Pollination and yield responses of cowpea (Vigna unguiculata L. Walp.) to the foraging activity of Apis mellifera adansonii (Hymenoptera: Apidae) at Ngaoundéré (Cameroon)

To determine the apicultural value of Vigna unguiculata (L.) Walp. (Fabaceae) and evaluate the Apis mellifera adansonii Latreille (Hymenoptera: Apidae) activity on its pod and seed yields, the bee foraging and pollinating activities were studied in Ngaoundéré. The experiment was carried out within the University of Ngaoundéré Campus on 210 flowers differentiated in two lots, based on the protection/ornot of plant inflorescences against insect visits. The bee’s seasonal rhythm of activity, its foraging behaviour on flowers, the fructification rate, the number and dry weight of seeds/pod, the percentage ofnormal seeds/pod, and the pod length were evaluated. Results show that A. m. adansonii foraged on plants throughout the whole blooming period. Worker bees intensively and preferably harvested nectar. The greatest mean number of workers foraging simultaneously was 500 per 1000 flowers. The mean foraging speed was 8.67 flowers/min. These findings allow the classification of V. unguiculata as a highly nectariferous bee plant. The number and dry weight of seed/pod, the pod length and thepercentage of normal seeds/pod from unprotected flowers were significantly higher than those of flowers protected from insects. The fructification rates were 62 and 48%, while the percentages ofhealthly seeds were 97.61 and 76.17%, respectively in unprotected and protected inflorescences. The installation of A. m. adansonii colonies close to V. unguiculata field could be recommended to improveits pods and seeds production in the region

The role of cow dung and kitchen manure composts and their non-aerated compost teas in reducing the incidence of foliar diseases of Lycopersicon esculentum (Mill)

Compost teas are fermented watery extracts of composted materials used for their beneficial effect on plants. A study was conducted in the field to compare the efficacy of cow dung and kitchen manure composts and their derived non-aerated compost teas on disease symptoms expression and severity of Lycopersicon esculentum. The experimental layout was a complete randomised block design comprising six treatments, each of which was repeated three times: the negative control plot (Tm-); the positive control or fungicide plot (Tm+); the cow dung compost plot (Cpi); the kitchen manure compost plot (Cpii); the compost tea derived cow dung plot (Tci); and the compost tea derived kitchen manure plot (Tcii). Compost tea derived cow dung was revealed to be richer in elemental nutrients (N, P, K) than compost tea from kitchen manure, and significantly (p < 0.0001) enhanced fruit yield per plant. Similarly, the two composts and their derived compost teas significantly (p < 0.0001) reduced the incidence and severity of disease symptoms compared to the controls, with the highest efficacy accounting for cow dung compost and compost tea. Although the non-aerated compost teas were not amended with micro-organisms, these results suggest that the two compost teas in use were rich enough in microbial pathogen antagonists, and therefore, are perceived as potential alternatives to synthetic chemical fungicides. Future work will attempt to identify these microbial antagonists with highly suppressive activity in the non-aerated compost teas. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.21100 Int. J. Agril. Res. Innov. & Tech. 4 (1): 88-97, June, 201

Study on the isolation and characterization of rhizobia strains as biofertilizer tools for growth improvement of four grain legumes in Ngaoundéré-Cameroon

Increasing the yield and economical efficiency of grain legumes in the Guinea-Savannah zone of Cameroon is a high researcher priority to assist growers in the rural areas. We report here a two-years study inthe production process of fertilizer containing rhizobia for a sustainable production of grain legumes in the region. To address the issue, nodulation and rhizobia strains characterization were assessed at Dang and Wakwa, two soils different in trapping rhizobia partners for groundnut, bambara groundnut, cowpea and soybean. This was a prerequisite step in the determination of the most efficient rhizobia strains for biofertilizer production. Results indicate that all the four grain legumes differently formed nodules in their roots system in the two experimental soils. Cowpea and soybean demonstrated a highly significant (p ≤ 0.001) potential in fixing atmospheric nitrogen through their nodules than groundnut and bambara groundnut. The dry weight of nodules in groundnut and bambara groundnut was significantly lower (0.0001 < p ≤ 0.038) than that of cowpea and soybean in the two soils. When rhizobia were isolated from root nodules of plant species, the number of isolates ranged from 2 to 4 per grain legumes. All the isolates were convex in elevation, smooth/humid on the surface, with regular edges, except one groundnut colony from wakwa soil. The colonies were either whitish for soybean, whitish/yellowish for cowpea, groundnut and bambara groundnut. The rhizobia biofertilizer produced for each grain legumes were stored in the refrigerator for field tests. This is a step forward for further molecular characterization of isolates to enable production of elite inoculum in the region.© 2009 International Formulae Group. All rights reserved.Key words: Grain legumes, nodulation, Rhizobium characterization, Rhizobium biofertilizer

