According to local estate management and based on information
from the Malaysian Cocoa Board (MCB, 2012), under current
common-practice cultivation factors (full-sun system with compound
NPK fertilizer application) cocoa clones PBC130 and
PBC123 represent the worst and respectively best available cocoa
clone at the estate in terms of pest and disease resistance and yield.
PBC130 trees are susceptible to both Vascular Streak Dieback (VSD)
(Ceratobasidium theobromae P.H.B. Talbot and Keane) and Black Pod
Disease (BPD) (Phytophthora palmivora E.J. Butler) and this clone
has a seed index (number of dried beans per 100 g) of 78 (Lee et al.,
1993) whereas PBC123 trees exhibit moderate resistance against
VSD (Bong et al., 1996), intermediate resistance against BPD, and a
seed index of 96 (Lee et al., 1993). Selection of these extremes
allowed to thoroughly examine the interaction effects of the clone
factor with all applied treatments.