VANILLA PRODUCTION
Introduction
It is now grown in Kagera Region (particularly in Bukoba district), Zanzibar and has been introduced in Kilimanjaro region (Hai & Moshi districts).
In Kagera areas, Vanilla has proved to be a very high value crop that has attracted the interests of the farmers and local authorities there, and elsewhere as a diversification crop, in a need to respond to falling price of traditional cash crops such as coffee
BOTANICAL DESCRIPTION
NOMENCLATURE
*Vanilla belongs to the family of Orchid: Orchidaceae which are a group of flowering plants (with 700 genera & 20000 species)
*Orchids are highly advanced group of Monocotyledons. Out of the many species – the largest proportion consists of ornamental species grown of the flowers.
The genus Vanilla contains three cultivated species.
*However, Vanilla fragrans (salibs.) Ames, syn.v. Planifolia Andrews, (other syn. Names: Epidendrum vanilla L., or Myrobroma fragrano salisb.) is the most commonly cultivated and the most important in terms of use & commerce.
Other species are:
i) V. pompone Schields = West Indian vanilla
ii) V. tahitensis S.W.Moost = Tahitien vanilla
Plant characteristics
· Vanilla is a perennial herbaceous, succulent vine
· The vine clumbs trees or other supports by means or adventitious roots (tendrils). It can climb up to a height of 10-15 m. However, in cultivation it is limited by training to shorter height to facilitate hand pollination and harvesting.
Roots
Have two types of roots:
(i) Aerial Adventitious roots :Are long whitish in colour, about 2 mm in diameter, produced singly opposite the leaves, are for attaching/fixing the plant on a support to which the plant climbs
(ii) Roots at the base (underground/soil roots) which form a network on the soil surface.
Stem: is a vine
– Is long cylindrical, simple or branched.
– Is dark green, succulent, photosynthetic with stomata.
Leaves: Large flat, flesh alternate, growing directly fro the stem node.
Tendril: At each node, a tendril is formed that holds the vine to a support
Buds: Each node is capable of forming a bud, which can develop into either, a new shoot, an inflorescence or new root.
Flowers: Born in clusters of several flowers. The flowers open successively over the flowering period.
– Contains a single stamen with 2 pollinia covered by a cap. The stigma that is concave, below and separated from the stamen by a thin flap-like rostellum.
Fruits: – Is a capsule or pod kwon in the trade as a bean.
-Each flower can produce a single bean/pod
-It is aromatic on drying
-It contains when ripe, many minutes seeds (0.3 mm)
-The capsule, splits longitudinally when ripe, liberating the seeds.
-In commercial production the pods are harvested before complete ripeness.
Origin & Distribution
· Is native to Central America and Mexico
· Is now cultivated in other parts of the tropics.
Major producing countries are:
– Madagascar
– La Reunion- Best quality
– Comoro
– Indonesia
– Srilanka
– Tahiti, Tonga, Fiji islands
– Uganda
– Recently Tanzania in Bukoba district & Zanzibar introduction are underway in Kilimanjaro Region.
ECOLOGICAL REQUIREMENTS
SOILS
– Requires light fliable soil with adequate but not excessive drainage.
– The soil must be supplied with a thick surface layer of humus in which the feeder roots spread.
– pH = 5-5.5
Climate
· Temperature: Optimum range 32ºc with average = 27ºc.
· Rainfall = > 1250 mm/yr with approx. 2 dry months to check growth and stimulate flowering. In Bub & Muleba districts there are two dry seasons, thus two flowering seasons are possible.
· Light: Light shades 1/3 – ½ are a must, provided by small trees/shrub.
· Humidity- should be high
CULTURAL PRACTICES
Propagation
– In commercial cultivation, propagation is by stem cuttings.
– Cuttings are taken from healthy vigorous plants.
– The length of the cuttings determine the time to 1st flowering.
– Short cuttings = 30 take 3-4 years
– Cuttings 90-100cm long, with about 12 nodes are more preferable.
