In order to evaluate the improvement of rubber productivity of rubber trees by late upward tapping. A study was conducted at SCASO (Société Civile Agricole du Sud-Ouest) on the PB 260 clone of the active metabolic class. The experimental set-up is a Fisher block design with eight treatments and three replications. The treatments compared were bled in reverse in the eleventh year of harvest, in quarter spiral every 3, 4, 5 and 6 days, with stimulation frequencies of 6, 8, 10, 12 and 13 times a year. The parameters measured were rubber production, isodiametric growth, sensitivity to dry notching of trees and physiological profile. The results show that the different latex harvesting technologies improve the rubber productivity of PB 260 (5469 kg.ha-1.yr-1) with a low dry-nut rate (1.2%) and satisfactory radial vegetative growth (3.9cm.yr-1). The physiological profile of the trees is balanced, but the treatments significantly influenced the different parameters except sucrose. Trees bled in S/4U d3 gave better results due to their high yield with an acceptable dry notch rate. Late reverse tapping is therefore a good latex harvesting technology for improving rubber productivity after down tapping.

No abstract

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.

Aims: It was aimed to investigate the relationship between two climatic parameters, temperature and relative humidity, and the flower-cutting interval of mangoes tree cv. Kent Study Design: The experimental design used was the completely randomized design with triplicate.

Resistance to internal browning of pineapple fruits depends on several factors such as the cultural techniques through mineral fertilization. The objective of this work is to study the effects of the potassium fertilization for pineapple on internal browning of fruit in post-harvest conservation. The experiments have been carried out on the site of the University Nangui Abrogoua (Abidjan, Côte d’Ivoire) of July 2015 to the end of October 2016. Potassium has been applied according to four modalities of treatments (T0; T1; T2 and T3) made in 2nd, 4, 6 and 7th months (respectively) after plantation. The incidence of internal browning (IB), the phenolic content, sugars and ascorbic acid have been determined after post-harvest conservation of fruit. The activity of phenolic biosynthesis enzymes (PAL and TAL) and oxidation enzymes (PPO and POD) were evaluated. The results showed that BI intensity in pineapple fruit decreases with the potassium amount applied in field. This IB drop was correlated with the content of reducing sugars, total phenols, activity of PAL and the PPO. No symptom of IB was observed on pineapple fruits under treatment T2 (34 g of K2O/plant). Potassium has a depressive effect on phenolic biosynthesis. In effect, it inhibits the IB in the both varieties of pineapple studied that are Smooth Cayenne and MD2.