BPV
Maître de Conférences
Scientific activity
Researcher profile
Faculty researcher at the University of Yaoundé I. Grade: Maître de Conférences.
Scientific publications
Parfait alexis ZOA, Fotso Fotso, Pierre François Djocgoue, Paulin Nana
Research Square
Simon Perrez Akoa, Jules Christian Djoko Kouam, Martine Louise Ondobo, Jude Manga Ndjaga, Pierre François Djocgoue, Pierre Effa Onomo
RePEc: Research Papers in Economics
Interest on Trinitario cocoa has continuously increased due to the fact that some genotypes of this group had inherited some characters of vigorosity from Forastero and the flavor grade of Criollo. The pronounced incompatibility between Trinitario clones orientates research on the crossing of Trinitario clones with other varieties of cocoa in order to increase productivity and cocoa beans quality. Polyphenols and methylxanthines are bioactive compounds responsible for the health benefits of cocoa and cocoa based products. Cocoa is a crop with a high content of bioactive compounds in the plant kingdom. This study aims at correlating genotypes, methylxanthines and polyphenols as well as antioxidant activity of beans and dark chocolate derived from Trinitario×Forastero hybrids. Total polyphenol content and total condensed tannin contents were determined by spectrophotometric methods. Individual bioactive compounds were identified by UPLC-DAD-ESI(+)-MS both in beans and dark chocolate bar. Results showed differences within beans of dark chocolate and between beans and dark chocolate. Beans from the hybrid (♀)SNK10×(♂)IMC67 recorded the highest polyphenol content (49.18±1.55mg CatE/g) considering the two matrices. The highest concentration of condensed tannins (22.81±0.69 mgCatE/g) was recorded in beans obtained from the hybrid (♀)ICS40×(♂)UPA134. Dark chocolate bar from beans of the hybrid (♀)ICS40×(♂)UPA134 was the richest in condensed tannins (18.25±0.71 mg CatE/g). The total polyphenol and total condensed tannin contents, the chemical composition as well as the antioxidant activity could be genotype-dependent and were affected negatively during roasting. In fact, roasting decreased the polyphenol content and consequently the antioxidant activity. (-)-epicatechin, theobromine, ferulic and chlorogenic acids and their derivatives, procyanidin C1, caffeine and salicylic acid 3-O-glucose/galactose were identified in beans and/or dark chocolate.
Charly Idriss Talla Ngangni, H.Y. Nsangou Moundignigni, Carole Ameli Kenne, Pierre François Djocgoue, Serge Hubert Zébazé Togouet
Open Journal of Ecology
Landfill leachates represent a major threat to freshwater ecosystems, particularly in rapidly urbanizing regions of Sub-Saharan Africa. This study investigated the effects of leachates from the Banefo landfill (HYSACAM) on the physicochemical characteristics and phytoplankton community structure of the Ntinetchoueh stream (Bafoussam, West Cameroon) over a seasonal cycle (April 2023 to February 2024). Five sampling stations were monitored, including sites exposed to leachate discharge. Water quality analysis revealed a relatively low temperature (21.3?C ± 0.24?C), a slightly alkaline conditions (pH 7.8 ± 0.14), and a moderate mineralization (339.42 ± 54.6 μS/cm), coupled with elevated CO2 (14.55 ± 6.35 mg/L) and nutrient concentrations, notably NH 4 + (0.8 ± 0.32 mg/L) and orthophosphates (0.88 ± 0.22 mg/L), indicating substantial organic pollution. At the impacted station (S3), leachate inputs significantly increased conductivity and nitrogenous compounds while reducing Dissolved Oxygen (O2) and pH. A total of 57 phytoplankton species were identified across four major classes, with Bacillariophyceae dominating community structure (79% of total density). Synedra ulna was the most abundant species, while Oscillatoria sp. and Navicula cryptocephala were the only regular species, whereas Bacillariaceae exhibited the highest taxonomic diversity. Species richness peaked upstream of contamination (S2), while maximum cell densities were recorded during the dry season. The predominance of accessory taxa (70.17%) reflects high ecological sensitivity to environmental stress. Overall, leachate inputs drive nutrient enrichment and physicochemical alterations, leading to significant shifts in phytoplankton structure and a decline in aquatic biodiversity.
Linda Lekuna Duna, Elie Kamseu, Juvenal Giogetti Deutou Nemaleu, Achile steve Nana, Cristina Leonelli, Pierre François Djocgoue
Next research.
Lucien M. Wandarh’asima, S. H. Zebaze Togouet, Pierre François Djocgoue, Mulongaibalu Mbalassa, Pascal Masilya Mulungula, Fabrice A. Muvundja and 2 more
World Water Policy
ABSTRACT Water quality assessment in freshwater ecosystems is crucial for understanding their health and ensuring safe water use for various domestic purposes. This study on Lake Kivu highlights the significance of physicochemical parameters in evaluating quality dynamics by the water quality index (WQI). The sampling for physicochemical characterization, including T°, DO, EC, pH, TDS, SiO 2 − , PO 4 3− , NO 3 − , salinity, transparency, and chlorophyll‐a, was collected in four campaigns: spatial (seven urban and seven rural drawing and bathing stations) and temporal (quarterly and seasonal), from August 2021 to June 2022, twice per season (rainy and dry). Eight parameters contributed to classifying the WQI, in global gradient, from strong to low of the average water quality. In rainy seasons, Lake Kivu water is slightly more disturbed but without spatially significant differences. WQI correlated significantly with nutrients ( r = −0.845 for PO 4 3− , −0.649 for NO 3 − , and −0.824 for SiO 2 − ; p = 0.000), T° ( r = −0.371; p = 0.005), and transparency ( r = −0.359; p = 0.007), which are raised and promote toxic algal blooms (particularly Cyanophyceae). Water quality at urban and rural drawing and bathing points is inadequate for sustaining aquatic life. Chemical treatment, disinfection, and rigorous monitoring are necessary for safe use. The correlation between WQI and nutrient levels during the rainy season suggests that improving governance in reducing nutrient inputs into Lake Kivu catchments can sustainably enhance water quality at these use points. Physicochemical parameters are essential, but their standalone analysis often fails to capture water variations adequately. Focusing on these physicochemical parameters related to toxic Cyanophyceae, the biological analysis offers a complementary perspective with a multiparametric approach, including the WHO cyanophycean standards, not used to date, for aquatic life and the health of beneficiaries/users.
