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International audience; As perennial plants, fruit trees must cope, individually, with the fluctuating threat of multiple pathogens over the years. In this long-lasting battle for plant immunity, disease resilience is emerging as a key mechanism for tree survival and fitness. More fundamental research is required to improve our understanding of disease resilience mechanisms, which in turn could be particularly relevant for a more sustainable fruit production. As this approach is novel for that field, we propose i) a clear definition of resilience for fruit producing trees, ii) a methodology for studying its phenotypic components which requires repeated measures of “resilience biomarkers”, iii) to decipher the genetic architecture of resilience components, and iv) an innovative strategy based on high-throughput phenotyping and genomics for identifying resilient genotypes. All in all, disease resilience appears as a meaningful breeding perspective in a context of unprecedented plant protection restrictions.

International audience; Prediction of plant production under pest or disease attack is usually estimated in the short term. Medium and long term production projections are rarely taken into account; and this is partly due to the lack of mechanistic dynamic approaches to model and simulate the interactions between the plant growth and the attacks at the organ level. Therefore, attacks feedback on the plant itself can hardly be assessed.The main objective of our study is to develop a framework and tools to couple plant growth and P&D attack models and even cultural management models (treatment, harvest). This framework will allow us to simulate the effects of attacks on production over the long term, and to better understand the underlying influencing mechanisms. We illustrate the implementation of this framework on the case of the Arabica coffee tree growth, subjected to coffee berry borer attacks.

RATIONALE - Because it is effective, flexible and environmentally friendly, Integrated Pest Management (IPM) against the coffee berry borer (CBB) is a method that tends to fit sustainably into the agronomic practices of arabica coffee producers. However, IPM must adapt to local agro- climatic conditions to be effective. Thus, we compared this method in two contrasting situations, one in Central America with a tropical climate and the other in North Sumatra with an equatorial influence. METHODS - We adapted the main IPM components, i.e. CBB trapping on plantations and near post- harvesting areas, sanitation harvesting, and pruning and/or plot maintenance operations, according to CBB dynamics. These dynamics depend on the phenology of the arabica coffee tree, which is characterized by limited duration of fruit production in Central America and almost permanent fruiting in North Sumatra. RESULTS - In Central America, trapping used 18 Brocap© traps/ha for four months during the post-harvest period (1). When trapping was combined with sanitation harvesting applied to the branches, infestations were reduced by more than 70% compared with control plots. Adding pruning and maintenance of the plots, infestations decreased by more than 90% (2). In North Sumatra, trapping with 25 Brocap© traps/ha for ten months per year reduced infestation levels by 50% on average in plots affected by CBB. When combined with sanitation harvesting from the ground and on the branches, less than three months after the two main flowering periods, the infestation rate dropped to less than 10%. In this area, pruning had no particular effect on infestations, but it helped to double production the following year (3). In addition, given the dispersion of pulping and drying areas in this region, setting traps near these areas allowed to capture emerging CBBs in order to prevent their return to plots. CONCLUSIONS & PERSPECTIVES - The control strategies proposed for Central America and North Sumatra have been developed to optimize the use of the different IPM component with a concern for efficiency, environmental friendliness and economy of means. However, they could be reinforced by other measures such as spraying with Beauveria bassiana spores at appropriate times and monitoring infestation levels. In other agro-climatic sites dedicated to coffee cultivation, such as those in Africa, other strategies can be imagined and exploit the "parasitoid" component naturally present on this continent.

