Variation in the amount of pollen per male flower on Abies sachalinensis

It is important to evenly increase the amount of scattered pollen per clone for maintaining high genetic variation in clonal seed orchards. It is thus imperative to determine not only the number of male flowers per tree, but also the amount of pollen per male flower in each clone. In this study, the existence of annual variation on the fresh weight of male flowers (FW) and the clonal and annual variation, and ramets’ variation with the same or different tree ages on the weight of pollen per male flower (WP) were investigated using 21 Abies sachalinensis clones for 3 years. The results indicated that there were significant differences in FW and WP among clones each year and the relationships between FW and WP were linearly significant for every year. WP also showed significant annual variation, while the re was also significant variation in ramets. The clonal repeatability regarding WP was 0.37—0.47 for data obtained for 2 or 3 years and the generalized linear mixed models with the random effects of clone, year, and ramet indicated that the effect of clone more strongly affected WP than other effects. These results suggested that WP on A. sachalinensis is a trait that is considerably influenced by clonal characteristics; there is thus a need to characterize this trait in each clone when using seed orchards.