Simon Perrez Akoa, Renaud Boulanger, Jude Manga Ndjaga, Pierre Effa Onomo, Marc Lebrun, Eliane Flore Eyenga and 3 more
Journal of Food Science and Technology
Linda Lekuna Duna, Cyriaque Rodrigue Kaze, Joëlle Nadia Nouping Fekoua, Wilfried Arsène Letah Nzouebet, Kamseu Elie, Pierre François Djocgoue and 2 more
Journal of Water Process Engineering
Pulchérie Matsodoum Nguemté, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Adrien Wanko
Soil and Sediment Contamination An International Journal
This study was conducted to show the effects of high PAH levels on the external and internal structures as well as the functioning of a Poaceae species – Bermuda grass – during phytoremediation process. Two modalities – Tn: unpolluted planted soil and Tp: polluted planted soil – are applied to the monoculture of Bermuda grass for pollution at 10%, 20%, and 30% (weight/weight) with fuel oil, and co-cropping with Goosegrass in soils polluted at 10%. Morphological results revealed that monoculture is better than co-cropping as the sociability of the two species is negatively affected by PAHs. Contrary to monoculture, in the co-cropping the relative growth rate of Bermuda grass morphological parameters is decreasing over time in Tp. For monoculture, the aboveground plant density of Bermuda grass in Tp is not significantly different to Tn, while its specific root length is higher in Tn than Tp. Anatomical and physiological analyses of Bermuda grass show that PAHs impacted the hydromineral nutrition of this species. In fact, the vascular bundles of the stems and roots of Bermuda grass were less numerous in Tp, and the chlorophyll synthesis was 50% inhibited. Despite the slower physiological processes of Bermuda grass in polluted soils, the phytotoxicity of very high PAH levels is not fatal to this species. Its development and evolution on soils highly polluted with PAHs and its phytoremediation potential (more than 95% for total petroleum hydrocarbons and up to 100% for chrysene) therefore recognize it as particularly suitable for hydrocarbon phytoremediation, with wide geographical application thanks to its cosmopolitan nature.
Georges Yannick Fangue-Yapseu, Romaric A. Mouafo-Tchinda, Martin Kenné, Pierre Effa Onomo, Pierre François Djocgoue
American Journal of Plant Sciences
The aim of this study was to determine the allelopathic effects of Azadirachta indica oil and aqueous extracts of Tithonia diversifolia and Thevetia peruviana on the growth and stimulation of metabolites involved in tomato plant resistance. Randomized in blocks within a shaded area, the different treatments prepared at 10% and 15% (v/v and w/v) in water were subsequently applied on tomatoes seeds to monitor the effect on germination, and on tomatoes leaves to monitor the effect on growth and resilience of the plants. The result showed that in stressful conditions all the treatments significantly inhibit (p T. diversifolia at 10% promotes a better aerial and root growth in tomato plants, T. peruviana at 15% induces the activation of resistance mechanisms in tomato plants by increasing protein levels to 104.5%, phenol levels to 183.33% and peroxidase enzyme activity to 586.15%. Therefore, allelopathic compound of wild plants would be a good alternative for growth promotion and resistance of tomato crops.
Pulchérie Matsodoum Nguemté, Ives Magloire Kengne Noumsi, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Adrien Wanko
Water
To address the soil–plant transfer modelling of 13 US-EPA Polycyclic Aromatic Hydrocarbons (PAHs), a mechanistic model—MM_19—has been developed based on the fugacity concept. For that, the Mackay_97 model has been improved in terms of reconsidering the losses related to the transport and transformation mechanisms taking place in the compartments—roots and aboveground shoots—of the three short-life species (Eleusine indica, Cynodon dactylon and Alternanthera sessilis). Model input parameters consist of both experimental and literature data, including the initial soil and air PAHs content, flowrates, PAHs physico-chemical properties, retention times and transport half-lives of PAHs inside plant species. Using in situ weather data and Penman’s law, xylem flows were estimated as the evapotranspiration for each plant. Model calibration was performed using a Generalized Reduced Gradient (GRG) nonlinear optimization solver method. Sensitivity analysis showed that the phloem flow was the most sensitive among all tested parameters. According to the Nash–Sutcliffe efficiency (NSE), the MM_19 model is more efficient than the Mackay_97 model for all three plant species. Finally, the impact of PAHs physico-chemical parameters on their sol-plant transfer was discussed in terms of slight, intermediate and high molecules weight. The NSE values showed that the MM_19 model is more efficient than the Mackay_97 model. Indeed, comparisons between experimental and simulated results in the MM_19 model showed similarities for each compartment of the plant species. Thus, the MM_19 model can be used to predict the soil–plant transfer of organic pollutants.
Claude Simo, Alice Virginie Tchiaze Ifoue, Liliane Corine Nouage Tayoukam, Romuald Nsouga Amougou, Victorine Obe Lombeko, Stephanie Alvine Njonzo-Nzo and 1 more
International Journal of Biological and Chemical Sciences
The cocoa tree (Theobroma cacao L.), also called "food of the gods", is a plant mainly cultivated for its beans. However, the cultivation of this plant is confronted with many parasitic attacks among which, attack due to Phytophthora megakarya which causes the most yield loss. The Control of this pathogen consisted in involving the use of aqueous and ethanolic extracts of pepper and two strains of Phytophthora megakarya in order to improve cocoa tolerance against the attack of this pathogen. These aqueous and ethanolic extracts were prepared in the laboratory and incorporated into Potato Dextrose Agar and Small Pea Agar culture media at concentrations (g / ml) of 10-1, 10-2, 10-3 and 10-4, each containing a strain of Phytophthora megakarya. The results obtained revealed that all pepper treatments significantly inhibited the growth of Phytophthora megakarya with a 100% inhibition rate in the aqueous extract regardless of the strain used and inhibition rates of 89.33%. ; 63.35%; 54.39%; 42.86%; 100%; 70.22% and 57.54% for the ethanolic extract depending on the concentrations applied. In vivo treatment of leaf discs and pods detached prior to infection with Phytophthora megakarya resulted in significant inhibition, thereby reducing the incidence rate of disease severity. The values of this incidence vary from 0.1 to 1.2 for a percentage ranging from 0.5% to 20% of the severity of the disease depending on the nature of the extract of applied pepper. At concentrations (g / ml) 10-1, 10-2, 10-3 and 10-4, the aqueous extract completely inhibited the growth of mycelium and the development of Phytophthora megakarya spores while the ethanolic extract of pepper showed its inhibitory power at the concentration 10-1 g/ml. The use of crude aqueous extracts or even diluted of pepper can therefore be considered in the fight against black pod desease in Cameroon.© 2019 International Formulae Group. All rights reservedKeywords: Phytophthora megakarya, Theobroma cacao, Capsicum annuum, percentage of inhibition, biological control, black pod desease
Matsodoum Nguemte Pulchérie, Suzanne II Nina Gregoire Ndemba Etim, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Ives Magloire Kengne Noumsi, Adrien Wanko Ngnien
International Journal of Phytoremediation
Soils pollution with hydrocarbons is on the increase, especially in developing countries like Cameroon. Identifying plant species capable of growing on hydrocarbon-polluted soils remains an essential step in phytoremediation, a low cost, solar energy driven clean up technique in which living green plants are used. Here, we report floristic surveys conducted in 4 cities of Cameroon to identify plants with phytoremediation capacities. A total of 13 hydrocarbon-polluted sites were surveyed in each city using the quadrat method. Unpolluted sites served as the control. 106 species belonging to 76 genera and 30 families were identified on hydrocarbon-polluted sites. Plant diversity was shown to be higher (166 species contained in 125 genera and 50 families) in the control sites. Poaceae, Cyperaceae, Asteraceae and Amaranthaceae families have a higher taxonomic richness on polluted sites (16, 15, 10 and 8 taxa respectively). Shannon diversity index of the hydrocarbon-polluted sites (1.6 to 2.7 bits/ind.) were significantly lower than the control sites (2.7 to 3.2 bit/ind.). Based on a relative frequency > 10% and abundance > 7%, our results show that more than 15 plant species could be tested in preliminary trials to determine their phytoremediation/cleaning-up capacities on hydrocarbon-polluted soils in the tropics.
