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Dacryodes edulis (G. Don) H.J. Lam is an underexploited oil-bearing fruit tree highly appreciated in the Central Africa rainforest. To improve horticultural management and provide relevant data to scientists for physiological studies, the reproductive phenology of D. edulis as well as their fruit (safou) development and ripening indexes has been defined and correlated to climatic conditions. Changes in safou were assessed in four production localities in Cameroon. Fruit-set-to-ripening time was evaluated over 2 consecutive production years. Four fruits developmental and ripening stages and their durations were determined as follows: The putative cell division (1–2 weeks); putative elongation (10–14 weeks); pre-ripening (2–7 weeks); and ripening phases (3–5 weeks). Rainfall, average, and cumulative temperatures were found to be correlated with the chronology of reproductive phenophases. The average temperature during the period ranging from the floral bud emergence to the fruit set can be used to predict the thermal time. Similarly, the average ambient temperature during the period from floral bud emergence to anthesis can help to determine the temperature to be cumulated during the ripening phase. These findings are considerable contributions that could help producers to enhance the industrial management of safou sector, reduce fruit perishability, and better control their harvesting time.

The physiological stage of mango maturity at harvest affects fruit quality at the time it is commercialized. The objective assessment of the mango maturity stage at harvest remains a challenge because of the multiple interactions between the visual aspect, the physicochemical composition, and the morphology of the fruit. This study aims to quantify the optimal harvest date to guarantee the maturity and quality of mango cv. ‘Kent’. In this study, which took place in Korhogo in northern Côte d’Ivoire, the maturity stage and the quality of fruits were measured on 240 Kent mangoes harvested at four different harvest dates (90, 95, 100, and 105 days after flowering). A morphological, physical, and chemical characterization (length, width, mass, soluble sugar content, dry matter, skin appearance, and mass loss) was carried out at each date on 30 fruits at harvest and 30 fruits after ripening at room temperature. The number of days necessary for ripening was quantified. The results showed that the optimal harvest date is 100 days after flowering for Kent mangoes in Côte d’Ivoire. Mangoes harvested at this date developed better organoleptic characteristics (less wrinkled skin, lower mass losses, and a shorter ripening time). Assessment of the harvest date, guaranteeing better ripening of the fruit, is of utmost importance for organizing harvests in the mango sectors in West Africa, and especially in Côte d’Ivoire.

The change of wine grape harvest from wet season (summer) to dry season (winter) by changing the pruning management has improved quality of wines produced in the Brazilian Southeast. However, the vines need to be spur pruned twice a year, i.e. with a 1st pruning in August (winter pruning) for a vegetative cycle during the hot and wet summer, and a 2nd pruning in January (summer pruning) for a productive cycle during the cold and dry season. This double pruning strategy is made necessary by the fact that latent buds developed during the dry season cycle are not fruitful to support a productive cycle in the following year. This histological study, performed in the South of Minas Gerais State (Brazil), showed that annual single pruning done in the wet season (in January) displayed a high rate of necrosis on primary and secondary buds (bud necrosis – BN). In April, 99 days after summer pruning (DASP), the rates of BN were 40 % and 50 % at basal and apical node positions, respectively, reaching 80 % of BN in December (322 DASP). As a consequence of BN, bud potential fertility was drastically reduced from 0.5 inflorescence primordial (IP) per bud (in July) to 0.06 (in December) and bud burst in the next cycle from secondary and tertiary bud axes. Vines managed by double pruning system (submitted to summer and winter pruning) displayed a much higher fruitfulness potential, i.e. 1.46 IP per bud in December (112 days after winter pruning) and limited BN occurrence (20 %). On single pruned vines, we also observed a significant decrease of starch content in canes, trunks and roots. Internal bud anatomy showed that a random cell breakdown started 70 days DASP. At 211 DASP, all buds showed a large starch granule concentration, raphides and crystals of calcium oxalate inside idioblasts of leaf primordia and also in cortical parenchyma of the vegetative axis. The bud starch content was increased and a positive correlation between necrosis and starch accumulation was observed. The impact of carbohydrate availability on bud necrosis development was discussed. This study showed that the necrosis development towards secondary and tertiary axis of the dry season buds is the main reason of unfruitfulness in the vineyards managed by single pruning in the wet season, making the double pruning compulsory., VITIS - Journal of Grapevine Research, Vol 58 No 3 (2019): Vitis

