International Research Journal of Plant Science (ISSN: 2141-5447) Vol. 4(8) pp. 236-247, September, 2013
DOI: http:/dx.doi.org/10.14303/irjps.2013.043
Available online http://www.interesjournals.org/IRJPS
Copyright © 2013 International Research Journals
Full Length Research Paper
Phenotypic variation in fruits and nuts of Cola
acuminata in three populations of the centre region of
Cameroon
Egbe Enow Andrew*1, Kuchambi Indah Eni2, Tchoundjeu Zac3
*1
Department of Botany and Plant Physiology, University of Buea, P.O.BOX 63 Buea, Cameroon
2
World conservation Society, Limbe, Cameroon
3
ICRAF Regional Office for West and Central Africa, Yaoundé, Cameroon
*Corresponding Author `s E-mail: egbe1@yahoo.com; Telephone: 237-77671037; Fax: 237 3332 22 72
Abstract
This study was carried out to quantify tree-to-tree variation in fruit and nut traits as to aid in the
selection of superior phenotypes for domestication and plantation establishment.
Detail
measurements of fruit and nut characteristics from 43 trees of Cola acuminata were made from three
populations in the Centre Region of Cameroon. A total of 1204 fruits were assessed. High significant
differences were noted in the mean fruit mass with range 82 to 330g, mean fruit length ranged from 89
to 154 mm, mean fruit diameter ranged from 44 to 73mm, mean number of nuts per fruit ranged 3 - 11,
mean nut mass with testa ranged from 53 – 205g while nut mass without testa ranged 42 – 164g. There
was also variation in the colour of the nuts and the number of cotyledons per nut and there were
significant differences in the three populations (P≤ 0.001). This paper provides quantified description
of tree-to-tree variation in fruit and nut traits within populations of Cola acuminata in the Centre Region
of Cameroon. In this study five plus trees were selected from these three populations which could be
used for cultivar development and plantation establishment.
Keywords: Selection, superior phenotypes, populations, domestication, nut and fruit mass, fruit length and
diameter.
INTRODUCTION
Land use management in the tropics has to do with the
provision of livelihood needs of subsistence farmers (food
security and cash generation), global needs for
international commodities (timber and plantation crops)
and international environmental services (biodiversity and
sinks for greenhouse gases to minimise global climate
change) for it to be truly sustainable. In order to attain
these goals, the domestication of indigenous fruits and
their integration in diverse agroforest are important
components of a strategy that provides economically
valuable timber and non-timber products traditionally
obtained from natural forest and important environmental
services resulting in a land-use that is both sustainable
and productive (Leakey and Tchoundjeu, 2001).
In the humid lowlands of West and Central Africa as in
other parts of the tropics, the products of indigenous
trees such as Irvingia gabonensis, Baill ex Lanen;
Dacryodes edulis, (G. Don) H.J. Lam; Ricinodendron
heudelotti (Baill) Hecker and Cola acuminata (P. Beauss)
Schott and Endl; are marketed in both local and regional
markets as a means of generating cash to supplement a
subsistence lifestyle (Ndoye et al., 1997). A sample of the
West African tree/shrub species appropriate for inclusion
in multistrata agroforest and for domestication identified
Egbe et al. 237
Cola acuminata as one of the species for the region
(Leakey, 1998). The seeds of C. acuminata have from 3
to as many as 6 cotyledons, with the seed splitting into a
corresponding number of pieces, (Tachie-Obeng and
Brown, 1998). These cotyledons (kola nuts) are the main
consumable part of its fruit. In Africa and especially West
and Central Africa where it originated, it is chewed as a
masticator and this plays a similar role to that of having
coffee or tea or to smoke cigarette in some countries of
Western Europe. The nuts also occupy an important
place in social customs and traditional practices of the
people of West and Central Africa such as in child
naming, marriage and funeral ceremonies (Olaokun,
1988, Atawodi et al., 1995). Economically, the nuts are
important subjects of trade in Africa and were used as an
exchange medium for goods and services before the
advent of money in parts of Africa (Nkongmeneck, 1985).
