Gene flow in Plantago I. Gene flow and neighbourhood size in P. lanceolata

Abstract

The genetic population structure and gene flow in the obligatory outbreeding plant species Plantago lanceolata L. were determined in the Westduinen (Wd) pasture population in the South-West of the Netherlands. Three experiments were performed: the measurement of genetic structure using allozyme variation, pollen flow in a wind-tunnel and the distribution of an allozyme marker in a garden experiment. The position and allozyme genotype of 524 plants from eight subpopulations in the Westduinen population were determined. The population exhibited local differentiation: genotype frequencies within subpopulations were mostly in Hardy-Weinberg equilibrium, and gene frequencies varied significantly between subpopulations. The wind-tunnel experiments showed that wind speed, source height and capture height of pollen influenced the pollen-mediated gene flow and therefore neighbourhood sizes. In the garden experiment a clear picture of actual pollen flow could be shown.Estimates of neighbourhood and gene transport parameters from the data of the three experiments indicated restricted gene flow: neighbourhood size (NJ was between 14 and 20 plants, mean gene transport per generation (M) between 02 and 14 metres. We argue that this combination of small effective number and low gene transport leads to the substructuring of the Westduinen population of P. lanceolata.

Population genetic structure of Banksia spinulosa

“…Dispersal of pollen and/or seed usually follows a leptokurtotic distribution, with most dispersal occurring within a few metres of the parent plant (e.g. Bos et al, 1986). Thus, individuals generally mate with neighbouring ones, generating small neighbourhood sizes (e.g.…”

Simulations of flowering time displacement between two cytotypes that form inviable hybrids

“…Neigh-bourhood sizes of the different runs are given in Table 2. These sizes were chosen because of the gene flow distances measured in Plantago lanceolata (Bos et at., 1986) and the densities of flowering Plantago media in sympatric cytotype populations in the Pyrenees (Van Dijk etal., 1994).…”

Gene flow in Plantago. II. Gene flow pattern and population structure. A simulation study

“…, 1985). Experiments in a wind tunnel with release and recapture of pollen on the same or at a lower level showed comparable pollen flow patterns (Bos et a!., 1986). These patterns are presented in fig.…”

“…In an earlier paper (Bos et aL, 1986) we measured gene flow in a P. lanceolata population and argued that in certain conditions restricted gene flow leads to substructuring of the population. In this paper the species P. lanceolata serves as an example to describe-among other things-the influence of the reproductive character "protogyny-growth syndrome" on the amount of inbreeding and genetic structure in a simulated population.…”