Browsing by Author "Thomas, G."

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    Canopy architecture, photosynthesis and yield of cocoa trees
    (2007-02-08) Thomas, G.; Balasimha, D.
    Five different types of canopy architecture viz., unpruned single storey (T1), unpruned double storey (T2), minimum pruning to give cone shape (T3), severe pruning (T4) and flat spreading canopy (Ts) were maintained in cocoa. Due to pruning, the canopy area and number of branches were significantly reduced. A significantly low light interception efficiency with correspondingly high PAR was noted in pruned treatments. Due to this effect, stomalal conductance and transpiration rate increased in T4 and T}, with a reduction in water use efficiency. Net photosynthetic rate did not show any significant treatment effect. Current photoassimilaies were translocated and the stored stem starch was mobilized to sustain the sink demand exerted by intense flushing observed in the pruned treatments. The maximum yield was obtained in T1 and T2. The low yields in T,, T4 and T5 treatments can be attributed to the following reasons: (i) the reduction in i canopy area and number of branches, (ii) carbohydrate exhaustion for flushing and subsequent carbohydrate stress at the ; time of flowering and pod load, (iii) high transpiration rate. It is concluded that cocoa requires a comparatively big and spreading canopy for better yield. Whenever pruning is found necessary, it should be restricted to maintenance pruning towards optimum leaf area index and removal of excessively shaded bottom or interior branches.