RATIONALE - Producers confronted with attacks by coffee pests and diseases tend to overestimate the level of attack on their plots and therefore over-treat their coffee trees (Rémond, 1996). In order to reduce chemical treatments on plants, we are developing an embedded decision-support tool to help estimate the health status of their plots, for use in South America and Africa. Embedded application are promising tools in view of the importance of mobile phones in people's daily lives (Berrou and Mellet, 2020). One disease and two pests are specifically targeted: leaf rust, Black twig borer and coffee berry borer. METHODS - The condition of the plot is evaluated using a sequential statistical procedure. The embedded application determines the number of plants to be sampled and guides the grower in entering the plant information. The various sensors in the phone are used for this guidance by mobilizing the GPS chip and the accelerometer to help determine distance travelled and direction. The architecture of the application follows a classical scheme with an initialization phase (description of the plot, targeted pests and diseases, etc.), a data entry phase using intuitive picture based selections, and a restitution phase, synthetizing the statistical analyses and proposing treatments from predefined tables. EXPECTED RESULTS- We expect an Android application that is easy to use, tested and approved by growers. As a first outcome, the application will provide information on the general health status of the plot and an index of heterogeneity. As a second output, the tool will propose an advice for a recommended action (treatment ...). CONCLUSIONS & PERSPECTIVES - The modularity of the application allows numerous upgrades. At a later stage, the integrated tool could include automatic data acquisition in the field by processing image captures. Statistical procedures may evolve and a production and attack development model could be included to refine recommendations for action. The ability to send analyses to a server could also feed models for the evaluation of attacks on a regional scale.

In Central America, coffee is grown in agroforestry systems. Since 2012, coffee leaf rust, caused by the fungus Hemileia vastatrix, has produced major epidemics in this region. To prevent future epidemics, the European Union through its PROCAGICA program (Programa Centroamericano de Gestión Integral de la Roya del Café) promotes the creation of an early warning system based on weather monitoring.To build models to forecast the disease we must first identify which microclimatic variables are responsible for rust development and then be able to estimate these variables under different agroforestry systems as a function of the data provided by weather stations, established at full sun. From a trial set up in Costa Rica where disease and weather data were monitored, we deduced, without a priori [1], that the different disease development stages (see figure) were the result of complex combinations of microclimatic variables acting at diffe-rent periods (times and durations). Then, to estimate the effect of agroforestry systems on these microclimatic variables, a second trial was conducted in Costa Rica within an altitudinal gradient. In each site, meteorological stations were set up in a full sun reference plot and coffee plots with different shade trees. Using boosted regression tree method, we found that microclimate under shading depends mainly on full sun weather with nonlinear relationship, hour, shade tree species, orientation, canopy openness and plot slope in this order.

Coffee rust epidemics that occurred in Latin America since 2008 have caused millions of dollars losses, job losses, and food security issues. In response to this crisis, Central American and Caribbean countries have been developing national surveillance systems to prevent future coffee rust epidemics. The European Union is supporting these initiatives through the PROCAGICA project led by IICA, which aims at increasing the national and regional capacity to prevent coffee rust and the resultant socio-economic crises. Indeed, pest and disease risk warnings and management recommendations may not be followed by producers' actions, meaning that outbreaks will impact producers' livelihoods. Responses must therefore also encompass the economic sphere. In addition, the project aims at promoting the establishment of a regional coordination to enable the exchange of information on epidemic risks between countries, as pests and pathogens can spread over large distances. The Central American early warning system network is based on harmonized national early warning systems coupling surveillance and monitoring, with expert knowledge and forecast models. The estimated risks of epidemic and socioeconomic crises will lead to actions specific to each country. The system will help launching general warnings and personalized recommendations to farmers. In this presentation we evaluate a range of modelling approaches for forecasting coffee rust and socio-economic crises associated to rust outbreaks, including Structured Equations Modelling of coffee rust, multi-criteria models, machine learning, agent based models and Bayesian models.

The African coffee white stem borer (CWSB) Monochamus leuconotus is a destructive pest of Arabica coffee in Africa. Documentation on outbreaks, spatiotemporal development and the relationship with different environmental conditions and coffee production system is limited. To underpin effective control measures, we studied aspects of local and regional pest drivers in Eastern Uganda. At the local scale, we (i) characterized the temporal development of CWSB and explored associations with environmental and shade-related indicators. During two growing seasons and on 84 coffee plots, we recorded CWSB incidence/infestation and microclimate on an altitudinal gradient and different shading systems. The bimodal rainfall, altitude and shade affected CWSB development through their effect on minimum temperature. At the landscape level, we (ii) analyzed the spatial pattern of CWSB. Data on CWSB were collected on 180 plots. Pest incidence showed a spatial arrangement varying by districts. A possible relationship with human movement and the landscape context contributing to pest spread is suggested. CWSB control measures should be synchronized with the bimodal rainfall patterns and an emphasis should be given to identifying and limiting pathways of pest spread from highly infested to new areas.

