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The present study occurred in the three climatic zones of Benin (6°25 -12° N) and aimed at investigating the level of morphometric and genetic variation and spatial genetic structure within and between threatened baobab populations. A total of 137 individuals from six populations were analysed using morphometric data as well as molecular marker data generated with the AFLP technique. Five primer pairs resulted in a total of 217 scored bands with 78.34% of them being polymorphic. A two-level AMOVA revealed 82.37% of the total variation within populations and 17.63% among populations (P<0.001). Analysis of population structure with allele-frequency based F-statistics revealed a global FST of 0.127±0.072 (P<0.001). The mean gene diversity within populations (Hw) and the average gene diversity among populations (Hb) were estimated at 0.309±0.000 and 0.045±0.072, respectively. Baobabs in the Sudanian and Sudan-Guinean zones of Benin were short and produced the highest yields of pulp, seeds and kernels in contrast to the ones in the Guinean zone. The molecular results indicate some degree of physical isolation of the populations collected in the different climatic zones. We also found morphological differences but further analysis must be done to establish their origin which is certainly an interaction between genotype and environment. Sampling options of the natural populations are suggested for in or ex situ conservation.
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Not. Bot. Hort. Agrobot. Cluj 38 (2) 2010, Special Issue, xx-xx
Print ISSN 0255-965X; Electronic 1842-4309
Notulae Botanicae Horti Agrobotanici
Cluj-Napoca
Conservation Genetics of Baobab (Adansonia digitata L.) in the
Parklands Agroforestry Systems of Benin (West Africa)
Achille Ephrem ASSOGBADJO1) , Romain GLELE KAKAI1) , Tina KYNDT2) , Brice SINSIN1)
1)University of Abomey-Calavi, Faculty of Agronomic Sciences, Laboratory of Applied Ecology, 05 BP 1752 Cotonou, Benin; assogbadjo@yahoo.
2)Ghent University, Department of Molecular Biotechnology, Coupure Links 653, B-9000, Ghent, Belgium
Abstract
e present study occurred in the three climatic zones of Benin (6°25 - 12° N) and aimed at investigating the level of morphometric
and genetic variation and spatial genetic structure within and between threatened baobab populations. A total of 137 individuals from
six populations were analysed using morphometric data as well as molecular marker data generated with the AFLP technique. Five primer
pairs resulted in a total of 217 scored bands with 78.34% of them being polymorphic. A two-level AMOVA revealed 82.37% of the total
variation within populations and 17.63% among populations (P<0.001). Analysis of population structure with allele-frequency based
F-statistics revealed a global FST of 0.127±0.072 (P<0.001). e mean gene diversity within populations (Hw) and the average gene
diversity among populations (Hb) were estimated at 0.309±0.000 and 0.045±0.072, respectively. Baobabs in the Sudanian and Sudan-
Guinean zones of Benin were short and produced the highest yields of pulp, seeds and kernels in contrast to the ones in the Guinean
zone. e molecular results indicate some degree of physical isolation of the populations collected in the dierent climatic zones. We
also found morphological dierences but further analysis must be done to establish their origin which is certainly an interaction between
genotype and environment. Sampling options of the natural populations are suggested for in or ex situ conservation.
Keywords: Adansonia digitata, climatic zones, morphometric variation, population structure
Introduction
e multipurpose baobab (Adansonia digitata L.) is a
key economic species used daily in the diet of rural com-
munities in West Africa (Assogbadjo et al., 2005a,b; As-
sogbadjo et al., 2008; Codjia et al., 2001, 2003; Sidibe and
Williams, 2002). e species contributes to rural incomes
(Diop et al., 2005) and has various important medicinal
and food uses (Assogbadjo et al., 2005a; Diop et al., 2005;
Sena et al., 1998; Sidibé et al., 1996; Sidibé and Williams,
2002; Yazzie et al., 1994).
Within baobab species, there is evidence indicating
the existence of a number of local forms diering in habit,
vigor, size, quality of the fruits and foliar vitamin content
(Assogbadjo et al., 2005a; Gebauer et al., 2002; Sidibé and
Williams, 2002). However, information about the ecol-
ogy, the morphological and genetic variation within and
between populations and the productivity of their various
organs is lacking (Sidibé and Williams, 2002).
e participatory domestication of indigenous fruits
has been proposed as an appropriate means to alleviate
poverty (Poulton and Poole, 2001), and could also have
positive benets on the environment since new plantings
of baobab would help to restore the declining resources of
this important tree.
e main objective of the present study is to dene
based on molecular analysis a better conservation strate-
gies for the baobab species in Benin. To this aim, Ampli-
ed Fragment Length Polymorphism (AFLP) analysis
(Vos et al., 1995) was applied to nd the intra-specic
genetic diversity of those locally recognised morphotypes
and on the whole populations in order to assess the genetic
diversity and dierentiation within and between baobabs
in Benin. Because AFLPs are known to map throughout
the genome of any particular species analyzed so far, this
high-volume DNA ngerprinting techniques gives fast
and ecient measurements of genome-wide diversity
(Powell et al., 1996). We used this technique to investigate
not only if the traditional classications of A. digitata are
conrmed by genome-level genetic dierentiation but also
if there is within the species some genetic variations which
should be conserved for the benet of local people.
Materials and methods
Study areas
e study was conducted in the three climatic zones of
Benin (112 622 km2 and 6.752.569 inhabitants in 2002),
located between 6° and 12°50 N and 1° and 3°40 E in West
Africa. e zones studied are: the Sudanian zone located
between 9°45’-12°25’ N, the Sudano-Guinean zone lo-
cated between 7°30’-9°45’ N and the sub-humid Guinean
zone (Dahomey Gap) located between 6°25’-7°30’ N.
