LECTURE 3

KOLA (COLA SPECIES)

Kola (Cola sp.)Cola nitida (Vent) Schott and Endl.

Cola acuminata (Beauv) Schott and Endl. Kola has a long history of cultivation and trade in West Africa, especially in Nigeria,

Ivory Coast, Sierra Leone, Guinea, Liberia, Ghana, Togo, Cameroon and Republic of Benin.

C. nitida is believed to have its centers of origin and diversity in the forested areas of Ivory Coast and Ghana, while C. acuminata originated from Nigeria-Gabon axis.

Cola sp., a family of Sterculiaceae with the following edible species, found in the forested regions of the countries mentioned above –

Cola nitida. C. acuminata. C. verticillata. C. ballayi. C. sphaerocarpa. C. anomala. C. gabonensis C. heterophylla C. simiarum

C. nitida and C. acuminata are the most important species economically and most widely cultivated.

C. nitida is brought into cultivation from its natural habitat. C. acuminata grows wild in the forest zone of southern Nigeria.

Since supplies of C. acuminata were adequate to meet the local demand, not until recently, no attention had been paid to its cultivation.

Cultivation and development of the 2 species became popular by the inception of CRIN.

Today CRIN conducts research into the cultivation, development and end-uses of kola. This had boosted the global economy of the crop.

The nuts from both species occur fresh in red, pink and white colours often in the same pod.

The C. nitida nuts are highly esteemed as a masticatory for its stimulating effect by the northerners.

C. acuminata nuts have high socio-cultural value in Southwestern Nigeria.

Thus the importance of kola as an article of trade dates back to over 800 years and the nuts were mainly derived from spontaneous kola trees.

Kola cultivation begins at the inception of twentieth century.Today, Nigeria produces over 88% of the world’s crop and

about 90% of this is consumed locally while the remaining 10% is exported.

Propagation of kola• Traditionally, kola is propagated by nuts sown at stake

between food crops or in traces of forest vegetation where it grows undisturbed.

• It may be pre-germinated on seedbed in a nursery near a stream, from where it is later transplanted bare-rooted at the age of 5 – 9 months.

• It may even be left unstirred in a heap at a cool spot and given occasional watering. Germination had been found to occur in a comparatively short period of 2 – 4 weeks when treated in such a way. The undevelop seedlings are transplanted at this stage.

• The success margin of these methods are low.

Propagation of kola contd.• Better seedling development is achieved when kola nut is firstly

germinated in a seed-box (pre-germination in the pre-nursery stage), transplanted into seedling’s bag (nursery stage) and eventually transplanted into the field.

• Transplanting into the seedling’s bag should be carried out as soon as the plumule emerges, the radicle elongates faster and develop long tap-root followed by mass production of lateral roots.

• If left too long in the rooting medium the mass production of root makes transplanting difficult.

• Rapid seedlings development is achieved when the root of the seedlings is well set in the seedling’s bag (root packing should be avoided).

• Germinated seedlings are kept in the seedlings bag under 50% shade until they are ready for transplanting.

The Kola Nursery Nursery site:

Select a site near a stream / water tap. Clear the site, especially in the dry season Construct pre-germinator (concrete or wooden) of about 1.2m x 4m or the length can

be as long as convenient for you, and 30 – 50cm deep. Each compartment is separated either by a path of 45cm wide or by a concrete wall. The site is provided with a shade whose density is adjustable or use shade trees or erect

removable shade of posts and palm fronds. The following equipments are essential in kola nursery –

Germinating or seed boxes Rooting propagators Seedling or polythene bag Head pans Large baskets Hand forks Hand trowels Spades Labels Indelible markers / pencils Biding wire / string Protective wire netting

The Kola Nursery Contd. Selection of nuts for sowing (pre-germination stage):

Nuts selected from elite parents of known pedigree.

Pods should be harvested at 120 – 130 days old after pollination: colour changing from deep green to inconspicuous brown and splitting sign.

Extract nuts before pod splitting and nuts dropping on the ground.

Remove fleshy seed coat (testa) and examine nuts for insect attacks.

Discard all bored nuts and store all healthy nuts (curing) for later sowing.

Cured nuts have better final germination than freshly harvested nuts of kola.

Kola nuts weighing 15g and above should be selected for raising seedlings.

Curing as a post-harvest handling method is important in order to reduce the fiercely long period of dormancy of kola nuts when sown.

Germination of kola nuts Cured kola nuts:

After curing, kola nuts are pre-germinated in a pre-germinator containing a growth medium of wet sawdust.

Nuts sown at horizontally on their sides to a depth of 5cm, watered and covered with a transparent polythene sheet / wet sack in order to keep the medium moist.

Germination and seedling growth may take 1 – 6 months after sowing (MAS) depending on the age of the nuts.

Sowing is done in November and transplanting done in May – June during rainy season.

Freshly harvested / uncured kola nuts:

Freshly harvested nuts of kola have to undergo scarification / cotyledon wounding before sowing. If not, germination proceeds till 9 MAS.