L'amélioration génétique du cacaoyer en Côte d'Ivoire est basée sur un schéma de sélection récurrente et réciproque ayant comme critères de sélection, la production, le rapport production / vigueur, la résistance à Phytophthora et aux mirides, et la qualité technologique. Les deux populations de base sont constituées, d'une part de Forastero Haut-amazoniens (HA) et d'autre part de Forastero Bas-amazoniens (BA) et de Trinitario (T). Le programme est à son deuxième cycle de sélection. Le premier cycle a abouti à la sélection et à la diffusion de cinq croisements d'intérêt agronomique. Pour le second cycle, le choix des géniteurs a été réalisé par une sélection de type " individus/famille ". Les familles ont été sélectionnées sur leurs performances, mais aussi sur la base du comportement des géniteurs du premier cycle. Les individus, dans les familles retenues, ont été sélectionnés sur les mêmes critères que pour les familles, auxquels s'ajoutent deux autres, les dégâts cumulés de mirides et l'appréciation du sélectionneur. Dans chaque population, 40 géniteurs " améliorés " ont été choisis. Un factoriel incomplet 20 x 20 dans lequel, chaque géniteur a été croisé de manière déconnectée avec 4 autres, a ainsi été mis en place en 2000 à la Station de recherche de Divo, pour chaque population. Les arbres dans chaque essai ont été plantés suivant un dispositif en randomisation totale de parcelles mono arbre. Les caractères évalués sont la vigueur, la production, le poids d'une cabosse et le taux de cabosses pourries. Après treize années de collecte de données, les résultats sur les paramètres génétiques (pourcentages d'additivité, aptitudes à la combinaison, corrélations, héritabilités et gains génétiques) sont présentés et discutés. Dans les deux populations, les pourcentages d'additivité dans la variance génétique sont particulièrement élevés (78 à 90 %) pour le poids moyen d'une cabosse et relativement plus faibles (27 à 65 %) pour le rendement et le taux de cabosses pourries. Cela suggère des effets d'additivité importants pour la taille de la cabosse et des effets de dominance accrus pour les deux derniers caractères. Un index de sélection combinant les quatre critères est construit pour améliorer l'efficacité de la sélection. Les listes des croisements et individus prometteurs au sein de chaque population sont fournies pour un taux de sélection de 1 %, dans la perspective de mettre en place des parcelles de validation des performances agronomiques de nouveaux hybrides et clones.

La production du cacaoyer, en nombre de fruits produits, et en nombre de graines par cabosse sont des caractères très variables mais peu héritables chez le cacaoyer. Des facteurs environnementaux influencent donc ces caractères. Dans ce travail, nous cherchons à déterminer quels sont les mécanismes qui expliquent la distribution du nombre de fèves par cabosse pour un clone donné. Nous utilisons un modèle à trois facteurs adapté des travaux de Ph de Reffye (1978) : le nombre de grains de pollen efficaces, le nombre d'ovules fertiles et la chute des cabosses en fonction de leur remplissage. L'approche bayésienne choisie permet de considérer les quatre paramètres du modèle permettant d'estimer l'effet des trois facteurs comme des variables aléatoires. La validation du modèle s'effectue sur 10 clones plantés au Togo dans un même site (Zozokondji). Le nombre de graines a été compté pour chacune des trois cents cabosses récoltées par clone. Les distributions observées du nombre de graines par cabosse présentent des formes différentes selon les clones. Le modèle permet d'ajuster correctement la distribution du nombre de graines par cabosse pour chaque clone. Les résultats montrent que les paramètres estimés pour chacune des distributions sont différents en fonction des clones. Les trois facteurs limitent la production de graines par cabosse mais ont une importance variable selon les clones. Les distributions en forme de loi binomiale correspondent à des clones qui ont peu de cabosses mal remplies et pour lesquels le pollen n'apparait pas comme un facteur limitant. D'autres distributions, plus étalées, correspondent à des clones pour lesquels le modèle estime que le pollen efficace est rare. Lorsqu'on utilise le modèle pour prédire l'effet d'une augmentation du nombre de grains de pollen efficace sur ces clones, la distribution se rapproche d'une loi binomiale. Notre modèle met en évidence que pour certains clones la pollinisation est, parmi les facteurs étudiés, le principal facteur limitant le remplissage des cabosses.

