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The size of pollination neighbourhoods has important consequences for mating patterns, seed production, gene flow, and patterns of genetic variation across populations. We examined the size of the pollination neighbourhood in a stand of a wind-pollinated clonal plant ( Typha latifolia L.; broadleaf cattail) by evaluating spatial patterns of pollen production and seed set by individual shoots. We then simulated spatial patterns of pollen availability to investigate the shape of the pollen dispersal curve. We detected significant positive spatial autocorrelations in seed set over distances up to 5 m. This spatial variation in patterns of seed set appeared to be driven by the local availability of pollen: we found significant cross-correlations between pollen production and seed set over distances of approximately 2 m. The simulations supported this inference; simulated pollen dispersal curves fit observed patterns of seed set when ∼99% of pollen was assumed to disperse over distances less than 2 m. Together, these results indicate that the majority of pollination events occur within very close proximity of pollen sources in T. latifolia. Although within-shoot selfing has long been assumed to be a major pollination mode in T. latifolia, our data indicate that pollination events in the stand were more likely to have involved between-shoot pollination. [ABSTRACT FROM AUTHOR]

We aimed to investigate inter-year variability in mating system and paternity in an experimental Norway spruce ( Picea abies (L.) Karst.) clonal seed orchard that was established with five geographically distinct populations. Using five nuclear microsatellite markers, we analysed 1396 progeny of five mother trees representing each of the populations in three successive mast-years. Selfing varied among mother trees, ranging from 0% to 18.3% with a mean of 13.9% in 1994, 10.1% in 2004, and 7.6% in 2006. Considerable background pollination was observed in each of the three studied mast-years and reached ca. 58%. The paternity assignment conducted showed an uneven male contribution to the seed crop, what was partly related to the number of ramets per paternal clone. All provenances contributed to the seed crop, but with different input, and two provenances dominated. Effective pollen dispersal was significantly determined by distance, with 72.2% of the seed crop resulting from crosses at a distance of up to 15 m. Our study indicated that despite considerable differences in the geographic origin of populations, inter-mating between clones from each population was possible, which generally agrees with the expectations related to the establishment of this seed orchard. [ABSTRACT FROM AUTHOR]