In the Sudanian zone, the annual mean rainfall is oen
less than 1000 mm and the relative humidity varies from
18% during the harmattan period (December - February)
Assogbadjo, A. E. et al./ Not. Bot. Hort. Agrobot. Cluj 38 (2) 2010, xx-xx
2
analyses of genetic diversity and structure were performed
using AFLPsurv version 1.0. (Vekemans, 2002) which is
based on the methods described by Lynch and Milligan
(1994). Nei’s (1973) gene diversity (also known as expect-
ed heterozygosity) as well as global and pairwise genetic
dierentiation (FST) values were computed. Signicance
of the genetic dierentiation between groups was tested
by comparison of the observed FST with a distribution of
FST under a hypothesis of no genetic structure, obtained
by means of 1000 random permutations of individuals
among groups. Moreover, a model-based (Bayesian) clus-
tering method was applied on the presence/absence matrix
to infer genetic structure in the dataset, using the soware
Structure version 2.0. (Pritchard et al., 2000).
Assessing and analyzing morphometric data in baobab
populations
e morphological characteristics of each baobab were
studied (at the abovementioned populations). For each
baobab sampled, the trunk diameter was measured at
breast height (1.3 m) (DBH). Tree height, crown diameter
and the number of branches were also determined. If fruit-
ing, the number of capsules was counted and their shape
noted. To estimate the productivity in pulp, seeds and ker-
nels, 600 fruits were sampled in each population. Length
and weight of total fruit and its contents (pulp + seeds)
was determined. e seeds were then removed by soaking
the contents in water. e seeds were counted and then
oven-dried at 50 to 60°C for 48 hours. e dry seeds were
boiled for 30 min in order to remove the seed coat, which
is a traditional technique for extracting the kernel. Kernels
were dried at 40 to 50°C for 48 hours and weighed. e
weight of the pulp (WP) in each fruit was obtained by
the following formula: WP= Wsp - Ws, where Wsp is the
weight of the capsule’s contents (seed with pulp), and Ws
is the weight of the seed without pulp. For each product
(pulp, seeds or kernel), the mean productivity was calcu-
to 99% in August. e temperature varies from 24°C to
31°C. e Sudanian zone has hydromorphic soils, well-
drained soils, and lithosols. e vegetation of this zone
is composed of savannas and gallery forests with trees of
smaller size.
e mean rainfall in Sudano-Guinean zone is unimod-
al, from May to October, and lasts for about 113 days with
total mean annual varying between 900 mm and 1110
mm. e annual temperature ranges from 25°C to 29°C,
and the relative humidity from 31% to 98%. e soils in
this zone are infertile mineral soils and ferruginous soils of
variable fertility. e vegetation of the Sudano-Guinean
transition zone is characterized by a mosaic of woodland,
dry dense forests, tree and shrub savannas and forest gal-
leries.
e rainfall regime in the Guinean zone is bimodal
from April to June and from September to November,
with a mean annual rainfall of 1200 mm. e mean tem-
perature varies between 25°C and 29°C and the relative
humidity between 69% and 97%. e soils are either
deep ferrallitic, and of low fertility or alluvial and heavy
clay soils. e vegetation in this zone has been strongly af-
fected by various agricultural activities and now forms a
mosaic of cultivated lands and small relic forest patches.
e original vegetation was dense semi-deciduous forests
and Guinean savannas. is zone represents about 10% of
Benin and supports 60% of the country’s inhabitants.
Sampling for DNA ngerprinting
In each climatic zone, 2 populations of baobab were
sampled. Tab. 1 summarises the characteristics of the sam-
pled populations, including geographic zone of origin and
co-ordinates. Six to 35 individuals were sampled within
each population and used for the morphometric, produc-
tivity and AFLP analyses. In this study, a baobab popula-
tion was dened as a group of baobab trees randomly and
naturally distributed in a traditionnal agroforestry system
that can be assimilated to a circle with a maximum of 50
km radius. Two dierent populations are isolated from
each other by a geographical distance of at least 50 km.
Within a population, baobab individuals were randomly
selected at a distance of at least 100 m, in order to avoid
the sampling of genetically related individuals. In total,
six populations of baobab represented by 137 individuals
were collected in the aforementioned zones. For each bao-
bab, four or ve leaves were harvested and dried in silica
gel for DNA extraction and AFLP analysis.
Genetic data analysis
DNA were isolated following the MATAB protocol
(Kelly et al., 2004) whereas AFLP analysis were performed
as described by Vos et al. (1995) with minor modications.
For each individual, the DNA ngerprints were scored by
visual inspection for presence (1) or absence (0) of spe-
cic AFLP-bands (Fig. 1). Only distinct, major bands
were scored. For statistical analyses, allele-frequency based
Fig. 1. AFLP electrophoresis showing the scored bands
Assogbadjo, A. E. et al./ Not. Bot. Hort. Agrobot. Cluj 38 (2) 2010, xx-xx
3
lated per tree allowing the calculation of average yield for
each population. With SASv8 soware, analyses of vari-
ance and the Newman and Keuls test were performed on
morphological data to describe and compare baobab pop-
ulations within and between the climatic zones.
