References of "Mergeai, Guy"
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See detailSegregation distortions in an interspecific cotton population issued from the [(Gossypium hirsutum x G. raimondii)² x G. sturtianum] hybrid
Diouf, Fatimata Bintou Hassédine ULg; BENBOUZA, Halima; Nacoulima, Nafissatou Lalaïssa ULg et al

in Tropicultura (in press)

The segregation ratio of 10 Gossypium sturtianum specific SSR markers belonging to linkage groups c2-c14, c3-c17, and c6-c25was analysed in the BC2S6 progeny of the [G.hirsutum x G. raimondii)² x G ... [more ▼]

The segregation ratio of 10 Gossypium sturtianum specific SSR markers belonging to linkage groups c2-c14, c3-c17, and c6-c25was analysed in the BC2S6 progeny of the [G.hirsutum x G. raimondii)² x G. sturtianum] (HRS) hybrid; based on chi-square test. All the marker loci tested were associated with skewed allele frequencies (P < 0.001) showing a strong SD with a zygotic selection. The possible causes and consequences of this massive segregation distortion are discussed [less ▲]

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See detailEffet du mode de conservation d’huile de Jatropha curcas L. sur son efficacité dans la lutte contre les principaux insectes ravageurs du niébé (Vigna unguiculata (L.) Walp. au Niger
Abdoul Habou, zakari; Toudou, Adam; Haubruge, Eric ULg et al

in Tropicultura (in press)

Jatropha curcas oil has an insecticidal activity harnessed by the farmers in Niger. In this study, we compared the insecticidal activity of two batches of oil conserved during 70 days, one exposed to ... [more ▼]

Jatropha curcas oil has an insecticidal activity harnessed by the farmers in Niger. In this study, we compared the insecticidal activity of two batches of oil conserved during 70 days, one exposed to light and the other kept in the dark. The insecticidal efficacy was evaluated in a field with three concentrations (5, 10 and 15%) trial on the main pests of Cowpea (Vigna unguiculata (L.) Walp) and in a laboratory test on Megalurothrips sjostedti Trybon (Thysanoptera: Thripidae) with different concentrations of crude oil (50; 100; 150 and 200 µl). No difference in insecticidal effect was found between the two modes of oil conservation, both in the laboratory and in the field. In the field, regardless of the mode of conservation, the concentrations of 10% of J. curcas oil enables a reduction of over than 80% of thrips, aphids, and bugs compared to the control. Its increased seeds yield more than 50%. The concentration of 15% gives an insecticidal effect comparable to that of the reference treatment (deltaméthrine) but induces phytotoxicity symptoms on the leaves of Cowpea. [less ▲]

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See detailAnalyse des perspectives de rentabilité de la culture extensive de Jatropha curcas L. dans la zone agroécologique de transition orientale du Sénégal : cas de la communauté rurale de Dialacoto
Terren, Marieke ULg; Cissé, Chérif; Mergeai, Guy ULg

in Cahiers d'Etudes et de Recherches Francophones. Agricultures (2013), 22(6), 568-574

The profitability prospects of the three main modes of extensive cultivation of Jatropha curcas L. in the Rural Community of Dialacoto were studied on 24 farms from 2008 to 2012. In the best tended ... [more ▼]

The profitability prospects of the three main modes of extensive cultivation of Jatropha curcas L. in the Rural Community of Dialacoto were studied on 24 farms from 2008 to 2012. In the best tended peasant plantations aged four or five years the dry seed yield obtained in sole cropping was less than 200 kg/ha. Under these conditions, it is very unlikely that the yield achieved in sole cropping exceeds 800 kg/ha in full production. The average yield per meter of live fences older than fifteen years was 0.9 kg/m. Considering the purchase price of jatropha seeds in 2012 in Senegal (65 F CFA/kg – 0.1 euro/kg), and given the bad productivity and the low precocity of the available planting material, the cultivation of jatropha (as a sole crop or in intercropping) is far less profitable than the main cropping system practiced in the region (groundnut/pearl millet/sorghum/cotton rotation with input application). Any improvement in the economic performance of the production of jatropha seeds requires the selection of varieties that are early, hardy and productive. The establishment of living hedges is for the moment the only installation method that can be recommended to farmers. In addition to providing supplementary income related to seed harvest, hedgerows provide different non-monetary benefits appreciated by farmers: land demarcation, soil protection against wind and water erosion, improved soil water balance and windbreak effect favourable to crop development, crop protection against wandering ruminants, and enclosure for the cattle. [less ▲]

