Does Criollo cocoa have the same ecophysiological characteristics than Forastero?

Abstract

Background: The Palma Real Mountain of Venezuela has Criollo and Forastero cocoa trees of over 50 years old. These individuals are considered ancestral representatives of high quality cocoa that have survived for many years in this location without any agronomic management.

Question: This study shows some physiological traits of these old trees, in order to determine whether differences exist in photosynthetic capacity and some biochemical parameters between the two types of cocoa growing under natural conditions.

Studied species:  Theobroma cacao L.

Study site and years of study: was done in the mountain Palma Real in the Island of Margarita, Edo. Nueva Esparta, in January 2008 and November 2009.

Methods: The individuals present in the area were initially characterized as Criollo or Forastero and gas exchange, chlorophyll a fluorescence and the response of the photosynthetic rate (A) to intercellular CO₂ concentration (C_i) and photosynthetic photon flux density (PFD), carbon isotope ratio (?¹³C), nitrogen isotope ratio (?¹⁵N), leaf N and chlorophyll content  were evaluated.

Results: The results showed that the gas exchange characteristics of Criollo cocoa differ slightly from those of Forastero. However, similar PFD saturation (~400 mmol m^-2 s^-1) with values of A at saturating light approaching 4 mmol m^-2 s^-1, carboxylation efficiency (CE) and photochemical activity, indicated a comparable photosynthetic capacity in both cocoa types.

Conclusions: There are apparently no physiological disadvantages in Criollo compared with Forastero trees and therefore both could be recommended as suitable materials for cultivation in similar environments, thereby expanding cultivation of high quality cocoa.