Results
Intra specic genetic variation and structuring of baobab
species in Benin
When bands from all 137 individuals were consid-
ered, levels of polymorphism within populations varied
between 89.4% and 98.2%, reecting a high level of poly-
morphism and variation within populations. e highest
estimate of the likelihood of the data, conditional on a
given number of clusters, was obtained when clustering all
genotypes into six gene pools. Results indicated that the
genetic structuring of the sampled individuals was cor-
related with their geographic origin. Nei’s gene diversity
(expected heterozygosity) within populations ranged be-
tween 0.26 and 0.37. A three level AMOVA partitioned
14.70% among the three regions of Benin and 5% of ge-
netic variation among populations within regions. Analy-
sis of population structure with allele-frequency based
F-statistics revealed a global FST of 0.127±0.072 (P=
0.001). e total gene diversity (Ht) was estimated to be
0.355±0.02 while the mean gene diversity within popula-
tions (Hw) and the average gene diversity among popula-
tions (Hb) were estimated at 0.309 and 0.045±0.072, re-
spectively. Pairwise genetic distances between populations
(FST), calculated using AFLPsurv 1.0, were statistically
signicant (P<0.001). Within the same climatic region,
the genetic distance is generally lower than 0.05, whilst
genetic distance between populations located in the dif-
ferent climatic zones were larger than 0.05. Mantel tests
comparing genetic dierentiation and geographic distance
per population showed a signicant correlation of 0.758
(P<0.001), indicating isolation by distance.
Morphological data, productivity in analyzed
populations
Morphological data and productivity of the analyzed
baobab individuals varied signicantly (P<0.05) among
populations and climatic zones. In the Sudanian zone, the
baobabs have large girths and crowns, and numerous fruits
with a high pulp, seed, and kernel production (Tab. 1).
Tab. 1. Morphological characteristics and mean production per individual for six baobab populations
Morphological feature
Guinean Sudano-guinean Sudanian
P1 P2 P3 P4 P5 P6
Mean σ Mean σ Mean σ Mean σ Mean σ Mean σ
DBH (cm) 149.23a66.89 147.15a57.29 176.35b33.64 173.04b40.32 201.51c97.88 202.55c54.90
Hm (m) 21.15a3.45 18.90b2.83 13.79c1.96 13.50c1.87 15.27d5.18 18.70b4.27
Dcrown (m) 14.27a3.69 14.22a1.13 16.95b5.99 16.58b4.62 16.56b4.66 16.58b3.98
NBranches 7a2.17 7a2.32 10b3.02 11b2.83 7a2.22 7a3.98
Ncaps/tree 49a46.12 67b36.15 188c70.77 225d203.50 137e92.54 138e132.51
Wcaps/tree (kg) 20.28a18.33 25.69b29.38 32.05c11.37 34.13d8.58 28.28e21.62 34.07f34.71
Lcaps (cm) 21.71a4.85 22.71a4.85 19.89b3.96 18.89b3.96 16.89c5.14 16.59c5.14
icknessCaps 0.45a0.15 0.45a0.15 0.43b0.09 0.43b0.09 0.43b0.07 0.43b0.07
WP/tree (kg) 3.62a3.19 1.93b1.55 6.13c1.98 6.51c1.46 4.94d3.75 4.83d3.83
Nseeds/tree 10969a9523 9326b8576 27565c9168 27635c8140 21188d20231 25455e20876
Wseeds/tree (kg) 4.22a3.97 4.62a2.68 9.21b7.06 11.09c10.85 16.93d16.31 17.04e16.72
Wkernel /tree(Kg) 1.40a1.32 1.54a0.89 2.31b2.10 2.70b2.57 3.67c2.35 3.70c3.62
Tab. 2. Correlation between distance based on individual
morphological features and pairwise genetic dissimilarity
values
Morphological
feature
Correlation with
genetic diversity Probability
DBH (cm) -0.00726 0.3168
Hm (m) -0.06655 0.0497*
Dcrown (m) -0.00568 0.4356
NBranches 0.07911 0.0198*
Ncaps/tree 0.05868 0.1584
Wcaps/tree (kg) 0.04529 0.1980
Lcaps (cm) -0.00188 0.4851
icknessCaps -0.14078 0.0099*
WP/tree (kg) 0.04825 0.2277
Nseeds/tree 0.04071 0.3069
Wseeds/tree (kg) 0.04441 0.2376
Wkernel /tree(Kg) 0.04441 0.2673
*= Signicant (Probability<0.05)
Legend Tab. 1 and Tab. 2: DBH= diameter at breast height; Hm= Height of tree;
Dcrown= diameter of the crown; NBranches= Number of branches; Ncaps=
Number of capsules; WCaps= weight of capsules; Lcaps= Length of capsule (cm);
ickness Caps= ickness of Capsule; WP= Weight of pulp; Nseeds=
number of seeds; Wseeds= Weight of seeds; Wkernel= Weig ht of kernel;
σ= standard deviation; P= population
NB: In the same line, gures with the same letters are not signicantly dierent.
Assogbadjo, A. E. et al./ Not. Bot. Hort. Agrobot. Cluj 38 (2) 2010, xx-xx
4
Baobabs from the Sudano-Guinean zone are short, their
diameter at breast height is intermediate between DBH
values measured in the Guinean and Sudanian region.
Populations in this zone produce the highest yield of pulp,
seeds and kernels. In the Guinean zone, the individuals
were tall but of a small diameter at breast height. ese
baobabs have capsules with high length and thickness but
produce only a small number of fruits with a low pulp,
seed and kernel productivity (Tab. 1).
Discussion and Conclusions
Relationship between morphometric data and genetic
variation
Morphometric data (Tab. 1) show signicant dierence
within and among baobab populations across the climatic
zones. Environmental eects on the biotic variables have
also been observed in other edible trees in Africa. Maranz
and Wiesman (2003) showed for the shea tree (Vitellatria
paradoxa) a signicant relationship between trait values
(fruit size and shape, pulp sweetness, and kernel content
of the species) and abiotic variables (temperature and rain-
fall) in sub-Saharian Africa north of the equator. Also,
Soloviev et al. (2004) showed for Balanites aegyptiaca and
Tamarindus indica (savanna trees) the signicant inu-
ence of dierent climatic zones of Senegal on fruit pulp
production. Moreover, Silva-Montellano and Eguiarte
(2003) were able to detect genetic dierentiation in popu-
lations of Agave lechuguilla along a latitudinal transect in
the Chihuahuan desert. e pattern of population dier-
entiation along this transect was congruent with patterns
of morphological and reproductive dierentiation found
(Silva-Montellano and Eguiarte, 2003).
