Sexual Asymmetry based on Flowering Assessment in a Clonal Seed Orchard of Pinus densiflora

Abstract

Abstract Two equations were formulated in order to estimate the degree of sexual asymmetry for monoecious species. The concepts of the equations were formulated on the basis of the effective population numbers of female and male parents [i.e, As (v)], and the differences of relative frequency between genders [i.e., As (x)]. These equations were applied to estimate the degree of sexual asymmetry based on the empirical data of flowering assessment in a clonal seed orchard of Pinus densiflora. The yearly variation in the production of female and male strobili was found. The effective population numbers at gamete levels (vf and vm) and clone level (vb) varied among 8 observation years. Both As (x) and As (v) were negatively correlated with effective numbers at gamete and clone levels. Averages of female and male strobilus production and estimates of sexual asymmetry were negatively correlated but the correlation was not significant. The correlations among effective number of clone (vb), arithmetic mean of female and male effective numbers (va) and estimate of sexual asymmetry [As (x)] were strong and significant. Relatively larger difference between vb and va were found when higher level of sexual asymmetry were observed.