Early selection of excellent high carbon sink families of Cyclobalanopsis gilva

Objective The aim is to provide excellent materials for improving the carbon storage of forest stands by screening high carbon sink families of Cyclobalanopsis gilva. Method The standard trees of Cyclobalanopsis gilva of different forest ages and diameter classes of 4-14 cm were selected.The aboveground and underground samples were collected by individual felling method and full digging method，respectively.The biomass and organic carbon content were measured，and the biomass and organic carbon models were constructed.The model was used to calculate the biomass and carbon storage of 42 families of 3-year-old Cyclobalanopsis gilva，analyze the genetic variation characteristics of growth and form traits of each family， analyze the genetic variation of biomass and carbon storage of each family，estimate the genetic gain，and screen out the excellent families of Cyclobalanopsis gilva with large biomass and carbon storage gain. Result （1）There was a significant family×block effect （P<0.01）in the growth and form quality traits of different families of 3-year-old Cyclobalanopsis gilva.The heritability of tree height， ground diameter，crown width and longest lateral branch length was high （0.470-0.518），and the heritability of single plant was relatively low.（2）The optimal fitting model of biomass and organic carbon of Cyclobalanopsis gilva was lnY=k₀ +k₁ lnD+k₂ lnH+k₃ lnCW.The fitting accuracy of aboveground part model was better than that of underground part， and the fitting effect of dry biomass and organic carbon model was the best.（3）There were significant or extremely significant family × block effects on biomass and carbon storage of different families of 3-year-old Cyclobalanopsis gilva.The heritability of family was higher than that of single plant.The genetic gains of biomass and carbon storage of living branches were the highest，which were 43.93% and 47.60%，respectively.（4）Based on the comprehensive comparison of family biomass，carbon storage，comprehensive selection index and BLUP breeding value，the top 10% were selected as the selection standard of excellent high-carbon sink families.Fujian JO1，Hunan CB8 and Hunan YS3 were selected as excellent high-carbon sink families.The genetic gains of biomass and carbon storage were 21.27% and 13.60%，respectively， and the realistic gains were 38.96% and 49.98%， respectively. Conclusion The heritability of 3-year-old Cyclobalanopsis gilva families is generally high，which is controlled by strong family genetic control.The selected 3 excellent high-carbon sink families of Cyclobalanopsis gilva can be used as excellent material selection for carbon sink afforestation.