- West Africa sweet potato diversity is structured partly by a climatic gradient. 112 accessions from Senegal and Togo were analyzed. - Genetic diversity analysis found higher diversity in tropical America compared to West Africa and Oceania. Five genetic groups were identified. - Morphological traits like root color, leaf shape discriminated genetic groups and were linked to climatic conditions. Group 2 was characterized by leaf traits, Group 5 by root and leaf color. - Genetic and morphological structuration was due to ecological factors like climate and environment, as well as farmer management. Conservation of this diversity is important for improving sweet potato under climate change.

1. 1
STRUCTURATION OF SWEET POTATO
(IPOMOEA BATATAS (LAM.)) DIVERSITY IN
WEST AFRICA AS EXPLAINED PARTLY BY A
CLIMATIC GRADIENT
Dr Kodjo GLATO

2. PLAN
 INTRODUCTION
 MATERIAL AND METHODES
 RESULTS AND DISCUSSION
 CONCLUSION AND PERSPECTIVES
2

3.  Climate changes damages to agriculture
 Conservation of germplasms and the studies of
their adaptative capacities appear important to
fight again food security and poverty
 Sub-saharan Africa, 240 millions, 30%
under nutrition (FAO, 2010). 3
INTRODUCTION: JUSTIFICATION OF THE
STUDIES

4.  Root and tubers play important role in Africa (Lebot,
2013).
La sweet potato is recognized to have powerfull
adaptatif potentiel climatiques conditions and agro-
systems environments
4
Resilience of agro-systems germplasms diversity

5. biotics and abiotics damages (Shimada et Otani,
2007).
Conservation Pathogens Organoleptics
Disinterested and unselfish of sweet potato culture
Genetic Erosion
Lost of adaptatif potentialities
ITRA (2006)

6. Existed diversity conservation and different climate
factor which shaped it appear indispensable for
qualitative and quantitative amelioration
Genetic diversity study and it relation
with climate is a priority:
6

7. MAIN OBJECTIF
Contribute to a better understanding and management of sweet
potato on farmers level, face food security challenges and
climatic changing conditions
7
 Determine genetic diversity of sweet potato cultivated in West
Africa under climatic gradient

8. 8
Collection (Lebot
2003).
Morphological characterisation

9. SENEGAL
TOGO
Area of studies
Climate: tropical arid
Climate: tropical
humid
Climate: sahelian
112 accessions
9

10. MÉTHODOLOGIE
 ADN extraction : method (Doyle and Doyle 1987).
20 mg dry young leave
10
quantitatif
Dosage Qualitatif Dosage
centrifugation+
TE

11.  GÉNOTYPAGE
11
Amplification: kit Qiagen
10µl + 2µl DNA
ABI 3130 XL 16 : migration
Roullier et al (2011)
Slight modifications T(°c)
Comparaison of the diversity:
Afrique - Océanie – Amérique Tropical

12. Data analyse
 Diversity analyse: R Software package ADEGENET
Binary data (0/1) : hexaploïd approch
12
Roullier
(2013)
• Togo + Senegal collections = west Africa data: 132
• Amérique selections 132:
• Océanie selections 132:
 Test of Wilcoxon: to compare diversity amongs continent
Data from
Roullier et al.
2013
Diversity comparaison:
Afrique - Océanie -
Amérique Tropical

13. 13
Genetic group analysis
Geographical Origin: Countries; villages et
climat
Correspondance between genetic and phenotype
 Kluskall-Wallis: traits related to genetic groups
 Wilcoxon: Specific traits related to genetic groups
Bonferroni corrected : p-value = 0,0024
P-value = 0,05

14. Results and Discussions
Diversity amongs West Africa, Oceania, Tanzania
Number of alleles
locus
West
Africa(i) Tropical America(1) Océania(1)
Ibc5 11 14 9
ib297 12 22 17
ibR16 5 9 10
J1809E 5 9 6
J206A 7 7 5
J263 4 7 4
J522A 7 7 8
ibs11 9 12 10
J544B 5 8 11
J315E 4 9 6
J116a 12 16 14
Total 83 120 100
Moyenne 7,36 10,90* 9,09
West Africa Tropical america
Oceania
West Africa -
Tropical America 0.008 -
Oceania 0.099 0.048 -
Wilcoxon: p-value 5%
14