Farmers in most of the countries of West and Central
Africa are gaining interest in the crop because of the
economic benefits derived from its sales (Dossa et al.,
1994). According to a market survey conducted in 1995
in some selected markets in two Regions of Cameroon;
the weekly net marketing margin per trader ranged from
8,000 FCFA to 13, 900 FCFA (Ndoye et al., 1998). In the
same paper, another study conducted in 1996 on a
broader market scale between Cameroon and Central
African Republic, revealed that the weekly net margin per
trader was 4,800 FCFA. Medicinally, because of the
polyphenol and caffeine contents of kola nuts, kola
extracts have been used in the manufacture of drugs
((vigogenol liquid and kola-Astier) against physical,
mental and sexual fatigue) wine, liquors and
confectioneries (Oladokun, 1988; Nkongmeneck, 1985).
Despite the enormous potential of kola nuts and its
place in social life in Africa south of the Sahara, very little
research efforts aimed at domesticating this species have
been initiated. Research has been carried out on other
fruit trees such as Dacryodes edulis (Plum), Irvingia
gabonensis
(Bush
mango)
Allablanckia
sp,
Ricinodendron heudelotti (Njansang). No such studies
are known to have been carried out on kola.
Most of the kolanut fruits marketed today are
harvested from natural stands (volunteer plants) retained
by farmers during the development of Cocoa/Coffee
plantations. With the current rate of deforestation,
farmers reluctance to plant due to the allogamus
reproductive system of kola, and the long fruiting period;
not many natural stands are left resulting in the fruits
becoming scarce and difficult to collect. Even in areas
where farmers attempt to plant, it is mainly by
transplanting wildings rather than seedlings from good
mother plants Seed multiplication of kola is successful
but it has been observed that Kola trees (seedlings) take
between 5 – 10 years before they commence fruiting in
addition to 6 months in the nursery (Asaah, 2005;
Quarcoo 1972). After producing fruits they can stay for 2
– 5 years before fruiting again. Some farmers have also
expressed their will to plant if they had improved planting
materials that are early fruiting and mast fruit. Thus
selection of kola trees with desired fruit and nut traits
complemented by early fruiting characteristics would
provide improved planting materials that could stimulate
farmers planting of the species (Leakey and Jaenicke,
1995).
Though kola nuts are economically valuable, this tree
displays a tremendous amount of variability when
evaluated as a plant. This variation is observed in terms
of nut taste (Slimy and non-slimy), nut colour (red, rose
and white), nut size, fruit size, number of cotyledons,
year-to-year variation in fruit production and tree-to-tree
variation in regularity of fruiting. An understanding of
theses variations will guide the conception of a
demonstration strategy for kola. Intra specific variation
was observed within Irvingia gabonensis (Atangana et al.,
2001; 2002a) in a biophysical characterization study.
Thus if these variations in kola are genetically controlled,
then with the application of vegetative propagation
techniques, trees with desired traits could be selected,
mass produced and integrated into farming systems. The
aim of the present study was to assess phenotypic
variation in fruit and nut traits within and between trees of
Cola acuminata in three populations in the Centre Region
of Cameroon. It is also to identify relationships between
fruit and nut characteristics and select candidate ‘plus’
trees for cultivar development. The use of this diversity
and the selection of ‘plus’ trees by farmers and
researchers is the starting point for the domestication of
this species based on already developed low cost
technology methods of vegetative propagation (Shiembo
et al., 1996, Tchoundjeu et al., 1998).
MATERIALS AND METHODS
Study area and selected sites
The study was carried out in Goura (4 o 34’N, 11 o 26’E),
Tchamogo (4 o 33’N, 11 o 28’E) and Bindamogo (4 o 30’N,
11 o 29’E) which fall in the humid forest ecological zone of
Cameroon. The zone is characterized by an altitude of
between 300-400m with annual rainfall of between 15002000mm. The rainfall pattern is bimodal with two rainy
seasons occurring from mid-march to mid- July and from
mid- August to mid- September (Ambassa-kiki, 2000).
