Comparison of pollen gene flow among four European beech (Fagus sylvatica L.) populations characterized by different management regimes.

The study of the dispersal capability of a species can provide essential information for the management and conservation of its genetic variability. Comparison of gene flow rates among populations characterized by different management and evolutionary histories allows one to decipher the role of factors such as isolation and tree density on gene movements. We used two paternity analysis approaches and different strategies to handle the possible presence of genotyping errors to obtain robust estimates of pollen flow in four European beech (Fagus sylvatica L.) populations from Austria and France. In each country one of the two plots is located in an unmanaged forest; the other plots are managed with a shelterwood system and inside a colonization area (in Austria and France, respectively). The two paternity analysis approaches provided almost identical estimates of gene flow. In general, we found high pollen immigration (~75% of pollen from outside), with the exception of the plot from a highly isolated forest remnant (~50%). In the two unmanaged plots, the average within-population pollen dispersal distances (from 80 to 184 m) were higher than previously estimated for beech. From the comparison between the Austrian managed and unmanaged plots, that are only 500 m apart, we found no evidence that either gene flow or reproductive success distributions were significantly altered by forest management. The investigated phenotypic traits (crown area, height, diameter and flowering phenology) were not significantly related with male reproductive success. Shelterwood seems to have an effect on the distribution of within-population pollen dispersal distances. In the managed plot, pollen dispersal distances were shorter, possibly because adult tree density is three-fold (163 versus 57 trees per hectare) with respect to the unmanaged one.

Callus induction and plant regeneration from explants of commercial cultivars of leek (Allium ampeloprasum var. porrum L.).

Plant regeneration capacity was studied for 8 cultivars and 4 accessions of leek (A. ampeloprasum var. porrum L.). Compact callus was induced on embryo and leaf explants on three different media. The highest frequency of compact callus formation (up to 90%) was obtained when mature, zygotic embryos were cultured on MS medium, containing 30 g/l sucrose and 1 mg/l 2,4-D. Regeneration occurred through somatic embryogenesis on MS medium, supplemented with 1 mg/l kinetin. Plants could be regenerated from all cultivars and accessions tested. These cultivars and accessions could be classified into three groups with respect to shoot formation frequency. The results suggest a distinct influence of the genotype on the morphogenic response of leek embryo explants in vitro.