Genome Size, Flowering, and Breeding Compatibility in Osmanthus Accessions

Extending the range of Osmanthus species into more cold-hardy climates would open new opportunities for adoption and use these by growers, landscapers, public. Breeding improvement is hindered few available cultivars a lack female or perfect flowers. The objectives this study were to evaluate floral morphology pollination biology in U.S. market. Thirty-three genotypes representing four evaluated McMinnville, TN, USA genome size, morphology, pollen viability, self- cross-compatibility. All diploid with 2C sizes ranging from 2.89 3.21 pg. Perfect flowers observed all O. armatus 82% heterophyllus genotypes. fortunei fragrans had male-only Pollen viability based on staining vitro germination ranged 8% 98% 6% 53%, respectively. was stigmas 94.2% collected 24 hours after cross- self-pollination. There significant association between cross type percentage tubes reaching ovaries; 72 h, reached ovaries 67% intraspecific crosses, 78% interspecific 0% self crosses (χ2 = 26.5, p < 0.001). This provides evidence self-incompatibility system insights challenges hybrid breeding.