Emile Minyaka, Claude Simo, Piau Jean Cyrille Mouen, Banen Colette Vanessa Madina, Pierre François Djocgoue, Ndoumou Denis Omokolo
AFRICAN JOURNAL OF BIOTECHNOLOGY
Black pod disease (BPD) is the major cocoa pathology constraint caused by an Oomycete, Phytophthora megakarya prevailing in African cocoa producing countries. The development of T. cacao planting material tolerant to BPD lies on cross-pollination of adequate parental genotypes which generate offspring with desirable traits. We assessed the susceptibility to BPD of offspring derived from three manual crosses (SNK13xUPA143, T79/501xUPA143 and UPA143xSNK64) using leaf discs test (LDT) which evaluates disease scores of hybrid genotypes. Cysteine involvement in T. cacao defence process against BPD has been studied for the potential use of this sulphur amino acid profile to identify tolerant cocoa hybrid genotypes. LDT displayed variable disease scores patterns. Within a given family, LDT revealed heterogeneity in disease scores. This heterogeneity may have been derived from polygenic character of T. cacao susceptibility to BPD. In SNK13xUPA143 family, 26.13% exhibited disease scores lower than two (tolerant hybrid genotypes). T79/501xUPA143 and UPA143xSNK64 generated 21.18 and 26.46% of tolerant hybrid genotypes respectively. This variability between families may have resulted from deferential susceptibility of parental clones; UPA143 being more susceptible than T79/501 followed by SNK13. SNK64 was the less susceptible to BPD. The percentages of tolerant hybrid genotypes in this study appeared to be consistent hence, SNK13xUPA143, T79/501xUPA143 and UPA143xSNK64 could be used to produce hybrids genotypes tolerant to BPD. Cysteine analysis was performed in none detached healthy and wounded-infected leaves of hybrid genotypes with variable disease scores. It appeared that cysteine was mobilized during the infection. Two main patterns were observed: in tolerant hybrid genotypes (disease score lower than 2), infection was associated to a significant reduction of cysteine content in young leaves while in susceptible hybrid genotypes, infection was associated to an increase (accumulation) of cysteine in young leaves. Cysteine could be involved in the synthesis of effective defence molecules against P. megakarya in tolerant hybrid genotypes. This set of finding may indicate that cysteine profile could be used to discriminate tolerant from susceptible hybrid genotypes of T. cacao to P. megakarya. Key words: Cocoa tree, black pod disease, hybrids genotypes, tolerance, cysteine.
P. O. EFFA, M.L. Ondobo, Pierre François Djocgoue, Nicolas Niemenak
African Crop Science Journal
Cocoa (Theobroma cacao L.) is an important allogamous tropical tree crop, whose centre of diversity is considered to be in Central America. Dry cocoa beans from five cocoa clones, and their intercrossed hybrids were analysed based on the variation of alkaloids and polyphenolic compounds contents, in order to gain insights on the heterosis and broad-sense heritability. Polyphenols and alkaloids were analysed at 280 nm by HPLC, using a Photodiode Array Detector (PDA); while anthocyanins were separated with the SEP-PAK Vac 6cc 1000 mg (waters) column and measured at 520 nm with a PDA. Dry cocoa beans displayed high content of purine alkaloids (2.1 and 8.8 mg g-1 for caffein and theobromine, respectively), and polyphenols (25 and 2978 μg g-1 for catechin and epicatechin, respectively). Among the five cocoa clones, SNK16 was the highest in purine alkaloid (caffein and theobromin) and flavanol (catechin and epicatechin); while T79/467 possessed the greatest quantity of cyanidin-3-galactoside and cyanidin-3-arabinoside. From all the parameters studied, anthocyanins (Cyanidin- 3-galactoside and cyanidin-3-arabinoside) exhibited the highest level of heterosis. Parental genotypes SNK16 and T79/467 showed good aptitudes for the combination of characters because their reciprocal hybrids F5 and F9, distinguished themselves by better levels of mid-parent heterosis values. Besides, the heritability value in strict sense of this Cyanidin-3-galactoside was very high. Absence of significant difference between genotypes, coming from reciprocal crossbreeding for Cyanidin-3-galactoside, suggests that this character in cocoa would be nuclear contrary to purine alkaloids and flavan-3-ols, where their transmission to offsprings can be stated as cytoplasmic.Key Words: Caffein, catechin, Theobroma cacao
Honoré Tekeu, Eddy Ngonkeu, Liliane Ngoune Tandzi, Pierre François Djocgoue, Joseph Martin Bell, Hortense A. Mafouasson and 3 more
International Journal of Biological and Chemical Sciences
Soil acidity is a limiting factor severely affecting the growth and yield of maize. The present study aimed at estimating the breeding value of inbred lines and to assess the test-cross performance of the hybrid maize under acid soil conditions. A line x tester analysis involving 63 test-crosses generated by crossing 20 maize inbred lines with 3 testers and between testers themselves, and 1 standard check was investigated during the cropping season 2012 in two contrasted regions with aluminum and manganese toxicity in Cameroon. Both treatments, acid soil and non-acid soil, using dolomitic lime were conducted in a randomized complete block design with 3 replications. Seven hybrids producing high grain yield (4.27 to 9.88t/ha), with high specific combining ability (SCA) and slow rate of yield loss were discovered such as tolerant for both types of acidic soils. Likewise, four inbred lines (ATP-46, 87036, and Cam Inb gp117, C4SRRA7) with high general combining ability (GCA) were retained as good progenitors. The GCA and SCA effects showed that the tolerance to aluminum toxicity was controlled by additive effects of genes while on acid soil with manganese toxicity, the contribution of non-additive effects of genes was dominant.Keywords: Inbred lines, hybrids, acid soil, GCA, SCA, humid forest zones
