The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with active or rapid metabolism (IRCA 18, IRCA 130, PB 235, PB 260 and PB 330), six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1 .y -1 ) with good radial vegetative growth (2.9 cm.y -1 ). Their trees show a wellbalanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies " S/2 d3 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 4/y " for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.

The classic latex harvesting system consists of top-down tapping for nine years before being immediately followed by reverse tapping. This period is often considered too long by the farmers. To address this concern, a study was conducted to determine the best period for down tapping to ensure good performance of agrophysiological parameters in reverse tapping of fast metabolising rubber clones. For this purpose, the PB 260 and IRCA 18 clones were used as plant material in Divo and Daoukro respectively, where the experiments were conducted. Five time frames for down-bleeding (5, 6, 7, 8 and 9 years = control) and two concentrations of ethephon (ET) stimulating paste (2.5 and 5% ET), except for the control which is stimulated only at 5% ET, were tested. The experimental design was a Fisher block design with 9 treatments and 4 replicates. Rubber productivity results (5262 ± 205 and 4951 ± 351 kg.ha-1.yr-1) showed that reverse tapping of these metabolically active clones preceded by 5 and/or 6 years of down tapping was the best (3723 ± 29 kg.ha-1.yr-1 ; control). Rubber production and average annual increment from these tapping periods (4.00 ± 0.42 and 3.60 ± 0.00 cm.yr-1 ; control) were the highest. Productivity gains were 41% for reverse tapping at 6 years stimulated at 5%. The dry notch rate was relatively low (3.30% LEM and 0% dry trees). The physiological profile was generally good. These results indicate that downward bleeding for 5 and/or 6 years allows these clones to express their best potential in reverse bleeding. These results are satisfactory and respond exactly to the concerns of the farmers.

The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with low or slow metabolism, six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1 .y-1 ) with good radial vegetative growth (2.9 cm.y -1 ). Their trees show a well-balanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies "S/2 d3 6d/7 Pa1(1) ET2.5% 4/y, S/2 d4 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 8/y” for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.

Aims: Rubber tree (Hevea brasiliensis Muell Arg.) is the main source of natural rubber. Its cultivation generates significant income for several companies and farmers around the world. However, its exploitation is threatened by the considerable drop in rubber yield which is due to the ignorance of tapping criteria in particular the optimal tapping depth. This study aims at improving rubber yield. Place and Duration of Study: The study was carried out in agro-industrial plantations of rubber tree in southeastern Côte d'Ivoire from June 2020 to January 2021. Methodology: The study took place in two phases: the first consisted in assessing the tapping depth of the plantations and the second in studying the influence of the different tapping depths on rubber yield and tapping quality. The first study was carried out with 347 tappers in 954 tapping tasks. The second study focused on 4 rubber tree clones (PB217, IRCA 41, IRCA 230 and IRCA18) belonging to the three metabolic activity classes. These clones were subjected to 4 treatments (T0: tapping to a depth of 0 to 1.5 mm; T1: tapping to a depth of 1 to 2 mm; T2: tapping to a depth of 1 to 1.5 mm, T3: tapping to a depth of 1.5 to 2 mm) in a completely randomized block design with 4 repetitions. This comparative study was carried out on the basis of yield and tapping quality parameters (bark consumption, wounds). Results: The results of the first study showed that the average tapping depth of the plantations inspected is 1.44 mm in half-spiral downward tapping and 1.82 mm in a quarter-spiral upward tapping. The tapping depth is influenced by the height of the tapping panel and by the clone. The results of the second study showed that tapping depth influences rubber yield and tapping quality. Indeed, tapping to a depth between 1 and 1.5 mm from the cambium induces the most significant yields but causes poor tapping quality. In contrast, tapping to a depth between 1 and 2 mm from the cambium gives lower yields but makes it possible to show better tapping quality. Conclusion: The tapping depth is influenced by the height of the tapping panel and by the clone. The tapping depth influences rubber yield and tapping quality.

Since the early 2000s, pineapple from Côte d’Ivoire has suffered a discount in its marketing due to the heterogeneity of the quality of its fruit and the arrival of MD2 on the international market. In order to help pineapple from Côte d'Ivoire once again win back the international market, Ananas comosus hybrids with an early natural coloring have been developed at the CNRA. The agronomic performances of these hybrids were tested at the research station of Anguédédou. Vegetative characteristics such as plant fresh mass, stem fresh and dry mass, number of leaves generated and leaf D fresh mass of these hybrids H1, H2, H3 and H4 were compared to those of cultivars Smooth Cayenne and MD2 at 2, 4 and 6 months. The results obtained showed no statistically significant difference in plant mass between hybrid H4 (2675 g) and cultivars MD2 (2645 g) and Smooth Cayenne (2763 g) after 6 months of planting. The fresh and dry mass of the stems of these three varieties were also statistically identical. Hybrid H4 leaf D fresh mass was very low (55 g) at six months of planting compared to the two cultivars (73 g each). Hybrids H2 and H3 at this same period gave leaf masses of over 80 g. Regarding the characteristics assessed, hybrids H4 and H3 had much more conformity with cultivars Smooth Cayenne and MD2.