Growth response of Moringa oleifera Lam. as affected by various amounts of compost under greenhouse conditions

Published online: 15 Dec 2017The study was carried out to assess the effect of domestic animal composts on growth performance of potted moringa. The study was conducted in the greenhouse for 55 days. Various quantities of composts (100–300 g) added to 800 g of soil were applied. A Randomized Complete Block Design (RCBD) with 14 treatments (each of which was replicated 12 times) was used, giving a total of 168 experimental units. Plant height, stem diameter, leave length and number of leaves were assessed for each treatment. Results indicate that cow dung compost (100 g, 200 g and 300 g) significantly increased the stem diameter of moringa by respectively 33.09%, 33.09%, and 29.93 as compared to that of the control 55 days after in the greenhouse. An increase in the number of leaves by 48.54% due to application of 100 g cow manure compost was observed after 40 days compared to the control. There were significant differences between treatments effects (p < .05) on all the parameters. Organic amendments in general and cow dung compost in particular could constitute the best fertilizer to improve growth moringa in pots

QTL analysis for resistance to foliar damage caused by Thrips tabaci and Frankliniella schultzei (Thysanoptera: Thripidae) feeding in cowpea [Vigna unguiculata (L.) Walp.]

Three quantitative trait loci (QTL) for resistance to Thrips tabaci and Frankliniella schultzei were identified using a cowpea recombinant inbred population of 127 F2:8 lines. An amplified fragment length polymorphism (AFLP) genetic linkage map and foliar feeding damage ratings were used to identify genomic regions contributing toward resistance to thrips damage. Based on Pearson correlation analysis, damage ratings were highly correlated (r ≥ 0.7463) across seven field experiments conducted in 2006, 2007, and 2008. Using the Kruskall–Wallis and Multiple-QTL model mapping packages of MapQTL 4.0 software, three QTL, Thr-1, Thr-2, and Thr-3, were identified on linkage groups 5 and 7 accounting for between 9.1 and 32.1% of the phenotypic variance. AFLP markers ACC-CAT7, ACG-CTC5, and AGG-CAT1 co-located with QTL peaks for Thr-1, Thr-2, and Thr-3, respectively. Results of this study will provide a resource for molecular marker development and the genetic characterization of foliar thrips resistance in cowpea

The role of cow dung and kitchen manure composts and their non-aerated compost teas in reducing the incidence of foliar diseases of Lycopersicon esculentum (Mill)

Compost teas are fermented watery extracts of composted materials used for their beneficial effect on plants. A study was conducted in the field to compare the efficacy of cow dung and kitchen manure composts and their derived non-aerated compost teas on disease symptoms expression and severity of Lycopersicon esculentum. The experimental layout was a complete randomised block design comprising six treatments, each of which was repeated three times: the negative control plot (Tm-); the positive control or fungicide plot (Tm+); the cow dung compost plot (Cpi); the kitchen manure compost plot (Cpii); the compost tea derived cow dung plot (Tci); and the compost tea derived kitchen manure plot (Tcii). Compost tea derived cow dung was revealed to be richer in elemental nutrients (N, P, K) than compost tea from kitchen manure, and significantly (p < 0.0001) enhanced fruit yield per plant. Similarly, the two composts and their derived compost teas significantly (p < 0.0001) reduced the incidence and severity of disease symptoms compared to the controls, with the highest efficacy accounting for cow dung compost and compost tea. Although the non-aerated compost teas were not amended with micro-organisms, these results suggest that the two compost teas in use were rich enough in microbial pathogen antagonists, and therefore, are perceived as potential alternatives to synthetic chemical fungicides. Future work will attempt to identify these microbial antagonists with highly suppressive activity in the non-aerated compost teas