The sites were chosen based on high kola producing
communities and accessibility.
238 Int. Res. J. Plant Sci.
Assessing phenotypic variation in fruits and nuts
Nut traits
With the assistance of local guides, 1204 fruits were
harvested from 43 non-planted kola trees during the
fruiting season; March – June.
These trees were
mapped out by use of a Geographic positioning system
(GPS) and their heights, crown diameter and diameter at
breast height (1.3m) were measured. Each tree crown
was divided into four quadrants; North, East, West and
South and 28 fruits were harvested from each tree, taking
seven fruits from each quadrant. The 28 fruits were then
weighed using a portable kitchen scale and their length
and diameters taken by use of a venier caliper. The fruits
were then split open with a knife and the number of nuts
in each fruit counted and recorded. The nuts were
weighed with and without testa using a small portable
electronic scale. The weight of the testa was derived as
difference of nut weight with testa and nut weight without
testa. The data was collated using Microsoft Excel 2010.
The amount and pattern of variation in each measured
characteristic was obtained using the mixed model
procedure (variance component analysis) and analysis of
variance (Genstat 8th edition). The relationship between
fruit and nut characteristics were examined using linear
regression analysis.
The nut traits assessed were nut number per fruit, nut
mass with testa, nut mass without testa, weight of testa
and cotyledon number and these showed highly
significant differences (P< 0.001) between sites and
between trees. Variance component analysis also
showed higher variation between sites than between
trees for all nut traits. Discontinuous variation was also
observed in the number of nuts per fruit (Figure 2).
Mean number of nuts per fruit ranged from 3 to 11.
Trees with the highest number of nuts were from T25 (11)
of Tchamogo (Table 2). Mean nut mass with testa
ranged from 53.3 to 205.2 g. Nuts from T17 (205.2 g)
and T35 (53.3 g) of Tchamogo had the highest and
lowest mean nut mass with testa. Mean total nut mass
without testa for all observations (n =9,884) was 90.27 g
and nuts from T17 (164.63 g) and T35 (42.26 g) of
Tchamogo had the heaviest and least weights
respectively. Nut testa weights ranged from 11.04 to
59.20 g and were highest for T19 (59.20 g) and least for
T35 (11.04 g). The number of cotyledons ranged
between 3 and 4 with the highest number observed in
B37 (4) of Bindamogo and the least in T35 (3) of
Tchamogo.
RESULTS
Fruit and nut characteristics across sites
Variations in C. acuminata fruits and nuts in the
Centre Region of Cameroon
Across three populations in the Centre Region of
Cameroon there were highly significant differences (P <
0.001) in the means of all morphological traits of fruits
and nuts that were measured (Table 3).
Fruit Traits
Fruit traits (mass, length and width) showed highly
significant differences (P< 0.001) between sites and
between trees. Variance component analysis also
showed higher variation between sites than between
trees for all fruit traits. Tree-to-tree variations were also
found to be continuous in all fruit traits (Figure 1 a, b and
c). The mean fruit mass ranged from 82.1 to 333 g.
Trees T17 and T35 of Tchamogo, had the highest and
least fruit masses respectively.
The diameter of the fruit ranged from 73.60 to 44.32
mm with a mean of 59.97 (n = 1,176). Fruits with the
largest mean diameter were found on B42 (73.60 mm) of
Bindamogo (Table1) and the least on T35 (44.32 mm) of
Tchamogo. The length of the fruits ranged from 89.53 to
154.71 mm with mean of 124.94 (n = 1,176). The longest
mean fruit length was found on T20 (154.71 mm) (Table
1) and the least on T35 (89.53 mm) of Tchamogo.
Regression analysis coefficients and additive traits in
fruit and nut traits in C. acuminata
There were both strong and weak linear relationships
identified between certain fruit traits in C. acuminata. The
very weak relationships were observed between fruit
mass and fruit length (r2 = 0.27). The strong linear
relationship was observed between fruit diameter and
2
fruit mass (r = 0.58). There was generally very weak
linear relationships observed between nut characteristics
in C. acuminate; these had a range of R2 =0.014 to 0.18
(Figure 4).
