Genetic Testing and Selection of Superior Clones in F₁ Hybrid Generationof Camellia oleifera

In order to screen excellent clones of Camellia oleifera,a multi-site joint determination experiment was carried out on 17 hybrid F₁ clones of C.oleifera.The results showed that there were significant or extremely significant differences in fruit traits among the tested C.oleifera clones,and the clone × location interaction effects of single fruit mass,yield per plant,and yield per square meter of crown width were significant.The repeatability of each fruit trait in the multi-site joint determination was relatively high,with repeatability values ranging from 0.589 to 0.862.However,the repeatability of most fruit traits at individual locations was lower than that observed in the multi-site joint determination.Compared with the control,6 hybrid F₁ clones such as ZY3,ZY10,ZY20,ZY22,ZY24 and ZY30 were screened out at the experimental sites of Shaxian,Fu'an,Fuzhou and Xianyou.The ranges of fresh seed extraction rate,dry seed extraction rate,kernel extraction rate,oil content in kernel,and fruit yield per square meter of crown width were 40.66%~45.47%,25.41%~26.68%,59.71%~65.05%,45.05%~46.58%,1.67~2.03 kg·m^-2,respectively.The average annual oil production in 6 years was 712.73~903.19 kg·hm^-2,which was 37.21%~73.87% higher than that of the control and 15.82%~46.77% higher than the average oil production of the 17 tested clones,meeting the selection criteria for excellent clones of C.oleifera.The tea oil quality of these 6 excellent F₁ clones was excellent.The ranges of oleic acid,unsaturated fatty acids,squalene,β-sitosterol,α-tocopherol and total polyphenol contents were 78.78%~81.46%,89.15%~90.05%,93.95~257.90 mg·kg^-1,195.80~246.23 mg·kg^-1,83.76~149.0 mg·kg^-1,8.18~24.36 mg·kg^-1,respectively.Correlation analysis showed that there was a certain correlation between fruit traits and the fatty acid composition and bioactive substances of tea oil.Among them,the contents of oleic acid,unsaturated fatty acids,and α-tocopherol were significantly positively correlated with single fruit mass,squalene was extremely significantly and significantly negatively correlated with yield per plant and annual averaye oil preduction,respectively,and total polyphenol was significantly correlated with fruit diameter and oil content in kernel,respectively.