In this study, we observed some parallel patterns of
morphological and genetic diversity in baobab. Although
it may well be that the variation observed in morphology
and other morphometric characters studied in baobab
were signicantly correlated with abiotic factors of envi-
ronment (Assogbadjo et al., 2005), there is also no doubt
that part of this variation within baobab populations could
be explained by genetic dierentiation. Indeed, the molec-
ular results indicate some degree of physical isolation of
the populations collected in the dierent climatic zones.
We also found morphological dierences but further ex-
periments (e.g. mapping studies) are needed to identify
specic genes or genome regions that might have a direct
inuence on the observed morphometric variation.
Conservation of baobab genetic diversity in Benin
As baobab seeds exhibited orthodox behaviour (Ra-
zanameharizaka et al., 2006), they can be conserved ex
situ in seed banks and also in situ or in circa as living trees.
Strategies for prioritizing the conservation of genetic di-
versity need to consider the level of diversity in an area,
and condition of, a particular region. e best option
should be to conserve seeds from non desirable baobab
(Assogbadjo et al., 2008) in ex situ in gene banks and the
living desired trees in situ as seeds and service suppliers.
e high levels of genetic variation present within popula-
tions suggested that large numbers of samples from a few
populations would capture a sucient amount of the spe-
cies’ genetic variability. However, such a practice would
increase the chance of missing rare alleles, particularly in
disjoint populations, which also expresses extreme pheno-
types for phenological traits related to climatic adaptation.
We suggested in these cases to sample for ex situ gene con-
servation, populations from dierent geographic areas and
individuals from all morphotypes to maximize genetic di-
versity for ex situ collections thereby increasing probabil-
ity of conserving rare alleles. We have also recommended
to sample seeds deployed for ex situ conservation in gene
banks from a high number of individuals and within all
climatic zones and morphotypes, thereby avoiding low
genetic diversity within seedlots and consequently low
risk of inbreeding depression and high adaptive capacity
to environmental variation in trees to be planted within
the parklands agroforestry systems. is could be done us-
ing the core collection concept and is important since it
can allow the sampling of dierent classes of alleles (wide-
spread, localized and rare).
Acknowledgements
is work is supported by the International Founda-
tion for Science (IFS) and Bioversity International (ex
IPGRI). We also thank AUF-BIOVEG network and
IRD (France) which provided travel grants for attending
conference at Cluj-Napoca in Roumania. We thank these
institutions and their donors. Our acknowledgement also
goes through local people of Benin.
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and Analysis 7(3):189-193.
... En Afrique de l'Ouest, depuis quelques années, le couvert végétal enregistre continuellement de fortes perturbations observées surtout au niveau des formations naturelles. Ces formations subissent une dégradation sans précédent, due à une forte pression anthropique qui se manifeste par des prélèvements à des fins alimentaires, médicinales, de carbonisation et de bois de feu Bamba et al., 2010), aux feux de végétation, à l'augmentation de la production animale et végétale, et aussi à l'exploitation forestière non contrôlée (Assogbadjo et al., 2010 ;FAO, 2015). D'après les derniers chiffres de la FAO (2011), le Bénin perd en moyenne 50.000 ha de forêts chaque année. ...
... Ainsi, la plupart des espèces forestières fournissant aux populations, surtout riveraines de forêts, des produits indispensables à leur survie et à leur bienêtre, connaissent une certaine dégradation de leurs populations. Parmi ces espèces, figurent des fruitiers sauvages les plus fortement consommés et utilisés par les populations locales au Bénin comme Adansonia digitata L. (Assogbadjo et al., 2010), Tamarindus indica L. (Fandohan, 2007), Sclerocarya birrea 16 (A. Rich.) ...
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L'évaluation et le suivi des espèces forestières constituent une source fondamentale d'informations pour la mise en place des stratégies de conservation efficaces et adaptées de ces espèces. La présente étude a pour objectif de déterminer la caractérisation structurale des peuplements naturels de D. senegalense J.F. Gmel. au Bénin. Quarante-huit placeaux de 1 ha chacun ont été installés de façon aléatoire dans les formations végétales pour réaliser l'inventaire forestier et les mesures dendrométriques de D. senegalense. Les différents paramètres structuraux ont été calculés en fonction des formations végétales. La densité des individus adultes est de 2,07 ± 1,58 ; 2,48 ± 2,11 et 1 pieds/ha respectivement dans les forêts denses, forêts galeries et agrosystèmes avec une différence non significative (P = 0,506). La surface terrière au niveau des formations varie de 0,22 ± 0,06 à 0,67 ± 0,68 m²/ha et le diamètre moyen varie de 47,73 ± 18,91 à 52,5 ± 7,78 cm. Cette espèce se caractérise par des populations de gros diamètres et âgées, avec de très faible densité d'individus adultes et des régénérations. La survie des régénérations est confrontée à des difficultés liées à l'habitat de l'espèce et aussi sous l'emprise de plusieurs pressions humaines. La sensibilisation des populations locales et riveraines des forêts parcourues à la sauvegarde des populations éparses existantes, la protection des juvéniles et la plantation de plants ex-situ sont importantes pour la conservation et survie de cette espèce.
