Efficacité et Rentabilité de L’utilisation du Compost à Base de Fiente de Poulet dans la Production de Plants d’hévéa de Pépinière en Sac

La raréfaction du terreau, horizon humifère de surface, qui constitue le substrat de culture pour la production des plants d’hévéa en sac, amène les pépiniéristes d’hévéa à recourir à divers types de fertilisants dont le compost, pour améliorer la croissance des plants. Cependant, très peu d’études ont été consacrées à l’évaluation de l’effet de l’utilisation du compost en pépinière d’hévéa. Cette étude a été initiée en vue d’évaluer les effets de l’utilisation du compost à base de fient de poulet sur la production et la rentabilité de plants d’hévéa en pépinière dans les zones agro-écologiques du sud-est et du centre de la Côte d’Ivoire. Le dispositif expérimental utilisé est un bloc complet randomisé à six milieux de culture (substrats + fertilisants) répétés trois fois. Des données agronomiques et du calcul économique du rendement ont été collectés et analysés. Les résultats obtenus en station et milieu paysan, ont montré que l’utilisation des substrats de culture à base de compost favorise une nette amélioration de la croissance des plants d’hévéa avec de faibles doses de compost comparativement au substrat témoin, non fertilisé. Sur les deux sites d’étude, la production des plants d'hévéa a été optimale et économiquement rentable avec la dose de compost de 300 g/plant, au sud-est et la dose 300 g/plant combinées à l'application fractionnée de 2 ; 3,5 et 5 g d’urée, au centre de la Côte d’Ivoire. Cependant, les doses plus élevées de compost (600 g/plant) ont eu un effet dépressif sur la croissance végétative des plantes d'hévéa, quel que soit le site. Les faibles doses de compost à base de fiente de poulet de 300 g/plant combinées ou non à l'application fractionnée d'urée peuvent donc être, dans les conditions de la présente étude, recommandées pour une production rentable de plants d’hévéa de pépinière en sac.   The scarcity of topsoil, the humus-bearing surface horizon that constitutes the substrate for the production of bagged rubber tree nursery, has led rubber nurserymen to resort to various types of fertilizers, including compost, to improve seedling growth. However, very few studies have been conducted to evaluate the effect of compost use in rubber nurseries. This study was initiated to evaluate the effects of using chicken manure-based compost on the production and profitability of rubber seedlings in nurseries in the agro-ecological zones of southeastern and central Côte d'Ivoire. The experimental set-up used is a complete randomized block with 6 growing media (substrates + fertilizers) repeated in 3 times. Agronomic data and economic yield calculations were collected and analyzed. The results, obtained on station and on-farm, showed that the use of compost-based substrates favored a clear improvement in the growth of rubber seedlings with low doses of compost compared to the unfertilized control substrate. At both study sites, rubber plant production was optimal and economically profitable with the 300 g/plant compost dose in the southeast and the 300 g/plant dose combined with the split application of 2, 3.5 and 5 g urea in central Côte d'Ivoire. However, the higher doses of compost (600 g/plant) had a depressive effect on vegetative growth of rubber plants at all sites. The low doses of chicken droppings-based compost of 300 g/plant combined or not with the fractional application of urea can thus be, under the conditions of the present study, recommended for a profitable production of bagged rubber tree nursery plants

Production Systems to Minimize the Latex Harvesting Cost of Rubber (Hevea brasiliensis)