Figure 5 illustrates trees that had good additive traits
in fruits and nuts. In Goura and Tchamogo populations
only one tree each was selected for these good additive
traits. However for the C. acuminate population at
Egbe et al. 239
350
300
250
200
Fruit
150
mass
(g) 100
50
G2
G12
G11
G16
G15
G10
G13
G1
G9
G6
G7
G14
G5
G8
G3
G4
G17
Goura
G2
G12
G15
G16
G1
G7
G14
G10
G8
G13
G11
G9
G6
G5
G3
G4
G17
B19
B8
B5
B9
B4
B3
B6
B7
B1
B2
Bindamogo
B4
B1
B10
B5
B8
B2
B3
B7
B6
B9
Fruit
length
(mm)
Tchamogo
T4
T7
T1
T10
T9
T8
T6
T12
T15
T11
T14
T2
T5
T13
T3
T16
T1
T4
T6
T13
T5
T7
T11
T2
T15
T14
T10
T9
T8
T12
T3
T16
0
180
160
140
120
100
80
60
40
20
0
Tchamogo
Bindamogo
Goura
Tchamogo
Bindamogo
G11
G11
G13
G12
G10
G15
G16
G7
G2
G8
G6
G5
G9
G14
G17
G4
G3
B9
B8
B10
B6
B4
B5
B3
B7
B1
B2
T1
T5
T14
T6
T13
T7
T2
T4
T8
T11
T10
T15
T9
T12
T3
T16
80
70
60
50
Fruit
40
diameter
30
(mm)
20
10
0
Goura
Figure 1. Continuous tree-to-tree variation in a) fruit mass, b) fruit length, c) fruit diameter of C.
acuminata at the various sites in the Centre Region of Cameroon.
240 Int. Res. J. Plant Sci.
Table 1. Mean fruit trait values of five best trees of C. acuminata for three sites in the Centre Region of Cameroon.
Traits
Fruit mass (g)
Site
Tchamogo
Bindamogo
Tchamogo
Tchamogo
Goura
Tree number
T17
B43
T20
T22
G13
Means
333.0 ± 75.17
328.6 ± 75.17
314.3 ± 75.17
296.4 ± 75.17
273.2 ± 21.17
Fruit diameter
(mm)
Bindamogo
Tchamogo
Tchamogo
Bindamogo
Tchamogo
B42
T17
T19
B41
T19
73.60 ± 6.49
72.29 ± 6.49
71.80 ± 6.49
71.15 ± 6.49
67.60 ± 6.49
Fruit length
(mm)
Tchamogo
Tchamogo
Bindamogo
Tchamogo
Bindamogo
T20
T23
B37
T26
B29
154.71 ± 16.11
148.66 ± 16.11
145.47 ± 16.11
139.64 ± 16.11
139.20 ± 16.11
160
140
120
Number of nuts
Mean
number of 100
nuts/fruit
80
60
40
20
TT
34
GT
9
G
T3
GT
6
GT
5
G
T7
GT
8
GT
15
M
T3
8
TT
25
TT
28
GT
2
G
T1
0
TT
23
TT
22
G
T3
6
TT
26
M
T4
M 2
T4
M 1
T3
1
G
T1
6
0
Individual Trees
Figure 2. Discontinuous tree to tree variation in number of nuts per fruit for C. acuminata
Egbe et al. 241
Table 2. Mean nut trait values of five best trees of C. acuminata for three sites in the Centre Region of Cameroon
Traits
Number of
Nuts/fruit
Site
Tchamogo
Tchamogo
Tchamogo
Tchamogo
Tchamogo
Tree number
T25
T22
T20
T24
T18
Means
11.32 ± 2.26
10.04 ± 2.26
9.77 ± 2.26
9.61 ± 2.26
9.54 ± 2.26
Nut mass
With testa
(g)
Tchamogo
Tchamogo
Tchamogo
Tchamogo
Bindamogo
T17
T22
T19
T32
B41
205.2 ± 41.23
162.5 ± 41.23
162.3 ± 41.23
161.9 ± 41.23
159.7 ± 41.23
Nut mass
Without
testa (g)
Tchamogo
Tchamogo
Bindamogo
Bindamogo
Tchamogo
T17
T32
B41
B42
T22
164.63 ± 32.73
131.13 ± 32.73
125.06 ± 32.73
122.39 ± 32.73
117.96 ± 32.73
Nut testa
weight
(g)
Tchamogo
Tchamogo
Tchamogo
Tchamogo
Tchamogo
T19
T21
T22
T17
T23
18.60 ± 11.95
46.0 ± 11.95
44.55 ± 11.95
40.56 ± 11.95
37.53 ± 11.95
Cotyledon
number
Bindamogo
Bindamogo
Bindamogo
Goura
Goura
B37
B30
B42
G13
G13
4.75 ± 0.35
4.73± 0.35
4.71 ± 0.35
4.71 ± 0.35
4.55 ± 0.35
Table 3. Fruit and nut characteristics of C. acuminata across three sites in the Centre Region of Cameroon.