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See detailGestion durable de la fertilité du sol dans un système agro-pastoral à Baraka-Fizi, au Sud-Kivu
Mto, W. W.; Mergeai, Guy ULg; Malumba Kamba, Paul ULg et al

in Malumba Kamba, Paul (Ed.) Gestion durable des agro-systèmes en milieu tropical humide (2013)

L'agriculture itinérante sur abattis-brûlis est identifiée parmi les principales menaces aux forêts et à la biodiversité de la localité de Baraka-Fizi en particulier et de la République Démocratique du ... [more ▼]

L'agriculture itinérante sur abattis-brûlis est identifiée parmi les principales menaces aux forêts et à la biodiversité de la localité de Baraka-Fizi en particulier et de la République Démocratique du Congo en général. Cet article propose un modèle agroforestier permettant la fixation des champs et la sédentarisation des élevages et conduisant à des utilisations rationnelles des terres. L'usage des émondes d'engrais verts comme fertilisants ; l'optimisation de leurs doses et modes d'application dans différentes associations de cultures ; les assolements collectifs et l'intégration de l'élevage bovin dans le système de production sont les principales directives de ce modèle. Une gestion optimale et durable de la fertilité des sols et l'amélioration de l'économie paysanne peuvent être attendues grâce aux effets synergiques entre les productions agroforestières (engrais verts), vivrières, fourragères et bovines. [less ▲]

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See detailIn vitro micropropagation of Jatropha curcas L. from bud aggregates
Medza Mve, Samson Daudet ULg; Mergeai, Guy ULg; Druart, Phillipe et al

in Journal of Technology Innovations in Renewable Energy (2013), 2

Entire plants were regenerated from nodes explants of Jatropha curcas L. following a procedure of bud aggregate induction on MS (Murashige and Skoog) medium supplemented with 25 mg.l-1 citric acid, 12.2 ... [more ▼]

Entire plants were regenerated from nodes explants of Jatropha curcas L. following a procedure of bud aggregate induction on MS (Murashige and Skoog) medium supplemented with 25 mg.l-1 citric acid, 12.2 mg.l-1 adenine sulfate, 15 mg.l-1 L-arginine, 2.46 µM IBA (indole-3-butyric acid), 30 g.l-1 sucrose and 7 g.l-1 of agar, and enriched with different balances of BA (benzyladenine) and L glutamine. The histological studies performed on aggregates showed that the buds result from both the development of axillary buds and adventitious budding starting from underlying tissues of the explant. The culture medium containing 6.65 µM BA and 25 mg.l 1 L-glutamine gave the best results with an average of 64 buds per aggregate after three weeks for all accessions tested. The buds developed into shoots when placed in a MS medium supplemented with 2.21 µM BA, 5.70 µM IAA (indole-3-acetic acid) and 15 mg.l-1 L arginine. These shoots were isolated and then rooted in MS containing 2.46 µM of IBA, 2% sucrose and 0.7% agar. The entire process took 13 weeks with a 98% survival rate in terms of plantlets acclimatization. We obtained a multiplication rate of 13 buds per explant and per subculture which is the double of those obtained in other recent works based on the micropropagation of J. curcas from node explants. This protocol is economically more profitable. [less ▲]

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See detailNear-infrared spectroscopy for analysis of oil content and fatty acid profile in Jatropha curcas L. flour
Terren, Marieke ULg; Lecler, B.; Baeten, V. et al

Poster (2013)

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See detailEffets de la couverture du sol avec Stylosanthes guianensis (Aublet) Swartz, de la taille et de la fumure minérale sur la production de Jatropha curcas L. dans la région de Kinshasa
Minengu, Jean de Dieu; Mobambo, Patrick; Mergeai, Guy ULg

in Oléagineux, Corps Gras, Lipides (2013), 21(2), 1-8

In order to evaluate the performance of Jatropha curcas L. in poor soil conditions, a test was conducted near Kinshasa on the Batéké plateau between July 2009 and December 2012 in the sites of Mbankana ... [more ▼]