HIGHLIGHTS Biomass production and cell wall composition are differentially impacted by harvesting year and genotypes, influencing then cellulose conversion in miniaturized assay. Using a high-throughput miniaturized and semi-automated method for performing the pretreatment and saccharification steps at laboratory scale allows for the assessment of these factors on the biomass potential for producing bioethanol before moving to the industrial scale. The large genetic diversity of the perennial grass miscanthus makes it suitable for producing cellulosic ethanol in biorefineries. The saccharification potential and year variability of five genotypes belonging to Miscanthus × giganteus and Miscanthus sinensis were explored using a miniaturized and semi-automated method, allowing the application of a hot water treatment followed by an enzymatic hydrolysis. The studied genotypes highlighted distinct cellulose conversion yields due to their distinct cell wall compositions. An inter-year comparison revealed significant variations in the biomass productivity and cell wall compositions. Compared to the recalcitrant genotypes, more digestible genotypes contained higher amounts of hemicellulosic carbohydrates and lower amounts of cellulose and lignin. In contrast to hemicellulosic carbohydrates, the relationships analysis between the biomass traits and cellulose conversion clearly showed the same negative effect of cellulose and lignin on cellulose digestion. The miniaturized and semi-automated method we developed was usable at the laboratory scale and was reliable for mimicking the saccharification at the pilot scale using a steam explosion pretreatment and enzymatic hydrolysis. Therefore, this miniaturized method will allow the reliable screening of many genotypes for saccharification potential. These findings provide valuable information and tools for breeders to create genotypes combining high yield, suitable biomass composition, and high saccharification yields.

Precision agriculture for banana crops has been little investigated so far. The main difficulty to implement precision agriculture methods lies in the asynchronicity of this crop: after a few cycles, each plant has its own development stage in the field. Indeed, maps of agronomical interest are difficult to produce from plant responses without implementing new methods. The present study explores the feasibility to derive a spatially relevant indicator from the date offlowering and the date of maturity (time to harvest). The time between these dates (TFM) may give insight in spatial distribution of vigor. The study was carried out using production data from 2015 acquired in a farm from Cameroon. Data from individual plants that flowered at different weeks were gathered so as to increase the density of TFM sampling. The temporal variability of TFM, which is induced by weather and operational constraints, was compensated by centering TFM data on their medians (TFMc). The mapping of TFMc was obtained using a classical kriging method. Spatial structures highlighted by TFMc either at the farm level or at the plot level, suggest that such maps could be used to support agronomic decisions.

Argan tree, a species endemic to Southern Morroco, is well known for its kernel oil used in cosmetics and health-food, but the corresponding pulp attracted less interest from researchers and little is known about its chemical composition and evolution during maturation. The pulp of argan fruits monthly harvested during the ripening period based on fruit color (April to July), was analyzed. With progressing ripeness various changes were observed in the chemical composition, such as (i) a four-fold increase of total soluble sugars content (glucose, fructose and saccharose), and of Fe (75–165 ppm), but also (ii) a drop of many components, such as proteins (10.1–6.4%), and cell wall polymers, lignin (14.9–5.9%) and hemicellulose and cellulose. Hexane-soluble compounds found in substantial amount (10.7% in April) also decreased with time: the pulp oil peak (8.3%) was in April and June, and that of polyisoprene in June (3.6%). Therefore the stage of maturity (harvest date) is to be considered, without affecting the quality of the argan oil.

International audience; The combined influence of maturation, ripening, and climate on the profile of bioactive compounds was studied in banana (Musa acuminata, AAA, Cavendish, cv. Grande Naine). Their bioactive compounds were determined by the Folin-Ciocalteu assay and high-performance thin layer chromatographic (HPTLC) method. The polyphenol content of bananas harvested after 400 degree days remained unchanged during ripening, while bananas harvested after 600 and 900 degree days exhibited a significant polyphenol increase. Although dopamine was the polyphenol with the highest concentration in banana peels during the green developmental stage and ripening, its kinetics differed from the total polyphenol profile. Our results showed that this matrix of choice (maturation, ripening, and climate) may allow selection of the banana (M. acuminata, AAA, Cavendish, cv. Grande Naine) status that will produce optimal concentrations of identified compounds with human health relevance.

