Effect of Exogenous Hormonal Stimulation on the Metabolic Partition between Plant Growth and Rubber Production of Hevea brasiliensis Clones According to the Class of Metabolic Activity in Cote d'ivoire
Lehi Malidy Irénée *
Laboratory of Biotechnology, Agriculture and Resource Development, UPR of Plant Physiology, Option Agrophysiology, Faculty of Biosciences, Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire and African Centre of Excellence - Climate Change, Biodiversity and Sustainable Agriculture (CEA-CCBAD), Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire.
Konan Djezou
CNRA (Centre National de Recherche Agronomique), Station de Recherche de Bimbresso, 01 BP 1536 Abidjan 01, Côte d'Ivoire.
Okoma Koffi Mathurin
CNRA (Centre National de Recherche Agronomique), Station de Recherche de Bimbresso, 01 BP 1536 Abidjan 01, Côte d'Ivoire.
Yoboue Ange Naté
Laboratory of Biotechnology, Agriculture and Resource Development, UPR of Plant Physiology, Option Agrophysiology, Faculty of Biosciences, Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire.
Konan Kouakou Séraphin
Laboratory of Biotechnology, Agriculture and Resource Development, UPR of Plant Physiology, Option Agrophysiology, Faculty of Biosciences, Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire and African Centre of Excellence - Climate Change, Biodiversity and Sustainable Agriculture (CEA-CCBAD), Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire.
Zouzou Michel
Laboratory of Biotechnology, Agriculture and Resource Development, UPR of Plant Physiology, Option Agrophysiology, Faculty of Biosciences, Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire and African Centre of Excellence - Climate Change, Biodiversity and Sustainable Agriculture (CEA-CCBAD), Félix Houphouët-Boigny University, 22 B.P. 582 Abidjan 22, Côte d'Ivoire.
Obouayeba Samuel
CNRA (Centre National de Recherche Agronomique), Station de Recherche de Bimbresso, 01 BP 1536 Abidjan 01, Côte d'Ivoire.
*Author to whom correspondence should be addressed.
Abstract
Aims: In order to achieve a good and sustainable harvest of Hevea brasiliensis rubber, the effect of exogenous hormonal stimulation on the metabolic partition growth-production of clones according to the class of metabolic activity was made.
Place and Duration of Study: The study was conducted for 9 years in the San-Pedro region in south-west Ivory Coast, precisely in the experimental industrial plantations of the former HEVEGO, now Southwestern Agricultural Civil Society Société (SCASO).
Methodology and Results: The rubber trees were planted at a density of 510 trees/ha in a completely randomised system. They were bled in S/2 d4 and stimulated to 2.5% Etephon at annual frequencies of 0, 1, 2, 4, 6, 8, 13, 18, 26, 39 and 78. The parameters measured were rubber production, trunk circumference, sucrose content, inorganic phosphorus, thiol groups and dry notch rate. The results showed that productivity increased with the intensity of stimulation (58.96 - 68.49 g.a-1.s-1 ; 39.83 - 66.69 g.a-1.s-1) over the intervals [0.6] and [0.26] stimulations respectively in clones with active and slow metabolism. The circumference of the trunk was marked by a less pronounced decrease in growth in slow metabolizing clones (0.52%) with good protection of the laticigene system (R-SH : 0.815 mmol.l-1) and low sensitivity to dry notching (1.6). Whatever the classes of metabolic activity of the clones, the agrophysiological parameters were strongly correlated with each other by a degree 2 polynomial function.
Conclusion: This polynomial function seems to reflect the existence of a good state of equilibrium between laticigenic metabolism and vegetative growth according to the class of metabolic activity of the Hevea brasiliensis clones.
Keywords: Hevea brasiliensis, vegetative growth, rubber production, stimulation, metabolic class of the clones.