Variations in agronomic and grain quality traits of rice grown under irrigated lowland conditions in West Africa

Rice breeding in West Africa has been largely skewed toward yield enhancement and stress tolerance. This has led to the variable grain quality of locally produced rice in the region. This study sought to assess variations in the agronomic and grain quality traits of some rice varieties grown in this region, with a view to identifying sources of high grain yield and quality that could serve as potential donors in their breeding programs. Forty‐five varieties were grown under irrigated conditions in Benin and Senegal with two trials in each country. There were wide variations in agronomic and grain quality traits among the varieties across the trials. Cluster analysis using paddy yield, head rice yield, and chalkiness revealed that 68% of the total variation could be explained by five varietal groupings. One group comprising seven varieties (Afrihikari, BG90‐2, IR64, Sahel 108, WAT311‐WAS‐B‐B‐23‐7‐1, WAT339‐TGR‐5‐2, and WITA 10) had high head rice yield and low chalkiness. Of the varieties in this group, Sahel 108 had the highest paddy yield in three of the four trials. IR64 and Afrihikari had intermediate and low amylose content, respectively, with the rest being high‐amylose varieties. Another group of varieties consisting of B6144F‐MR‐6‐0‐0, C74, IR31851‐96‐2‐3‐2‐1, ITA222, Jaya, Sahel 305, WITA 1, and WITA 2 had high paddy yield but poor head rice yield and chalkiness. The use of materials from these two groups of varieties could accelerate breeding for high yielding rice varieties with better grain quality for local production in West Africa

La pêche artisanale au Sénégal : qualité de la matière première destinée aux entreprises exportatrices

Les conditions d’hygiène de la pêche artisanale au Sénégal ne respectent pas toujours les normes de qualité requises. Ce présent travail se propose d’étudier la qualité de trois espèces de poissons démersaux ; la sole limande (Syacium guineensis), le mérou à points bleus (Cephalopholis taeniops) et le rouget (Pseudupeneus prayensis) débarqués par la pêche artisanale. Ces espèces sont suivies depuis la capture jusqu’à leur acheminement en usine. L’évaluation sensorielle de la fraîcheur du poisson a consisté à tester la qualité par le toucher, l’odorat, la vue et le goût. Le dosage de l’azote basique volatil total (ABVT) a permis de déterminer la teneur totale en azote des bases azotées volatiles résultant de la dégradation des composés azotés du poisson lors de l’altération. La méthode d’analyse microbiologique utilisée est celle qui consiste à incorporer un volume donné de la prise d’essai et de ses dilutions dans un milieu de culture solide. A l’analyse sensorielle, les trois espèces, aux différentes étapes, étaient de très bonne qualité. Les valeurs de la flore mésophile aérobie sur le poisson à la capture sont très faibles contrairement au débarquement et à l’entrée en usine. Au niveau des branchies et de la peau, les résultats montrent une augmentation significative de la flore au débarquement et à l’entrée en usine. Au niveau des viscères, la flore augmente jusqu’au débarquement puis décroît. Les résultats des analyses chimiques ne reflètent pas forcément les risques de dégradation du poisson.Mots-clés : pêche artisanale, poisson, qualité matière première, exportation, Sénégal.Artisanal fisheries in Senegal: Quality of raw materials for exporting companiesHygienic conditions of artisanal fisheries in Senegal do not always respect the required quality standards. This study expects to scrutinize the quality of bottom fish sole (Syacium guineensis), grouper blue spotted (Cephalopholis taeniops), red mullet (Pseudupeneus prayensis) disembarked by artisanal fisheries. These species are followed since the capture until their routing in factory. The sensory evaluation of fish freshness was to test the quality through touch, smell, sight and taste. The determination of total volatile basic nitrogen (ABVT) allowed determining the total nitrogen content of volatile nitrogenous bases resulting from the degradation of nitrogenous compounds in fish spoilage. The used-microbiological-method is the one that consist in incorporating a given volume of the sample and its dilutions in a solid cultural medium. The results of sensory analysis on the three species at different stopovers were very good. The values of the aerobic mesophilic flora on the fish caught are very low compared to the one landed at the entrance to the factory. At the gills and skin, the findings show a significant increase in flora and landed at the entrance to the factory. In the viscera, flora increases and then decreases until the debarkation. The results of sensory and chemical analysis may not reflect the risks of degradation of fish.Keywords : artisanal fisheries, fish, quality, raw materials, exportation, Senegal

Yield loss of Oryza glaberrima caused by grain shattering under rainfed upland conditions