International audience; One of the most currently promoted new crops for biodiesel productions the perennial species Jatropha curcas L. (Euphorbiaceae) due to its promising high seed yields with high oil concentrations (33–39%) and oil quality that reaching the international biodiesel standards. Although there have been different evaluations of genotypes growing under the same environmental conditions, revealing great variability for seed and oil quality, no reports are available about the effect environmental conditions during grain filling over such traits. The objectives of this work were to determine (i) the effect of harvest dates on seed quality and oil concentration, (ii) if such changes can be explained by the average temperature during grain filling and (iii) how harvest dates could affect biodiesel quality. An experiment was carried out during 29 months in experimental plots located in Formosa, Argentina. A systematic fruit harvest was conducted during 15 different dates on 10 plants with similar height (≈1.80m). Environmental conditions during the experiment were appropriate to create a broad individual seed weight range (326–752mg) and significant differences were found among harvest dates. Seed oil concentrations were significantly different among harvest dates with a maximum value of 38.7±0.6% on 08 August 2011 and a minimum of 19.6±1.8% on 17 March 2010. Oil concentration increased linearly as seed weight increased up to a value of 605mg, after which higher seed weight was not associated with greater seed oil concentration. Oil concentration was largely (r2=0.85) explained by the kernel percentage through a linear regression (y=−25.9+0.967x). Variations in seed weight and oil concentration were not associated with changes in average temperature during grain filling, suggesting that fluctuations in the source-sink relation through the growing season could explain the variations found among harvest dates. Temperature during seed filling period strongly affected oil composition and higher temperatures were associated with higher oleic acid and lower linoleic acid concentrations, although this effect generated only small effects on the biodiesel quality. Environmental conditions during grain filling modified seed quality and oil composition, while its concentration was not affected. This work reveals the existence of harvest dates effects on seed quality and oil concentration, although unrelated with the environmental conditions explored during grain filling period.

Centella asiatica, is a wild plant used extensively for its healing properties. In order to establish a rational management, the present study evaluates the effects of time and rate of collection on biomass yield and content of active ingredients. Six collection frequencies were considered (monthly, bi monthly, quarterly, four-monthly, semi-annual and annual). This study shows that the yield of leaf biomass and content of active ingredients vary seasonally according to rainfall, increasing during the rainy season (November to April).The reconstruction of the biomass is maximal if collections are spaced at least three to four months apart. The annual recurrence of repetitive collections causes a loss of productivity of leaf biomass, is significant in the second year of operation. These results offer the best compromise between least effort required for gathering by farmers and greatest yield of biomass and active material, advocating a rate of quarterly collection during the rainy season.

BACKGROUND: The effect of temperature on chilling injury during fruit growth was studied in a new banana hybrid CIRAD925 in which seasonal variability in chilling susceptibility was observed when fruits were stored at 13 ∘ C. RESULTS: The relationship between the response to chilling (presence/absence) and the temperature during banana fruit growth was examined with a logistic regression model. An explanatory variable X N,P was defined as the mean temperature during a period, expressed in weeks, which began N week(s) after flowering and lasted P week(s). The model was calibrated with 143 bunches with a green life of 30 ± 5 days and validated with 156 bunches grown in six plots under different growing conditions. Chilling injury was best predicted by the mean temperature during the period beginning 1 week after flowering and lasting 5 weeks (X 1,5 ). Above a mean temperature of 24.1 ∘ C in the period concerned, banana fruits had a 95% probability of chilling injury at 13 ∘ C. Below a temperature of 23.4 ∘ C, banana fruits only had a 5% probability of chilling injury. CONCLUSION: The results provide a tool to predict chilling susceptibility in banana fruit whatever the thermal conditions in tropical regions.

