Effect of Zinc Levels on Growth, Chlorophyll Content and Biomass Allocation of Cocoa Varieties

A pot experiment conducted at ICAR-CPCRI, RS, Vittal, provided practical insights into the effects of varying zinc levels (0.25, 0.75, and 1.25 mg/7L pot) on the growth, chlorophyll content and biomass allocation of eight cocoa varieties. The study revealed significant varietal differences and a positive influence of zinc application on growth parameters. Notably, the variety VTLCC-1 exhibited the highest plant height (138.73 cm) and stem diameter (11.40 mm) under the medium zinc level, as well as the greatest leaf count (70.33) under the high zinc level. In contrast, VTLCH-4, grown with a low zinc level, recorded the highest total chlorophyll content (4.79 mg g⁻1). Additionally, VTLCS-1, grown with a low zinc level showed a higher shoot-to-root ratio of 8.74, and varieties VTLCH-4 and VTLCS-1 recorded the highest root-to-shoot ratio of 0.25 at a high Zn level. This underscores the unique responses of different cocoa varieties to varied Zn levels in terms of growth, chlorophyll content and the allocation of biomass, providing valuable information for sustainable cocoa production.