Strategy for establishing a pollen cryobank of wild species of Passiflora L.

Cryopreservation of pollen stands out as a significant strategy in conserving species diversity, serving as a tool for genetic enhancement. This study investigated crucial factors for pollen cryopreservation, revealing unprecedented results linked to dehydration conditions and periods, encompassing peculiarities of the evaluated species. Data on the cryopreservation of wild passion fruit species are presented, outlining an innovative and efficient protocol to influence future research on pollen cryopreservation, reinforcing genetic improvement, and establishing a cryobank for pollen from wild species of the genus. Pollen grains from eight Passiflora species were evaluated, subjected to dehydration in a desiccator with silica gel and an oven at 35 °C at intervals of 0, 20, 40, or 60 min. The dehydrated material was subsequently cryopreserved for 24 h, followed by in vitro germination tests and measurements of pollen tube length to determine the optimal dehydration time for each species. Furthermore, controlled pollination was performed using pollen cryopreserved for 24 h. This pollen exhibited germination rates ranging from 71% (P. edmundoi) to 28% (P. misera), while fresh pollen showed germination rates from 89% (P. edmundoi) to 37% (P. organensis). Field tests involving controlled pollination using cryopreserved pollen resulted in fruiting rates from 50% (P. edmundoi) to 40% (P. gibertii), producing seeds with germination percentages ranging from 67 to 99%. These in vitro and in vivo results highlight the effectiveness of cryopreservation as a technique to conserve sets of haploid genes within the cryogenic bank.