Work

The flowering dynamics and breeding system in Camellia hainanica 'H4'

Year: 2025

Type: article

Abstract: Camellia hainanica, 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 C. hainanica '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 & dry, and air drying', maintaining 93% viability after 5 h in vitro germination—significantly exceeding C. oleifera (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 Apis cerana identified as the most effective pollinator. These findings demonstrate that low natural yield in C. hainanica stems from pollinator limitation and partial self-incompatibility. Strategic introduction of managed pollinators and inter-varietal planting are recommended to enhance cross-pollination efficiency.

Source: Tropical Plants

DOI: 10.48130/tp-0025-0012