– Thus, the longer the piece of cutting, the quicker the plant will begin to flower.
Time of planting
· At the beginning of the rainy season. Cloudy condition favour rooting and sprouting.
· Recommended spacing is 1.2- 1.5 × 2.5×3.0, 1.5, 1.8, or 2.0m on the row and 2.5, 2.7, or 3.0m between rows.
Plant population:
– 1.5× 2.5 – 2667
– 1.8× 2.7 – 2057
– 2.0× 3.0 – 1667
When intercropped with other crops, a space of 1.5m should separate vanilla from the other plants in order in to allow walking around.
Establishment of support and shade trees
Vanilla is grown preferably with (or in) live trees which provide support and shade.
Support
Since vanilla is a vine, it is creeping/climbing. In order to enable it to grow off the ground, it needs support. The plant has tendrils which enables it to naturally climb trees or other forms of support.
Shade
Light shade is a must for vanilla. Too dense shade or full sunlight are both harmful.
– Strong sunlight – lead to sun burn of leaves, which turn yellow.
– To heavy shade, growth is slowed down and pest problem increase
– Trees in vanilla field provide a buffering effect against rapid cooling as heating and thus regulate the heat release to the ground
– If vanilla established on a new land, then it is preferable to undertake partial land clearing, leaving some trees at the required distances.
– Otherwise, trees have to be established (planted), before the vanilla.
The ideal trees should have the following characteristics:-
– Must be strong enough to support the vine even in strong wind.
– Its growth habit should allow easy access to the vanilla plants.
– It must have low lying branches over which the vines can be trained (at 1.2m) to hang down.
– It must be fast growing; it must be one which provides light shade.
– It can be pruned when necessary.
– It will be of advantage if the plant can be established from large cuttings. So it can already be supportive at planting (if planted at the same time as vanilla).
– If it can provide an economic product.
– The most commonly used trees in Madagascar are: the physic nut (Jatropha curcas L.) and Casuarinas esquisetifolia
Other recommended trees include:
– the Bauhinia spp
– Gliricidia sepium
– Pandanus spp.
– Ficus spp.
Planting vanilla
-Cutting of the recommended length (90-100m = 12 nodes) is collected.
-There are kept under sheds for about 7 days before planting to allow wilting.
– 3-5 leaves and tendrils from the base of the vine are removed
– Dig a shallow trench (5-10cm) at the base of the support tree.
– Lay the base (3-5 nodes) of the vanilla vine in the trench.
– Bend the remaining vine part from the base of the support upward and tie it loosely on the support.
-Cover the vine in trench with soil and press down gently to make good contact between soil and vine. Leave the bottom end of the vine above the soil. This provides a means to check the growth take off/ survival of the cutting.
a. Mulching:
*Vanilla is shallow rooted. In fact the roots remain almost entirely on the soil surface. Thus mulching is very important.
– It feeds the plant,
– It keep the soil moist
– Lighten the soil
– Provides the ideal rooting environment
– Suppresses weeds
*The vanilla should be kept mulched permanently.
*Use composted/ decomposed materials, Dry grass is also good
2. Looping
When the vine has grown to a height of about 1.2m, it is bending to hang down till it reaches the soil. The growing tip allowed climbing the support again as at planting.
By so doing:-
-The vine is kept within reach
The practice renews and increases the plant root system. This is very favourable to good growth, yield and long life of the plant.
· 2-4 nodes should be buried in the mulch, leaving 3-4 nodes proximal to apex to constitute part of the stem (vine) which will climb the support.
· As during planting, leaves on the buried nodes should be removed.
· Do not loop all the vines. Some will be needed to flower at the beginning of the season. The long vines should be left to initiate flowering.
· Do not tie the vines around trees (support) horizontally. This makes management difficulty.
· A well managed vanilla plant should have at least 3 coils or looping.
