Pollen Viability and Stigma Receptivity in Zephyranthes: Implications for Controlled Pollination

Knowledge of pollen viability, pollen longevity, and stigma receptivity in Zephyranthes remains limited despite their importance for successful hybridization. Therefore, this study evaluated these reproductive traits in four Zephyranthes species (Z. traubii, Z. candida, Z. grandiflora, and Z. citrina) and one cultivar, ‘Pim Chomphu’, to provide baseline reproductive information for controlled pollination. Pollen viability was evaluated using tetrazolium staining at different collection times and storage conditions, whereas stigma receptivity was assessed using 6% hydrogen peroxide (H2O2), with reproductive outcomes following controlled self-pollination evaluated at the corresponding time points. Tetrazolium-based pollen viability exhibited taxon-specific temporal patterns; however, viability was generally high at 11:00, corresponding to 1 day after anthesis (1 DAA) in Z. traubii and the day of anthesis (0 DAA) in the remaining taxa. The combined protocol of desiccation followed by storage at −5 °C or −20 °C maintained tetrazolium-based pollen viability for up to 120 days. Although all taxa showed positive H2O2-based stigma responses across the evaluated time points, reproductive outcomes following self-pollination differed markedly among taxa. Z. citrina set fruit at all pollination times, whereas Z. candida failed to set fruit. The remaining taxa showed variable fruit set and seed germination depending on pollination timing. These results indicate that positive H2O2-based stigma responses should be interpreted as biochemical indicators of potential stigma receptivity and considered together with subsequent reproductive outcomes. These findings provide baseline reproductive information to support pollen management and controlled pollination in Zephyranthes.