Responses of Maize and Tomato Crops to Fertilization with Three Agroforestry Litter Species (Annona senegalensis, Terminalia macroptera and Parkia biglobosa)

The objective of this study was to assess the effect of Annona senegalensis, Parkia biglobosa and Terminalia macroptera litters amended to soil in order to improve growth and yield of tomato and maize plants. Trials were conducted at the University of Ngaoundere in a complete randomised block design for each of the two crops. Treatments consisted for each crop of a control (T) and three litters-based fertilizers of A. senegalensis (AS), P. biglobosa (PB) and T. macroptera (TM). The analysis of variance (ANOVA) was used to compare means between treatments. The results obtained indicate that the chemical characteristics of litters varied from one plant species to another. The pH of the three litters AS, PB and TM (6.06; 6.02; 6.07) was acid, while nitrogen content ranged from 2.43% (PB) to 1.40% (TM). A significant difference was observed between treatments for plant height of tomato (p = 0.0016) and maize (p = 0.039). The litters of&nbsp;&nbsp;A. senegalensis (80.33 g) and P. biglobosa (70.60 g) stimulated a significant production of more maize biomass compared to that of the control (37.26 g). The tomato biomass produced under soil amended with litter of A. senegalensis (27.33 g) and T. macroptera (31.27 g) was significantly more abundant (p = 0.035) than that of control (17.31 g). For tomato plants, the highest yield was observed for the treatment litter of A. senegalensis (7.35 t/ha), while the lowest yield accounted for the control (3.48 t/ha). The yield variation between treatments was in the following order: AS&gt; PB&gt;TM&gt;T. As for maize, the yield varied from 4.15 t/ha (litter of T. macroptera) to 1.66 t/ha (control), and was classified between different treatments as: TM&gt; PB &gt; AS&gt; T. Among the three tested litters, Annona senegalensis litter was the best for tomato, whereas Terminalia macroptera litter was better for maize production

THE ROLE OF COW DUNG AND KITCHEN MANURE COMPOSTS AND THEIR NON-AERATED COMPOST TEAS IN REDUCING THE INCIDENCE OF FOLIAR DISEASES OF Lycopersicon esculentum (Mill)

Compost teas are fermented watery extracts of composted materials used for their beneficial effect on plants. A study was conducted in the field to compare the efficacy of cow dung and kitchen manure composts and their derived non-aerated compost teas on disease symptoms expression and severity of Lycopersicon esculentum. The experimental layout was a complete randomised block design comprising six treatments, each of which was repeated three times: the negative control plot (Tm-); the positive control or fungicide plot (Tm+); the cow dung compost plot (Cpi); the kitchen manure compost plot (Cpii); the compost tea derived cow dung plot (Tci); and the compost tea derived kitchen manure plot (Tcii). Compost tea derived cow dung was revealed to be richer in elemental nutrients (N, P, K) than compost tea from kitchen manure, and significantly (p < 0.0001) enhanced fruit yield per plant. Similarly, the two composts and their derived compost teas significantly (p < 0.0001) reduced the incidence and severity of disease symptoms compared to the controls, with the highest efficacy accounting for cow dung compost and compost tea. Although the non-aerated compost teas were not amended with micro-organisms, these results suggest that the two compost teas in use were rich enough in microbial pathogen antagonists, and therefore, are perceived as potential alternatives to synthetic chemical fungicides. Future work will attempt to identify these microbial antagonists with highly suppressive activity in the non-aerated compost teas

Variation in nodulation and growth of groundnut (Arachis hypogaea L.) on oxisols from land use systems of the humid forest zone in southern Cameroon