Use a sharp knife / other sharp objects to scarify or create wounds at the sides of each cotyledon before sowing.

With this nut treatment method, germination completes within 3 MAS. Thus the problem of long dormancy period in C. nitida is overcome. C.

acuminata readily germinates when sown. The former has 2 cotyledons while the latter has more than two.

Potting of Kola Seedlings Gently remove pre-germinated nuts without damaging the roots and

transplant them into the seedling (poly) bags filled with fertile top soil (nursery stage).

While transplanting, the cotyledons should not be broken and should be placed at the centre of the seedling bag and partially exposed.

The seedlings are kept under shade, adequately watered for vigorous growth and hardening.

Raising of seedlings through this method ensure satisfactory final stand than sowing at stake.

However, pre-nursery and nursery stages are combined when nuts are scarified and sown in seedling bags containing well-aerated growth medium (river sand / sawdust) enough to support the germinating nuts to transplanting stage.

Transplanting precautions are as given in cocoa.

Plate 1: Seedlings of C. nitida in the nursery.

Plate 2: A seedling of C. nitida in the nursery.

Vegetative Propagation Conventionally feasible vegetative methods in kola consist of –

Rooting of stem cuttings (tips of branches) Marcotting of stem Budding Grafting

Rooting of stem cuttings: Kola cuttings are successfully rooted under a high humidity and low temperature

chamber. This condition can be obtained in a special propagator made of concrete or wooden

materials covered with transparent polythene sheet to keep it in humid state. It is kept under a 50% shade density of trees.

The floor of the propagator is firstly lined with fine granite chips or washed gravel to a depth of 5cm. This is covered with 30cm layer of sifted sawdust.

Choice of cuttings: Cuttings should be taken from selected vigorously growing and healthy kola trees free

from mineral deficiencies. Flushes of 2 – 4 months old with dull green stems which are becoming brownish and

just woody with deep green leaves are best for rooting. The cuttings should be 15 – 20cm long. Older cuttings are difficult to root. Taking the cuttings: Cuttings are taking in the morning (with a knife or secateurs) or anytime that the

weather is cool / dull Pack your cuttings in polythene sheet moistened with water, or their base dipped in a

bucket of water and covered with polythene sheet.

Vegetative Propagation Contd.Setting the cuttings:

Prior to setting, the lower leaves and flower buds are removed and 6-10 leaves are left at the tip.

Refresh the cut surface of the cuttings by cutting obliquely inside water. Set cuttings at 8 – 10cm deep in the rooting medium. Gently water the set cuttings and cover the propagator with wooden

frames. Cutting must not be set too deep because the roots will be induced to

grow horizontally, especially with shallow rooting medium. After the first day, the cuttings are watered thrice daily using a knapsack

sprayer watering cans until the leaves are wet. This is to maintain a high humidity around the cuttings in the propagator.

Examine the propagator once a week for the first 8 weeks to check the drying up of the rooting medium.

Too little watering results in loss of leaves and death of cuttings. Too much of water in the medium results in water logging, poor

aeration and rotting of the bases of the set cuttings and eventual death of cuttings.

Vegetative Propagation Contd.Potting of rooted cuttings (ramets):

Roots begin to appear at 8 weeks after setting, 1 – 4 or more straight, thick but fragile roots develop with tiny lateral roots.

Such ramets are potted.

Prior to potting inside polythene bags, the poly bags should have been filled with fertile top soil.

Ramets are gently and carefully transplanted there without any damage to the developing and fragile roots.

Ramets with leaf chlorosis are transplanted into a medium of a mixture of compost and fertile top soil in equal proportion for improved performance

Vegetative Propagation Contd.Hardening the ramets:

The potted ramets need to harden before exposure to normal atmospheric conditions. They thus, are transferred into the hardening chamber.

In kola, hardening takes 4 weeks and no water is added during this period.

Maintenance of ramets in the nursery:

After hardening, ramets are placed in a shaded environment to allow the plant to settle and resume development.

Daily watering is carried out.

Ramets remain in the nursery for between 9 and 18 months.

Flowering occurs about a year of ramets in the nursery and fruiting may occur if pollination occurs.

Any flowers developed by ramets while in the nursery, must be aborted.

Again, before transplanting into the field, the ramets are hardened up.

Transplanting of kola seedlings or ramets into the field. Transplanting of kola into the selectively thinned forest:

In transplanting C. nitida, all tall trees with well-developed canopy are removed because the crop is robust and fast growing.

In transplanting C. acuminata, the taller trees are left as overhead shade. Trees with lower canopy are removed. This is because the crop flourishes under shade and not as tall as C. nitida

Plantation maintenance operations are as described under general plantation maintenance.

Kola can also be transplanted under regrown forest or open land: The transplants treated to open land transplanting should be provided with irrigation

and shade of tree species: Tephrosia, Cajanus, Crotalaria species or any other temporary shade-providing trees. These shade trees are later thinned.

