scholarly journals Relationship between the Intensity of Latex Harvesting and the Tapping Panel Dryness Expression of Clone GT 1 of Hevea brasiliensis Muell Arg in South-East Côte d'Ivoire

Author(s):  
Obouayeba Samuel ◽  
Konan Djezou ◽  
Diarrassouba Moussa ◽  
Lehi Malidy Irénné ◽  
Koffi Antoine ◽  
...  

Tapping panel dryness is an important limiting factor in rubber productivity of Hevea brasiliensis. In order to assess the sensitivity to this syndrome, the effect of two intensive latex harvesting technologies on moderately metabolized GT1 clone, has been studied in the South-Eastern region of Côte d'Ivoire. The rubber trees were planted according to the experimental mono-tree device, "One tree one plot design" a tree constituting a repetition, and 31 trees per treatment, selected on circumference and health status criteria. The parameters measured were rubber production, circumference increase, physiological profile and tapping panel dryness sensitivity. The results showed that induction of tapping panel dryness in latex harvesting system, S/2 d/3 6d/7 ET 10 % Pa 1 (1) 1/ w) was significantly low (0.18 ± 0,22 %) than that of the control (S d/1 6d/7 unstimulated, 1.43 ± 1.45 %). Productivity of this particular system was also good (62 ± 16.32 g.a-1.s-1) and it especially has less stress that can cause physiological fatigue, or even the notch dry. Otherwise, Rubber production, radial vegetative growth, physiological parameters of the latex and the tapping panel dryness rate were influenced by the two treatments applied to GT 1. In addition, the medium and high sucrose contents (16.5 ± 3.01%) and thiol group (0.51 ± 0.13 mmol.l-1) of the latex in the treatment (S/2 d/3 6d/7 ET 10% Pa 1 (1) 1 / w), were instrumental in the response to this stimulation. The sensitivity to the tapping panel dryness is in very close linear relation with the harvest intensity of the latex to which the GT 1 clone has been subjected. These results corroborate and confirm the moderate sensitivity to the tapping panel dryness of GT 1 clone.

Author(s):  
A. P. Moro ◽  
B. Y. C. Adou ◽  
M. Diarrassouba ◽  
D. Konan ◽  
E. F. Soumahin ◽  
...  

The downward tapping on virgin bark of the lower panel (BO) is immediately followed by the upward tapping on virgin bark of the upper panel (HO), consecutively. To determine the agro-physiological advantages of one tapping over another, a study of the downward and upward tapping of the GT 1 and PB 260 clones of Hevea brasiliensis was carried out in southwestern Côte d'Ivoire. For this purpose, the rubber trees were tapped in a downward half-spiral (S/2) at the opening for nine consecutive years, followed by upward quarter-spiral tapping (S/4U) for four consecutive years. The agronomic parameters (rubber production and vegetative growth), tapping panel dryness and the latex micro-diagnosis, were evaluated. For GT 1 clone, the transition from the downward tapping panels to the upward tapping panels resulted rubber productivity gain of 35%. Meanwhile for PB 260, rubber productivity gain was 37%. Regardless of the clone and tapping direction, the higher the rubber productivity of a respective tapping panel, the lower the isodiametric growth of the tree trunk was recorded. Latex harvesting systems, and clone’s combination, did not influence the tapping panel dryness or the physiological profile of the trees. Finally, it should be concluded that upward tapping is more productive than downward tapping, but the quantification of the gains in this rubber production depends on the clone.


2018 ◽  
Vol 14 (33) ◽  
pp. 369
Author(s):  
Ballo Esperence Kouadio ◽  
Soumahin Eric Francis ◽  
Ballo Koffi Celestin ◽  
Elabo Agnyman Eliathe Angeline ◽  
Adou Bini Yao Christophe ◽  
...  

Land preparation method and preceding crops affect the evolution of rubber trees. Its ignorance and/or poor execution do not allow the efficient development of the agronomic and economic potentialities of plantations. In order to remove this constraint, a study was undertaken in southwestern Côte d'Ivoire. The rubber trees were planted at 510 trees/ha according to a Fisherblock experimental design, of six preceding crop treatments with three repetitions. Only one latex harvesting system was applied (S/2 d/4 6d/7 ET 2.5% Pa 1 (1) 6/y). The parameters measured were rubber yield, annual average girth increment, physiological profile, sensitivity to tapping panel dryness and sensitivity to root rot caused by the genus Fomes. The results showed that the rate of rubber trees found in the plots was good (90.73± 0.47 %) and had varied with land preparation method depending on the preceding crops. Vegetative growth at tapping (2.05±1.36 cm.year -1 ), and average rubber yield (2053±179 kg.ha-1 .year -1 ) and the rate of tree loss due to the genus Fomes (8.33±0.42%) were influenced by land preparation method. The good productivity, the good physiological state of the rubber trees were characterized by a well balanced physiological profile and a tapping panel dryness rate (3.60 ± 1.74%), independently of treatments. The Agroeconomic results showed that mechanically prepared fallow (813641 FCFA.ha-1 .year -1 ) was the best preceding crop and land preparation method. This technical result has two main interests for the national rubber-growing industry, since it actively participates in the national policy for fighting against deforestation but also contributes to the establishment of a secondary forest by the attributes of the rubber-growing plant cover.


