Floral characterization and pollen germination protocol for Castanea crenata Siebold & Zucc

•The androgynous and staminate catkins showed similar pollen viability frequency.•Cultivars ‘Morioase’ and ‘Tamatsukuri’ showed the highest percentage of viability, but lower amounts of pollen per anther and per flower.•The cultivars showed differences for in vitro pollen germination.