Response of cocoa trees (Theobroma cacao) to a 13-month desiccation period in Sulawesi, Indonesia

In South-east Asia, ENSO-related droughts represent irregularly occurring hazards for agroforestry systems containing cocoa which are predicted to increase in severity with expected climate warming. To characterize the drought response of mature cocoa trees, we conducted the Sulawesi Throughfall Displacement Experiment in a shaded (Gliricidia sepium) cocoa agroforestry system in Central Sulawesi, Indonesia. Three large sub-canopy roofs were installed to reduce throughfall by about 80% over a 13-month period to test the hypotheses that (i) cocoa trees are sensitive to drought due to their shallow fine root system, and (ii) bean yield is more sensitive to drought than leaf or stem growth. As 83% of fine root (diameter <2 mm) and 86% of coarse root biomass (>2 mm) was located in the upper 40 cm of the soil, the cocoa trees examined had a very shallow root system. Cocoa and Gliricidia differed in their vertical rooting patterns, thereby reducing competition for water. Despite being exposed for several months to soil water contents close to the conventional wilting point, cocoa trees showed no significant decreases in leaf biomass, stem and branch wood production or fine root biomass. Possible causes are active osmotic adjustment in roots, mitigation of drought stress by shading from Gliricidia or other factors. By contrast, production of cocoa beans was significantly reduced in the roof plots, supporting reports of substantial reductions in bean yields during ENSO-related drought events in the region. We conclude that cocoa possesses traits related to drought tolerance which enable it to maintain biomass production during extended dry periods, whereas bean yield appears to be particularly drought sensitive.

Bibliographic Details

Main Authors:	96938 Moser, G. autor/a, 86259 Leuschner, C. autor/a, 77768 Hertel, D., 78518 Hölscher, D. autor/a, 84353 Köhler, M. autor/a, 85957 Leitner, D. autor/a, 94089 Michalzik, B. autor/a, 106931 Prihastanti, E. autor/a, 124626 Tjitrosemito, S. autor/a, 117358 Schwendenmann, L. autor/a
Format:	biblioteca
Language:	eng
Published:	Berlín (Alemania): Springer, 2010
Subjects:	THEOBROMA CACAO, GLIRICIDIA SEPIUM, PLANTACION, PLANTAS DE SOMBRA, AGROFORESTERIA, RAICES, CAMBIO CLIMÁTICO, RESISTENCIA A LA SEQUIA, RESPUESTA DE LA PLANTA, RENDIMIENTO DE CULTIVOS,
Online Access:	https://doi.org/10.1007/s10457-010-9303-1
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