The comparison of performance of coffee under shaded and sun-exposed conditions has been explored in numerous studies. The beneficial effects of shading on coffee sustainability through the mitigation of microclimatic extremes have been quantified and are generally wellestablished. It has also been acknowledged that the extent to which shaded systems are advantageous depends on the biophysical context. Particularly in studies on pest and disease dynamics, this variability of shade effects across sites has resulted in contradictory assumptions. In this study, we (i) quantified microclimatic differences between three coffee production systems (coffee shaded by trees, (CT), intercropped with banana (CB), or sun exposed (CO) as a function of different environmental sites. We then (ii) related microclimatic indicators to the intensity of two fungal diseases (Coffee Leaf Rust (CLR), and Coffee Berry Disease, (CBD) of Arabica coffee. Along an altitudinal gradient from 1000 to 2200 m.a.s.l.) and in diverse production systems on the slopes of Mount Elgon, Uganda, we collected hourly data on temperature and relative humidity during the 2015/2016 season in 27 plots. Microclimatic indicators to compare included diurnal temperature range (DTR), the accumulated hours of relative humidity above 95 % (RH>95) during night, and the accumulated hours of temperatures below the dew point (Temp95 and Temp95. Our findings confirm the mitigation property of shading to microclimatic extremes. However, the widely accepted assumption of shade conserving moisture is not applicable considering the spatio-temporal context. (ii) The fact that unshaded systems at high altitudes expose better conditions for dew formation than compared to shaded systems could be a key mechanism explaining the high CBD intensity under unshaded systems and the contradictory CLR responses along the gradient of altitude and shading intensities.

In the western part of Venezuela, producing arabica coffee around the town of Biscucuy is traditional. The production area is located in the Andean piedmont, on the municipality of Sucre, in the state of Portuguesa. A development plan was set up by the municipality of Sucre to improve the agronomic practices and the quality of coffees with the aim of a better valorisation. The purpose of this study is to get a first insight in the aroma potential of these coffees, quite unknown in the coffee world till now. This study shows that coffees from Biscucuy area may have a good sensorial potential. The variability of the cultivars seems to involve differences in the sensorial profiles much more important than the variability due to the altitude or location.

In a coffee plantation with one annual harvest and a marked dry period, how sanitation harvesting should be done to reduce damages caused by the coffee berry borer (CBB) on the harvest? For two consecutive years, in El Salvador, we measured quantities of attacked and healthy residual fruits in March, as well as attacked and healthy new fruits before the harvest in September, in control plots and in plots with sanitation harvesting. In year 1, the sanitation harvesting was done by a team of farm workers without supervision, in year 2, sanitation harvesting was made by a team supervised by a leader previously trained. None sanitation harvesting had reduced significantly residual berries on ground. Unsupervised sanitation harvesting led to a 65% reduction of residual berries on branches. Supervised sanitation harvesting led to a 93% reduction of residual berries on branches. As a result, unsupervised sanitation harvesting doesn't lead to a significant reduction of infested berries on new harvest. On the contrary, a supervised sanitation harvesting leads to a significant reduction of infested berries on new harvest (70 % infested berries less than control plots). Residual berry from branches seems to influence new harvest attacks and can be eliminated by supervised sanitary harvest. So, the elimination of residual berries, from branches made through a rigorous sanitation harvesting, is a useful contribution to the control of the CBB.