In order to evaluate the performance of Jatropha curcas L. in poor soil conditions, a test was conducted near Kinshasa on the Batéké plateau between July 2009 and December 2012 in the sites of Mbankana and Mongata. The results show significant differences (p < 0.05) between the treatments applied on the vegetative growth and yield. Ground cover with Stylosanthes guianensis permitted to reduce significantly the rate of fruit abortion of Jatropha and to increase the average number of seeds per capsule. The combination of pruning, mineral fertilizers application, and Stylosanthes cover improved drastically the yields obtained in the 3rd year of production compared to the control with respectively 498.73 ± 5.88 kg of dry seed ha-1 in Mbankana and 552.95 ± 5.03 kg ha-1 in Mongata. In the control plots, yields were 167.85 ± 6.57 kg ha-1 of dry seeds in Mbankana and 172.28 ± 5.96 kg ha-1 of dry seeds in Mongata. [less ▲]

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See detailDescription of Phaseolus vulgaris L. aborting embryos from ethyl methanesulfonate (EMS) mutagenized plants
Silué, Souleymane; Diarrasouba, Nafan; Fofana, Inza Jesus et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(4), 563-571

The aim of this study was to describe the embryos abortion process and the inheritance of the embryos abortion trait in Phaseolus vulgaris plants deficient in seed development. These plants were isolated ... [more ▼]

The aim of this study was to describe the embryos abortion process and the inheritance of the embryos abortion trait in Phaseolus vulgaris plants deficient in seed development. These plants were isolated within the second generation of an ethyl methanesulfonate (EMS) TILLING population of P. vulgaris cv. 'BAT93'. Mutant embryos show abnormalities mainly in suspensors, shoot apical meristem (SAM) and cotylédons from the globular to the cotyledon stages and abort before maturity compared to those observed in wild-types samples. Mutant embryos show also hyperhydricity and contain low amount of chlorophyll. Genetic analyses of F1, F2 and F3 populations from the crosses carried out between the mutagenized plants with aborting embryos and the wild-type plants indicated that the embryo abortion phenotype is maternally inherited and controlled by a single recessive gene. These Phaseolus mutant plants with aborting embryos constitute a valuable material for plant embryogenesis studies. [less ▲]

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See detailEvaluation des performances de la production de graines par tamisage manuel du sol chez trois variétés de Stylosanthes guianensis (Aublet) Swartz, dans les conditions du Plateau des Batéké (RDC)
Bulakali, B.P.; Aloni, J.; Palata, J.C. et al

in Tropicultura (2013), 31(4), 253-259

In manual agriculture with low resources level, Stylosanthes guianensis is one of the most interesting cover crop for developing direct seeding mulch-based cropping systems. To promote its cultivation in ... [more ▼]

In manual agriculture with low resources level, Stylosanthes guianensis is one of the most interesting cover crop for developing direct seeding mulch-based cropping systems. To promote its cultivation in the RDC, the performances of a seed production method by sieving of the soil were evaluated for three varieties of Stylo (a local ecotype, CIAT 184 variety, and 202cc variety) in two sites of the Batéké plateau characterized by contrasted fertility levels. The results obtained demonstrate the interest of the seed multiplication method tested, both in quantities and quality of the produced seeds. The production cost of one kg of seeds varies with the soil fertility, the planting date, and the cultivar. Among the three compared varieties, CIAT 184 variety produced the highest quantity of seeds. If sown at the beginning of the long rainy season, after a long fallow, in one of the most fertile soils of the plateau, this cultivar can produce 600 kg ha-1 seed in the first year of cultivation with a production cost of USD 1.31 kg-1, equivalent to less than 0.5 man.day.kg-1. [less ▲]

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See detailAnalyse de la faune entomologique associée à Jatropha curcas L. dans la région de Maradi au Sud-est du Niger
Abdoul Habou, Zakari; Toudou, Adam; Haubruge, Eric ULg et al

in Entomologie Faunistique = Faunistic Entomology (2013), 66

Jatropha curcas L. is a shrub belonging to the Euphorbiaceae family. It is cultivated in Africa as living fence, and for its seeds, rich in oil that can be used as Biofuel. The inventory of insects ... [more ▼]