Trait
Mean fruit mass (g)
Mean fruit length (mm)
Mean Fruit diameter
(mm)
Mean nut mass with
testa (g)
Mean nut mass without
testa (g)
Mean number of
nuts/fruit
Mean number of
cotyledons
Mean weight of testa
Goura
199.2± 5.63
120.79±1.23
58.33± 0.49
Sites
Bindamogo
218.1± 5.63
124.92± 1.23
63.03± 0.49
Tchamogo
224.8± 5.63
129.10± 1.23
59.70± 0.49
Probability
P = < 0.001
P = < 0.001
P = < 0.001
103.9±3.14
123.7±3.14
123.2±3.14
P = < 0.001
84.56± 2.49
92.90± 2.49
94.34± 2.49
P = < 0.001
7.493± 0.17
8.536± 0.17
8.342± 0.17
P = < 0.001
4.306± 0.03
4.425± 0.03
4.221± 0.03
P = < 0.001
19.29± 0.91
30.82± 0.91
28.81± 0.91
P = < 0.001
242 Int. Res. J. Plant Sci.
50
y = 0.2421x - 2.2834
40
2
R = 0.1809
30
Weight of
testa (g) 20
Weight of testa
10
0
0
50
100
150
200
250
Nut mass (g)
a
Weight of testa
50
y = 2.6228x + 4.631
40
R = 0.1697
2
Weight 30
of testa 20
(g)
10
0
0
2
4
6
8
10
12
Number of nuts/fruit
b
y = 0.0199x + 5.7351
12
2
R = 0.0419
Number
10
of
8
nuts/fruit
6
and
number of 4
cotyledons
2
/fruit
Number of nuts/fruit
Mean number of
cotyledons/fruit
y = -0.0001x + 4.3042
2
R = 0.0161
0
0
50
100
150
200
250
Nut mass (g)
c
Figure 4. The linear relationships between nut characteristics in C. acuminate
(a) Weight of testa per Number of nuts (b) weight of testa (c) number of nuts
per fruit and number of cotyledons/nut
Egbe et al. 243
Mean fruit mass
Mean fruit length
Mean fruit diameter
3
7
Mean Nut mass wout testa
400
350
300
Fruit
250
and nut 200
traits 150
100
50
0
0
1
2
4
5
6
8
9
10 11 12 13 14 15 16 17
Tree numbers
Mean fruit mass
Mean fruit length
Mean fruit diameter
Mean Nut mass wout testa
500
400
Fruit 300
and nut200
traits
100
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Tree numbers
Mean fruit mass
Mean fruit length
Mean fruit diameter
Mean Nut mass wout testa
4
7
400
Fruit 300
and nut
200
traits
100
0
0
1
2
3
5
6
8
9
10
11
Tree Numbers
Figure 5. Variations between trees in a) Goura, b) Tchamogo and c) Bindamogo and the selection of
plus trees base on fruit and nut traits.