Latex harvesting is the most costly activity in natural rubber production and the shortage of available skill and unstable latex harvester are the main factor affecting in Rubber cultivation and its lead to increase cost of production. Low frequency system (LFT) with the hormonal stimulation is a solution to solve this problem that minimize the cost of latex harvesting. Therefore, a study was conducted for nine years on production systems that minimize the cost of latex harvesting in southwestern Côte d'Ivoire with clones IRCA 130, GT 1 and PB 217 of Hevea brasiliensis. These production systems differ from each other by an increase in tapping frequency, in comparison with the standard tapping (d3) on the above clones in southwestern Côte d'Ivoire. The results indicated that production systems that minimize the cost of latex harvesting admittedly resulted in losses of rubber yield per hectare per year from 1 to 37%, but improved the yield per tree per tapping as well as the productivity of the tapper from 20 to 46%, in year. Moreover, these systems contributed to the improvement of the vegetative growth of trees and kept the rate of dry trees in low level (less than 7%). Furthermore, these systems also helped to reduce the cost of tapping labor from 1 to 50%, as well as operating costs from 2 to 47%, in comparison with European Scientific Journal October 2018 edition Vol.14, No.30 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 191 the standard tapping (d3). Finally, in the context of a shortage of tapping labor, these systems help increase the farmer’s profit margin from 26% to 113%, as well as the tapper’s income from 26% to 89%. Therefore, it appears that the use of low frequency harvesting system with the appropriate stimulants appears as a solution to minimize latex harvesting cost and unavailability of harvesters in rubber cultivation

Influence of Carbohydrates on Callus Proliferation During Somatic Embryogenesis in Pineapple [Ananas Comosus (L.) Merr. (Bromeliaceae) Var. Cayenne Smooth Cultivar CI 16]

The improvement of pineapple (Ananas comosus var. Smooth Cayenne) by means of in vitro culture is less studied in Côte d'Ivoire despite the importance of this plant for this country’s economy. Our work consisted in highlighting nature and concentration effects of carbohydrates on the proliferation of calli in pineapple as a prelude to efficient embryogenesis. Callus proliferation was carried out from the base of pineapple vitroplants leaves. Thirty (30) explants were cultured on the tested culture medium. MS medium (micro- and macro elements of Murashige and Skoog) supplemented with vitamin Gamborg B5 was used as base medium to which were added 0.05 mg/L BAP, 3 mg/L picloram, 2 mg/L glycine, 1,000 mg/L glutamine, 100 mg/L casein hydrolyzate and 30 g/L carbohydrate. Sucrose was tested at different concentrations (20, 25, 30, 35 and 40 g/L). The results revealed that callus proliferation is strongly influenced (p ˂ 0.0001) by nature and concentration of carbohydrate. Sucrose with the highest dry matter content (61.34 mg) has a higher callogenic potential than the other studied carbohydrates. The concentration of 30 g/L sucrose significantly improved the calli proliferation in pineapple. Galactose and maltose were less favorable to proliferation

Effect of different preceding crops and land preparation methods on the agrophysiological and health parameters of Hevea brasiliensis Muell. Arg clone GT 1 in southwestern Côte d'Ivoire

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

Variation des Composés Phénoliques suite à l’Elicitation du Cotonnier suivie d’Inoculation à Fusarium Oxysporum F. Sp. Vasinfectum

La fusariose causée par Fusarium oxysporum f. sp. vasinfectum est une maladie qui entraîne le plus de dommages dans la culture cotonnière. Cependant, l’utilisation de pesticides notamment les fongicides comme solution pour faire face à l’agent pathogène s’est avérée non seulement inefficace mais entraîne des problèmes de toxicité, de pollution de l’environnement, de santé et même de biodiversité. L’objectif de ce travail a été d’étudier la variabilité de la production de composés phénoliques impliqués dans le système de défense naturelle du cotonnier. Ainsi, l’application des éliciteurs MeJA et FOS11 (10%) sur les plants de cotonnier suivis d’inoculation à FOV a permis la synthèse de novode composés phénoliques en plus des composés préexistants. Par ailleurs, l’accumulation des composés phénoliques a été amplifiée suite à l’application de ces deux éliciteurs suivie de l’inoculation à FOV. Les plants de cotonnier ont été donc équipés de composés qui ont anticipés l’attaque de FOV. Toutefois, la FOS11 (10%) a induit la production d’un plus grand nombre de composés phénoliques que le MeJA. La FOS11 (10%) a donc été retenu comme meilleur éliciteur naturelle de la stimulation des défenses naturelles du cotonnier. Fusarium blight caused by Fusarium oxysporum f. sp. vasinfectum is a disease that causes the most damage in cotton growing. However, the use of pesticides, especially fungicides as a solution to the pathogen, has proven to be not only ineffective but also leads to problems of toxicity, environmental pollution, health and even biodiversity. The objective of this work wasto study the variability of the production of phenolic compounds involved in the natural defense system of the cotton plant. Thus, the application of the MeJA and OSF 11 elicitors (10%) on the cotton plants followed by inoculation with FOV allowed the de novo synthesis of phenolic compounds in addition to the preexisting compounds. Moreover, the accumulation of phenolic compounds was amplified following the application of these two elicitors followed by inoculation with FOV. The cotton plants were therefore equipped with compounds that anticipated the FOV attack. However, OSF 11 (10%) induced the production of more phenolic compounds than MeJA. OSF 11 (10%) was therefore chosen as the best natural elicitor of the stimulation of the natural defenses of cotton