The general perception of Oryza glaberrima as low yielding is a potential drawback to intraspecific breeding of this species. Yields of 21 O. glaberrima accessions were evaluated alongside four O. sativa check varieties under two conditions in which panicles were both covered by paper sacks to avoid grain shattering (potential yield plot) and also not covered (control plot) in a rainfed upland field of Benin in 2010 and 2011. Average potential yields of O. glaberrima with panicles covered were 2.42 and 3.65 t ha-1 in 2010 and 2011, respectively, while those of O. sativa were respectively 2.99 and 3.49 t ha-1. Although there was no significant difference between potential yield and control yield in O. sativa, 19 O. glaberrima accessions showed significant yield reduction by grain shattering — the average percentages of lost yield by shattering were 57.88% in 2010 and 66.76% in 2011. These results suggest that low yield of O. glaberrima is due to grain shattering and that its potential yield would not be inferior to O. sativa if the grain shattering problems were overcome. Two O. glaberrima accessions, TOG 12303 and TOG 9300, possessing strong resistance to grain shattering comparable to O. sativa checks, were identified.Keywords: Panicles, paper sacks, potential yield, yield reduction

Dosage des polyphénols et activité anti-oxydante de feuilles et d’inflorescences mâles de Borassus aethiopum, Mart. (Arecaceae)

Borassus aethiopum est une plante de la famille des Arécacées. C’est un géant palmier qui présente un tronc dur appelé stipe, des racines fasciculées et des feuilles longues en forme d’éventail. Elle est presque cosmopolite et ses différentes parties sont utilisées dans nombreux domaines : économiques, écologiques,  alimentaires et sanitaire. En effet, sur le plan sanitaire, la pharmacopée utilise l’alcinât des feuilles en boisson dans l’eau pour traiter la bilharziose viscérale  (Sakande, 2004). L’objet de notre étude est de déterminer la teneur en polyphénols et de tester l’activité antioxydante d’extraits de feuilles en comparaison avec ceux des inflorescences mâles. Ainsi, la méthode colorimétrique de Folin Denis, décrite par Bassène (2012) a été utilisée pour le dosage des polyphénols. L’activité antioxydante a été déterminée par les méthodes chromatographique sur couche mince selon Takao et al. (1994) et colorimétrique décrite par Sakande (2004). Les teneurs en polyphénols totaux obtenues sont 13,56% et 5,6% Eq d’acide tannique respectivement dans les feuilles et les inflorescences mâles. Les teneurs  respectives en tanins dans les feuilles et les inflorescences mâles ont été évaluées à 13,46% et 5,47% Eq d’acide tannique. La chromatographie sur couche mince a révélé une activité antioxydante dans les extraits de feuilles et d’inflorescences mâles. Par la méthode colorimétrique utilisant le DPPH, les  résultats obtenus en mg Eq d’acide ascorbique sont 4 et 5 mg Eq respectivement dans les extraits d’acétate éthyle et butanolique de feuilles ; les extraits d’acétate d’éthyle et  butanolique  d’inflorescences mâles respectifs ont une activité antioxydante évaluée à 10 et 20 mgEq d’acide ascorbique. Les résultats obtenus de cette étude  montre que les extraits de feuilles ont des teneurs en polyphénols et en tanins supérieures à celles des extraits d’inflorescences mâles. L’activité antioxydante a été deux fois plus importante dans les extraits de feuilles que dans les extraits d’inflorescences mâles. Cependant, dans les feuilles l’extrait d’acétate d’éthyle  renferme deux fois plus de polyphénols et de tanins que l’extrait butanolique ; l’activité antioxydante est aussi plus élevée dans ce premier extrait.Mots clés : Borassus aethiopum, feuilles, inflorescences mâles, polyphénols, tanins, activité antioxydante

Urban agriculture in Senegal: effect of wastewater on the agronomical performance and hygienic quality of tomato and lettuce

The use of wastewater in urban agriculture has gained a lot of interest in Senegal. The aim of this works was to assess the effect of wastewater on the agronomical performance of two vegetable crops and the hygienic threats as compared to tap water. We also compared the effect of irrigation mode and the addition of fertilizers. Results showed that there were no significant differences between the two irrigation modes. Thesturdiness at 2 months had a positive effect on the number of plant (tomato) at the harvest, the yield and fruit average weight. Considering the following parameters studied (overall yield, corrected yield, number of fruit per treatment and fruit average size, there were significant differences between plants (lettuce) treated with tap water and those treated with wastewater. In a chemical point of view, samples from aspersion and draining watering mode treatments were similar in term of their content in heavy metals. On the lettuce, results showed a low presence of worms on crop watered with wastewater. On the other hand, lettuce watered with theaspersion technique contents much more germs of pathogens than those watered in draining mode. As for tomato, there was a total absence of worms and other pathogenic germs in both irrigation modes. This studysuggests that use of wastewater in horticulture with a moderate fertilization and taking into account soil chemistry could be gainful to urban farmers. The study addresses the issue of preliminary studies on the wastewater and soil quality before deciding on the adequate crop to grow

Leaf Eh and pH: A Novel Indicator of Plant Stress. Spatial, Temporal and Genotypic Variability in Rice (Oryza sativa L.)

