Drivers of conservation and utilization of pineapple genetic resources in Benin

Valuation of farmer knowledge has been seen as a route to promote sustainable use of plant genetic resources. In pineapple production systems in Benin, inadequate knowledge of cultivation practices can lead to a number of inconveniences including abandon of some varieties and cultivars. To understand how farmers' knowledge and cultivation practices impact the sustainable utilization of pineapple genetic resources, we surveyed 177 pineapple farmers in southern Benin. We assessed farmers' knowledge and analyzed the relationship between their knowledge and factors such as age, education, and locality of provenance. Pineapple production system was dominated by men (96% respondents). According to farmers, Smooth cayenne is international market-oriented while Sugarloaf mainly targets domestic and regional markets. All farmers recognized that Smooth cayenne provided more income (USD 5,750/ha) than sugarloaf (USD 3,950/ha) in the production systems of southern Benin. The high value of median scores in comparison with the range of possible score showed that most farmers agreed and shared relatively similar knowledge. Correlation matrix and multiple linear regressions showed a significant relationship between farmers'practices and their knowledge of the plant; their knowledge of pineapple varieties is based on fruits traits. Also, farmers' knowledge was associated with locality of provenance. Constraints and options for genetic resources conservation and utilization in the pineapple production systems in Southern Benin were discussed based on current knowledg

Effect of two cytokinins in combination with acetic acid α-naphthalene on yams (Dioscorea spp.) genotypes’ response to in vitro morphogenesis

The effect of two growth regulator combinations was studied on the morphogenesis in vitro of 3 genotypes of yams (Kounondakou, Gnon-boya and RB 89579). Benzyl aminopurin (BAP) and zeatin (ZEAT) were tested, respectively at a concentration of 0.5 mg/l with the galzy glutamine basic medium containing naphtalene acetic acid (NAA) (0.5 mg/l). Stem fragments were used as explants. The number of stripped buds and explants having stem and roots are sampled after 2 weeks in culture. The dry matter content, the number of roots and leaves and the height of each young sprout were determined after 5 weeks in culture. The results obtained indicated that no break in leaf growth was observed on the control medium (without cytokinin) but media with BAP and zeatin presented a good plants aerial part development. A significant interaction (p < 0.05) was observed between the genotypes and the typeof cytokinin. However, the highest bud sprouting and shoot development were obtained with BAP. Thus, BAP can be considered as cytokinin having a good morphogenic aptitude when compared to zeatin for yam micropropagation.Keywords: Cytokinin, auxin, morphogenesis, yam, Beni

Effets de différentes combinaisons hormonales sur l’organogenèse in vitro de quelques cultivars locaux et variétés améliorées de Manihot esculenta Crantz (manioc-Euphorbiaceae) cultivées au Bénin

Manihot esculenta (Euphorbiacee) est une plante a racine amylacee dfune grande importance economique. La multiplication par voie vegetative bien que favorisant une grande homogeneite genetique demeure le principal facteur dfattaque par les ravageurs. Ce travail vise a analyser les effets de differentes combinaisons hormonales sur lforganogenese in vitro de quelques cultivars locaux et varietes ameliorees du Benin. Les microboutures uninodales sont desinfectees et mises en culture dans les milieux de base MS (Murashige et Skoog) additionnes de differentes combinaisons de regulateurs de croissance : ANA (acide naphtalene ƒ¿-acetique); (BAP) (benzylaminopurine); kinetine. Les effets des differentes combinaisons ont ete etudies sur les parametres de croissance apres huit semaines de culture. la combinaison (MS+ANA) a permisdfobtenir les moyennes les plus elevees de caulogenese (8,62}0,8 cm) et de phyllogenese (5,5}0,3) chez le cultivar Ahouandjan, alors que la combinaison (MS+KIN) a donne lfeffet contraire chez la variete 92/0057avec une hauteur (0,14}0 cm) et une phyllogenese (1,30}0,1) . Le nombre moyen eleve de racines formees (4,0}0,5) a ete obtenu chez le cultivar Agric Sazoue sur la combinaison (ANA+KIN) pendant qufon obtenaitla longueur moyenne la plus elevee de racine chez le cultivar Ahouandjan (6,30}0,7 cm) sur le milieu (MS+ANA). Ces resultats permettront dfameliorer les techniques de production de vitroplants utilises poursemence

Gestion traditionnelle et statut des ressources génétiques du sorgho (Sorghum bicolor L. Moench) au Nord-Ouest du Bénin