Latex micro diagnosis, modern management tool of rubber plantations of clones with moderate metabolism GT 1, RRIC 100 and BPM 24

Objective: The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. This study was done to determine the best latex harvesting system (s) of clones with moderate metabolism (GT 1, RRIC 100 and BPM 24).Methodology and Results: Six latex harvesting technologies were  applied to these clones in a bulk statistical device from Fisher to four rehearsals. The rubber trees were tapped in downward half spiral stimulated or not, for nine years after the opening of the tapping panel. The agronomic parameters (latex 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 (2234 kg.ha-1.y-1) with good radial vegetative growth (2.4 cm.y-1). Their trees showed a well-balanced physiological profile and an acceptable sensitivity to the tapping panel dryness (3.2 %). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technology "S/2 d4 6d/7 Pa1 (1) ET2.5% 4/y” for the best.Conclusion and application of results: This index, favourably  influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.Key words: latex-harvesting technology, rubber clones, moderate  metabolism, tapping panel dryness, physiological parameter

Contribution of Latex Micro Diagnosis to Modern Management of Rubber Plantations: Case of Clones With Low or Slow Metabolism PB 217 and PR 107

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

Latex Micro Diagnosis, Modern Management Tool of Rubber Plantations of Clones With Active or Rapid Metabolism IRCA 18, IRCA 130, PB 235, PB 260 and PB 330

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.y1) 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

Influence of Downward Tapping Delay on Agronomic Parameters of Upward Tapping Rubber Trees

The nine-year period of downward tapping prior to upward tapping is often considered too long and irrelevant. Thus, a study was carried out to determine the minimum time needed for downward tapping for which the agronomic parameters (rubber production, vegetative growth) of the rubber trees could best be expressed in upward tapping. Clones with slow (PB 217 and IRCA 41), moderate (GT 1) and fast (PB 260 and IRCA 18) metabolisms were used as plant material in the experiments carried out in Gagnoa, Bettié, Daoukro, San Pedro and Divo. The rubber trees were tapped in a half-spiral downward direction at different times followed by quarter-spiral upward or upward tapping. The experimental design was a Fisher block design with 9 treatments and 4 replications. The results showed that upward tapping preceded by downward tapping for 5 and/or 6 years was the best regardless of the metabolic activity class of the clone. Rubber production expressed in kg.ha-1. year-1 [Slow (5y-2675 ± 79) (6y-2488 ± 59) (T9y-2238 ± 45); Moderate ((5y-5417 ± 127) (6y-5094 ± 141) (T9y-3993 ± 58); Fast (5y-5210 ± 239) (6y-4733 ± 500) (T9y-3723 ± 245)] resulting from these upward tappings increased with an increasing gradient of clone metabolism without, however, detrimental to vegetative growth (cm. yr-1) [Slow (5 yr-3.90 ± 1.27) (6 yr-4.05 ± 1.48) (T9 yr-3.40 ± 1.13); Moderate ((5 yr-3.02 ± 0.25) (6 yr-2.80 ± 0.05) (T9 yr-2.39 ± 0.02); Fast (5 yr-4.27 ± 0.42) (6 yr-3.97 ± 0.28) (T9 yr-3.60 ± 0.05)]. These results show that upward tapping in year 6 is more advantageous than tapping in year 10