... It is therefore urgent to develop strategies for its conservation in order to avoid its disappearance. The conservation of a forest species requires knowing the information about the level of genetic diversity and the extent of genetic differentiation within and between natural populations of that species (Assogbadjo et al. 2010). Several studies have been carried out on systematics and parataxonomy (Calvin 2007;Houénon et al. 2021), ethnobotany (Kouyaté et al. 2009;Agbo et al. 2019a), spatial and temporal distribution (Agbo et al. 2019b), phenology (Kouyaté 2005), morphological variability (Kouyaté 2005;Agbo et al. 2018) and pharmacology (Sani et al. 2014) of D. microcarpum. ...
... The development of effective strategies for the conservation and sustainable management of forest genetic resources requires an analysis of the diversity and genetic structure of these plant species which requires the use of highly informative genetic molecular markers (Liu et al. 2012). DNA molecular markers, including RAPD (Ercisli et al. 2008;Vanijajiva 2011), AFLP (Schenk et al. 2008;Assogbadjo et al. 2010) and RFLP (Bhattacharjee et al. 2002;Yan et al. 2005), were used to assess genetic diversity at the molecular level of many populations of plant species. In recent years, microsatellite markers (SSR) have become popular and powerful tools used for the assessment of genetic diversity due to their codominance, high rate of polymorphism, and putative in uence on transcribed genes (Benemann et al. 2012;Huda et al. 2019;Karam et al. 2019). ...
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The main objective of this study is to investigate the patterns of genetic diversity and phylogenetic relationships within populations of Detarium microcarpum (Fabaceae) relative to different spatial conditions. Seventy-eight (78) accessions of D. microcarpum belonging to six populations (Phytogeographic districts) were sampled. In order to have very good quality DNA for molecular analysis, an optimization of the DNA isolation protocol was made. The molecular analysis of the accessions was carried out using 7 chloroplast microsatellite markers. The polymorphism rate (P) is 85.71% and the Polymorphism Information Content (PIC) was in the range of 0.43 (Ntcp_9) to 0.73 (Ccmp_2) with an average of 0.59. Allelic richness (A) ranged from 1.41 to 2.85 with an average of 2.04. The observed heterozygosity (Ho) ranged from 0.23 to 0.60 with an average of 0.39. The expected heterozygosity (He) ranged from 0.43 to 0.60 with a mean of 0.50. Wright's fixation index (F IS ) ranged from − 0.17 to 0.47. The effective allele (Ae) is between 1.77 and 2.53 with an average of 2.02. Wright differentiation index (F ST ) was 0.024. Phylogenetic analysis revealed that the N ST value was significantly higher than the G ST value (N ST = 0.452; G ST = 0.190; P < 0.05). A relatively low h d haplotype diversity is obtained (H d = 0.320). AMOVA analysis showed that 17.35% of the variation existed within populations but 45.80% among populations within the species. Neighbor-Joining phylogenetic tree of D. microcarpum revealed three non-distinct clusters haplotypes showing the existence of gene flow between populations of the species. Our findings of genetic structure and gene flow of D. microcarpum populations based on different spatial conditions is caused by evolutionary forces such as scattering and pollination.
... Indeed, protected areas such as Pendjari and W Parks offer the best conditions for the species. Nevertheless, some authors reported the difficulties of germination of the species in natural refugia (Assogbadjo et al., 2010) and this is related to factors intrinsic to the species and damages caused by animals such as elephants. In addition, human pressure caused by population expansion, and their activities remain the real threat for the species and enhances its vulnerability. ...
Article
African baobab (Adansonia digitata) is an agroforestry species used by local people for many purposes such as food, medicine, craft, etc. It is uncertain how climate change will impact the suitability of the habitat for the species in Benin. This study aimed to assess the present-day distribution and forecast the probable impact of future climate, and provide sustainable management strategies for the species in Benin. Records of the species were gathered both from fieldwork and through available databases. Environmental data comprised both climatic and soil layers. We transferred the present-day models into future climates under two scenarios (RCP 4.5 and RCP 8.5) using Maxent software. Our results showed high suitability of the Benin territory for African baobab in the present. In addition, high stability of suitable areas was observed for the species in the future across Benin. However, some protected areas are predicted not to effectively conserve the species in the future. We believe that both ex-situ and in-situ conservation measures will help to maintain the African baobab population in the future.
... Consequently, morphological diversity in a given taxon might result from local adaptation (i.e., genetic differentiation driven by selection) or phenotypic plasticity (i.e., differentiation induced by environmental differences without genetic differentiation) without implying reproductive isolation. Similarly, geographically structured molecular genetic diversity within species could just result from the history of their populations with no evidence of speciation (e.g., Gomez et al. 2009;Assogbadjo et al. 2010;Debout et al. 2011;Born et al. 2011;Demenou et al. 2016). Nonetheless, molecular data sometimes uncover deep speciation signals, while morphological divergence is absent or weak. ...
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In the pantropical mimosoid legume genus Parkia, taxonomic classification has remained controversial in Africa due to clinal phenotypic variations. Three species (P. biglobosa, P. bicolor, and P. filicoidea) are currently recognized, ranging from West to East Africa, with partially overlapping ranges across different floristic regions. However, additional taxa (species or varieties) have been suggested by different authors. To assess species boundaries of African Parkia and phylogeographic patterns within species, we genotyped 889 individuals using 10 microsatellite markers and compared our results with existing morphological descriptions. Bayesian genetic clustering confirmed the species boundaries assessed from morphological traits and did not reveal introgression but identified genetic discontinuities within each species. Six moderately differentiated genetic clusters were recovered in P. biglobosa (pairwise FST: 0.05–0.19), while P. bicolor and P. filicoidea, each, displayed four well-differentiated clusters (FST: 0.18–0.41 and 0.11–0.34, respectively). Within each species, genetic clusters occurred in parapatry. Parkia biglobosa clusters were congruent with the longitudinal clinal variation in leaflets sizes but 26% of individuals presented admixed genotypes. Genetic clusters in P. bicolor and P. filicoidea followed environmental gradients as well as phytogeographic subdivisions. They were also largely congruent with morphological discontinuities described in previous taxonomic studies and < 10% individuals showed admixed genotypes. We conclude that only one species (P. biglobosa) should be considered in the Guineo-Sudanian savanna. However, P. bicolor and P. filicoidea might each represent a complex of (sub)species. Thus, the hypotheses of cryptic species within P. bicolor and P. filicoidea should be further investigated by testing reproductive barriers.