International audience; Age of plant and environmental conditions during growing may affect texture (friability) and taste of boiled cassava roots. We investigated the quality of boiled roots of seven cultivars harvested at 10, 12 and 14 months in three different seasons. Sensory taste (sweet or bitter) of boiled cassava root could not be correlated with sugar content and/or cyanide potential, which both interfere with taste perception; hence, bitterness is not a good indicator of the poisonous character of cassava roots. Improved cultivars generally showed lower friability scores, independently of plant age (10-14 months) or season. Rainfall before harvest directly lowers dry matter and mealiness of boiled roots. Cultivar and rainfall effects are discussed in relation to pectins (higher content for improved cultivars) that are suspected to be the major biochemical cause of vegetable mealiness.

Introduction . La pomme Cythere est un fruit economiquement sous-exploite au Cameroun par manque de connaissances sur les techniques de culture de l’espece, la conservation post-recolte de son fruit et sa valeur nutritionnelle. L’objectif de notre etude a ete d’analyser certains changements morphologiques et biochimiques qui se produisent au cours du developpement de la pomme Cythere et de chercher a evaluer le temps s’ecoulant entre la nouaison et la maturation des fruits, afin de prevoir une date probable de recolte au Centre Cameroun. Materiel et methodes . Certains parametres morphologiques (longueur, diametre, volume et poids du fruit) et biochimiques (teneurs en eau, en sucres totaux, en lipides, proteines et en elements mineraux, teneur en chlorophylles a et b ) des fruits de S. cytherea ont ete mesures a partir de leur nouaison jusqu’a leur maturation. Resultats et discussion . Les valeurs des parametres morphologiques mesures sur le fruit ont augmente au cours du temps et leur evolution a suivi une courbe a allure sigmoidale. Les valeurs maximales ont ete obtenues a la vingt-huitieme semaine avec pres de 128 g pour le poids frais, 19 g pour le poids sec, 69 mm pour la longueur, 58 mm pour le diametre et 116 mL pour le volume. Les chlorophylles a et b ont diminue au cours du developpement du fruit. La teneur des fruits en elements mineraux a diminue avec le temps et le potassium a ete l’element le plus abondant. Sa teneur a varie de 1,6 % a 0,9 % entre la sixieme et la trentieme semaine apres nouaison. Les sucres totaux ont augmente avec le temps alors que les teneurs en lipides et les proteines diminuaient. Trente semaines apres la nouaison, les valeurs ont ete de 13,76 % de matiere fraiche pour les sucres, de 0,47 % de matiere seche pour les lipides et de 0,43 % de matiere seche pour les proteines. Conclusion . La composition de la pomme Cythere donnerait a ce fruit une valeur nutritive aussi importante que celle de certains fruits tropicaux plus connus comme la banane, la mangue et l’ananas.

Cette methode est utilisee pour prevoir la date de recolte des regimes de banane des le stade floraison. Elle facilite la recolte de regimes ayant un meme âge physiologique. Le principe, les principaux avantages, le temps necessaire et les resultats attendus de l'application de la methode sont presentes. Materiel et methodes. Le detail des quatre etapes de la methode (installation de la sonde de temperature, marquage des regimes au stade de floraison, calcul de la somme des temperatures, evaluation de la date de recolte des regimes) est decrit. D'eventuels problemes sont discutes. Resultats. L'application de la methode permet de tracer une courbe de la somme des temperatures accumulees par les regimes qui doivent etre recoltes a l'âge physiologique de 900 degre-jours. (Resume d'auteur)

In Africa and particularly in Côte d'Ivoire, the exploitation of Hevea brasiliensis clones having strong vegetative growth based on the criterion of vigour adopted so far has raised physiological and physical problems characterized by a high rate of tapping panel dryness and wind damage. A study was conducted on three clones of Hevea brasiliensis (PB 235, GT 1 and PR 107) belonging respectively to classes of fast, moderate and slow vegetative growth, in order to determine the right moment for an exploitation which would minimize those drawbacks. Trunk measurements, bark collecting and histological sections followed by laticifers counting made on rubber trees aged from one to fifteen years, have enabled to describe the process of establishment of bark and laticifers. The intensity of development and thickening of the bark and the rate of laticifer emission are described respectively by distinct hyperbolic and logistic sigmoid functions. However, their temporal evolution is strongly marked by an irreversible decrease of the whole process of formation, whatever the clone, from six years after planting. Furthermore, the density of laticifers per mm2 switches, whatever the clone studied, from a number greater than 5, the first six years (5-8 < ?lv

