Rooting Ability of Cocoa (Theobroma cacao L.) Stem Cuttings: Effect of Genotype, Cutting Type, Hormone Concentration and Their Interactions

Abstract

Aims: This study aimed to evaluate the rooting ability of stem cuttings of eight-year-old cocoa hybrids disseminated in the 5th agroecological zone of Cameroon. Study Design: The experiment was a 6 x 2 x 3 randomised complete block design with three replications. Place and Duration of Study: The study was conducted at the multipurpose agricultural research station Nkoemvone – Ebolowa from February to September 2017. Methodology: The studied factors were six genotypes (G1 = IMC67 x SNK 64, G2 = SNK 620 x MA 12, G3 = T79/501 x SNK 109, G4 = T79/501 x SNK 64, G5 = SNK 413 x UPA 143 and G6 = UPA 143 x SNK 64), two Cutting types (C1 = Orthotropic and C2 = Plagiotropic) and three rooting hormone concentrations (H1 = 2 tablets per liter of water, H2 = ½ tablet per liter of water and H3 = 1 tablet per liter of water). Rooting ability was evaluated by assessing percentage of rooted cuttings, number of root per rooted cutting and the length of the longest root per rooted cutting. Results: Analysis of variance results indicated that genotype, hormone concentration and most of their interactions were highly significant while cutting type was not significant on the measured traits. The best rooting was obtained with genotype G4 for all the measured parameters. It was shown in this experiment that genotype G4 could be propagated using Rhizopon hormone, with a concentration of ½ tablet per litre of water and plagiotropic cutting type. This is also noticed in their interaction terms, where genotype G4/Hormone concentration 2 and 3 were the best combinations for all parameters.  Conclusion: Significant differences among genotypes are an indication that different genotypes may require different conditions for their propagation. As such investigations into the requirement for the propagation of the other genotypes should be considered in the future.