... Such loci would increase sterility effects and development 'decisions' between male and female functions (Meagher, 1988). Baobabs have relatively low diversity across large geographic areas (Baum et al., 1998;Tsy et al., 2009), but high diversity within populations (Assogbadjo et al., 2010) with high levels of polymorphism and polysomic inheritance (Assogbadjo et al., 2006;Assogbadjo et al., 2009;Larsen et al., 2009). This makes identifying genetic markers for morphological variation and sexual behaviour complex but it also allows for evolutionary change to take place (Wilson, 1994). ...
Article
Baobabs (Adansonia digitata) are iconic and highly valued trees that characterise many semi-arid environments across Africa. The aim of this study was to describe leaf, flowering and fruit phenology, flower production and fruit-set patterns of southern African baobabs. This was done on a sample of 106 trees across five land-use types at monthly intervals over two-years. Rainfall in the first year (2006/7, Year 1) was only 275 mm, but doubled in the second year (516 mm; 2007/8, Year 2), being below and above the long term mean of 461 mm, respectively. Leaf flush preceded the onset of rains (October) in 88% of trees in Year 1, but after the onset of rains (August) in all trees in Year 2. Leaves flushed in November and were retained until April and in October and retained until March, respectively. Leaf fall occurred one month later in Year 1 (May) than in Year 2 (April). Flowering followed a steady-state pattern, lasting for 1–5 months with peak flowering in November in both years. For adult trees, flower number/tree (Year 1: 711 ± 72 (S.E.) and Year 2: 287 ± 33), but not fruit-set (mean of 20 ± 4%) varied significantly between years. Flower number showed a logarithmic relationship with tree size (stem diameter) (R² = 0.3830, P < 0.0001), while fruit-set was unrelated to tree size (R² = 0.0045, P = 0.5081). Flower number and fruit-set did not vary between five land-use types, but length of flowering did, with village trees flowering for the longest period. Baobabs are hermaphrodite plants with both male and female reproductive structures in the same flower. Yet, across Africa many people refer to individual trees as being ‘male’ (fruiting is absent or minimal) or ‘female’ (substantial fruiting). Producer ‘female’ and poor-producer ‘male’ trees, did not differ in flowering phenology (number, timing and length of flowering), but fruit-set over two sequential years differed greatly between producer (33.5 ± 5.2%) and poor producer (0.2 ± 0.1%) trees. Leaf flush was responsive to early rains and hence baobabs appear to be facultative early greeners. However flowering and fruit-set patterns were not significantly different between these two years, despite the large rainfall difference. Although flower production was not different between producer and poor-producer trees in either year, fruit set was three orders of magnitude higher in producer than poor-producer trees. These quantitative results suggest that baobabs may be functionally dioecious and thus a complete characterization of the reproductive biology is required. Mechanisms underlying this pattern are discussed in terms of tree age, environment, pollination, genetics and evolutionary biology.
... Comparison of this result on climatic variable can only be made with other studies in Africa. There was observed significant differences in morphological traits in Baobab in relation to climatic conditions (Assobadjo et al., 2010;Maranz and Wiesman, 2005) in Shea tree (Vitellaria paradoxa) and (Soloviev, 2007) in Balanites aegyptiaca and Tamarindus indica. ...
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ABSTRACT The once sustainable agroforestry system in the Sudano-Sahelian zone of Cameroon has been abandoned and trees overexploited. A study on the variability in seed and seedling traits of Faidherbia albida (DEL.) A. Chev populations from different climatic zones was carried out. Six populations were selected from Sudanian (Poli, Garoua III, and Figuil) and Sahelian (Yagoua, Moulvoudaye and Maroua I) climatic zones and harvested seeds were transported to the experimental farm of IRAD Yagoua for pretreatment and growth experiment. Four pretreatments (98% sulfuric acid, hot water, scarification and soaking in water for 24 hours) were used to initiate the germination. After one month, the rate of germination (%) was recorded and seedlings were transplanted in three substrates for seedling growth evaluation. Growth traits (Survival, plant height, root collar diameter, number of leaves, root length, plant fresh weight and plant dry weight) were measured after three months. The experimental design was a single tree plot randomized complete block design with 30 blocks. Results indicated there was significant difference (p = 0.002) among pre-treatments for the germination. The highest rate of germination was recorded with seedlings from scarified seeds (78.33%), followed by those from seeds treated with sulfuric acid (76.67%). Seeds and seedling traits were significant among populations with Yagoua recording the highest in most of the traits measured. Scarification can assist in seed germination and movement of seeds between populations and climatic zones should be considered during conservation programs. © 2019 International Formulae Group. All rights reserved. Keywords: Faidherbia albida, agroforestry parklands, seed pretreatments, seedling traits, conservation, Sudano-Sahelian, Cameroon.
... This shows high diversity that exist among the baobab population studied. Assogbadjo et al (2010) also found within and between population variability in their study on baobab diversity in Benin, although, the traits they studied were mostly quantitative compared with the qualitative traits in this . CC-BY 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. ...