Claude Simo, Pierre François Djocgoue, H.D. Mbouobda, P. O. EFFA, Thaddée Boudjeko, Zenabou Ndiang and 1 more
AFRICAN JOURNAL OF BIOTECHNOLOGY
Black pod disease is an important fungal infection in cocoa (Theobroma cacao L.) which causes high production losses. In Cameroon, these losses reached 80% of cocoa production depending on ecological zones. In order to contribute to the efficiency of selection methods used in resistance or tolerance to black pod disease with the aim of improving on cocoa farming, the content of phenolic compounds was analyzed on the genotypes of two hybrid families (F79:♀T79/467x♂SNK13 and F13:♀SNK13x♂T79/467) of cocoa which are different in productivity and vulnerability to black pod disease. After artificial inoculation of the pods by mycelium of Phytophthora megakarya, the content of the phenolic compounds significantly increased in all genotypes of the two families. The heterosis effect of each family revealed a higher variability within both families. These results alike showed that productive and tolerant genotypes (F1307, 1314, F7902 and F7928) have a high phenols content and positive heterosis meanwhile the less tolerant and productive genotypes (F1321, F1326, F7904 and F7911) have a weak content and negative heterosis. Key words: Cocoa, disease, tolerance, heterosis effect, phenolic compounds, hybrid progenies.
Pierre François Djocgoue, Hermann Desiré Mbouobda, Thaddée Boudjeko, Pierre O. Effa, Dénis Ndoumou Omokolo
DOAJ (DOAJ: Directory of Open Access Journals)
The black pod disease of cocoa (Theobroma cacao), caused by Phythophthora megakarya, is responsible for 80% loss of cocoa production in Cameroon. The principal method of ameliorating crop losses is through the use of black pod resistant and high productivity hybrid cocao clones. In order to assess the possible role of amino acids and carbohydrates in the defence of T. cacao against P. megakarya, comparative analyses (quantitative and qualitative) of sugars and amino acids were carried out on leaves of parental genotypes, ICS95, ICS84 and hybrids (families F25:♀ICS84 X ♂ICS95 and F30: ♀ICS95 X ♂ICS84 ). A reduction in soluble sugar contents of parental genotypes ICS84, ICS95 and 30% of hybrid genotypes was noted under conditions of infection. Qualitative analyses of sugars showed that most cases of infection were characterized by the disappearance of sucrose and the persistence of glucose. Amino acids content increased in 70% of genotypes after injury or infection. In parental tolerant clone ICS84 and hybrid genotypes F3011, F2551 and F2552, proline appeared solely during conditions of infection, suggesting its implication in the defence mechanism of T. cacao against P. megakarya. A significant positive relationship was observed between amino acid contents and the severity of necrosis. There was a very weak relationship between sugar and amino acid contents in parental genotype, and those of the progeny. PCA of the length of necrosis, sugar level, amino acids and phenolics showed that under infection, the increase in content of phenolic compound was concomitant with reduction in amino acid content.
Pierre François Djocgoue, Claude Simo, H.D. Mbouobda, Thaddée Boudjeko, Djioda Joseph Nankeu, Ndoumou Denis Omokolo
Journal of Plant Pathology
H.D. Mbouobda, Fotso, Pierre François Djocgoue, Ndoumou Denis Omokolo, I. El Hadrami, Thaddée Boudjeko
Phytoparasitica
Pierre François Djocgoue, Thaddée Boudjeko, H.D. Mbouobda, Djioda Joseph Nankeu, I. El Hadrami, Ndoumou Denis Omokolo
Journal of Phytopathology
Abstract The black pod disease caused by Phytophthora megakarya is responsible for 80% of the cocoa production loss in Cameroon. To assess the resistance of cocoa plants against this pathogen, necrotic lesions, phenolic content and qualitative alteration of phenolics were conducted in ICS84 and ICS95 clones (two Trinitario introduced from Trinidad) and their hybrids (families F30 and F25) derived from reciprocal cross breeding between these two parental clones after inoculation. The existence of strong hybrid vigour has been shown. Ninety percentage of the hybrid's genotypes manifested a positive heterosis effect for the development of lesion size. This suggests the existence of hybrid vigour with a genetic additive effect. F3086, F2509, F2552 and F2586 hybrids were characterized by localized lesions. Those hybrids genotypes can be considered as elite clones. In relation to analysis of total phenolics and lesion size, no maternal effect was detected in the transmission of these characters. A significant and negative correlation ( r = −0.683) (P < 0.01) has been observed between necrosis evolution and phenolics accumulation. The values of the heritability of lesion size and the total phenolic content in offsprings did not permit to show the maternal effect. Qualitative analyses of phenolics showed high flavonones content in cocoa leaves. Qualitative analyses of phenolics in ICS84, ICS95 clones and their hybrids showed a modification of the phenolics profiles, notably concerning apigenin and luteolin derivatives due to the inoculation. These compounds, along with others that were not identified, could have a role in the reaction and mechanism of defence of cocoa against P. megakarya.