Chemical analysis of effluvia emitted by coffee berries reveals the existence of numerous volatile organic compounds that are attractive to the coffee berry borer (CBB) Hypothenemus hampei Ferrari, and which are poorly understood. Only ethanol and methanol have a clearly demonstrated attractant potential when mixed; they are widely used as bait to trap this pest. Methylcyclohexane, ethylbenzene, nonane, octen-3-ol, phenylethanol, trans-2-hexenal and benzaldehyde induce an electrophysiological reaction and/or a positive olfactometric response in the CBB. Camphene and ?-pinene show a repellent effect for the CBB when widely released and cis-3-hexenol and 1-hexanol disrupt attraction of the pine shoot beetle. These compounds were tested under field conditions, in order to confirm their attractant or repellent potential. The seven potentially attractive compounds were tested separately with BROCAP® traps in the field, in association or not with a blend of ethanol and methanol. The compounds tested alone did not attract significantly more than water; associated with a blend of ethanol and methanol, they did not attract significantly more than ethanol-methanol alone. The four compounds selected for their repellent properties were tested in combination with a blend of ethanol and methanol, under the same field experiment conditions. We demonstrated that the repellent action of cis-3-hexenol and 1-hexanol was significant. The results of field trials with the assumed attractive volatile organic compounds disagreed with those obtained under laboratory conditions, according to the literature. In addition, compounds whose repellent properties are confirmed offer the possibility of integrating them in pull-push experiments.

International audience; This study was aimed at determining whether climatic conditions during bean development affected the chemical composition of the seed, the sensory perception of the coffee beverage and combinations of volatile compounds in green coffee. Using 16 experimental plots in Reunion Island displaying broad climatic variations, we showed that chlorogenic acids and fatty acids in the seed were controlled by the mean air temperature during seed development. By contrast, total lipid, total soluble sugar, total polysaccharide and total chlorogenic acid contents were not influenced by climate. Volatiles were extracted by solid phase micro-extraction and the volatile compounds were analysed by GC-MS. The results revealed that, among the climatic factors, the mean air temperature during seed development greatly influenced the sensory profile. Positive quality attributes such as acidity, the fruity character and flavour quality were correlated and typical of coffees produced at cool climates. Two alcohols (butan-1,3 diol and butan-2,3 diol) were closely correlated with a reduction in aromatic quality, acidity and an increase in earthy and green flavours. We assumed that high temperatures induce accumulation of these compounds in green coffee, and would be detected as off-flavours, even after roasting. Climate change, which generally involves a substantial increase in average temperatures in mountainous tropical regions, could be expected to have a negative impact on coffee quality. (Résumé d'auteur)

Dans une caféiculture dominicaine en pleine évolution, les acteurs de la filière, institutionnels et privés, souhaitent améliorer la commercialisation de leur café. Ils veulent accéder aux marchés à forte valeur ajoutée des cafés spéciaux (dont les cafés de terroir) afin de permettre aux caféiculteurs de voir leur travail mieux rémunéré. Pour caractériser les cafés dominicains et identifier les facteurs qui influencent leurs qualités organoleptiques, une étude agroenvironnementale a été menée dans toutes les zones caféicoles du pays. Sur deux années de récolte, 676 échantillons de café ont été prélevés, préparés et soumis à des évaluations organoleptiques. Le premier objectif de caractérisation des cafés dominicains a donné lieu à une classification ascendante hiérarchique qui permet d'établir une typologie sensorielle de ces cafés. Cinq types distincts ont ainsi été mis en évidence. Le géoréférencement des parcelles permet aussi de dresser une " carte sensorielle " des cafés de République dominicaine. Le deuxième objectif est de caractériser les terroirs par l'étude des facteurs de l'environnement physique qui peuvent influencer la qualité organoleptique du café. Les plus importants sont l'altitude et les variables climatiques qui y sont liées (températures, rayonnement solaire, pluviométrie¿), le matériel végétal et la nature du sol. L'ensemble des données acquises lors de cette étude a permis de construire une base de données géoréférencées qui, mise à disposition des producteurs, leur permettra d'établir des échelles territoriales permettant de garantir la typicité et la stabilité de leurs cafés de terroir.

Trapping is a method currently used to control the coffee berry borer (CBB) #Hypothenemus hampei# Ferr. It was developed then validated in plantations of #Coffea Arabica#, of moderate "technical input", cultivated under shade at medium altitude, and representative of many coffee plantations of Central America. Trapping has been little studied in farming systems in full sunlight (which is generally associated with high "technical input"). An experiment was set up in Nicaragua to evaluate the effectiveness of trapping within this specific framework. The experimental design comprised thirteen random sites in the studied plantation. Each one was composed of two paired plots of similar configuration: one with trapping, the other without. In full sunlight conditions there was a linear relation between the initial infestations of CBB and the captured females, but the efficiency was low. Populations of CBB developed better under self-shading and at the same time, trapping helped to reduce infestations where coffee trees formed a closed cover. Possible solutions to improve the performance of the trapping method in full sunlight conditions are laid out, in particular, changing pruning practices of the coffee trees and stripping branches of residual berries after harvest. (Résumé auteur)