244 Int. Res. J. Plant Sci.
% Colour occurrence in C. acuminata fruits
90
80
70
60
50
40
30
20
10
Goura
Tchamogo
Colour 45
Colour 26
Colour 16
Colour 4
Colour 5
DR
Colour 34
Colour 97
Colour 11
Colour 15
Colour 13
Colour 45
Colour 26
Colour 16
Colour 4
Colour 5
DR
Colour 34
Colour 97
Colour 11
Colour 15
Colour 13
Colour 45
Colour 26
Colour 16
Colour 4
Colour 5
DR
Colour 34
Colour 97
Colour 11
Colour 15
Colour 13
0
Mbindamogo
Figure 6. Percentage of Colour occurrence in C. acuminata nuts in the various sites in the Centre
Region of Cameroon
Bindamogo, three trees were selected as plus trees for
their additive traits in fruit and nut characters. There
were also considerable differences in the colour of the
nuts within trees and fruits of C. acuminata. The most
common of the identified nut colours within fruits were
Plum (45), Clove pink (26) and Summer rose (16)
(Kornerup and Wanscher, 1978).
DISCUSSION
Forest and non-timber forest products (NTFPS) enhance
rural livelihoods by generating cash for subsistence
farmers (Ndoye at al., 1998). Cola spp are of the NTFPs
that have commercial potential in local, regional and
international markets. Also, in response to falling Cocoa
and coffee prices, and reacting to market opportunities,
farmers have increasingly diversified their revenue by
planting and exploiting other tree crops. In carrying out
this, they increase and stabilize the returns from their
land. Enriching existing farms with selected (plus) trees
of Cola can permit all year round production and an
improvement in their livelihoods. This study which
quantifies the variation in fruit and nut traits of Cola
acuminata provides a good fundamental knowledge
about the range of variation in several important traits
across environmentally and culturally different sites.
The results which indicate considerable tree-to-tree
variation in fruit/nut traits is consistent with results from
other indigenous fruit trees such as Irvingia gabonensis
(Atangana et al., 2001; 2002a), Ngo Mpeck et al., (2003)
for Ricinodendron heudelotti, Waruhiu et al., (2004) for
Dacryodes edulis and Leakey et al., (2005a, 2005b) in
Sclerocarya birrea studies. This considerable tree-to-tree
variation is typical of that found in a population of an out
breeding species and offers an opportunity to identify
individual trees with fruit traits well above the average of
the species (Leakey et al., 2005a).
The coefficient of variation in fruit mass varied by
34.6% and fruit length, fruit width, nut mass with and
Egbe et al. 245
without testa and number of nuts were 12.9%, 10.4%
35.6%, 36.3% and 27.5% respectively. These differences
reflect the fact that fruit mass, which are themselves
affected by differences in fruit length and diameter, are
integrated in others traits. This additive impact on fruit
mass and differences in fruit length and diameter are
further emphasized by their strong correlation and this
was also observed in earlier studies with other species
(Leakey et al., 2000a and Atangana et al,. 2001).
However the differences in traits across populations
could possibly be explained by differences in climatic and
human responses to different survival/ regeneration
pressures and this is consistent with the findings of
Leakey et al., (2000a) on Irvingia gabonensis.
The extensive and continuous intraspecific variation
found in this study offers the opportunity for selection.
However, trees with superiority in one trait were not
necessarily superior in other traits and consequently it
was difficult to find the rare trees with superiority in many
traits. Nonetheless, a total of five trees were selected as
plus trees with three outstanding trees based on nut traits
and according to farmers preferences were identified as
plus trees from the three populations. These selected
trees if multiplied vegetatively, would offer considerable
improvements in the selected trait over the average for
the three populations. Similarly, Leakey et al., (2000b)
and Atangana et al., (2001) experienced this when
quantifying variation in Irvingia gabonensis. They then
focused on the identification of a combination of traits that
together formed either a fruit or a kernel ideotype.
Currently this ideotype approach has been adapted for
kola though with only a single fruit product; the edible
nuts. Selection of these trees that best fit the nut
ideotypes would give potential gains to farmers based on
their preferences. However, as the different organoleptic
components of taste and consumer preferences are
elucidated, it is possible that specific combinations of
unrelated morphological and organoleptic traits (including
nut colour) may need to be combined to identify other nut
ideotypes.