Pierre François Djocgoue, Thaddée Boudjeko, Djioda Joseph Nankeu, Mousseni Ives Bruno Efombagn, Salomon Nyassé, Dénis Ndoumou Omokolo
Plant Pathology Journal
H.D. Mbouobda, Thaddée Boudjeko, Pierre François Djocgoue, T. J. J. Tsafack, Dénis Ndoumou Omokolo
Journal of Biological Sciences
Djioda Joseph Nankeu, Annie Ewane, Thaddée Boudjeko, Nicolas Niemenak, Pierre François Djocgoue, Ndoumou Denis Omokolo
Journal of the Cameroon academy of sciences
Ndoumou Denis Omokolo, Djioda Joseph Nankeu, Nicolas Niemenak, Pierre François Djocgoue
Crop Protection
Denis Omokolo Ndoumou, Pierre François Djocgoue, Langute Pandurang Nana, Martine Debost
Biologia Plantarum
The relationship between susceptibility to black pod disease and activity of peroxidases in crude extracts and soluble phenols and saccharides contents was studied in the pod cortex and in the seeds of three cacao clones: SNK413 (lowly susceptible), SNK10 (highly susceptible) and ICS95 (mildly susceptible) and in the F1 (SNK413ĂSNK10) and the F'1 (SNK10ĂSNK413) progeny. Phenol content and peroxidase activity in seeds increased as the pods matured; they were not the same in the proximal, middle and distal parts within the same pod at maturity. This variation could be correlated to the stage of development of the seeds. Total soluble saccharides and ketohexoses in the pod cortex did not vary significantly from one clone to another and could not be related to the susceptibility of the pods. Nevertheless, their contents were 2 to 4 times less in the F1 and F'1 progeny. Total soluble phenols, flavanol and hydroxycinnamic derivatives in the pod cortex were higher in the SNK413 clone. Hydroxycinnamic derivatives were not detected in the SNK10 clone and this character was transmitted to the progeny when SNK10 was male (F1 progeny). Phenolic cornpounds decreased in the F1 and F'1 progeny. These results suggest that phenolic compounds and peroxidase activity could be correlated to the susceptibility of cacao clones to black pod disease and that crossing two clones of different susceptibility produces hybrids with lower phenols and saccharides contents which may be responsible for their poor tolerance to black pod disease.
Abdoallah Sharaf, Lucky T. Nesengani, Ichrak Hayah, Josiah Kuja, Sinebongo Mdyogolo, Taiwo Crossby Omotoriogun and 94 more
In 2022, around 54 % of African students were denied student visas to study in the United States (US), compared to 36 % of Asian students and 9 % of European students, despite African immigrants in the US often being more highly educated than the US native-born population. This issue cannot be attributed solely to the dichotomy between the Global North and South in visa regimes, but it is also evident among African nations across regional economic blocs. The African BioGenome Project (AfricaBP) Open Institute for Genomics and Bioinformatics, which aims to overcome barriers to capacity building through its distributed African regional workshops, prioritizes grassroots knowledge exchange and innovation in biodiversity genomics and bioinformatics. In 2023, we orchestrated the implementation of 27 capacity building workshops on biodiversity genomics and bioinformatics, covering 10 African countries across 5 African geographical regions. The AfricaBP Open Institute regional workshops raised awareness of biodiversity genomics and bioinformatics among 3788 registered participants, and trained 408 African scientists in hands-on molecular biology, genomics, and bioinformatics techniques. Here, we discuss the implementation of transformative strategies by deploying the AfricaBP Open Institute multi-country, multi-institution, and multi-partner hybrid regional workshop model, including the proposed creation of an African digital database containing sequence information relating to biodiversity and agriculture.
Abdoallah Sharaf, Lucky T. Nesengani, Ichrak Hayah, Josiah Kuja, Sinebongo Mdyogolo, Taiwo Crossby Omotoriogun and 94 more
Nature Genetics
Jude N. Manga, Géraldine Mandiang A. Bep, Simon Perrez Akoa, Helene A. Mewouo, Martine Louise Ondobo, Etienne Akoutou Mvondo and 3 more
Journal of Plant Biochemistry and Biotechnology
Jules Christian Djoko Kouam, Jude Manga Ndjaga, Simon Perrez Akoa, Martine Louise Ondobo, Pierre Effa Onomo, Pierre François Djocgoue and 2 more
Tropical Plant Pathology
Eddy M. L. Ngonkeu, Ariane Damdjo, Aminatou Fanche Mongoue, Honoré Tekeu, FOKO Arlette, Patrick Tsimi and 5 more
AFRICAN JOURNAL OF BIOTECHNOLOGY
Fungal diseases are one of the major causes of losses on wheat yield in the world. Recent studies on plant defense mechanisms have highlighted the role of amino acids and total polyphenols in disease tolerance. Thus, with the objective of identifying on the basis of morphological and physiological variables the high-performance wheat accessions in high and low altitude, we characterized sixteen wheat accessions via quantification of polyphenols (TPP) and amino acids (AA) and identified fungal diseases affecting wheat in Centre Cameroon. Using the set of the three hexaploid wheat cultivars where the 11 microsatellite markers data was available, a total of 29 alleles were detected among cultivars and the number of alleles per locus ranged from 2 to 3 with an average of 2.64. Gene diversity ranged from 0.44 to 0.67 with an average of 0.59, increasing with the number of alleles. Microsatellites markers used had an average Polymorphic Information Content (PIC) value of 0.50, indicating that these markers are useful and will make a contribution to the studies in hexaploid wheat. The assessment of wheat plant to disease tolerance permitted to identify Septoria, Fusarium wilt; tanned spot and powdery mildew in high and low altitude. Analyzes of TPP and AA have made it possible to discriminate accessions that are tolerant to diseases. Hence, accession Atilla 1 was highly tolerant and had high levels of TPP (3.5 ± 0.36 μg/mg) and AA (40.1 ± 1.21 μg/mg) while the accession Sup 152 highly susceptible to disease had low levels (2.3 ± 0.1 and 2.1 ± 0.36 μg/mg, respectively). This study will contribute to the extension of wheat in areas where conditions similar to the study sites will be localized. Key words: Amino acids, bread wheat, high and low altitude, fungal diseases, polyphenols.
Linda Lekuna Duna, Nzeukou Nzeugang Aubin, Fen Florence Fombutu, Pierre François Djocgoue
International Journal of Environmental Monitoring and Analysis
This study highlights the use of Remote Sensing to detect environmental changes obtained on Land Use / land Cover Changes in the Etoa clay quarry, neighboring the town of Yaounde (Cameroon) during a period of 26 years (1989-2015). Remotely sensed data in the form of Landsat image and pattern classification were used to create maps. For accuracy Google Earth was used as a reference to yield data. The post classification change detection method was used to value the land cover change with the clay quarry. Land use of the urban growth was estimated by time series analysis of satellite Landsat images. Spectral indices calculated from the images were used to evaluate change in buildup area, vegetation and hydrology. Results show that vegetation, covers 200 hectares of land, build up area 240 hectares and hydrology 185 hectares. The change analysis between 1989-2015 showed a decreasing trend in vegetation from 69% to 32% (a decrease in 37% vegetation cover), hydrology from 14% to 30% (thus a 16% increase in water bodies) and build up area from 17% to 38% (a 21% increase). The excavation of clay materials increases every year leaving behind many dangerous clay pits filled with water which calls for concern.
