Yield efficiency analysis in a cocoa clonal orchard derived from reciprocal grafting

Analysis of trunk cross-sectional area (TCSA) and yield components were conducted among six full-sib families, and among thirty-six clones established from reciprocal grafting using scions from ortet selection in the six families. The objective was to analyze how full-sib family traits impact rootstock and scion characteristics to attain high yield efficiency in grafted cacao orchards. The study included two experiments: experiment 1 had six cocoa genotypes tested as hybrids whereas experiment 2 involved evaluation of 36 rootstock/scion combinations derived from the six genotypes in the first experiment. Both experiments were laid out in RCBD with four replications. Stem diameter and yield data were measured over a 4-year period. Diallel analysis was effective in summarizing the relationship between the six genotypes, distinguishing among them either as effective rootstock and/or scion types. Significant general compatibility (GC) was observed for all traits studied, but specific compatibility was not significant for any trait. This suggests lack of interaction between rootstock and scion genotypes in the expression of the traits. Patterns of GC revealed the distinctive performance of CRG 0314, as being suitable both as a rootstock type and productive scion, reflecting the attributes of its full-sib counterpart. Two-way ANOVA similarly showed significant rootstock and scion main effects, but no significant interaction for any trait, emphasizing that a good rootstock would be suitable for any productive scion type. Clonal performance reflected full-sib family attributes. Full-sib family performance was evident in rootstock types particularly for TCSA, whereas the impact on scion was mostly for yield related traits. High yield efficiency was achieved by two pathways: scions of high yield potential on invigorating full-sib rootstock, or scions of high yield potential on low vigour rootstocks.