Also, varying number of nuts per fruit within individual
tree samples (discontinuous variation) indicates that this
trait is affected by some environmental factors and is not
only a genetic trait. A possible explanation for this
variability in nut number per fruit could be due to low
pollination efficiency, self incompatibility, insect attack on
flowers or physiological abscission, nutrient deficiency
and other environmental stress (Egbe and Oladokun,
1987). If low pollination efficiency is the main cause of
lower nut numbers in the fruits, then the setting up of
beehives in male cola trees, or the grafting of male scions
into the crowns of female trees, might be of advantage.
Strong linear relationships were found between some
of the traits that characterize a good fruit such as fruit
mass, fruit length, fruit diameter and nut mass, indicating
that big nuts could necessarily be found in big fruits. A
similar result was reported by Atangana et al., (2002a)
and Leakey et al., (2000a) in I. gabonensis.
Consequently, overall fruit size is evidently an important
and easily selected trait for plus trees that are targeted
for the production of large nuts. Leakey et al., (2002)
also observed that fruit size was also taken into account
by retailers when fixing the prices per fruit and the price
per kilogram of pulp for Dacryodes edulis.
Most farmers depend on a few crops such as Kola
nuts for their income. The testa which comprises about
20% of the total fruit mass is eaten for its sweet taste.
This part of the fruit could be exploited further as this
could greatly add value to the plant and make a large
difference in the income of the farmers and community as
a whole. Some farmers argued that large fruits contain
large nuts and hence used fruit size as criteria for
selecting trees to harvest. This remark was evident as
strong relationships were observed between fruit size and
nut mass. This observation also confirms some farmer’s
presumptions of selection criteria for I. gabonensis
(Atangana et al., 2001) and I. wombolu (Asaah et al.,
2003). It also supports the fact that both fruit and nut
characteristics are very important for the domestication of
Cola spp and to improve on the ecology of C. acuminata
within the Centre Region of Cameroon.
The various coloured nuts occurring on one tree and
even within a fruit might depend on the type of pollen that
fertilizes the ovule of the mother tree. According to
Voelcker, (1935) the inheritance of cotyledon colour is
purely Mendelian and it is determined by the interaction
of a number of genes. He added that the colour of the
nuts has been shown to be determined by the genetic
constitution of the tree on which the flowers are borne
and of the tree which yields the fertilizing pollen.
Consumers of kola nuts used colour to judge the state of
maturity and also the taste of the nuts. According to
them white Cola nuts were likely to be non-slimy, and had
a ‘sweet’ taste. This accounts for the white colour being
the most preferred across all the sites. However, it was
observed that very few trees had fruits which contained
the white Cola nuts.
CONCLUSION
Identification of intra-specific genetic variability of the
priority species, and the vegetative propagation
techniques to capture the combinations of genetic traits
246 Int. Res. J. Plant Sci.
found in superior individual tree is fundamental in their
incorporation into agroecology or community forest. This
clonal approach enables the capture of desired traits
while stimulating early fruiting and thus time reduction
between investment in tree planting and returns obtained
from the harvesting of tree products which is important in
livelihood enhancement and thereby reducing rural
poverty. The five plus trees were selected based on their
additive effects on the fruit and nut traits from these three
populations. Therefore these trees could be used in
cultivar development of C. acuminata within the Centre
Region of Cameroon.
ACKNOWLEDGEMENT
This work was funded by the African Network for
Agriculture, agroforestry and Natural Resource Education
(ANAFE). Our sincere appreciation also goes to the
farmers in the three communities in the Centre Region of
Cameroon where the study was carried out We also
acknowledge Mr. Alain Atangana for his guidance in data
analysis.
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How to cite this article: Egbe EA, Kuchambi IE, Tchoundjeu Z (2013).
Phenotypic variation in fruits and nuts of Cola acuminata in three
populations of the centre region of Cameroon. Int. Res. J. Plant Sci.
4(8):236-247