Artificial pollination as a tool to improve fruit set and yield in macaw palm (Acrocomia aculeata (Jacq.) Lodd. ex Mart.)

Abstract

The low efficiency of natural pollination in the macauba palm limits the productive potential of the species. To address this constraint, we evaluated the effectiveness of artificial interventions applied to the inflorescence and pollination process as strategies to increase fruit set following characterization of inflorescence developmental stages. Inflorescences were monitored from their emergence until natural opening. Before natural opening, physical interventions were performed to promote floral exposure, and subsequent effects on fruit set were assessed. Artificial pollination was carried out on spathes subjected to forced opening (stage IV) and on naturally opened spathes, with fruit set and fruit biometric traits quantified thereafter. Following analysis of pollen viability at stages III, IV, and V, artificial pollination was performed using pollen from both immature (stage IV) and mature (stage V) inflorescences to assess their relative fertilization efficiency. Inflorescences displayed asynchronous phenological development, with variation detected among genotypes. The physical interventions did not influence fruit set. In contrast, artificial pollination markedly enhanced fruit set without altering fruit biometric parameters, with greater gains observed in forced-opening spathes (4.6-fold increase) compared with naturally opened spathes (3.2-fold increase). Pollen collected from inflorescences at stages IV (immature) and V (mature) exhibited high viability (> 90%), and pollen from immature inflorescences performed comparably to that from mature inflorescences in promoting fertilization. The study underscores artificial pollination as a promising management strategy to enhance fruit production in this species.

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