Author(s):  
M. J. Mangoua ◽  
K. A. Kouassi ◽  
G. A. Douagui ◽  
I. Savané ◽  
J. Biémi

This study is carried out in the Baya watershed in the eastern region of Côte d'Ivoire to highlight access to drinking water issue in the fratured areas of Côte d'Ivoire. It aims at mapping the groundwater reservoirs to optimize the future installment of new boreholes for a satisfactory success rate. For the methodological approach we use Landsat 7 satellite images to map fracture networks with the use of the directional filtering technique. The induced permeabilities from these fractures were calculated using Fanciss’s method. The multicriteria analysis and Hydrogeological Information System with Spatial Reference were adopted to map groundwater reservoirs. Structural mapping by remote sensing permitted the development of detailed fractures maps with more than 6,998 listed fractures responsible for the formation of fracture aquifers in the Baya watershed. The size of these fractures is spread over two orders of magnitude. The main orientations are NE-SO (N70-80), corresponding to the Eburnean orientations, E-O (N90-100) and NO-SE (N100-120), associated with the Liberian orientation. Induced permeabilities vary from 1.20.10-8 to 4.62.10-5 m/s with a regional average of about 5.32.10-6 m/s. The zones with strong induced permeabilities that coincide with those of high fracturing densities brought us to have five reservoirs in the basin, with two large reservoirs, two media and three small ones. This groundwater flows into the mainstream waters from two main directions.


2019 ◽  
Vol 133 (1) ◽  
pp. 13516
Author(s):  
Kouadio Espérence Ballo ◽  
Francis Eric Soumahin ◽  
Jean Lopez Essehi ◽  
Justin Yatty Kouadio ◽  
Samuel Obouayeba

2013 ◽  
Vol 317 (317) ◽  
pp. 51 ◽  
Author(s):  
Aurélien Masson ◽  
Jean-Marc Julien ◽  
Luc Boedt

L'importance de l'hévéa (caoutchouc), Hevea brasiliensis, en tant que culture de rente ne cesse d'augmenter justifiant de s'intéresser à de nouvelles techniques de clonage plus efficaces que le greffage (écussonnage) traditionnellement utilisé pour la production industrielle de matériel de plantation de qualité supérieure. Les bonnes performances sur le terrain (croissance rapide, haut rendement) des hévéas produits par embryogenèse somatique n'ont été constatées jusqu'à présent qu'à l'échelle expérimentale. La propagation de masse in vitro par embryogenèse somatique ou microbouturage de clones d'hévéas sur leurs propres racines reste pénalisée par un manque de réactivité de la plupart des génotypes sélectionnés et par des coûts de production prohibitifs. Face à cette situation, la propagation par bouturage de clones matures sélectionnés issus de micropropagation in vitro a été tentée par la SoGB en Côte d'Ivoire comme une alternative possible à l'utilisation exclusive des techniques in vitro. Les deux clones matures industriels, A (70 ans) et B (53 ans), ont d'abord été rajeunis in vitro par embryogenèse somatique puis micropropagés en plus grand nombre par microbouturage. Après acclimatation, les microboutures enracinées in vitro ont été rempotées dans des pots individuels pour être gérées de manière intensive comme pieds-mères destinés au bouturage. Après 3 semaines en conditions horticoles adéquates, les taux d'enracinement obtenus pour les boutures des clones A et B ont été respectivement de 74,6 % (1203/1613) et 76,5 % (198/259). Les racines adventices néoformées étaient généralement vigoureuses. A l'issue d'une phase d'acclimatation réussie, les boutures se sont développées de façon conforme pour atteindre 4 mois plus tard une hauteur de 25-30 cm suffisante pour être plantées au champ. En sus d'une plus grande vigueur et conformité sur le terrain, les clones issus de bouturage peuvent être produits plus rapidement, sur des surfaces plus réduites à moindre coût et dans des conditions de travail plus faciles par rapport aux plantes issus d'écussonnage. Des analyses en cours devraient permettre d'établir les avantages comparatifs des boutures par rapport aux plants écussonnés en ce qui concerne d'autres caractères à fort impact économique tels que le rendement de latex.


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