Aflatoxin control and prevention strategies in maize for Sub-Saharan Africa

Mycotoxins are secondary fungal metabolites that contaminate agricultural commodities and can cause sickness or death in humans and animals. Risk of mycotoxin contamination of food and feed in Africa is increased due to environmental, agronomic and socio-economic factors. Environmental conditions especially high humidity and temperature favour fungal proliferation. Farming practices in Africa sustain fungal and toxin contamination of food and feed. The socio-economic and food security status of the majority of inhabitants of sub-Saharan Africa leaves them little option in choosing good quality products. Several technologies have been tested in Africa to reduce mycotoxin risk. Field management practices that increase yields may also prevent aflatoxin. They include use of resistant varieties, timely planting, fertilizer application, weed control, insect control and avoiding drought and nutritional stress. Other options to control the toxin causing fungi A. flavus contamination in the field are use of atoxigenic fungi to competitively displace toxigenic fungi, and timely harvest. Post-harvest interventions that reduce mycotoxins are rapid and proper drying, sorting, cleaning, drying, smoking, post harvest insect control, and the use of botanicals or synthetic pesticides as storage protectant. Another approach is to reduce the frequent consumption of ‘high risk’ foods (especially maize and groundnut) by consuming a more varied diet, and diversifying into less risky staples like sorghum and millet. Chemo-preventive measures that can reduce mycotoxin effect include daily consumption of chlorophyllin or oltipraz and by incorporating hydrated sodium calcium aluminosilicates into the diet. Detoxification of aflatoxins is often achieved physically (sorting, physical segregation, flotation etc.), chemically (with calcium hydroxide, ammonia) and microbiologically by incorporating probiotics or lactic acid bacteria into the diet. There is need for efficient monitoring and surveillance with costeffective sampling and anlytical methods. Sustaining public education and awareness can help to reduce aflatoxin contamination. Keywords: Aflatoxin, Sub-Saharan Africa, Control measure

Variation in seed morphometric traits, germination and early seedling growth performances of Tamarindus indica L.

The purpose of this work was to address provenance variation in Tamarindus indica seed’s morphometric traits, germination and early seedling growth. Seed samples were sampled from three populations in Benin and examined for variations in seed morphometric traits, germination response to pretreatment, and seedling growth. Overall, seed traits significantly differed and showed positive correlation with humidity gradient. The effect of the interaction provenances*pre-treatments was significant on the mean germination time (p < 0.0001) but not on the final percentage of germination (p = 0.937). Both direct sowing and cow dung solution soaking ensured 90% of germination while boiled water soaking seemed to annihilate the capacity of seeds to germinate. Seeds from the Guineo-Congolian region took fewer days to geminate (13.4) than that from the Sudanian region (20.3). Growth speed also varied, with the Guineo-Congolian provenance reaching 46.1 cm (height) and 0.89 cm (collar diameter) and the Sudanian provenance, 40.4 cm and 0.57 cm respectively, after six month of growth. Results evidence that pre-treatment is not necessarily relevant to reach a high germination percentage for tamarind seeds but may speed germination. The Guineo-Congolian provenance may be preferably used as rootstock onto which further selected cultivars will be grafted and used to rejuvenate traditional agroforestry systems.© 2010 International Formulae Group. All rights reserved.Key words: Seed emergence, seedling growth, early growth speed, Benin

Fusarium infection and mycotoxin contamination in preharvest and stored maize in Benin, West Africa

Please read the abstract in the section 00front of this documentThesis (PhD (Microbiology))--University of Pretoria, 2004.Microbiology and Plant Pathologyunrestricte

Infection of maize by Fusarium species and contamination with fumonisin in Africa