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The diversity in baobab was studied on 75 trees located at Adaklu District and Ho and Hohoe Municipalities. Thirteen morphological traits were used in the characterisation based on Bioversity descriptors for baobab. GenStat edition 12 was used to analyse the diversity as well as germination and growth data. Group average hierarchical clustering with Jaccard similarity coefficient discriminated among most of the baobab trees. Clustering was not based on location although few trees that were not discriminated were from the same communities. The clustering can be used in selecting trees for further studies and domestication. Germination tests were conducted with soaked, boiled and sulphuric acid treated seeds. Only the sulphuric acid treated seeds had germination significantly higher than the control. More studies should be done to find easier way of breaking seed dormancy of baobab. There were significant differences in 100 seed weight, seed length and thickness among seeds from three different trees. However, there were no significant difference in seed width of the same sample. Seed size traits should be considered in selecting baobab for domestication because of the high variability revealed. Observation on seedling growth revealed less than 10 leaves in the first month and increased to about 20 in the fourth month. Growth in girth was 5mm and 8mm in the first and fourth months respectively. Seedling height of 17cm in the first month reached 40cm in four months. Information from this research is valuable for further work on domestication of baobab.
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Article
The diversity in baobab was studied on 75 trees located at Adaklu District and Ho and Hohoe Municipalities of Ghana. Fourteen morphological traits were used in the characterisation based on Bioversity descriptors for baobab. Genstat edition 12 was used to analyse the diversity as well as germination and growth data. Group average hierarchical clustering with Jaccard similarity coefficient discriminated among most of the baobab trees. Clustering was not based on location although few trees that were not discriminated were from the same communities. The clustering can be used in selecting trees for further studies and domestication. Germination tests were conducted with baobab seeds soaked or boiled in water or treated with 95% sulphuric acid. Only the sulphuric acid treated seeds had germination significantly higher than the control. More studies should be done to find easier way of breaking seed dormancy of baobab. There were significant differences in 100-seed weight, seed length and thickness among seeds from three different trees. However, there were no significant difference in seed width of the same sample. Seed size traits should be considered in selecting baobab for domestication because of the high variability revealed. Observation on seedling growth in terms of number of leaves, stem girth, and plant height suggest slow growth of the plant. Information from this research is valuable for further work on domestication of baobab.
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The Adansonia (baobab) genus comprises seven species in Africa, six of which are endemic to Madagascar. Depending on the species, baobabs develop in widely varying ecosystems, including arid zones and savannahs, as well as dry and wet forests. Seeds from all species exhibited orthodox behaviour, tolerating dehydration to a moisture content of around 5%. There was no physical dormancy in the two species belonging to the Brevitubae section, A. grandidieri and A. suarezensis. Their seeds germinated without any prior scarification. The five other species, belonging to Adansonia and Longitubae section, have seeds with water-impermeable coats. In the case of A. digitata and A. za, the proportion of water-impermeable seeds was around two-thirds, whereas with A. rubrostipa, A. madagascariensis and A. perrieri, the proportion was >90%. Treatments allowing for the removal of physical dormancy needed to be markedly more severe with A. madagascariensis than with the other species. None the less, it seems impossible to link these characteristics and the interspecific differences to a strategy for adaptation by these species to their environment.
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Africa has abundant wild plants and cultivated native species with great agronomic and commercial potential as food crops. However, many of these species, particularly the fruits and nuts, have not been promoted or researched and therefore remain under-utilized. Moreover, many of these species face the danger of loss due to increasing human impact on ecosystems. Sudan, as in many other African countries, is endowed with a range of edapho-climatic conditions that favor the establishment of many plant species, most of which are adapted to specific ecological zones. Among these plants is the baobab (Adansonia digitata L.) which is a fruit-producing tree belonging to the family Bombacaceae. The baobab has an exceedingly wide range of uses ranging from food and beverages to medicinal uses. Despite its potential, which is well recognized, very little is known about the tree phenology, floral biology, husbandry or genetic diversity. In this article, we have aimed to bring out detailed information on various aspects of its botany, ecology, origin, propagation, main uses, genetic improvement and especially its importance for nutrition and poverty alleviation in the Sudan.
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A method is presented by which the gene diversity (heterozygosity) of a subdivided population can be analyzed into its components, i.e., the gene diversities within and between subpopulations. This method is applicable to any population without regard to the number of alleles per locus, the pattern of evolutionary forces such as mutation, selection, and migration, and the reproductive method of the organism used. Measures of the absolute and relative magnitudes of gene differentiation among subpopulations are also proposed.
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The leaves of the baobab tree (Adansonia digitata L.) are a staple of populations in many parts of Africa, especially the central region of the continent. Among the people who comprise the Hausa ethnic group in particular, it serves as the main ingredient of a soup called "miyar kuka." However, the literature contains few studies of the nutritional quality of baobab leaf. In the present report, we show that baobab leaf contains 10.6% (dry weight) protein and an amino acid composition which compares favorably to that of an "ideal" protein: valine (5.9%), phenylalanine + tyrosine (9.6%), isoleucine (6.3%), lysine (5.7%), arginine (8.5%), threonine (3.9%), cysteine + methionine (4.8%), tryptophan (1.5%). In terms of mineral content, baobab leaf is an excellent source of calcium, iron, potassium, magnesium, manganese, molybdenum, phosphorus, and zinc. These data indicate that in terms of both quality and quantity, baobab leaf can serve as a significant protein and mineral source for those populations for whom it is a staple food.
