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• In coffee plants, the water status were significantly affected by prolonged conditions of soil water deficit. • The early decreases g s indicate that coffee plants have a higher degree of stomatal sensitivity to a limited supply of water in the soil. • The reductions in photosynthetic processes are related to stomatal limitations. • The F v /F m and ETR showed no sensitivity under the water stress in coffee plants. In the coffee-growing areas of Colombia, the vulnerability of soils to conditions of water deficit has been determined and this limitation has been projected to increase its intensity and severity during extreme climatic scenarios, which constitute one of the factors limiting coffee production. The objective of this study was to evaluate the effect of prolonged water deficit conditions on the physiological performance of coffee plants cv. Castillo ®. The evaluations were carried out in 13-month-old "Castillo®" variety plants established in a greenhouse which were subjected to two conditions: well-watered at field capacity and water deficit in the soil-applied through withholding the water supply for 40 days, using a completely randomized experimental design. Leaf water potential (Ψ pd and Ψ md), gas exchange, and chlorophyll fluorescence parameters (F v /F m and ETR) were measured. In the plants with water deficit, Ψ pd and Ψ md were decreased significantly. Five days after restricting the water supply, the g s was significantly reduced to 95% at the end of the experiment compared to plants without stress. The F v /F m and ETR parameters showed no sensitivity under the water deficit conditions. Plants under water deficit decreased A max by 81% , I sat by 61%, and R d by 50%, as compared to plants without stress. The transpiration and water-use efficiency decreased, while C i had a greater concentration in plants under water deficit. These results indicate the physiological performance coffee cv. Castillo ® plants were significantly affect by prolonged conditions of soil water deficit and that the reductions in photosynthetic processes were related to stomatal limitations. [ABSTRACT FROM AUTHOR]

Since 2008, Colombia has been experiencing an epidemic of the coffee rust Hemileia vastatrix. The altitude range of the disease has expanded, and nursery and young plants that were usually not attacked by the disease are now significantly affected. To determine whether this new epidemic has been caused by a new pathogenic isolate, the molecular diversity of the pathogen causing the epidemic in different regions of the country was assessed, using AFLP molecular markers on isolates collected from coffee fields prior and after the year 2008. We also evaluated the aggressiveness of isolates collected from diverse coffee-producing areas and from different coffee genotypes. Isolates collected before and during the present epidemic were quite similar both genetically and with regard to their aggressiveness. Out of a total of 349 fragments amplified from 6 AFLP primer combinations, 48 (13.2%) were polymorphic and only 18 were unique among H. vastatrix isolates representative of pre-2008 and post-2008 epidemic populations. We conclude that the epidemic was caused by the excessive rainfall that has occurred in Colombia since 2006 and that extended to 2011 and not by the arrival of a new isolate of the pathogen or a change in virulence of the species present in the country. [ABSTRACT FROM AUTHOR]