Is coffee flowering the bottleneck in climate change adaptation?

Rahn Eric, Läderach Peter, Vaast Philippe. 2019. Is coffee flowering the bottleneck in climate change adaptation?. In : 27th Biennial ASIC Conference, Portland, 16-20 September 2018. Book of abstracts 2019. ASIC, SCA. Portland : ASIC, Résumé, 1 p. Biennial ASIC Conference. 27, Portland, États-Unis, 16 Septembre 2018/20 Septembre 2018.

Résumé : RATIONALE Flowering is a particularly important trait in coffee (Cofjea arabica L.). It determines the coffee yield, quality and production costs. It defines the critical period of highest demand for nutrients, water and pest and disease control. During this development phase, the plant is most susceptible to extreme climatic conditions. Factors such as temperature, light, soil and air water availability, carbon-to-nitrogen ratio, crop load and genotype can affect flowering. Recent advances in understanding the physiological mechanisms of the coffee plant, including the effects of elevated atmospheric [C02], have greatly improved our abilities to predict possible impacts of climate change on coffee's photosynthetic capacity and allocation of photoassimilates. Yet, we know very little regarding the effects of climate change on reproductive processes and hence final crop yield. The question arises thus, whether flowering might constitute the process most affected by increasing temperature and changes in rainfall pattern and intensity, even though the coffee's physiology might be able to partially adapt. This study reviews current knowledge on coffee flowering and its possible response to climate change. We use a simulation model to evaluate the impact of possible changes in climate on flowering success. METHODS We use a process-based coffee model with a detailed flowering module representing different assumptions regarding flowering initiation, intensity, and success, accounting for multiple flowering events. The flowering module was implemented using an age-structured matrix population model that classifies the flowering process into five development stages: Nodes, floral initiation, ready to flower, pinhead stage, and bean maturation. The model is compared to observation data registered in Cajibio, Cauca, Colombia and climate change scenarios are explored using different assumptions. RESULTS We highlight important knowledge gaps related to coffee flowering success. The key question will be whether floral initiation, abnormal flowering, and flower abortion are caused by heat and water stress independent of carbohydrate supply and hence unaffected by elevated atmospheric [C02]. Heat sterility reduces bean yield independent of atmospheric [C02], yet we know little about these temperature thresholds, nor whether differences exist among coffee varieties. We show how climate variability (e.g. El Nino-Southern Oscillation[ENSO]) affects flowering and biennual bearing in different climatic conditions, requiring careful adaptation of agronomic management depending on ENSO year. CONCLUSIONS & PERSPECTIVES By combining field observations and simulation models we can test different assumptions on how climate affects coffee flowering (number of events, intensity and survival) and hence agronomic management needs, labour demand, bean yield, and profitability. Closing the knowledge gaps of the mechanisms of flowering success as affected by temperature, rainfall, and light will require detailed flowering data sets distributed across the coffee growing regions to test our current assumptions. Consequently, we would like to take this opportunity to develop a network to share data between instiutions and researchers on this strategic issue.

Mots-clés Agrovoc : Coffea arabica, floraison, changement climatique, photosynthèse, modèle de simulation

Mots-clés géographiques Agrovoc : Colombie

Classification Agris : F60 - Physiologie et biochimie végétale
F63 - Physiologie végétale - Reproduction
P40 - Météorologie et climatologie
U10 - Informatique, mathématiques et statistiques

Auteurs et affiliations

• Rahn Eric, CIAT (COL)
• Läderach Peter, CIAT (VNM)
• Vaast Philippe, CIRAD-PERSYST-UMR Eco&Sols (VNM)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/593449/)

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