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Introduction. Adansonia digitata L., Balanites aegyptiaca (L.) Del. et Tamarindus indica L. figurent parmi les especes fruitieres de cueillette les plus appreciees par les populations sahelo soudaniennes. Leur role sur le plan nutritionnel et sur la generation de revenus est important. La degradation des ecosystemes constitue une menace sur la ressource en fruits de cueillette et sur la diversite genetique de ces especes. La premiere etape du programme de domestication mis en œuvre au Senegal consiste a en caracteriser la variabilite naturelle, dans le cadre d'une demarche participative visant la selection d'accessions interessantes pour la qualite des fruits. L'objet de cette etude a ete de comparer, pour chacune des especes, les fruits de differentes accessions. Materiel et methodes. Les analyses ont porte sur une caracterisation biometrique des fruits, completee par une analyse chimique sommaire (eau, sucres solubles totaux, acidite libre totale). Resultats et discussion. Pour la totalite des criteres etudies, l'exploitation des donnees a montre des differences significatives entre les accessions au sein de chaque espece. Pour les caracteres biometriques, un gradient decroissant de variabilite apparait selon la sequence: Adansonia vers Tamarindus vers Balanites. Le critere de « valeur reelle de la pulpe » a permis de cibler des accessions plus interessantes que d'autres. Les caracteres chimiques ont presente une moindre variabilite. Conclusions. Les differentes accessions etudiees presentent une variabilite exploitable pour la diffusion aux populations locales de varietes performantes d'especes fruitieres repondant a leurs besoins et a leurs moyens.
Article
This study was carried out in the Sudanian (9°45'–12° N), Sudano-Guinean (7°30'–9°45' N) and Guinean (6°25' – 7°30' N) zones of Benin. The distribution and relative abundance of the baobab was studied by means of megatransects and by surveying a number of selected sites. In each zone, an estimate was made of pulp, seed and kernel production from 1200 fruits harvested from 30 individuals. In the Sudanian zone and in some regions of the Dahomey-Gap in the Guinean zone, a population density of 5 baobabs per km2 was recorded. In the Guinean zone, a density of only 1 baobab per km2 was recorded. The baobab population's occurred on sandy soils in the Sudanian and Guinean zones and on sandy–clayey soils in the Sudano-Guinean zone. Flowering and fruiting of the baobab is seasonal. The morphology and productivity of individual baobabs varied significantly from one zone to another. The zones with high values of potential evaporation, rainfall, relative humidity, temperature, pHwater and percentage of fine silt are associated with a low seed and fruit pulp production. The higher the pHKCl, the percentage of total nitrogen, organic carbon and organic matter, the higher the number of seeds produced by an individual baobab. The higher the clay and crude silt content of the soil, the better the productivity.
Article
Introduction. Very characteristic of Sahelian areas, Adansonia digitata L. belongs to the Bombacaceae family. Essentially exploited in a spontaneous state for its fruits or its leaves, the baobab plays an important role in the local traditional cultures. The plant. This very big tree is clearly distinguishable from the other Adansonia species endemic in Madagascar and Australia, mainly by its very large trunk (up to 10 m in diameter), its pendular flowers and its rounded crown. It produces (150 to 300) g dry berries with a woody epicarp, most of the time ovoid, called “monkey bread”. These fruits contain many seeds in a whitish and floury pulp. The compounded leaves consist of five to seven digitate leaflets. The baobab distribution area is very large. Very rustic, it is found in most of South Sahara's semi-arid and sub-humid regions as well as in the west side of Madagascar. The plant phenology depends on the rains profile, flowering and foliation occurring during the rainy season. Pollination is done by bats. The tree can be propagated by seeding or vegetative multiplication. The fruit. It consists of (14 to 28)% of pulp with a low moisture content, acidic, starchy, rich in vitamin C, in calcium and magnesium. After separating of the seeds, the pulp is traditionally used as an ingredient in various preparations or to make beverages. In spite of some deficiency in lysine and the presence of some anti-nutritional factors, the seeds are an interesting protein source. They contain about 15% of lipids. After cooking or grilling, they are either directly consumed or used like thickeners in powder form. The leaves. They are rich in vitamins (especially C and A) and in iron, and contain mucilage (10% dm). The youngest can be consumed as vegetables, but they are often dried and then reduced into powder. Conclusion. Among the food products obtained from the baobab, the fruit pulp seems to have the strongest economic potential. Nevertheless, the local markets have to be evaluated. The development of the production of baobab fruits needs more investigation into the agronomy of the tree.
Article
Aim  Woody vegetation patterns in African savannas north of the equator are closely connected to human presence, but the distinctions between natural and anthropogenic landscapes have not been clear to many observers. Criteria for identifying savanna landscapes on a continuum of intensity of anthropic impact are explored.Methods  A key savanna tree species, Vitellaria paradoxa (Sapotaceae), was used as model for evaluating anthropic impact. Fruits harvested from tree populations across the species range were analysed for variation in traits valued by indigenous peoples. A simple selection index was used to scale tree populations from a hypothetical wild state to a hypothetical domesticated state. Index values were compared with trait values along climate zone gradients and evaluated in the context of indigenous savanna management practices and historical species distribution reports.Results  Trait values such as fruit size and shape, pulp sweetness, and kernel fat content show a significant influence of temperature and rainfall. At the same time, the mean values of groups of traits vary perpendicular to the general climatic zone gradient. Selection index values between Vitellaria populations vary up to sixfold, with highest values in central Burkina Faso. Comparison of present day Vitellaria distribution with historical range limits show range expansion by human migration.Main conclusions  The prevalence of major economic tree species in the savannas of Africa north of the equator is a strong indicator of human involvement in tree dispersal. This conclusion is supported by paleobotanical evidence and by recent Vitellaria range expansion as a result of human migration. The presence of high mean values of several Vitellaria fruit traits in central Burkina Faso suggests that selection for desired characteristics has occurred. The impact of indigenous savanna peoples on woody species composition and spatial distribution is probably much greater than usually thought and is the result of a deliberate strategy of altering the landscape to provide needed human resources.