Improving biological nitrogen fixation through legume nodulating bacteria (LNB) inoculation requires knowledge on the abundance and effectiveness of indigenous population in the ferralsols. Nodulation of groundnut was examined under pots experiment in four location sites of the Humid-forest zone: Bertoua in the East; Ebolowa in the South; Bokito and Yaoundé in the Centre Regions of Cameroon and within each of the locations, in four land use systems (LUSs) of different levels of disturbance: mixed farming (1 to 3 years old); fallows (3 to 5 years old); cocoa plantation (&gt; 20 years old); forest (&gt; 30 years old). Results indicate that, soils under investigation are acidic with pH ranging from 3.68 in the Ebolowa forest to 6.92 in mixed farming at Bokito. Groundnut formed nodules in all the four LUSs. Soils from plantations and forests were poorly nodulated, whereas those from mixed farming and fallows were highly nodulated, with a positive and significant correlation (r 0.406; p &lt; 0.0001) observed between nodulation and plant biomass in all the studied sites. These results suggest a high variation in groundnut nodulating bacteria density in soils from diverse LUSs of the humid forest zone of Cameroon; although, there was a site effect.Key words: Acid soil, Arachis hypogaea, biomass, land use systems, multilocal, nodulation

Variabilité des Composés Phénoliques chez Vigna unguiculata (L.) Walp. (Légumineuses) et Influence de l\'Inoculation par les Rhizobia et les Champignons Mycorhiziens sur Leur Biosynthèse

The major objective of this preliminary work is to assess the variability of phenolic compounds and the modification of their metabolism by symbiotic microorganisms (rhizobia and mycorrhiza). Three experiments have been carried out: the variability of phenolic compounds of 13 varieties of cowpea; the influence of the inoculation of 10 mycorrhizal strains on the biosynthesis of phenolic compounds, under green house and the effect of the double inoculation by rhizobia and mycorrhiza in two sites (Nkolbisson and Mbalmayo) on phenolics biosynthesis. The results show that: there is an important variability in cowpea seed polyphenol concentration, because the most rich variety has 33 times phenol compared to the less rich one; mycorrhiza fungi are able to significantly modify the metabolism of polyphenols biosynthesis in cowpea; the double inoculation of rhizobia and mycorrhiza may reduce the amount of phenolic compounds in cowpea, but a qualitative increase of the number of phenolic compounds was noticed. These observations are also related to ecological factors such as insects pests. From these results it is suggest that more basic studies are needed to improve our knowledge on the role of these compounds for plants defense. Key words: phenolic compounds, mycorrhiza, rhizobia, spectrophotometry, thin layer chromatography, Vigna unguiculata. Résumé Cette étude préliminaire se propose d\'évaluer la variabilité des composés phénoliques du niébé (Vigna unguiculata (L.) Walp.) et la modification de leur métabolisme par les microorganismes symbiotiques (rhizobia et mycorhizes). Pour cela, trois expérimentations ont été menées. L\'analyse des composés phénoliques de 13 variétés de niébé, l\'influence de l\'inoculation de 10 souches de mycorhizes sur la synthèse des composés phénoliques du niébé en serre et l\'effet de la double inoculation des biofertilisants rhizobien et mycorhizien sur la synthèse des composes phénoliques, en conditions de champ, sur deux sites (Nkolbisson et Mbalmayo). Les résultats obtenus montrent que: la variabilité de la teneur des graines de niébé en polyphénols est importante, car la variété la plus riche a une teneur en phénols 33 fois plus élevée que la variété la plus pauvre. Les champignons mycorhiziens sont capables de modifier significativement le métabolisme de la synthèse en polyphénols des feuilles de niébé; la double inoculation du niébé avec les biofertilisants entraînerait une baisse significative de la teneur en phénols totaux des graines, mais surtout une augmentation qualitative du nombre de composés phénoliques en champ. Ces modifications dépendent, aussi fortement de facteurs écologiques liés au site comme la présence d\'insectes ravageurs. A partir de ces résultats, nous suggérons un approfondissement des connaissances sur le rôle de ces composés pour la défense des plantes. Mots clés: chromatographie sur couche mince, composés phénoliques, mycorhizes, rhizobia, spectrophotométrie, Vigna unguiculata. (Af. J. of Science and Technology: 2002 3(2): 127-135