15.  Tropical america: domestication and diffusion zone
Roullier et al. (2011)
 Africa and Oceania: introduction zone
High diversity
Weak diversity
15
Résultats et discussions

16. 15(T) + 3(S)
27(T)
56(T) + 4(S)
8(S)
15(T) + 4(S)
16
5 genetic groups

17. 17
Tropical
accessions
Sahelian
Accessions

18.  Adaptatif Capacities
Climatic gradient: tropical humid, Tropical
arid, sahelien
 Ecologic conditions
Mutations
18
Adaptations

19. Indicateurs
de climat d’où ces
dénominations
Appellation selon la
zone d’appartenance
(Rouiiler et al., 2011)
Structuration due
- aux facteurs écologiques: environnement et
climat
- Gestion paysanne: introductions et sélections
Même remarque en
Amazonie sur le manioc
(Rival et Mckey 2008)
19
+

20. 20
Traits Codes K= 5
Storage root shape FGt 0.57
Predominant skin colour CPt 1.9*10
-6
Secondary skin root colour CSt 0.01
Predominant flesh colour CPc 7.2*10
-3
Secondary flesh colour Csc 0.08
Secondary flesh color distribution Dcsc 0.92
Vine internode length Lnoe 0.78
Internode diameter Dianoe 0.11
Predominant vine colour Cpliane 0.03
Port Port 0.06
vine tip pubescence psomet 2.8*10
-7
Leaf lobes type Tylobe 6.1*10
-4
General outline of the leaf FGfeuille 1.3*10
-4
Number of lobes Nlobe 6.3*10
-5
Shape of central leaf lobe Flobec 1.3*10
-4
Mature leaf colour Cfm 0.5
Immature leaf colour Cfim 1.0*10
-4
Leaf lenght Lfeui 0.25
Petiole length Lpétio 0.01
Vine colour CNerv 2.3*10
-4
Petiole colour Cpétiole 1.2*10
-4
Total 9
Morphological
characteristics
which
discriminate
genetic groups

21. 21
Groupe 1 Groupe 2 Groupe 3
Colour of the vine
group 2 0.180
group 3 0.180 0.873
group 5 0.180 0.00058 0.0 0058
Root skin principal colour
Group 2 0.679
group 3 0.00042 0.00063
group 5 0.0019 0.0024 0.67
Type of lobe
group 2 0.063
group 3 1 0.0027
group 5 1 0.05 1
Leaf general outline
group 2 0.050
group 3 0.98 0.0015
group 5 0.032 0.827 0.002
Number of lobe
group 2 0.03
group 3 1 0.00024
group 5 1 0.027 1
Central lobe shape
group 2 0.02
group 3 1 0.001
Grou 5 1 0.025 1
Immature leaf colour
group 2 0.06
group 3 0.55 0.066
group 5 0.007 0.017 0.00075
Pubescence
group 2 9,00E -05
group 3 0.00052 0.0058
group 5 0.08 0.00020 0.033
Petiole colour
group 2 0.68
group 3 0.129 0.0039
group 5 0.557 0.686 0.0155
specific traits close to genetic groups
Group 2: Number of lobe, centrale lobe
shape, pubescence
Group 5: root tuber colour, immature
leaf colour, immature leaf colour
 morphological traits are
qualitatif
 Environment effects
héritabilities
Genetic
link
Same remark in Siérra léonne
Solankey et al. (2015) on sweet potato

22. .
Leaf with lobes Leaf with no lobe Leaf with no lobe, purple
vine
Leave wit no lobe, white root
flesh colour
21 accessions 28 accessions 8 accessions 38 accessions

23. Conclusion et perspectives
 genetic and morphogical structuration according to
climate
23
 Base of strategic to be used to improve the sweet potato
culture under climate changind environment.

24. 24
in Vitro and on farm conservation of the
accessions
Increase the number of accessions, SSR markers and cover a lot
of countrie’s accessions
Perspectives

25. Thanks
25