Les prévisions de dates de récolte d'ananas sont essentielles à la planification du travail et aux efforts de commercialisation des fruits frais. L'objectif de cette étude a été de développer un modèle basé sur la température de l'air minimale et maximale du jour afin de prévoir les dates de récolte d'ananas quel que soit l'environnement dans lequel la plante est cultivée. Pour la modélisation, deux phases de développement du fruit ont été distinguées : période entre induction du développement du fruit et ouverture de la première fleur et période entre ouverture de la première fleur et récolte. Pour la première phase, les prévisions sont basées sur l'accumulation des unités de chaleur à partir de la température de l'air essentiellement. Quant à la seconde phase, les unités de chaleur sont accumulées à partir de la température estimée du fruit. Le modèle a été calibré et testé à partir de nombreuses données en provenance de plusieurs pays producteurs et sous différents environnements et latitudes : Queensland, Australie, Côte d'Ivoire, Hawaï, Thaïlande. Le modèle a prédit les dates de récolte avec une erreur moyenne de 11,3, 12 et 5d respectivement pour chacun des pays. Cette marge d'erreur reste acceptable pour la plupart des planteurs d'ananas

National audience

Chapitre 6; National audience

Chapitre 7; National audience

International audience; The length of time between harvest and the onset of the climacteric rise in fruit respiration depends both on the harvest stage and the storage conditions of mango fruit (Mangifera indica cv Cogshall). We therefore propose classifying fruit according to a Ripening class index (Rci) that takes both storage time and climacteric stage into account. Batches of fruit thus obtained are more homogeneous than those sorted according to their storage time or their climacteric stage alone, as shown by the lowest root mean square error values obtained for the majority of the physico-chem. criteria measured, such as total sol. sugars, starch, and total sol. solids contents, titratable acidity, pH, firmness and the ratio of total sol. sugars to total org. acids. The advantage of this classification system for monitoring postharvest changes in mangoes stored at 12 or 20 °C has been demonstrated. The Rci was used to study the impact of agronomic conditions such as the leaf-to-fruit ratio and harvest stage on the changes in physico-chem. criteria traditionally used as quality descriptors. Sugar content increases with the increase in carbon supply and the harvest stage, whereas the titratable acidity and the hue angle decrease during ripening. This type of index can be used to validate the relevance of harvest indicators by verifying the homogeneity of the changes in stored batches or for more effectively assessing the impact of a storage technique on fruit metab. [on SciFinder(R)]

We aimed to define a more robust indicator for banana harvest date that ensures an optimal fruit green life (GL). Our hypothesis was that development rather than growth would account for GL more accurately. To this end, five indicators were compared: one related to fruit size (i.e., growth, expressed as the diameter of fruit); two related to fruit age [i.e., development, expressed as the age of fruit measured in the number of days or in degree days (°Cd) from inflorescence emergence]; and two related to metabolism during maturation (i.e., the concentrations of malate and citrate in the pulp). Different treatments (e.g., fruit removal, leaf shading, bunch bagging, defoliation, water deficit, and flooding) were applied to modify the fruit growth rate. On different dates between the emergence of the inflorescence and harvest, fruit GL and the five indicators were measured. The results showed that there was a decreasing exponential relationship between GL and accumulated °Cd from inflorescence emergence (r2 = 0.77). This was more reliable than the relationships between GL and fruit diameter (r2 = 0.39), or between GL and fruit age, expressed in days (r2 = 0.39). Relationships were also established between GL and malate or citrate concentrations, but they were not sufficiently reliable to estimate GL. The results illustrate that GL is related to fruit development, and that °Cd is a more reliable criterion for harvest date than the number of days, or fruit diameter, because it is less sensitive to different fruit growth rates. Banana growers in the French West Indies usually use fruit diameter and age in days to determine harvest date. However, they face problems of fruit ripening during transportation. The use of °Cd as an indicator may help to determine the optimum harvest date more accurately.

