Path analysis of the efficiency in the bud-flower-fruit transition of pitahaya: the biochar-Trichoderma viride combination improves yield in Hylocereus costaricensis and H. undatus cv. Vietnam White

Abstract

Introduction: Pitahaya (Hylocereus spp.) is an emerging fruit crop, yet the physiological mechanisms by which bioinputs enhance reproductive efficiency and yield remain poorly understood. This study evaluated the effects of rice husk biochar combined with Trichoderma viride on reproductive development and fruit production in two pitahaya genotypes. Methods: A field experiment was conducted in Jaén, Peru, using a randomized complete block design with four treatments (control, biochar, T. viride, and biochar + T. viride). Reproductive traits and fruit yield were monitored over two production cycles and analyzed using generalized linear models and path analysis. Results: The combined biochar + T. viride treatment enhanced reproductive performance in a genotype-dependent manner. In H. costaricensis, it significantly increased flower production and fruit yield, while path analysis identified flowering as the key mediator of yield and revealed a reproductive carrying-capacity threshold of approximately 17 flowers. In contrast, H. undatus cv. Vietnam White showed only marginal responses to bioinput application. Discussion: These findings demonstrate that the effectiveness of biochar and T. viride depends on genotype-specific reproductive strategies. The combined bioinput treatment substantially improved reproductive efficiency and yield in H. costaricensis, whereas the limited response of H. undatus suggests lower phenotypic plasticity and distinct patterns of resource allocation By integrating longitudinal field evaluations with path analysis, this study provides a physiological framework for precision bioinput management based on reproductive carrying capacity and genotype-specific crop responses, offering new insights for sustainable pitahaya production.