Jatropha curcas L. is a shrub belonging to the Euphorbiaceae family. It is cultivated in Africa as living fence, and for its seeds, rich in oil that can be used as Biofuel. The inventory of insects associated with these shrubs present in Maradi (South-eastern Niger) was conducted by combining beating, trapping and visual observation methods. The inventories were carried out from July to September 2010 and were repeated at the same period in 2011. A total of 1761 insects were collected on J. curcas. These insects belong to 45 different species belonging to 30 families. Coleopterans are the most numerous with 32% of captured insects, followed by Hymenopterans (24%), Orthopterans (14%), Dipterans (13%), Heteropterans (10%) and Isopterans (4%). Among the captured insects, only Heteropterans, Orthopterans and some Coleopterans can cause damage to J. curcas in Niger. [less ▲]

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See detailAttempted cultivation of Jatropha curcas L. in the lower Senegal river valley: story of a failure
Terren, Marieke ULg; Saverys; Jacquet de Haveskercke, Paul et al

in Tropicultura (2012), 30(4), 204-208

With the objective of determining whether it would be possible to sustainably produce Jatropha curcas L. seeds on the marginal land situated close to the Senegal River, a 6-hectare pilot plantation was ... [more ▼]

With the objective of determining whether it would be possible to sustainably produce Jatropha curcas L. seeds on the marginal land situated close to the Senegal River, a 6-hectare pilot plantation was cultivated under drip irrigation between September 2007-November 2011, close to the village of Bokhol (Lat. 16°31’N, Long. 15°23’W). A series of tests were conducted on this plot, in order to identify the best cultivation methods for the area (date, density and method of planting, appropriate type of pruning, fertilisers to be applied, irrigation method, etc.). The average yields obtained at this site, after four years of cultivation (less than 500 kg.ha-1 of dry seed), using the best known production techniques, are significantly lower than anticipated, compared to the available figures for the irrigated cultivation of Jatropha in other parts of the world. The main causes of this failure are the plant’s limited useful vegetation period of six months per year, instead of twelve, and the scale of attacks by a soilborne vascular disease, which destroyed over 60% of the plantation within four years. [less ▲]

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See detailPrincipal disease and Insect pests of Jatropha curcas L. in the lower valley of the Senegal river
Terren, Marieke ULg; Mignon, Jacques ULg; De Clerck, Caroline ULg et al

in Tropicultura (2012), 30(4), 222-229

Jatropha curcas L. seed oil is proven to be toxic to many microorganisms, insects and animals. Despite its toxicity, Jatropha is not pest and disease resistant. The following major pests and diseases ... [more ▼]

Jatropha curcas L. seed oil is proven to be toxic to many microorganisms, insects and animals. Despite its toxicity, Jatropha is not pest and disease resistant. The following major pests and diseases affecting Jatropha in the lower valley of the Senegal river have been identified: the leaf miner Stomphastis thraustica (Meyrick, 1908) (Lepidoptera, Gracillariidae), the leaf and stem miner Pempelia morosalis (Saalmuller, 1880) (Lepidoptera, Pyralidae) and the shield-backed bug Calidea panaethiopica (Kirkaldy, 1909) (Heteroptera, Scutelleridae), which can cause flower and fruit abortion. Damage from these pests was particularly great during the second year after the plantations were set up (2009) and before later receding. Nevertheless, the worst attacks were caused by a vascular disease transmitted through the soil, which killed 65% of the plants in four years. It is mainly characterised by collar and root rot, which causes foliage to yellow and wilt, before the plant eventually dies. These threats should increase if larger areas are planted with Jatropha. Considering the scale of the damage caused by these attacks in Bokhol, the development of an integrated pest management programme adapted to the local context should be considered. [less ▲]

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See detailIntérêts de mettre en place une filière courte basée sur la culture du jatropha (Jatropha curcas L.) dans la communauté rurale de Dialacoto
Barbier, Jérémy; Cissao, Malang; Tacourou, Bocar et al

Report (2012)

Opportunities to develop a local chain of production, transformation, and marketing based on jatropha cultivation were investigated from 2008 to 2012 in the rural community of Dialacoto (Tambacouda Region ... [more ▼]

