Abstract: The Ginkgo trees have a documented history of cultivation by the Chinese for close to a thousand-year. The China possesses more than 70% of Ginkgo resources in the world. For selecting leaf-used cultivators, the genetic parameters of main quantitative characters of Ginkgo leaves from fine seedling adult trees were studied in this paper. The analyses results showed that F values of thirty characters indexes were significantly different at the 0.05 or 0.01 level. Variability coefficient and repeatability(R) of characters were related to branch ages. ECV was higher than GCV on one-year-old branch, but conversely on two or three-year-old branches. Repeatabilities(R) of leaves characters on two or three-year-old branches were more than those on one-year-old branches. Rs of ten characters were more than 80%. The relative genetic advances (ΔG′) of leaves fresh wt./S.S. (on 2-year-old branch), leaves dry wt./S.S. (on 3-year-old branch), leaves area/S.S. and leaves fresh wt./m.L.S.(on two-year-old branch) were 91.6%, 80.1%, 80.0% and 75.1% respectively. The correlation anlyses showed that the genetic correlations of 34 pairs of leaves characters were significantly or more significantly different. The genetic correlations of 9 pairs of leaf characters were more than 0.80. The correlation heritabilities[h(x_i,y_j)= COV_G(xi,yj)/σ²P(x_i)·σ²P(y_j)] were more than 70% between area per leaf and leaf width, area per leaf and leaf fresh wt., fresh wt. Per leaf and dry wt., dry wt. per leaf and leaves dry wt./m.long shoot. There was a great variance among individual trees on leaves characters. The direct and indirect selection on characters indexes of Ginkgo leaves were studied in this paper.

Key words: Ginkgo, Repeatability, Genetic advance, Genetic correlation, Correlation heritability