Fusarium is one of the major fungal genera associated with maize in Africa. This genus comprises several toxigenic species including F. verticillioides and F. proliferatum, which are the most prolific producers of fumonisins. The fumonisins are a group of economically important mycotoxins and very common contaminants of maize-based foods and feeds throughout the world. They have been found to be associated with several animal diseases such as leukoencephalomalacia in horses and pulmonary oedema in pigs. Effects of fumonisins on humans are not yet well understood. However, their occurrence in maize has been associated with high incidences of oesophageal and liver cancer. Infection of maize by Fusarium species and contamination with fumonisins are generally influenced by many factors including environmental conditions (climate, temperature, humidity), insect infestation and pre- and postharvest handling. Attempts to control F. verticillioides and to detoxify or reduce fumonisin levels in maize have been undertaken. However, more research studies are urgently needed in order to understand more about this toxin. Fumonisins are less documented because they are recently discovered mycotoxins compared to aflatoxins. To date in Africa, apart from South Africa, very little information is available on Fusarium infection and fumonisin contamination in maize. It is a matter of great concern that on this continent, millions of people are consuming contaminated maize and maize-based foods daily without being aware of the danger. Key words: Fusarium, fumonisins, maize, Africa. African Journal of Biotechnology Vol. 2 (12), pp. 570-579, December 200

Analysis of pre- and post-harvest practices of cowpea (Vigna unguiculata (L.) Walp.) in Benin

Cowpea is an important leguminous crop in Benin. Practices such as farming and storage conditions may influence the production yield and the grain quality. In this study, pre- and post-harvest practices ofcowpea were analysed in relation to the quality of the grains. A survey on cowpea farming activities was conducted in the four agro-ecological zones of Benin. Three localities producing cowpea were selected in eachagro-ecological zone. Information was obtained through individual interview and focus group discussions. Cowpea was mainly cultivated either as a monocrop or intercropped with maize and groundnuts in the fouragro-ecological zones. Cowpea infestation by insects on farm and in storage was a major problem mentioned by farmers. To prevent insects’ infestation in storage, cowpeas were thoroughly sundried at harvest andadequately sorted prior to storage. Such post-harvest practices could limit cowpea grains quality deterioration. Cowpeas were mainly stored in bags for about 3 months. About 23 cowpea based foods were identified. Majorcowpea foods were ata (akara), moin-moin and adowe. Common processing operations included sorting, washing, dehulling of cowpeas, boiling and frying. These processing operations as practiced by processors are generally recognized as a good practice in food preparation

Impact of indigenous storage systems and insect infestation on the contamination of maize with fumonisins

Four storage systems of maize commonly used by farmers in Benin, West Africa, were tested to determine their impact on infection of maize by Fusarium and subsequent contamination with fumonisins. The study showed that Fusarium incidence was significantly higher when maize was stored on a cemented floor in a house, a non ventilated facility (40.3 ± 17.4%), than in the other tested systems (p &lt; 0.05). The lowest Fusarium incidence was recorded when maize was stored in a bamboo granary that is a ventilated facility (25.5 ± 13.5%) (p &lt; 0.05). All maize samples from the tested storage systems were found to be fumonisin positive, with levels ranging from 0.6 to 2.4 mg/kg. Fumonisin level, overall, was found to decrease over the storage period, but not significantly in all the tested storage systems. Damage by lepidopterous pests was significantly and positively correlated with both infection of maize with Fusarium and contamination by fumonisin. In contrary, damage by coleopterous insects was significantly and negatively correlated with infection of maize with Fusarium and contamination by fumonisin. Avoiding the use of non-ventilated systems to store maize and reducing insect infestation in field and during storage are very important recommendations for farmers.Keywords: Maize, storage systems, Fusarium, fumonisins, insect infestatio

Climate change impact projection on spatial distribution of Zanthoxylum zanthoxyloides (lam.) z & t. – a threatened medicinal plant in Benin (West Africa)