In the context of the SUCRETTE project, the CIRAD (Centre de coopération Internationale en Recherche Agronomique pour le Développement), in collaboration with Spot Image Company, conducts research activities to study the potentialities of remote sensing for sugarcane monitoring. Among different operational products that can be derived from satellite images, we present here how a time series of SPOT4 & 5 satellite data could be used as a decision support tool for planting survey and harvest monitoring of small-scale cane fields. A pilot study was set up in Guadeloupe (French West Indies) where the individual sugarcane fields are progressively mapped in the framework of the AGRIGUA project. The objectives were to provide the fraction of harvested fields throughout the milling season and a summary map of ploughed fields at the end of the planting season. The spectral properties of the different cane field status - full covered green canopy, stressed canopy, crop residues and bare soil - showed that harvested and ploughed fields could be easily mapped with high accuracy (more then 90%) thanks to a field-base approach. The resulting maps were then integrated within a decision support system devoted to sugarcane management. This on-shelf GIS permits to visualize maps and edit monthly statistics of the management practices in each administrative area.

Malgré sa culture très ancienne, et une progression constante, la production du manguier reste faible et irrégulière. Cependant, l'orientation vers de nouveaux types de commercialisation demande des exigences accrues sur la qualité des fruits et la régularité d'approvisionnement des marchés. Une des hypothèses de la faible productivité du manguier évoquée dans la littérature est que la gestion des ressources carbonées peut limiter la mise en place et la croissance des organes reproducteurs. La forte consommation énergétique lors de la floraison limiterait la disponibilité des ressources carbonées pour la croissance des fruits. Par ailleurs, une phase prolongée de grossissement des mangues limiterait à son tour la mise en place des rameaux florifères. A la Réunion, nous nous proposons d'optimiser, à l'échelle de l'arbre, les relations source/puits pour les assimilats carbonés avec comme objectif l'amélioration de la production et de sa qualité chez le manguier. Le contrôle de la ramification, effectué par un défourchage des pousses végétatives tendres, et l'élimination d'une certaine proportion des inflorescences nous permettent, sur une première campagne de mesures, de préserver les performances agronomiques de l'arbre (rendement et calibre des fruits) et de concentrer la période de récolte. Ces résultats devront être confortés. Ils nous permettront de proposer un mode de conduite du verger conduisant à une production régulière de mangues de qualité.

Ce cédérom reprend les données du "Manuel du planteur d'ananas Bouteille" publié en 2000, auquel s'ajoute une photothèque étendue à d'autres variétés. Il comporte notamment une application destinée à prévoir de manière précise les dates de récolte et donc de mieux planifier la culture

The harvesting of bananas for export is constrained by the need to transport the production by sea to the importing country, which takes 10-20 days from the West Indies to Europe. The fruit must arrive before the start of the climacteric rise. The fruit must therefore be harvested early enough to have a green life (GL, time elapse, in degree-days, between cutting the fruit and the climacteric rise) longer than the transport time. Our aim is to find an indicator of harvesting date which would give rise to a constant GL at harvest. For this purpose, it was assumed that GL depends on fruit maturity and thus on its developmental stage at harvest. Several indicators of development were considered: - the fruit age expressed in degree-days (dd, base temperature 14°C) accumulated since inflorescence emergence, - the relation between GL and pulp organic acid content.