Honoré Tekeu, Eddy Ngonkeu, Sébastien Bélanger, Pierre François Djocgoue, Amina Abed, Davoud Torkamaneh and 5 more
Research Square
Abstract Grain size is a key agronomic trait that contributes to grain yield in hexaploid wheat. Grain length and width were evaluated in an international collection of 159 wheat accessions. These accessions were genetically characterized using a genotyping-by-sequencing (GBS) protocol that produced 73,784 single nucleotide polymorphism (SNP) markers. GBS-derived genotype calls obtained on Chinese Spring proved extremely accurate when compared to the reference (> 99.9%) and showed > 95% agreement with calls made at SNP loci shared with the 90K SNP array on a subset of 71 Canadian wheat accessions for which both types of data were available. This indicates that GBS can yield a large amount of highly accurate SNP data in hexaploid wheat. The genetic diversity analysis performed using this set of SNP markers revealed the presence of six distinct groups within this collection. A GWAS was conducted to uncover genomic regions controlling variation for grain length and width. In total, seven SNPs were found to be associated with one or both traits, identifying three quantitative trait loci (QTLs) located on chromosomes 1D, 2D and 4A. In the vicinity of the peak SNP on chromosome 2D, we found a promising candidate gene (TraesCS2D01G331100), whose rice ortholog (D11) had previously been reported to be involved in the regulation of grain size. These markers will be useful in breeding for enhanced wheat productivity.
Honoré Tekeu, Eddy Ngonkeu, Sébastien Bélanger, Pierre François Djocgoue, Amina Abed, Davoud Torkamaneh and 5 more
Scientific Reports
Grain size is a key agronomic trait that contributes to grain yield in hexaploid wheat. Grain length and width were evaluated in an international collection of 157 wheat accessions. These accessions were genetically characterized using a genotyping-by-sequencing (GBS) protocol that produced 73,784 single nucleotide polymorphism (SNP) markers. GBS-derived genotype calls obtained on Chinese Spring proved extremely accurate when compared to the reference (> 99.9%) and showed > 95% agreement with calls made at SNP loci shared with the 90 K SNP array on a subset of 71 Canadian wheat accessions for which both types of data were available. This indicates that GBS can yield a large amount of highly accurate SNP data in hexaploid wheat. The genetic diversity analysis performed using this set of SNP markers revealed the presence of six distinct groups within this collection. A GWAS was conducted to uncover genomic regions controlling variation for grain length and width. In total, seven SNPs were found to be associated with one or both traits, identifying three quantitative trait loci (QTLs) located on chromosomes 1D, 2D and 4A. In the vicinity of the peak SNP on chromosome 2D, we found a promising candidate gene (TraesCS2D01G331100), whose rice ortholog (D11) had previously been reported to be involved in the regulation of grain size. These markers will be useful in breeding for enhanced wheat productivity.
Simon Perrez Akoa, Jules Christian Djoko Kouam, Martine Louise Ondobo, Jude Manga Ndjaga, Pierre François Djocgoue, Pierre Effa Onomo
Journal of Food Research
Interest on Trinitario cocoa has continuously increased due to the fact that some genotypes of this group had inherited some characters of vigorosity from Forastero and the flavor grade of Criollo. The pronounced incompatibility between Trinitario clones orientates research on the crossing of Trinitario clones with other varieties of cocoa in order to increase productivity and cocoa beans quality. Polyphenols and methylxanthines are bioactive compounds responsible for the health benefits of cocoa and cocoa based products. Cocoa is a crop with a high content of bioactive compounds in the plant kingdom. This study aims at correlating genotypes, methylxanthines and polyphenols as well as antioxidant activity of beans and dark chocolate derived from Trinitario&times;Forastero hybrids. Total polyphenol content and total condensed tannin contents were determined by spectrophotometric methods. Individual bioactive compounds were identified by UPLC-DAD-ESI(+)-MS both in beans and dark chocolate bar. Results showed differences within beans of dark chocolate and between beans and dark chocolate. Beans from the hybrid (♀)SNK10&times;(♂)IMC67 recorded the highest polyphenol content (49.18&plusmn;1.55mg CatE/g) considering the two matrices. The highest concentration of condensed tannins (22.81&plusmn;0.69 mgCatE/g) was recorded in beans obtained from the hybrid (♀)ICS40&times;(♂)UPA134. Dark chocolate bar from beans of the hybrid (♀)ICS40&times;(♂)UPA134 was the richest in condensed tannins (18.25&plusmn;0.71 mg CatE/g). The total polyphenol and total condensed tannin contents, the chemical composition as well as the antioxidant activity could be genotype-dependent and were affected negatively during roasting. In fact, roasting decreased the polyphenol content and consequently the antioxidant activity. (-)-epicatechin, theobromine, ferulic and chlorogenic acids and their derivatives, procyanidin C1, caffeine and salicylic acid 3-O-glucose/galactose were identified in beans and/or dark chocolate.
Simon Perrez Akoa, Pierre Effa Onomo, Jude Manga Ndjaga, Martine Louise Ondobo, Pierre François Djocgoue
Scientia Horticulturae
Honoré Tekeu, Liliane Ngoune Tandzi, Eddy E. M. Ngonkeu, Pierre François Djocgoue
Book Publisher International (a part of SCIENCEDOMAIN International)
Soil acidity is a limiting factor that has a significant impact on maize growth and yield. The aim of this study was to determine the breeding value of inbred lines and to evaluate the hybrid maize test-cross output under acid soil conditions. During the 2012 cropping season in Cameroon, a line x tester analysis involving 63 test-crosses created by crossing 20 maize inbred lines with 3 testers and between testers themselves, as well as 1 standard check, was conducted in two contrasted regions with aluminium and manganese toxicity.. Both acid and non-acid soil treatments with dolomitic lime were tested in a randomised full block design with 3 replications. Seven hybrids producing high grain yield (4.27 to 9.88 t/ha), with high specific combining ability (SCA) and slow rate of yield loss were discovered such as tolerant for both types of acidic soils. Likewise, four inbred lines (ATP-46, 87036, and Cam Inb gp117, C4SRRA7) with high general combining ability (GCA) were retained as good progenitors. The GCA and SCA effects revealed that additive effects of genes mediated resistance to aluminium toxicity, while non-additive effects of genes dominated on acid soil with manganese toxicity. However, for a potential extension, a molecular characterization of the selected varieties will be needed.
