Evaluation of Growth and Wind Resistance Traits and Selection of Elite Individuals in Female Casuarina equisetifolia Plants

To elucidate the genetic variation patterns of growth and stress resistance traits in Casuarina equisetifolia,181 female individuals selected from the National Casuarina Germplasm Resource Bank at the Chihu State-Owned Shelter Forest Farm in Hui’an County,Fujian Province were used as experimental materials.Based on field survey data collected after Super Typhoon "Doksuri" in 2023,tree height,diameter at breast height(DBH),individual stem volume and wind resistance grade were measured.Principal component analysis(PCA)and hierarchical cluster analysis were comprehensively employed to screen superior individuals combining rapid growth and strong wind resistance.The results showed that the mean values of tree height,DBH,individual stem volume and wind resistance grade of the tested female plants were 9.04 m,11.34 cm,0.0127 m³ and 3.22,with coefficients of variation of 20.83%,29.29%,66.88% and 39.49%,respectively;differences in all traits among individuals reached highly significant levels(P<0.01).Two principal components were extracted by PCA,with a cumulative variance contribution rate of 92.54%,representing a comprehensive growth factor(PC1)and a comprehensive wind resistance factor(PC2),respectively.Cluster analysis classified the population into four groups,among which Group II(growth-dominant type)accounted for 13.8% and exhibited the optimal combination of growth and wind resistance.Ultimately,18 fast-growing and wind-resistant elite individuals were selected,which can serve as core parental materials for improved variety breeding,seed orchard establishment and hybrid breeding of shelter forests along the southeastern coast of China.