
• Sow the seed to a depth equal to its smallest diameter. Alternatively, sow to a depth so that the seed is only just visible, and thereafter cover with a layer of coarse sand, around 1-2 cm thickness.
• Each seed source would require 8-10 square-meters of bed, or more, i.e. a total of 200-300 square-meters if all 27 seed sources are received.
• Provide shade and keep the bed moist, but not wet. Release the shade gradually and as soon as possible after seedlings have established themselves.
• Thinning is done as required depending on germination and plant development. A final ideal spacing for stump production would correspond to an average of some 250-400 square-centimetres per plant.
• Mulching and hoeing/weeding is done frequently. If irrigation is stopped during the dry season, the transplant beds may be protected from drying-out (cover the beds with grass, straw, or similar).

Alternative 2 - Sowing in germination beds and pricking out:

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• Saw seeds at a spacing of 1-3 cm on a germination bed of medium-fine sand. Seeds are sown so that their surface is just visible. No further coverage is made. The total area of germination bed for 27 seed sources would be a maximum of 30 square meters.
• Protect the beds from birds and rodents as well as possible.
• Provide shade to the beds and keep moist, but not wet.
• Immediately when a seed starts to germinate, i.e. the root appears or the seed is lifted, it is transplanted to the open bed taking care not to damage the root in the process.
• The initial spacing may be for example 10 x 10 cm if germination is high, and subsequent thinnings would have to be done to leave an average final spacing of some 15 x 15 up to 25 x 25 cm depending on plant development during the growing season. However, if germination appears sporadic then plant at the final spacing. The total area of transplant bed needed would depend on the germination obtained, and would be around 150 square meters for 50% germination.
• Shade is necessary af ter transplanting. This shade is removed gradually as seedlings are established and according to weather conditions.
• Tend beds as described above.

Alternative 3 - Sowing in containers and transplanting small seedlings:

• Sow in polyethylene pots of dimensions: 10 cm height, 3-5 cm diameter (~ 5-8 cm flat width) in normal soil mixture. Tubes of the same dimension may be used instead of pots.
• As far as possible prepare the pots 3-4 weeks in advance of sowing and allow weed seed to germinate as for open rooted beds.
• Sow 2 seeds per pots. Thin according to germination; transplant to any empty pots if necessary. Up to <13,500 pots will be needed if all seed sources are included.
• Protect the beds from birds and rodents as well as possible.
• Provide shade to the pots and keep moist, but not wet.
• When seedlings are 5-10 cm high (the tap root must not have reached the bottom of the pot) then - keeping the ball of soil intact - transplant to open nursery beds at a spacing of 15 x 15 cm to 20 x 20 cm. (Alternatively use local experience for seedling height and spacing). The total area of transplant bed would be as for alternative 2.
  
  

The Network is not expecting to collect data on growth performance.

The nursery should be protected as well as possible against damage due to flooding, fire and animals.

If such protection cannot be ensured, then it may be beneficial to make two to three replicates (blocks), each containing all sources. Ensure that each seed source is not always placed at the same end or side of the beds. This may be done by shifting the position of the seed sources systematically.

In addition to this, extra space must be left between seed sources in order to avoid confusion regarding the identity of seed sources.

Total number of seeds sown, together with the total number of usable plants produced, must be counted and recorded. This information will be used to verify that the genetic variation of each seed source planted out into the field has remained at an acceptable level.

Be sure to label each seed source with proper identification. Use the prescribed seed source name (see section 2 above). Use weatherproof ink or similar when writing on the labels, and ensure that the labels cannot easily be removed.

When the soil in the site of the field trial is moist to a depth of 25-30 cm, or according to local experience, planting may commence.

Immediately when the plants have been lifted from the bed, they are taken to a shady place and if necessary further protected from desiccation. The stumps are prepared as soon as possible as follows:

• To qualify for stumps, seedlings need to have the following dimensions: minimum 10 mm - ideally 20 mm - at root collar; stem length minimum 40-50 cm, ideal 100 cm. (in India large 2 year old stumps survived better than smaller one-year old stumps).
• Plants are lifted - using a well sharpened spade. The tap root is pruned in the process, but leaving at least 30-40 cm of the root.
• Trim the tap root further to keep a minimum of (25-) 30 cm below the root collar.
• Lateral roots are trimmed as necessary to facilitate planting, depending on method of planting, i.e. how large plant holes should to be made.
• The stem is pruned to leave 20-30 cm of the stem above the root collar, and any side branches and leaves are cut off as close as possible to the stem, without damage to the stem. This will leave a sufficient number of buds for sprouting. Leaving a longer stem may enable the wind to whip and loosen the plants. In India as little as 2.5 cm of the stem is left with apparently good success!
• The root part of the stump must be dipped immediately in a slush of mud and bundled in wet leaves before finally packing in baskets or crates with 50-100 stumps in each. Exposure of the roots to desiccation may significantly reduce the plants, ability to survive after planting.

Stumps prepared this way may be stored for a few days in the shade at, or near, the planting site.

(In the Sudan during rainfall of 400-600 mm, the plants are lifted with a ball of earth, and the stems are pruned to leave 30-60 cm, but no root pruning is done).

- March 1995 -

Note:

1. Mr. Vichien Sumantakul, Senior Researcher, Silvicultural Research Division, Forest Research Office, Royal Forest Department, Bangkok 10900, Thailand.
Mr. Rajendra B. Joshi, Executive Director, Forest Research and Survey Cebntre, P.O. Box 3339, Kathmandu, Nepal.
Prof. Dr. Le Dinh Kha, Director, Research Centre for Forest Improvement, Forest Science Institute of Vietnam, Chem Tu-Liem, Hanoi, Vietnam.
Mr. E.B. Lauridsen, Senior Researcher, Danida Forest Seed Centre, Krogerupvej 3A, 3050 Humlebaek, Denmark.