Pulchérie Matsodoum Nguemté, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Ives Magloire Kengne Noumsi, Adrien Wanko Ngnien
Water Air & Soil Pollution
Pulchérie Matsodoum Nguemté, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Ives Magloire Kengne Noumsi, N. A. Wanko
Proceedings of the World Congress on New Technologies
To assess the phytoremediation potential of 6 plant species -Eleusine indica, Cynodon dactylon, Alternanthera sessilis, Commelinpa benghalensis, Cleome ciliata and Asystasia gangetica -on a soil contaminated with fuel oil (82.5 ml/kg of soil), experimentations have been conducted from March to August 2016. Only 3 plants (E. indica, C. dactylon and A. sessilis) survived and developed throughout the 150 days of experimentation. Only E. indica plants growing on polluted soils exhibited the best visual scores (3 to 4) throughout the study. C. dactylon stems in polluted soils were more reddish than those growing on unpolluted soils. Plants of A. sessilis growing on contaminated soils had a significantly greater stunting compared to its control (unpolluted). The relative growth indexes (RGI) of the growth parameters measured during the study shows similarities between plants of E. indica and C. dactylon on polluted and unpolluted soils; unlike A. sessilis, whose plants had significant growth delays compared to the control on contaminated soils. Soils physicochemical parameters do not present any difference between the beginning and the end of the experiments; excepted nitrogen levels which are significantly higher at the end than at the beginning of experimentation in all soils. TPHs concentration in soils have been reduced to more than 80% for E. indica and C. dactylon, to 77% for A. sessilis and 57% in non-planted soil. Bioconcentration and translocation factors values helped to understand the bioavailability and the soil-plant transfer of different classes of PAH established in this study according to their physicochemical properties. They also indicate that E. indica and A. sessilis promoted rhizodegradation and phytoextraction of hydrocarbon-polluted soils whereas C. dactylon was only implicated into rhizodegradation. However, E. indica and C. dactylon out-yielded A. sessilis in the phytoremediation capacity of fuel oil-contaminated soils.
W. E. Dassie, A. C. Nkouna, Pierre François Djocgoue
Resume Les missions de suivi-evaluation de la gestion forestiere mettent a contribution de nombreux outils parmi lesquels les manuels et guides de procedure. Le succes des missions d’evaluation est donc etroitement lie a la qualite meme de ces outils, dont certains semblent pour le moins controverses. C’est dans un contexte de polemiques, autour de l’objectivite du processus de suivi-evaluation de la gestion des forets camerounaises, qu’a ete conduite cette etude. Elle s’interesse aux ecarts de conception dans les principaux outils de suivi-evaluation de la gestion des forets du Cameroun. Pour cela, des manuels et guides usuels de portee nationale, sous-regionale, et Internationale ont ete confrontes a l’aide du Test de Student d’une part, et des analyses de proportions d’autre part. Les comparaisons concernaient les aspects organisationnels des demarches, et la repartition generale des differents parametres au suivi-evaluation des composantes environnementales. Il en ressort que: Sur le plan du test de Student, independamment des criteres de comparaisons retenus, le manuel propose par le MINFOF (Ministere des Forets et de la Faune) n’a pas ete significativement different des autres manuels (MINEPDED (Ministere de l’Environnement, de la Protection de la Nature et du Developpement Durable), OIBT (Organisation Internationale des Bois Tropicaux) /OAB et FSC (Forestry Stewardship Council)). Toutefois, sur le plan quantitatif, les analyses ont revele des disparites plus ou moins importantes de proportion d’affectation. Ainsi, la confrontation des parametres d’organisation generale des demarches (Structuration, methodologie, suivi-evaluation de la legalite) a revele des d’ecarts moyens de 17,44 a 35,07% entre la demarche du MINFOF et respectivement celle de l’OIBT/OAB, de la FSC et du MINEPDED. Les plus fortes disparites organisationnelles concernaient principalement les elements methodologiques et le suivi-evaluation de la legalite. Les proportions de parametres affectes au suivi-evaluation de la gestion des composantes environnementales (abiotiques, biotiques et sociales) ont egalement presente des disparites de l’ordre de 1,59% a plus de 46%. Au terme de ces differentes analyses, un systeme integre et pondere de suivi-evaluation a ete suggere, comme contribution a l’amoindrissement des ecarts observes entre les divers outils de gestion forestiere au Cameroun. Abstract The monitoring and evaluation missions of forest management usually need the contribution of many tools including manuals and procedural guides. The success of assessment missions would be closely linked to the quality of these tools, in which some seem at least controversial. It is in a context of controversy around the objectivity of the monitoring and evaluation process of forest management in Cameroon, that this study has been conducted. It was principally interested in conception differences between the main monitoring and evaluation tools of Cameroonian forests management. For this, the national, sub regional and International usual manuals and guides were confronted, help by the Student Test, and analysis of proportions. Comparisons concerned organizational aspects, and the distribution of different parameters used for monitoring and evaluation. It emerged that: In term of Student Test, independently of selected criteria comparisons, the manual proposed by the MINFOF was not significantly different from others manuals and guides (MINEPDED, ITTO (International Timber Tree Organization)/ ATO and FSC). However, quantitatively, the analyzes revealed disparities more or less important. Thus, the comparison of monitoring and evaluation parameters of procedure organization (structuring, methodology, monitoring and evaluation of the legality) revealed average differences of 17.44 to 35.07% between MINFOF approach and respectively that of the ITTO / ATO, FSC and MINEPDED. The greatest organizational disparities were mainly observed in methodological parameters and the proportion of parameters allocated to monitor and evaluate legality. The proportions of parameters allocated to monitoring and evaluation of environmental (Abiotic, biotic and socials) components management, also showed disparities from 1.59% to more than 24.51%. Following these analyzes, an integrated and weighted monitoring and evaluation system was suggested, as contribution to lessen differences observed between the various tools of forest management in Cameroon.