Introduction. L'exportation des plantains du Cameroun vers l'Europe se fait actuellement par avion, d'où des coûts de transport élevés. Par suite, les conditions de conservation, à l'état vert, de plantains récoltés à différents stades de maturité ont été étudiées afin d'envisager la possibilité d'une exportation par bateau (durée de 15 j environ). Matériel et méthodes. Des régimes de plantain 'French clair', 'Bâtard' et 'Big Ebanga' ont été échantillonnés. Quatre stades de récolte (SdR) ont été testés. Après traitement fongicide, les échantillons ont été emballés en gaine plastique perforée, puis conditionnés en cartons pour bananes d'exportation. Après 2 j à la température ambiante (25-30 C, 80-90 % humidité relative), deux lots ont été constitués : l'un conservé en chambre froide (12-14 C ; 85-95 % HR) pendant 15 j, l'autre laissé à la température ambiante. Les fruits des deux lots ont été analysés. Résultats. Les meilleurs SdR se situent à 1 semaine environ avant l'apparition du premier doigt tournant pour le cultivar 'French Clair' (intervalles floraison coupe ou IFC : 79 j), 1 à 2 semaines pour le 'Big Ebanga' (IFC : 71-78 j) et 2 à 3 semaines pour le 'Bâtard' (IFC : 68-75 j). Les cultivars qui conviendraient le mieux aux critères des plantains actuellement commercialisés en Europe sont 'Big Ebanga' et 'Bâtard'. Discussion et conclusion. Le développement de ces cultivars et des itinéraires techniques adaptés sont indispensables pour encourager l'exportation par navires réfrigérés vers l'Europe et permettre aux Camerounais de mieux faire face à la concurrence des plantains d'origine latino-américaine.

Le réseau de parcelles d'essai n'a pas subi de changement notable en 1998. La parcelle de palmistes rouges dont la plantation était prévue en décembre 97 à Bois Blanc a finalement été mise en place en mars 98. Cet essai porte sur l'intérêt des apports de matière organique pour la plantation puis la conduite du palmiste rouge. Sur cette jeune parcelle, ainsi que sur celle de G. Maillot à St Benoit, de nouvelles méthodes de suivi de la croissance, plus légères, ont été appliquées dès la plantation. Les autres parcelles de palmistes, plus âgées, ont été en partie récoltées en 1,998. Les relevés de la croissance y sont poursuivis sur les plants restant. Pour le goyavier-fraise, la parcelle située dans les Hauts de Ste Suzanne n'est plus suivie. Le faible développement des plants sur un terrain très hydromorphe ne reflète pas les potentialités de la culture du goyavier-fraise dans cette zone. De plus, le goyavier-fraise n'est pas prioritaire pour le développement de la partie haute de l'exploitation familiale qui a été reprise par un fils. Des travaux ont été conduits sur une parcelle de friche entretenue de goyavier-fraise dans les Hauts de St Joseph. Ils sont présentés dans la suite du document. La plupart des suivis des parcelles de grenadilles violettes ont été arrêtés pour diverses raisons développées plus loin dans ce document. Quelques observations ont été faites sur la parcelle de la Plaine des Palmistes

Compilation de diverses données, tableaux et figures concernant principalement la technologie et la chimie du cacao : analyse de la qualité, défauts, fermentation et arôme, matériel pour la technologie après récolte et equipement industriel pour l'industrie de la chocolaterie avec les adresses de fournisseurs, des organismes professionnels et entreprises en France. Les périodes de récolte et diverses données de production des pays producteurs complétent ce rapport

A la Réunion, le cycle de développement de l'ananas `Victoria' varie de 10 à 18 mois selon l'altitude et l'ensoleillement. Pour répondre à une demande saisonnière sans cesse croissante, des études au champ et des simulations ont permis de déterminer les dates de traitements d'induction florale optimales. Ces résultats permettront de faire coïncider l'offre et la demande

Pour diversifier la gamme de litchis cultivés à l'île de la Réunion, une collection a été constituée, qui sert de base à des travaux de sélection. Des descripteurs de fleurs et de fruits ont été déterminés pour caractériser les variétés. La liste des variétés de litchis de la collection du CIRAD-FLHOR à la Réunion illustre cet article

Après un rappel des principaux aspects de la cristallisation et des méthodes d'investigation possibles, les auteurs décrivent celle utilisée pour mesurer la vitesse de cristallisation : la relaxation de tension, appliquée dans une plage assez étendue de température. Des échantillons de caoutchouc naturel des clones GT 1 et PR 107 ont été étudiés en fonction de leur date de récolte et de leur usinage. Les résultats sont analysés en s'appuyant sur la relation de Bruzzone et Sorta qui conduit à la détermination d'un point de fusion à l'équilibre, caractéristique de la vitesse de cristallisation. Leur interprétation statistique a permis d'émettre des hypothèses et tirer des conclusions à partir des différences de comportement observées, notamment en ce qui concerne l'influence de la température de séchage

International audience