· Looping is preferably done during the wet season
Weeding:
Is done by hand pulling of weeds around the vanilla plants. Cultivation should be avoided.
Stimulation/ Flowering induction
Flowering is induced by three factors:
· A dry season. Thus where irrigation is done it should be stopped.
· Increase in sunshine (light) level. This enhanced by pruning the shade/ supporting trees.
· Decapitation- the vine is cut back at 5 leaves from the apex.
Flowering start 2-3 months after induction. If the conditions are not dry enough, flowering will be poor.
Pollination
· The flowering of vanilla is such that self-pollination of individual flowers is impossible. This is due to the separation of stamen from stigma by the rostellum.
· The flowers of vanilla open early in the morning. They are all receptive for 8 hours, after which they wither.
· Thus pollination should be done between 9-10pm in dry sunny conditions.
Pollination is less successful in the afternoon, in wet and cloudy conditions
-Hand pollination is done using a splinter of bamboo, or other materials (stick) of the size of a tooth pick.
· Hold the flower, push the labellum down with thumb to release the column
· Remove the stamen cap with stick to expose the pollinia
· Push the Rostellum up with the stick to bring the pollinia & stigma in contact.
* Only flowers on the lower side of the raceme are pollinated so that the pods can hang down freely to produce straight pods.
· Usually, only one flower opens in each inflorescence in a day.
1- Florescence = 10 flowers
1 plant = 10-12 inflorescences.
The work capability of an experienced pollinator is 1000 – 2000 flower per day.
· Flowering starts 1- 3 years after planting depending on the size of the planting materials & management.
· Maximum productivity is reached 7-8 years after plant
· Economic life span 10 years
Harvesting
· Occurs 6-9 months after pollination
Pods of the same cluster do not mature at the same time. So harvesting is selective of individual pods based on five developmental stages as follows:
1. Immature bean = uniformly green Not good
2. Bottom end of the bean has turned yellow. Is the earliest stage for good harvest.
3. Yellow colour spread on the tip turning brown.
4. The tip turn black & bean start to split open
5. Whole bean split open
Stages 2-3 are the best stage for harvest.
After harvesting
The hanging vines that produce are cut off. It will have initiated a new shoot which gives a new vine for looping or flowering.
Yield
Optimum = 3-5 kg of fresh beans per plant.
Pest & Diseases
1. Root rot- this is the most serious disease. It leads to wilting, and death of plants
Management
– Sanitation
– Maintenance of good drainage
– Ensure sufficient looping to encourage healthy plant growth
– Avoid excessive shade
– Apply copper fungicides by soil drenching
2. Viral diseases: shoot stunting and distortion, chlorotic leaves localized on the vine.
Physiocological disorders
· Sunburn: is due to excessive sunlight, while inadequate sunlight can lead to shoot rot.
Processing
Is known as curing
Procedures
1. Sorting: after harvest to uniform quality beans.
2. Blanching: Beans are blanched in hot water at 60- 63ºC for approximately 3 minutes;
3. Sweating: Blanched beans are kept hot for 48 hrs, in insulated boxes (at 40-45ºC)
-the beans turn colour to chocolate
-Aroma will start to evolve.
4. Drying:
– Beans are removed from sweating boxes and spread on blankets and exposed to the sun or drying racks. The beans stay in full heat of sun for 2-2½ hours, while they are turned 3-4 times to evaporate the exuded water. Then the blankets are folded over the beans & left again in the sun for 2 hours.
By this, the beans become very hot and start sweating again causing fermentation to accelerate. After 4-6 hours, the beans are pilled together in insulated boxes to keep the beans hot overnight.
The beans continue to sweat & ferment.
This stage is repeated for 10-20 days depending on the type of beans.
Small poor beans = 10-12 days
Immature beans = 15-20
Ripe non split beans =12-15
Ripe split = 10-12
– Thereafter are spread on trays & dried in shed, put to 30% moisture content.
The dried beans are finally tied in bundles. Number of beans per bundle is determined by the market.
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