Climate change constitutes nowadays another kind of threat for useful plant species in West Africa. This study aims to identify the suitable areas for&nbsp; conservation of Zanthoxylum zanthoxyloides under the current and the future climate. The occurrences of Z. zanthoxyloides were associated with&nbsp; current and four future scenarios data. Two Species Distribution modeling methods (MaxEnt and MaxLike) were used in R software packages and&nbsp; the results were compared for identifying the most acceptable method. MaxLike method results were more valid than Maxent’s giving the latter’s&nbsp; uncertainty. With MaxLike’s method, about 52% of Beninese territory was detected to be suitable for Z. zanthoxyloides production in the current&nbsp; climatic conditions. These areas were localized in southern and central Benin with a good coverage by the included protected areas. The predicted&nbsp; distributions of Z. zanthoxyloides in Benin under the four different emissions scenarios have shown a no significant impact of climate change on its&nbsp; current suitable areas. The challenge for conservation of Z. zanthoxyloides in climate change conditions is needless. It is suggested further&nbsp; investigations in impacts of land uses and medicinal uses on survival of Z. zanthoxyloides for better positioning of the suitable conservation&nbsp;&nbsp; strategies in present situation of limited resources for conservation

Impacts du labour conventionnel sur le rendement cotonnier dans la commune de Kétou, Bénin

This work examines the effect of the frequency of plowing with the three-disc plow on ferralitic soil and the development of cotton plants. Addressing this problem, a number of plowings varying from 0 to 15 were carried out on plots of 400 m² organized into 7 treatments according to number of plowings (P0, P1, P2, P4, P8, P12, P15) and arranged randomly in three replications. The germination rate was assessed by counting the number of plants present per plot over the number of seeds planted. The cotton yield was obtained by weighing harvests per plot. The results show that the best germination rates were obtained with P1 (94%), P2 (80%), P0 (68%) and P4 (62%) and the lowest ones with P8 (48%), P12 (39%) and P15 (36%). The number of capsules per plot at 4 months increased from 2121 (P0) to 2198 (P2) and gradually decreases to 1243 (P15). The cotton yield of the first harvest at 6 months followed the same trend, going from 125 kg/ha (P0) to 161 kg/ha (P2) and decreasing to P15 (44 kg/ha). Keywords: Plow, Gossypium hirsutum, emergence, capsules, yieldCe travail porte sur l’effet de la fréquence de labour à la charrue à trois disques sur le sol ferralitique et le développement des plants de cotonnier. Abordant cette problématique, un nombre de labour variant de 0 à 15 est effectué sur les différentes parcelles élémentaires de 400 m² réparties en 7 traitements (P0, P1, P2, P4, P8, P12, P15) et disposés aléatoirement dans les trois blocs expérimentaux. L’évaluation du taux de germination a été effectué par comptage du nombre de plants présents par parcelle sur le nombre de graines mises en terre. Le rendement de coton graine est obtenu par pesée par parcelle. Les résultats montrent que les meilleurs taux de germination sont obtenus avec les passages P1 (94 %), P2 (80%), P0 (68%) et P4 (62%) et les faibles avec les P8 (48%), P12 (39%), et P15 (36%). Le nombre de capsules par parcelle à 4 mois augmente de P0 (2121) à P2 (2198) et diminue progressivement jusqu’à P15 (1243). Le rendement cotonnier de la première récolte à 6 mois a suivi la même tendance allant de 125 kg/ha (P0) à 161 kg/ha (P2) et décroît jusqu’à P15 (44 kg/ha). Mots clés: Charrue, Gossypium hirsutum, levée, capsules, rendemen

Impact potentiel du changement climatique sur les avantages socioculturels et pecuniaires tires de Cochlospermum kunth

