1

Cultivation of Thaumatococcus daniellii (Family Marantaceae) seedlings.

By Barbara Sweetman June 2014

Note. (Information contained in this report and attached photographs have been available to CNRA , Abidjan over the last 24 years).

Note This report was originally prepared for an interested party who were planning a T.d. project in The Ivory Coast. Some information has been removed to protect the identity of those involved. I hope by publishing this report it will help all those who wish to secure the future of Thaumatococcus daniellii by growing T.d. in plantations.

It is my opinion after 24 years being involved with this plant the uncontrolled (ruthless methods) collection of the fruit from the wild will eventually lead to disastrous consequences. It is obvious to me, that some (Thaumatin producers) who advertise on the web. that they are collecting fruit in a sustainable way are in fact encouraging the destruction of a valuable wild African product that grows under secondary equatorial forest and therefore helps to protect the last remaining forest in these regions of West Africa.

Seeds obtained from Ghana, Cameroun and a wide geographically area of wild T.d. populations in the Ivory Coast were grown at the CNRA Anguededou rubber plantation.

2

Over a period of at least 22 years of selection processes seeds now harvested from the fruit picked in the Anguededou T.d. plantation have been shown to be high yielding.

Specially selected Seedlings (Seeds from fruit harvested in February 2014 from the Anguededou T.d. plantation was treated in the same month at Adiopodoume Fruit cutting station in preparation for germination in May 2014.

Pre-germinated seedlings have also been prepared by B.Sweetman from fruit obtained from different regions of Ivory Coast only and will produce a population of genetically dissimilar individuals if the above mentioned seedlings are lost.

Thaumatococcus daniellii propagation is mainly by development of clones from original seeded plants. (New ramets are formed when part of the rhizome is separated in some way from the parent plant)This leads to communities or ‘demes’ of T.d. that are genetically similar.

Reasons why selection of seedlings is important.

Seedlings obtained after 22 years of selective processes in the plantation at Anguededou ensures recombination of variable genetic material is such that fruiting results in a relatively high proportion of three seeded fruits depending also on the right growing conditions i.e. environmental factors especially the presence of the right pollinators and a suitable moist micro-climate at the base of the petioles.

The 2008 fruit harvest from the Anguededou plantation gave higher proportions of three seeded fruits than was recorded in earlier harvests over the previous 16 years.

Pollination and self-incompatibility will be dealt with in more detail in following reports.

It must be mentioned here that a characteristic of the family Marantaceae to which T.d. belongs is that all carpels of the ovary may not be fertile.( ref. Variations of T.d. in Cote d’Ivoire and Ghana D.Sijtsma Wageningen).

Only one ovule of the possible three in the flower needs to be fertilised for a fruit to develop with a seed and an aril containing Thaumatin.

One seeded and two seeded fruits are on average more numerous than three seeded fruits, which have been shown to contain ‘higher values of thaumatin’ and more of it than the one or two seeded fruits from a specific harvested area depending on the stage of ripeness. In other words three seeded, ripe fruits (6 months or more) from wild T.d. of the Lakota Region of I.C. may be higher in value than three seeded, ripe fruits of the same age, from the wild T.d. of the Alepe region of I.C. but in each case generally higher than the one seeded and two seeded, ripe fruits of the same age picked at the same sites.

Seedlings instead of Rhizomes.

3

Note: Using rhizomes is not the preferred method of growing T.d. plants for fruit production, even though this may be very successful and is the preferred option for propagating T.d. for the harvest of leaves only, it has been shown that planting seedlings initially leads to a better fruit yield.

Note: Advice on the of germination of fresh seeds and dried seeds to enable transport over long distances is available if required.

Spacing of Seedlings at planting

Extensive research has been done the spacing of seedlings. Planting the seedlings too far apart results in initial poor results. The maximum distance between seedlings needs to be 25 cm in all directions. That means 20 seedlings per square metre. Therefore half a hectare can be planted with the ‘specially selected seedlings’ from Anguededou Plantation. It is thought the reason for such a close planting distance is that a rapidly closing canopy of growing seedling leaves results in shading and therefore the correct micro-environment for flowering and fruiting. Also it has been seen that when the rhizomes are restricted either by the walls of a container or by each other within reason, there is a better fruiting response. Hence planting them too far apart will initially delay the ability for the plants to set fruit. After several years this difference will no longer play a role as the rhizomes will spread out.

Suggested conditions for optimal vegetative growth, flowering and fruiting of T.d.