Le sorgho, Sorghum bicolor (L.) Moench, est une importante ressource alimentaire au Bénin. Sa culture est essentiellement pratiquée au centre et au nord du pays. Afin de mieux comprendre le niveau de diversité et les systèmes traditionnels de gestion et de conservation des variétés locales cultivées au Nord-Ouest du pays, une enquête basée sur une approche participative de recherche a été conduite dans 13 villages régulièrement distribués dans la zone. Au total, 45 variétés locales (61 noms vernaculaires) ont été inventoriées, présageant d’une grande diversité génétique du sorgho dans le milieu. Le nombre moyen de variétés locales inventoriées est de cinq par village et de deux par ménage. La distribution des variétés à travers la zone d’étude a été déterminée et les principaux facteurs y afférant étudiés. La couleur des grains, la durée du cycle végétatif ou la valeur marchande sont les plus importants critères utilisés par les producteurs pour la dénomination, l’identification, la classification et la sélection des variétés. Les systèmes traditionnels de sélection et de gestion des semences varient substantiellement d’un village à un autre et d’une ethnie à l’autre. Aussi, l’étudea-t-elle révélé l’existence dans certains villages d’une menace de disparition des variétés à cycle végétatif long et à grains blancs. Des efforts concertés devraient donc être déployés pour la valorisation et la préservation des ressources génétiques de cette céréale afin d’accroître sa production pour une meilleure sécurité alimentaire au Bénin.Mots clés: Bénin, diversité variétale, conservation, Sorghum bicolo

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

PRODUCTION ET ACCLIMATATION DE PLANTS DU GROS BASILIC (OCIMUM GRATISSIMUM) REGENERES IN VITRO : EFFET DE L’ACIDE NAPHTALENE ACETIQUE (ANA) SUR L’ENRACINEMENT

The present work aims to study the effect of Naphthalene Acetic Acid (NAA) on the rooting and acclimatization of Ocimum gratissimum plantlets. The cutting contain one knot (Explants) used are from the plantlets of first generation R0 of Ocimum gratissimum in the stage of multiplication and aged between 4 and 6 weeks. Explants (1cm) were inoculated on half Murashige and Skoog (MS/2) supplemented with 20g/L of sucrose and 7g/L of agar with different concentrations of Naphthalene Acetic Acid NAA (0; 0.5; 1 and 2mg/L) for root induction. After eight (8) weeks of culture, the rooting rate, the number of roots formed and the length of the primary root is determined by counting of roots by plantlets and the measuring of root length is made by a ruler. The experimental design was constituted of four tests with two repetitions. Each test includes 15 tubes represented treatments. The results showed that MS medium diluted to half and supplemented with 2mg/L NAA supports the root induction (4.70±0.5) while that with 1mg/L of NAA has produced the lowest average of roots (2.70±0.5). In acclimatization, 80% of rooted plants are able to survive. The conditions for successful rooting techniques in vitro under the effect of NAA (2mg/L) followed by the production of acclimated plants can be used for other research work on essential oils from plantlets of the specie studied

Hormonal influence on the in vitro bud burst of some cassava varieties and accessions from Benin

This work tested the effect of different growth regulators on Manihot esculenta explants cultured. Nodal segments were disinfected and cultivated on Murashige and Skoog’s basal media. The effects of the different combinations on bud burst were observed after five weeks of culture. The results show an interaction between the growth regulators and the genotypes of the varieties and accessions. Most of the varieties and accessions (Gbèzé, Kpètévikoutou, Ibadan and Sèkandji) obtained the maximal bud burst in the media MS supplemented with 0.2 mg/l BAP and MS supplemented with 0.2 mg/l KIN. However, with segments cultivated in medium, containing 0.2 mg/l KIN, 1 in 15 showed bud burst for the accession Agric Comé. Naphthalene acetic acid effect varied according to the genotype and the cytokinin used, whereas on 0.1 mg/l NAA combined with 0.2 mg/l with the variety 92/0057, 14 in 15 budded. However, no bud burst was observed with 0.1 mg/l NAA combined with 0.2 mg/l BAP.Keywords: In vitro culture, Manihot esculenta Crantz, bud burst, NAA, BAP, KinetinAfrican Journal of Biotechnology Vol. 12(13), pp. 1475-148

EFFET DU CHARBON ACTIF SUR LA CONSERVATION DE LA VARIETE DE MANIOC (MANIHOT ESCULENTA) RB 89509 MENACEE D’EXTINCTION AU BENIN.

In situ conservation of different cultivars of cassava (Manihot esculenta) implies many problems such as climatic risks, diseases, devastators and financial difficulties. This work contributes to the maintenance of RB 89509 variety of Manihot esculenta through in vitro culture. Two cultures media were used: medium of Murashige and Skoog (MS) and medium of Murashige and Skoog (MS) added with activated carbon. The effects of activated carbon were studied on the growth parameters (number of leaves, number of roots, number of nodes, height of stem, length of internodes, length of principal root) of plantlets aged of twenty months. The results show that the average number of leaves, the average number of nodes and the length of main root are more significant at the plantlets present on medium containing the activated carbon; while the number of roots, the height of stem and the length of internodes are more significant at the plantlets present on medium without activated carbon. Moreover, it is noted an drying of the plantlets on the medium without activated carbon. The activated carbon allowed a better conservation of the plantlets