écosystémiques fournis par deux espèces du genre Cochlospermum fortement exploitées au Bénin. Cent quatre femmes commerçantes de Cochlospermum ont été interviewées dans trois marches principaux. Les savoirs des femmes de différents groupes sociolinguistiques sur les usages spécifiques du Cochlospermum ainsi que les quantités vendues de poudre de racine de l’espèce et les revenus tirés ont été estimés et comparés au moyen d’indices ethnobotaniques et des marges brutes, sur la base des déclarations des enquêtés. Les probabilités d’occurrence du Cochlospermum ont été générées après modélisation de sa distribution avec l’algorithme MAXENT. Ensuite, les valeurs moyennes actuelles et futures du revenu monétaire et de l’indice d’importance culturelle ont été estimées et liées aux coordonnées géoréférencées des centroïdes des cellules de la grille contenant les probabilités d’occurrence de Cochlospermum, puis projetées sur des cartes. Le nombre moyen d’usages par enquêté était le plus élevé chez les commerçantes Mokolés et près de deux fois plus grand que chez les commerçantes des autres groupes sociolinguistiques (Chi 2 = 62, p &lt; 0,001). Les quantités de poudre de racine de Cochlospermum vendues annuellement par commerçante sont en moyenne similaires sur les marchés considérés soit 31,19 kg. Toutefois, les marges brutes tirées à Angaradébou sont significativement plus élevées que celles de Natitingou. Les deux scénarios de changement climatique entrevoient une augmentation potentielle des avantages pécuniaires tirés de Cochlospermum et un renforcement potentiel de son importance socioculturel. Cochlospermum pourrait alors être une candidate clé à l’autonomisation des femmes dans un contexte de changement climatique.&nbsp; English title: Climate change and socio-economics of Cochlospermum Abstract This study assessed the potential impact of climate change on ecosystem services provided by the two species of the genus Cochlospermum in Benin. One hundred and four female traders of different sociolinguistic groups were sampled and interviewed. Women’s knowledge of the specific uses of Cochlospermum as well as the quantities of Cochlospermum root powder sold and the income derived were estimated and compared using ethnobotanical index and gross margins, based on the statements of the respondents. The probabilities of occurrence of Cochlospermum were generated after modelling its distribution using MAXENT algorithm. Then, the average values of the current and future monetary income and the index of cultural importance were estimated and linked to the georeferenced coordinates of the centroids of grid cells containing Cochlospermum probabilities of occurrence and then projected on maps. The average number of uses per respondent was highest among Mokolé traders and almost twice as high as among those from other sociolinguistic groups (Chi 2 62, p &lt;0.001). The quantities of Cochlospermum root powder sold annually were on average similar on the markets considered, i.e. 31.19 kg. However, the gross margins drawn at Angaradébou were significantly higher than those at Natitingou. Both used climate change scenarios foresaw a potential increase in the monetary benefits derived from Cochlospermum and a potential enhancement of its socio-cultural importance. Cochlospermum could then be a key candidate for the empowerment of women in a context of climate change. Keyword: wild edible plants; income; Bray Curtis index; Cultural importance index, Maxent, climatic projection

Identification and divergence studies of genotypes of Tamarindus indica (Fabaceae) with superior pod traits

Tamarind (Tamarindus indica L.) crop improvement depends on availability of diversity in the germplasm collection. An evaluation of 35 genotypes of tamarind was carried out to assess variability and character association and to identify diverse genotypes with superior pod traits. Variability studies for pod traits revealed that, genotype CPT–9 was desirable for eight traits and genotype CPT–26 exhibited the lowest values for six traits. A wide spread of variation was observed for pod weight (9.5 - 83.7 g), pulp weight (4.8 - 51.2 g), seed weight (2.4 - 12.2 g), shell weight (2.3 - 18.1 g), pod length (9.0 - 25.5 cm) and pod width (1.8 - 5.5 cm). Higher estimates of heritability for pod traits such as shell weight, pod weight, pulp weight, and vein weight coupled with higher genetic advance indicated possibility of progress by selection. Pulp weight per pod showed highest positive genotypic and phenotypic correlations with pod weight (rg = 0.99, rp = 0.98), vein weight (0.92, 0.91), shell weight (0.93, 0.91), pod length (0.89, 0.79), pod width (0.92, 0.86), and pulp: seed ratio (0.81, 0.77). The first three Principal Component (PCs) explained large portion (85.53 %) of the total variation. Clustering analysis resulted into two broad clusters. Genotypes in cluster-2 (CPT–1, CPT–2, CPT–3, CPT–9, CPT–10, CPT–11, CPT–17, CPT–22, and CPT–33) had combination of desirable traits and can be directly selected for further improvement by breedin