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; BACKGROUND: Knowledge of the sensory diversity of a wide range of dessert bananas would be helpful in breeding programmes and so diversify the banana market. Descriptive sensory profiling was thus used to assess 13 cultivated bananas and four new triploid hybrids at an eating stage. RESULTS: A specific vocabulary was defined to describe the sensory traits of dessert bananas. The 17 cultivars assessed were ranked in five sensory clusters, which differed mainly in the intensity of sourness and sweetness. The first cluster, which contained the standard banana (Cavendish), received the lowest sourness and the highest sweetness and banana flavour scores. The second cluster was the sourest and firmest and had the highest chemical flavour score. The third cluster was characterised by the highest melting score, the fourth by the highest mealiness, astringency, grassy odour and flavour scores and the fifth by a balance between sourness and sweetness and the highest heterogeneous texture score. Firmness and sourness were correlated with rheological pulp firmness and titratable acidity respectively. CONCLUSION: The results led to the identification of relevant attributes that grouped the sensory diversity of dessert banana into five clusters. Combined with hedonic data, these results should help breeders to select banana hybrids. (C) 2011 Society of Chemical Industry

A sensory profile of 20 fonio (Digitaria exilis) landraces from Mali, Guinea and Burkina Faso was established using descriptive sensory analysis. A set of five descriptors was selected by consensus by a panel with 23 members during successive training sessions. Descriptors belonged to the main quality criteria for a well cooked fonio that were previously identified by consumers in group interviews. Each landrace was tasted and scored in triplicate by the panelists. A good correlation was found between descriptors indicating that they were not redundant. The efficiency of the panel as a whole was confirmed for both agreement and reliability. Principal component analysis and hierarchical cluster analysis were used to describe the variability of sensory profiles of the landraces. The 20 fonio landraces clustered into four sensory profiles. Sensory criteria of variability were first visual characteristics (colour and impurities). The second criterion of sensory variability was a textural characteristic, the consistency of cooked grain. Landraces from Guinea and Mali were variable for both visual and textural characteristics; those from Burkina Faso appeared to be more homogenous.

The texture of 64 mangoes of different commercial varieties was analyzed by a trained sensory panel. The intensities of the characters "firmness," "crunchiness," "melting" and "juiciness" were noted from 0 to 10. Soluble solids content, visible/ NIR spectrum and texture of the same fruits were determined using instrumental methods. Texture was determined by means of mechanical and acoustic tests. Four sensory classes were identified by agglomerative hierarchical clustering from among the fruits analyzed andwere characterized in terms of the measured physicochemical parameters. The relationships between the sensory and instrumental texture variables were visualized using a multiple factorial analysis. The prediction of sensory attributes from instrumental data was better for firmness, crunchiness and melting than for juiciness. Power-law or logarithmic models were proposed to predict firmness (r = 0.89), crunchiness (r = 0.89) and melting (r = 0.88). Multivariate models (multiple linear regression, partial least squares regression) were also proposed.

The flavour attributes of cocoa liquors prepared from some cocoa clones planted in the International Clonal Trials of eight different countries were evaluated over two years on seven main flavour traits to examine individual and combined clonal and environmental effects. Fermented and dried cocoa bean samples were prepared in each country according to standardized protocols and the samples were evaluated for any defects before liquors were prepared according to a standard method. Sensory evaluation was undertaken by three panels, one consisting of two panellists and two consisting of one panellist. The results showed low coefficients of correlation between panels for the descriptors evaluated. However, the Multiple Factorial Analysis showed some common features between panels, depending on the axes. With regard to specific flavour attributes, acidity, bitterness and astringency were opposed to cocoa flavour intensity whilst floral flavour appeared to be the most independent flavour trait, related mainly to the clone for the two years' data that were analysed. Significant year and country effects were observed for cocoa flavour, acidity and astringency. The interaction between clones and countries (environment) were nonsignificant (P=0.05), although the P values were relatively low (varying between 0.06 and 0.34).