A wealth of knowledge has been published in the last decade on redox regulations in plants. However, these works remained largely at cellular and organelle levels. Simple indicators of oxidative stress at the plant level are still missing. We developed a method for direct measurement of leaf Eh and pH, which revealed spatial, temporal, and genotypic variations in rice. Eh (redox potential) and Eh@pH7 (redox potential corrected to pH 7) of the last fully expanded leaf decreased after sunrise. Leaf Eh was high in the youngest leaf and in the oldest leaves, and minimum for the last fully expanded leaf. Leaf pH decreased from youngest to oldest leaves. The same gradients in Eh-pH were measured for various varieties, hydric conditions, and cropping seasons. Rice varieties differed in Eh, pH, and/or Eh@pH7. Leaf Eh increases and leaf pH decreases with plant age. These patterns and dynamics in leaf Eh-pH are in accordance with the pattern and dynamics of disease infections. Leaf Eh-pH can bring new insight on redox processes at plant level and is proposed as a novel indicator of plant stress/health. It could be used by agronomists, breeders, and pathologists to accelerate the development of crop cultivation methods leading to agroecological crop protection

Can yield gap analysis be used to inform R & D prioritisation?

The phrase “biggest bang for a buck” is associated with the policy making question that governments and development agencies face: “Where and which crops should receive highest priority for improving local and global food supply?”. A first step of prioritisation is to identify region x crop combinations for which high impact can be anticipated. We developed a new method for this prioritisation exercise and applied it to data from the Global Yield Gap and Water Productivity Atlas (GYGA). Our prioritisation distinguishes between two policy objectives (humanitarian and economic) and builds upon the relative yield gap and climate risk. Results of the prioritisation are presented and visualised in Google Earth

Avantages des biodigesteurs sur le bois de chauffe dans les élevages laitiers à Kaolack (Sénégal)

Le déficit énergétique constitue une contrainte à l’épanouissement des ménages ruraux notamment, au niveau de l’énergie de cuisson. Les femmes utilisent le bois de chauffe pour les besoins énergétiques de la cuisson mais aussi, pour la pasteurisation du lait. Cette étude met en évidence les avantages de l’utilisation des biodigesteurs sur le bois de chauffe dans les élevages laitiers à Kaolack (Sénégal). Cent seize ménages ont été enquêtés dont 58 détenteurs de biodigesteurs. Les résultats montrent que les ménages possédant un biodigesteur avaient plus de temps pour se consacrer à des activités rémunératrices ou pour le bien être de la famille avec un tiers (32,75 %) qui mettent moins de 2 h par jour pour la recherche du bois et 2 h pour la cuisson d’un repas contre (67,25 %) de ménages sans biodigesteurs qui y consacraient 2 à 6 h par jour et plus de 3 h pour la cuisson d’un repas. Plus du quart (25,86 %) des ménages avec biodigesteurs utilisaient le biogaz comme source d’éclairage. De même, 36,20 % préparent les repas et pasteurisent le lait avec le biogaz. Il est également constaté une réduction de la fréquence des pathologies respiratoires et oculaires mais aussi des dépenses pour l’achat de combustible et de compost.Mots clés: Biogaz ; bois ; élevages laitiers ; économie des ménages ; Kaolack ; Sénégal Biodigester benefits on wood heating in dairy farming of Kaolack (Senegal)The energy deficit is a major constraint to the development of rural house holds including at cooking energy. Women use firewood for cooking energy needs but also for the pasteurization of milk. This study highlights the benefits of using biogas digesters on firewood in dairy farms in Kaolack (Senegal). One Hundred sixteen households were surveyed of which 58 possessed biodigester.The results show that households with a biodigester had much more time devoted to income-generating activities or for the welfare of the family. One third (32.75 %) of biodigester owners take less than 2 hours per day for wood search and 2 hours for cooking a meal against (67.25 %) of house holds without biodigester who spent 2 to 6 hours per day and put more than 3 hours to cook meal. More than a quarter (25.86 %) of households with biodigester used biogas as a lighting. Similarly, 36.20 % Cook food and pasteurize milk with biogas.The used of biogas expenses for the purchase of fuel as well as the compost for filed fertilization. It seem that biogas utilization reduce the incidence of respiratory and eye diseases.Keywords: Biogas ; wood ; dairy farms ; household economy ; Kaolack ; Senegal