Effects of some bean characters on germination and seedling growth of cocoa (Theobroma cacao, L.)

Abstract

Raising of cocoa (Theobroma cacao, L.) seedlings is hampered by some often neglected traits. Three experiments were set up to test the effects of bean size (by weight): plumpy beans (mean weight (MW) 3.2g; n=20), medium-sized (MW=2.1g; n=20) and slaty (MW=1.3g; n=20), location of beans within pods: (beans extracted from stalk-end, middle and pointed-end of pods) as well as beans extracted from pods harvested from different locations on the tree: trunk, lower canopy and upper canopy on germination and seedlings growth. The experiments were laid out in completely randomised design with 4 replications. Data collected on % germination of the beans and growth of the seedlings were analysed using ANOVA at P<0.05. At 14WAS, % germination was between 82.5% for plumpy beans and 75% for each of medium and slaty beans. At 14WAS, seedlings raised from plumpy beans had significantly higher plant height (23.02cm) compared to those from slaty beans (20.53cm). Beans at the pointed-end of a pod had highest % germination of 88-3 % while the beans at the middle and the petiole-end of the pod had 81.7%. At 14WAS, the seedlings raised from beans focated at the pointed-end of the pod were significantly taller (25.2cm) than those of the beans located at the middle (23.85cm) and petiole-end (23.26cm) of the pod. Beans extracted from pods harvested from the lower canopy had highest % germination (92.5%), followed by beans of pods harvested from the trunk (85.0%) while beans of pods harvested from the upper canopy had the least germination percentage of 5% at 14WAS. Seedlings from beans extracted from pods on the trunk and lower canopy of a cacao were significantly taller (25.6cm) than those from upper canopy (10.68cm) at l4WAS. Seedlings from plumpy beans had highest DMY of 2.89g Compared to 1.92g and 1.22g produced by seedlings raised from medium-sized and slaty beans respectively, while the best DMY were obtained from trunk-bean-seedlings (2.58g/plant) and lower canopy-bean-seedlings (2.3g/plant). The upper canopy-bean-seedlings had significantly lower DMY (1.4g/plant). Germination and growth of cocoa seedlings were found not to be affected by weight classes of beans tried in this study and longitudinal positioning of cocoa beans in a pod, but, affected by position/location of cocoa pods on the tree.