Pulchérie Matsodoum Nguemté, Guy Valérie Djumyom Wafo, Pierre François Djocgoue, Ives Magloire Kengne Noumsi, Adrien Wanko Ngnien
Revue des sciences de l eau
Les écoulements et les transferts de matières à travers les sols et sous-sols sont des processus qui impactent les ressources en eau. Ainsi, la restauration des milieux dégradés participe à la préservation de la qualité de la ressource. Afin de contribuer à la décontamination des sols pollués par phytoremédiation - technique de dépollution basée sur l’action des plantes en association avec les micro-organismes du sol - des inventaires floristiques de sites potentiellement pollués et non pollués (témoins) par les hydrocarbures ont été réalisés dans quatre villes du Cameroun. Sur la base d'indicateurs floristiques, six espèces ont été sélectionnées, et leurs capacités phytoremédiatrices testées dans un sol pollué par du fioul à 82,5 mL∙kg ‑1 de sol pendant 150 jours en présence de trois modalités : Tn - sols non pollués plantés (6), To - sols pollués non plantés (3) et Tp - sols pollués plantés (18). La biodiversité des sites pollués (106 espèces, 76 genres et 30 familles) est moins élevée que celle des témoins (166 espèces, 125 genres et 50 familles). Les espèces les plus fréquentes ( Fr i &gt; 10 %) et abondantes (7 % &lt; A &lt; 10 %) sur les sites potentiellement pollués sont dominées par 15 espèces tropicales; parmi lesquelles, Eleusine indica (L.) Gaertn., Cynodon dactylon (L.) Pers., Alternanthera sessilis (L.) R. Br. ex DC†, Commelinpa benghalensis L., Cleome ciliata Schum. et Thonn., et Asystasia gangetica (L.) T. Anderson, sont utilisées dans des essais de phytoremédiation des sols contaminés au fioul domestique. Seules trois de ces espèces, notamment E. indica , C. dactylon et A. sessilis ont pu survivre et se développer. Contrairement à A. sessilis , E. indica et C. dactylon ne présentent pas de différence significative pour les paramètres de croissance considérés entre les modalités Tn et Tp. Les espèces E. indica et C. dactylon seraient donc plus tolérantes au fioul domestique que l’espèce A. sessilis .
Pulchérie Matsodoum Nguemté, Adrien Wanko Ngnien, Guy Valérie Djumyom Wafo, Ives Magloire Kengne Noumsi, Pierre François Djocgoue
World Academy of Science, Engineering and Technology, International Journal of Environmental and Ecological Engineering
Pierre Effa Onomo, Jude Manga Ndjaga, Martine Louise Ondobo, Jules Christian Djoko Kouam, Pierre François Djocgoue
IOSR Journal of Biotechnology and Biochemistry
Phytophthora megakarya is an Oomycete which has a negative impact on Cameroon cocoa production. An assessment of the level of virulence of different isolates of P. megakarya in mono or coinfection was performed on some hybrids of cocoa (Theobroma cacao L.) obtained from reciprocal crosses. The isolates tested on eight cocoa hybrids obtained by hand pollinisation were Bakoa, Le4 and Lebdi. Contents of soluble amino acids, sugars, polyphenols and proline were determined using standard methods in mono or coinfected cocoa pods. This study revealed that, the development of the necrotic area in the cortex of cocoa pods was genotype-dependent and isolate-dependent after infection. For this reason, the classification in terms of virulence of isolates was the following: Lebdi<Le4<Bakoa. However, SNK 413 x T 79/501 and T 79/501 SNK 413 hybrids were the most tolerant while UPA 134 x ICS 40 and T 79/467 SNK 13 hybrids proved to be the most sensitive to threeP. megakarya isolates. Bakoa + Le4 combination was the most aggressive among the other combinations.Groupings of samples were observed using principal component analysis (PCA) and hierarchical cluster analysis.Significant and negative correlations were found between necrosis and three biochemical metabolites (total polyphenols, soluble sugars, Proline andsolubleamino acids) in cocoa hybrids suggesting that these metabolites could be considered as markers of resistance in T. cacao/P. megakarya interactions.
Joseph Armathé Amougou, Jules Rémy Ndam Ngoupayou, Pierre François Djocgoue, Stanislas Bessoh Bell
L’extension spatiale du bassin de la Sanaga sur 3 o 35’ dans le sens latitudinal et 5 o 15’ sens longitudinal le soumet en amont a une zone de contact foret-savane au nord-est et les hautes terres au nord-ouest couvert par un climat tropical humide, une zone forestiere en aval couvert par un climat equatorial. Les ecoulements montrent une allure en cloche, n’illustrant qu’un milieu tropical. Ce travail a pour objectif principal d’analyser l’evolution des parametres hydroclimatiques au sein du bassin de la Sanaga et d’evaluer l’impact de la variabilite climatique sur la disponibilite en eau de la Sanaga a Edea. Dans la poursuite de cet objectif, on s’est servi des donnees des precipitations, et des temperatures et des debits du fleuve de 1944 a 2008. Ces donnees secondaires ont ete analysees par les methodes statistiques. Il ressort de cette etude que le bassin de la Sanaga est couvert par un climat tropical humide dans sa section superieure ou la moyenne interannuelle de 1515 mm, un climat equatorial guineen dans sa section moyenne avec une moyenne interannuelle de 1492 mm et un climat equatorial type camerounien qui comprenant la zone ouest et la Basse Sanaga dont est la moyenne interannuelle 2593,8 mm. La pluie moyenne tombee dans le bassin est 1859 mm par an. Les precipitations ont progressivement diminue dans ce bassin avec une baisse de 246,7 mm en valeur absolue entre les sous periodes 1944-1982 et 1982-2008, soit 12,64 % en valeur relative. La temperature a legerement augmente de 0,53 °C au sein du bassin de la Sanaga. Le module annuel des debits est de 1864,3 m 3 /s, le minimum est de 1098,42 m 3 /s et le maximum est de 2625,04 m 3 /s. Les debits ont progressivement diminue dans le bassin avec une baisse de 302,6 m 3 /s en valeur absolue entre 1944 a 1982 et 1982 a 2008, soit 15,23 % en valeur relative. Ces resultats montrent egalement une baisse des quantites de precipitations couplee a une hausse de temperatures. Les impacts directs au sein du bassin sont une forte evaporation et une diminution des ressources en eau.
Claude Simo, Pierre François Djocgoue, H.D. Mbouobda, P. O. EFFA, Thaddée Boudjeko, Dénis Ndoumou Omokolo
Plant Pathology Journal
Thaddée Boudjeko, Pierre François Djocgoue, J. D. Nankeu, H.D. Mbouobda, Dénis Ndoumou Omokolo, I. El Hadrami
Australasian Plant Pathology
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