Flowering and fruiting characteristics and evaluation of spring flowering plants of Camellia oleifera hybrid offspring

To breed novel Camellia oleifera cultivars characterized by spring flowering, superior fruit economic traits, and excellent oil quality, this study conducted a comprehensive evaluation of distant hybridization progeny, aiming to screen elite spring-flowering germplasm resources.

Twenty-seven initially selected spring-flowering superior individuals from the hybrid progeny of ‘Youza 2’ (YZ2) × ‘Deyou 2’ (DY2) served as experimental materials. Systematic observations were made on their flowering phenology, floral organ morphology, pollen viability, and fruit economic traits. Data were analyzed using correlation analysis, difference analysis, and principal component analysis.

Significant segregation in flowering traits was observed among the 27 spring-flowering Camellia oleifera superior individuals. The earliest initial flowering date occurred in YD21, while the latest was recorded for YD11. YD26 exhibited the longest full-bloom period, lasting 32 days. Floral organ traits showed varying degrees of variation among individuals, with style number ranging from 3 to 5 lobes and petal number ranging from 5 to 10. Notably, YD22 displayed the largest flower diameter (89.56 mm), consistent with entomophilous characteristics. Correlation analysis revealed highly significant positive correlations (P<0.01) between petal number and style number, and between flower diameter and style length, indicating coordinated regulation in floral organ development. Pollen viability varied markedly among individuals, ranging from 35.35% to 83.31%. YD17 demonstrated the highest pollen viability (83.31%), and the phenomenon of “pseudo-pollen” was observed. Regarding fruit traits, YD6 possessed the thinnest pericarp (1.32 mm), with its fresh seed yield rate (52.99%) and kernel oil content (51.17%) being significantly superior to parental performance. YD17 exhibited the highest fresh seed yield rate (63.31%), standing out prominently among the population. Unsaturated fatty acids accounted for 85.40%-88.01% of the total fatty acids in the oil. YD11 displayed the highest oleic acid content (79.77%).

Comprehensive evaluation identified superior individuals YD3, YD7, and YD17 as outstanding performers for key economic traits, including fruit size, seed yield rate, and oleic acid content. These individuals represent valuable germplasm resources for further breeding and research.