Opportunities to develop a local chain of production, transformation, and marketing based on jatropha cultivation were investigated from 2008 to 2012 in the rural community of Dialacoto (Tambacouda Region, Eastern Senegal). The researches have mainly concerned how to integrate jatropha cultivation in existing cropping systems, the modalities to process the seeds with a manual Bielenberg press, and the opportunities for a local transformation and marketing of oil and oilcakes obtained by pressing seeds. The ways to integrate the cultivation of jatropha in the traditional farming systems were studied using two participatory investigation methods and by carrying out agronomic trials on experimental plots. An action research was conducted with three groups of six farmers in order to determine the best modalities of installation and maintenance of jatropha plants. The fields of 24 farmers where jatropha plants were installed as a sole crop, intercropped with cultivated annual plants, or as a living hedge were closely monitored. These fields were selected among the 295 plots that had been planted before or at the beginning of the project. Under the current conditions of remuneration of jatropha seeds in Senegal (65 Fcfa / 0,1 EUR kg-1 dry seeds), and given the low seed yield (less than 200 kg ha-1 for the best tended plots after five years) and the low precocity of the available planting material, the sole and the intercropping of jatropha is not profitable. The development of efficient intercropping systems adapted to the farmer's constraints seems possible, subject to the selection of varieties of jatropha both early and productive, and to an increase in the purchase price of the seeds. Substantial research involving directly the farmers remains to be carried out to develop these intercropping systems. The establishment of living hedges is for the moment the only installation method that can be recommended to farmers. In addition to providing supplementary income related to seed harvest, hedgerows provide different benefits appreciated by farmers: land demarcation, soil protection against wind and water erosion, improved soil water balance and windbreak effect favorable to crop development, crop protection against wandering ruminants, and enclosure for the cattle. These various benefits and the low risk taken by installing hedgerows explain that this method of planting was the most often selected spontaneously by farmers. The production cost of a liter of jatropha filtered oil using a Bielenberg press rises to 1056 FCFA (1.62 EUR). At such a cost, jatropha oil is not competitive compared to its direct use for diesel engines in rustic Lister type used to operate multifunctional platforms. The production of soap is the only local outlet with high potential for oil produced with a manual press. The price of locally produced soap with this oil is competitive compared to that of the industrial soap available on the market and its quality is highly appreciated by potential customers. The use of oil as a bio-pesticide and as fuel for lighting could be interesting opportunities but further investigations are needed to confirm this. This applies also to the use as fertilizer of the oilcakes produced by pressing seeds. [less ▲]

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See detailPrincipes toxiques, toxicité et technologie de détoxification de la graine de Jatropha curcas L. (synthèse bibliographique)
Nesseim, Thierry Daniel Tamsir; Fillet, Marianne ULg; Mergeai, Guy ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 531-540

The use of meal from the crushing of Jatropha curcas seed for livestock feed is limited owing to the variable amounts of seed available. This availability depends on the level and variety of toxic and ... [more ▼]

The use of meal from the crushing of Jatropha curcas seed for livestock feed is limited owing to the variable amounts of seed available. This availability depends on the level and variety of toxic and antinutritional compounds contained in the seed at a given time; the most important of these compounds are phorbol esters and curcin. The phorbol esters present in J. curcas seed are euphorbiaceae diterpenes, known for their inflammatory action resulting in irritation and toxicity to insects, fish and mammals. These compounds are sometimes completely degraded in soil and they may be reduced by physical, chemical or biological processes, with a reduction ratio of between 50 and 95%. Curcin is an irritating toxalbumin with lectin activity; it is inactivated by heat treatment at 121 °C for 30 min. Other antinutritional compounds are also present in J. curcas seed, such as saponins and an inhibitor of trypsin activity. This trypsin-inhibiting compound interferes with the digestion process and its reduction is achieved through thermal, chemical or biological treatments. The elimination of, or at least a reduction in the levels of, these molecules represents a rerequisite for using J. curcas meal in the livestock feed sector. [less ▲]

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See detailScaphandre La science rencontre l'art: L'art
Haubruge, Eric ULg; Bay, Daniel ULg; Semal, Jean et al

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

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