Study on the Selection of Superior Fruit-bearing Trees in the Seedling Population of Sapindus mukorossi

The study focuses on 116 individual trees of Sapindus mukorossi using principal component analysis (PCA). Starting from the sample correlation matrix, the analysis examines variations in 18 traits, including individual tree growth, yield, fruit phenotype, and internal compound content, to select superior tree types of S. mukorossi suitable for different uses. The results show that the coefficient of variation for economic traits such as saponin and oil yield of individual S. mukorossi trees exceeds that of traits like fruit phenotype. Based on the selection criterion that the cumulative contribution rate of trait variance is greater than 80%, five main components of economic traits for fruit use were identified (with eigenvalues greater than 1), namely fruit weight, fruit peel weight, kernel oil content, fruit peel saponin content, and individual tree fruit yield, contributing 24.834%, 19.624%, 14.104%, 11.887%, and 9.292%, respectively. Significant principal component values were calculated using the vector model of each principal component. With a selection rate of 5%, six plus trees were identified for each type: high-yield type, high-yield and high-oil type, high-yield and high-saponin type, and comprehensive type. The practical increase in major component values ranged between 223% and 311%, indicating significant production potential in cultivation applications.