(Several reports can follow to deal with pollination and optimum times for fruit harvesting)

(1)Rainfall and Temperature range… minimum of 1500-up to 2000 mm with a maximum up to 4000mm per annum (e.g. At the foot of Mount Cameroun) in some very specific regions on well drained soils. Rainfall needs to be well distributed during the rainy seasons.

4

Temperatures –tropical with high atmospheric humidity (mean annual temperatures of 25 to 30 degrees centigrade ).

(2) Altitude -up to 1300 metres

(3) Light Conditions-shaded or semi-shade....... vital for early growth of seedlings. High light intensity is detrimental and retards flowering and fruiting. Too much shade will also retard flowering and fruiting hence T.d. grows well in Secondary forest but not well in Black forest.

It must be noted here that well established rhizomes in the secondary forest regions of Ivory Coast will easily regenerate in full sunshine after slash and burn agriculturalists have passed through, however as the areas are left to go fallow for over a year after crops(manioc) have been harvested the forest closes in again and gives the shade needed for the flowering and fruiting of the T.d. plants.

Note: High shade of deciduous forest trees in ‘secondary forest’ is ideal but it grows and fruits extremely successfully under shade of a certain type of Rubber tree that regularly sheds its leaves. It has been observed growing well under cover of mature Cacao Trees especially in plantations where the occasional ‘deciduous’ tree has been left to grow giving ‘high shade’.

(4) Weed control by hand is essential until the T.d. has established a leafy canopy. This needs to be done at least four times before the canopy is established or growth will be very poor if weeds are prevalent in the planted plots. Any form of insecticide applications will be detrimental to the ‘pollinators’ (To be discussed in following reports) except for a one off application of a mollusc repellent when flowering occurs.

(5) Soil Conditions-T.d has a shallow root system and if successful flowering and fruiting is the aim the top 10 cm of the soil profile should be of a loamy consistency. It must be well aerated, friable and have a high water holding capacity to sustain the plant over the dry seasons. At the same time it needs to be well drained in the rainy seasons and with a humus litter layer of up to 3cm at the top of the soil profile.

Note: The T.d. rhizome root system occurs in the top 10 cm however a few adventitious roots may extend to 30 cm in depth thus the rooting system of T.d. normally only exploits the top 20-30 cm of the soil profile, as compared to the lateral root system of cacao which can exploit 30-45cm according to S.V. ADU and J.A. Mensah Ansah, 1969.

From 10cm to 20 cm depth the soil can be sandy clay, moderately well drained and must be well structured.

According to Ahenkorah (1969) Cacao mainly exploits the same horizon as T.d. for its nutrients, although if severe drought occurs Cacao has the ability to exploit deeper layers than T.d. In

5

conclusion, as long as there is at least 20cm depth of fairly well aerated soil with high available water and required nutrients T.d. vegetative growth should be successful.

(An ideal situation would be well-drained deep soils, soft incompletely weathered rocks occurring within 1.0 to 1.5 m of the surface with high nutrient reserves. A structured clay loam easily penetrated by roots, retentive of moisture during the dry seasons permitting the free circulation of air and moisture is desirable and a good humus layer with level or gently sloping ground.)

(6) Increased nutrient status – T.d. has been seen to grow in relatively poor soils however more research needs to be done on the possible effects of adding fertilisers at specific times in the growing cycle (for example available phosphorous tends to decline in unfertilised soils of Cacao plantations)to increase flowering and fruit set.

Note: T.d. plants growing in low nutrient soils tend to have higher nitrogen content in their leaves. This may indicate there is more vegetative growth and could possibly therefore result in a delayed fruiting response. More research needs to be done on this.

(7)Desirable pH of soils-low

(8) Topography- Level or gently sloping …depressions and lower slopes may enhance moisture conditions resulting in enhanced vegetative growth, flowering, pollination and fruiting both for T.d.

(9)Micro-environment . Leaf litter is very important to create the layer of humus around the base of the petioles with reproductive nodes to encourage the pollinators.

With T.d. the effect of mulching may vary according to the time of planting and the type of mulch available. The advantages of mulch are as follows.

(1) Protects the soil and prevents ‘hard crusting’ of the soil in exposed locations) (2) It should aid rainfall infiltration and conserve soil moisture. (3) It should reduce surface temperature of the soil.(4)Prevents the growth of weeds(5) Help to establish the right micro-environment to establish the insect necessary for pollination.

Disadvantages of mulching. (1) ) Wet weather mulching may result in the release of butyric acid which is toxic to young roots.(2)Infestations of unwanted insects.

6

However more research needs to be done on this.

