The flowering dynamics and breeding system in <i>Camellia hainanica</i> 'H4'

<italic>Camellia hainanica</italic>, a newly identified species in Hainan Province, China, is an edible oil tree with low fruit set under natural pollination. This study examined the flowering dynamics and reproductive system of <italic>C. hainanica</italic> 'H4'. Flowering occurred from mid-October to late December, peaking in early November. Each flower produced 2,373,649 ± 139,795 pollen grains. Stigmatic receptivity, measured via benzidine-hydrogen peroxide method, peaked during the initial and peak flowering phases. Orthogonal array experiments identified optimal pollen storage at '−80 °C, sealed &amp; dry, and air drying', maintaining 93% viability after 5 h <italic>in vitro</italic> germination—significantly exceeding <italic>C. oleifera</italic> (70.47%−87.91%). Pollination experiments revealed partial self-compatibility, with geitonogamy yielding a lower fruit set than xenogamy. No fruit set occurred in direct bagging or emasculation without pollination, indicating reliance on cross-pollination. The pollen-ovule (P/O) ratio (114,117.76) and outcrossing index (OCI = 4) suggested a partially self-compatible, outcrossing breeding system dependent on pollinators. Floral visitation peaked at 10:00 and 14:00, with <italic>Apis cerana</italic> identified as the most effective pollinator. These findings demonstrate that low natural yield in <italic>C. hainanica</italic> stems from pollinator limitation and partial self-incompatibility. Strategic introduction of managed pollinators and inter-varietal planting are recommended to enhance cross-pollination efficiency.