Seedlings of 6 – 9 months old are easy to transplant. Older seedlings can also be transplanted, provided the roots are intact, but such

seedlings are treated to 80 – 90% leaf area reduction in order to reduce transpiration. Care should be taken not to damage the taproot during transplanting. Transplanting is done when the weather is cool in the month of May or June Temporary shade is needed for the first 2 year especially during the dry season. C. nitida is planted at a spacing of 7m x 7m while C. acuminata is transplanted at 4m x

4m.

Botany of kola The adult tree develops into a dome-shaped pattern of growth.

In an unpruned kola tree, the foliage and fruits produced often reach the ground level, thus makes for easy harvest and insect and disease attacks.

Closely spaced trees tend to etiolate and grow tall thus leading to loss of foliage and branches. Flowering:

C. nitida seedlings take between 3 – 7 years before flower initiation, but ramets (of the 2 species) may flower in the first year of transplanting into the filed or it may even flower while in the nursery.

C. acuminata seedlings take up to 10 – 15 years before flowering but, if proper cultural operations are given it may flower in 4 – 5 years.

Both C. nitida and C. acuminata posses functional male and female flowers in the same inflorescence. Flowers of C. acuminata are smaller than those of C. nitida.

C. nitida flowers between May and January and reaching peak of fruit production in September followed by a light production in January.

C. acuminata flowers between December and February. Sporadic flowering may occur in August / September.

In both species, the stamens of the same flowers are not functional, thus self pollination does not occur within the flower – self incompatibility.

Botany of kola contd.

Compatibility in kola is very variable. Both self and cross – incompatibility do occur in the crop.

Kola is self sterile. A tree may remain unproductive except it is pollinated through mechanical agencies such as man, animals, insects or wind or through an adjacent kola tree established for the purpose.

It takes up to 120 – 130 days between pollination and fruit – (pod) maturity.

The pods of the 2 species vary in size and botanical description.

Kola pods contain 10 – 14 nuts arranged in double rows.

The kola nuts are protected by an elastic skin which is the seed coat – kola testa.

Kola testa may be white, pink, red, yellow or purple and is sweet when pod is fully matured.

Botany of kola contd. For commercial purpose, the kola nuts are separated into white, pink and red colours.

Nut colours in kola play an important role in price determination / market value. White nuts being highly-priced.

In a kola plantation, the colour of nuts vary from tree to tree. In some cases, there is variation in nut colour within a kola pod.

There 2 factors determining the nut colour in kola:

The colour of the nut of the parent kola trees.

The colour of the nuts from which the surrounding kola trees were raised.

Harvesting in kola is carried out when the pods become in-conspicuously brown.

Pods are harvested before they split and fall on the ground. This guides against weevil infestations.

Harvesting is done 2 times a month during the fruiting season which spans September – January, sporadic fruiting occurs in July / August and October - December is the peak period of production.

Harvesting equipment include sharp knife and hooked knife tied to a long pole (go-to-hell).

Post-harvesting Handling Processing:

Remove the kola testa by soaking in water for about 18 – 24 hours. Wash the skinned nuts in water again, collect in a basket to drain off excess water and

spread nuts thinly on a shaded mat / bench / other spread for about 2 – 3 hours. Defective nuts are separated from the lot and sorting done on the basis of size.

Curing: The good nuts are placed in either lined or unlined baskets, frequently stirred and lightly

covered with banana / plantain leaves for about 5 days. In the process, considerable sweating which reduces the moisture content of the nuts

occurs. Cured nuts taste sweeter than uncured nuts. If curing period is too long, excessive moisture loss occurs and nuts may become dried

and wrinkled. Storage:

The cured nuts are wrapped in green but partially dried leaves and packed inside large baskets and kept in shaded / cool spot for marketing.

In the store, the nuts should be periodically checked to ensure that they are not overheated. If overheating occurs, the nuts should be stirred thoroughly and left uncovered for 2 days.

If drying is observed, the lining of the leaves should be increased and the top of basket weighed down to check moisture loss.

In this traditional method, kola nuts are stored for about 12 months.

Insect Pests of KolaField pest:

Stem borers (Phosphorus virens)The kola weevil (Balannograstris colea)

Nursery pest:CaterpillarMealy bugRed spider

Desirable kola nut qualityA good kola nut should:Be slimyNot be astringently bitter in tasteResult in quick salivation when chewedBe palatable and crisp.

Plate 3: A pod of C. nitida infested by kola weevil (Balannograstis colea)

Economic Uses Of Kola Nut

For preparation of kola type beverages such as Coca cola.

A source of essential oils for flavourings in confectionary industries.

For the preparation of chococola – a type of chocolate containing cocoa and Cola.

A source of alkaloids – caffeine and theobromine in pharmaceutical preparations.

As a masticatory for its stimulating effect.

A source of materials for cloth dying.

Economic Uses Of Kola Nut Contd. The bark of the pod is used in traditional concoctions to reduce

labour pain.

The tree bark is used for the treatment of swellings and fresh wounds.

The root is good as chewing sticks for tooth cleansing.

The wood is useful for local carving and boat building.

Source of foreign exchange to the country.

Employment generation

For socio-cultural uses such as wedding, child naming or other traditionally important occasions.