(10)Adequate protection of leaves , fruits and flowers . Protection of the growing T.d. plants to prevent local villagers cutting the leaves for commercial purposes. Leaves, especially now that plastic bags are to be banned have high commercial value. Cutting the stems and leaves will prevent flowering and fruiting for up to two years after the initial reproductive nodes have formed. These form after 18 months to 2 years of growth after planting the seedlings. This means a total of 4 years till any meaningful harvest of fruit is obtained and only if the leaves are not removed again.

The education of the local people, notices threatening fines or actual guards to survey the plots during the day may be necessary!

(11)Irrigation in the dry season

This has not been tried in Ivory Coast however research in Nigeria has shown irrigation in the dry season increases fruit yield. (Ref. Cultivation of T.daniellii-the sweetener, Dr I. C. Onwueme .World Crops May 1979)

(12) Harvesting of fruit

During the flowering and fruiting periods the plants need to be left completely undisturbed except for the application of mollusc repellent as the new flowers and young fruits fall off extremely easily when disturbed.

The longer the fruit has to ripen the higher the yield of Thaumatin. Some fruits have been observed to last up to three years on the plant without deteriorating. A balance has to be stuck between harvesting the fruit or losing it to small mammals and agents which cause rotting. Recommended time to harvest after the initial two year developmental stage (during which there will be no significant fruit yield from the seedlings) can be discussed in following reports.

7

(13) Pests In the Ivory Coast we have had very little trouble with any form of pest except molluscs (Arioniadac and Diosliudae…according to a publication for C.N.R.A Gnagny, Traore, Mangara and Sweetman) that destroy the flowers.

Possible anti-mollusc treatment-Caldehyde

Two years ago a caterpillar (not identified) destroyed the leaves of the T.d. in the Anguededou plantation. A spray was used to destroy the caterpillars and as it was the dry season the pollination of flowers was not at risk. Occasionally white patches are observed on the T.d. leaves. It is assumed this is caused by caterpillar damage but as only small patches of damage appear nothing was done to prevent it.

Severe infestations of grasshoppers in Ghana and Nigeria have been reported.

Ants are not seen as a pest of T.d. (See following reports on pollination)

(14)Husbandry of the mature T.d. plants in plantations

Other than the slashing back of rhizomes that encroach on the ‘pathways’ adjacent to the Cacoa trees the ‘digging’ out of about 50% of the rhizomes of a plot every 10 years is advisable. From our experience in the rubber plantation the rhizomes become so profuse and tangled the yields of fruit begin to drop. After a thinnning out of rhizomes the yields were shown to improve. More research needs to be done on this.

(15) Pollinators

(1)It must be mentioned here that traps or use of catapults or other means of trapping birds in the planted areas by villagers must be stricly prevented in the same way as cutting of the leaves mentioned above.

(2) No insecticides must be used on and around the T.d. This would eliminate the insects needed in conjunction with the birds to pollinate the flowers.

(3)The planting of ‘Passion fruit creepers ‘on tall trees in the vacinity of the sites selected for planting will encourage the pollinator a sunbird.

8

Photo. By B.Sweetman

9

A T.d. plant with a mollusc on the inflorescence. Anguededou plantation, Ivory Coast.

Photo by B.Sweetman

Soil debris on the inflorescence of T.d. hiding an ant trail to an external flower nectary. Ants are not considered to be a pest or pollinator of T.d.Anguededou plantation, Ivory Coast.

10

Photo B.Sweetman

Young plants of Thaumatococcus growing under rubber trees Anguededou plantation, showing the type of shade required. These plants are the offspring from different regional T.d. plants Including Ghana, Cameroun and Ivory Coast.

11

Nectarinia olivacea (Olive sunbird with its beak entering the flower of Thaumatococcus daniellii, Anguededou plantation , Ivory Coast.

12

.

Three swollen petiole bases (leaves are not visible)of T.d. of Cameroun origin Anguededou plantation, attached to pieces of rhizomes with adventitious roots showing fruiting spikes with closed flowers or ripe red fruit. A growing point is also visible arising from the rhizome of the first petiole on the right of the photograph. Adiodopodoume, Route Dabou.

13

Flowers and fruit of Thaumatococcus daniellii from Cameroun seeds.

Anguededou Plantation Ivory Coast.

14

Thaumatococcus daniellii inflorescence with closed and open flowers from plants growing at Adiodopodoume, Ivory Coast. Two small developing fruits are visible the rest have aborted. Numerous aphids are also visible. Adiodopodoume , RouteDabou.

15

,