Effects of pruning on flowering and yields of Cacao Nacional Boliviano

Abstract

Abstract Cacao Nacional Boliviano (CNB), the native cacao germplasm group in the Bolivian Amazon region, possesses distinct morphological, genetic, phenological and organoleptic characteristics. It is highly sought after in the global fine-flavour chocolate market, and has importance for conservation of cacao genetic diversity. However, CNB cultivation is minor and yield levels low. Aiming to develop profitable CNB cultivation practices adapted to its distinct phenology and genetic basis, we compared parameters on CNB flowering, yields, biomass and harvesting effort in three agricultural systems with and without pruning and varying management intensity: agroforestry with pruning (AF), underplanted secondary forest with (SFwP), and without pruning (SFnP). Repeated measures linear mixed models using Restricted Maximum Likelihood were applied for statistical analysis. While AF and SFnP yielded 127.6 ± 21.4 kg ha −1 and 212.4 ± 22.2 kg ha −1 on average, reaching > 300 kg ha −1 after 11 and 9 years, respectively, SFwP yields remained significantly lower than SFnP, with an average of 58.0 ± 9.5 kg ha −1 and maximum yield of 122.6 ± 36.5 kg ha −1 . This study demonstrates there may be a trade-off between pruning intensity and yield in AF and SFwP, as observed on young CNB trees’ yield developments and yield increases during two years without pruning in mature trees. Based on preliminary results and CNB-specific phenology, we suggest a moderate pruning intervention early in July (allowing recovery time before start of flowering season in August), along with the need for validation of our findings and further investigation into management practices tailored to CNB.