EFFECTS OF SHADE DENSITY AND ORGANIC FERTILIZER RATE ON GROWTH AND EARLY FIELD ESTABLISHMENT OF SOME COCOA (Theobroma cacao L.) GENOTYPES

Abstract

ABSTRACT Cocoa is an important tropical commodity tree crop. Its estimated world production was 5.9 million tons in 2024. Cocoa is fraught with problems of cultivated varieties among others. Thus, newly-released varieties were tested under shade densities and compost rates in the nursery and fields of the Federal University of Agriculture Abeokuta and Owena station of Cocoa Research Institute of Nigeria. The nurseryexperiment was 3x9x4 factorial in split-split plot laid out in Completely Randomized Design replicated three times. Three shade densities (0, 25, and 50%), Nine cocoa varieties (F3-amazon, CRINTc-1, CRINTc-2, CRINTc-3, CRINTc-4, CRINTc-5, CRINTc-6, CRINTc-7, CRINTc-8) and four compost rates (0, 0.8, 1.7 and 2.5 tons/ha) were allotted main, sub and sub-sub-plot treatments respectively. Data were taken on Percentage emergence and growth. The field trialwas 4x2x4 factorial in split-split plot laid out in Randomized Complete Block Design replicated four times. Main plot comprised four shade densities (0, 50, 100 and 200 of cocoa planting densities), sub plot comprised two cocoa varieties (F3 Amazon and Polyclonal) while sub-sub-plot contained four compost rates (0, 2, 4 and 6tons/ha). Data taken on Percentage survival and growth were subjected to analysis of variance procedures. Treatment means were separated by Duncan’s Multiple Range Test (P≤ 0.05). At 4 Weeks After Sowing (WAS), highest seedling emergence of 90% was recorded from sown under 50% shade while, lowest emergence of 54% was recorded on those sown under 0% shade. At 18 WAS, seedlings raised from CRIN TC-1 at 50% shade and 0.8 tons/ha compost produced tallest plant (49.3cm) while those raised from CRIN TC-4 at0% shade and zero compost had shorter plant (22.7cm). On the field at Owena,F3-amazon with 2 tons/hacompost application and Polyclonal with 6 tons/hacompost transplanted under 200% shade had higher survival rate (80%) compared to the least survival (31%) recorded in Polyclonal treated to zero compost application and 0% shade. On the field at Abeokuta, F3-Amazon with 6 tons/hacompost and Polyclonal with 4 tons/hacompost under 200% shade had higher survival rate of 49 and 48% respectively, compared to the least (13%) recorded under F3-Amazon treated to zero fertilizer and 0% shade.Cocoa seedlings transplanted under 100% shade was 99.2cm in height while the unshaded transplants were 76.0cm height tall at Owena. Seedlings transplanted under 200% shade was 69.4cm taller than the unshaded transplants with 55.4cm height at Abeokuta. Cocoa transplant with 4 tons/hacompost were taller (99.2cm) compared to the unfertilized (77.8cm) in Owena while in Abeokuta, cocoa transplantswith 6 tons/hacompost were taller (70.1cm) compared to the unfertilized (50.8cm). In conclusion, sowing of cocoa seed under 50% density with 1.7 tons/ha compost was optimum for growth of cocoa seedlings in the nursery. Transplanting of cocoa seedlings under 200% shade density and with 6 tons/ha was compost was optimum for the survival and growth on the field.