Agronomic Potential of Some Rubber Tree Clones (Hevea brasiliensis) of the Fast Metabolic Activity Class in the Absence of Hormonal Stimulation in Southwestern of Côte d’Ivoire

Abstract

Fast-metabolism clones of rubber tree (Hevea brasiliensis) are appreciated for their good agronomic performance with little hormonal stimulation, due to their high intrinsic metabolic activity. They are highly demanded and therefore exposed to a significant risk of overexploitation. In order to solve this problem, a study was carried out in a completely randomized design with clones IRCA 111, IRCA 130 and PB 260 planted at a density of 510 plants/ha in southwestern of Côte d’Ivoire for nine years. A single tapping system, that is every four days (d4) with different hormonal stimulation regimes (0/y; 2/y; 4/y; 6/y; 8/y; 13/y; 18/y; 26/y and 39/y), was applied to all treatments. The parameters measured in rubber trees were rubber yield, radial vegetative growth, physiological profile and sensitivity to tapping panel dryness. The results indicated that non-stimulated rubber trees of clones IRCA 111 and IRCA 130 showed the best rubber yields while two annual stimulations were necessary for clone PB 260. Moreover, the lack of hormonal stimulation had no negative impact on the vegetative growth, physiological profile and sensitivity to tapping panel dryness of the rubber trees. Clones IRCA 111 and IRCA 130 can therefore be tapped in S/2 d4 without hormonal stimulation.