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Nobuhiro Tomaru - One of the best experts on this subject based on the ideXlab platform.

  • Pollen Flow and effects of population structure on selfing rates and female and male reproductive success in fragmented Magnolia stellata populations.
    BMC Ecology, 2013
    Co-Authors: Suzuki Setsuko, Teruyoshi Nagamitsu, Nobuhiro Tomaru
    Abstract:

    Background Fragmentation of plant populations may affect mating patterns and female and male reproductive success. To improve understanding of fragmentation effects on plant reproduction, we investigated the Pollen Flow patterns in six adjacent local populations of Magnolia stellata, an insect-pollinated, threatened tree species in Japan, and assessed effects of maternal plant (genet) size, local genet density, population size and neighboring population size on female reproductive success (seed production rates), and effects of mating distance, paternal genet size, population size and separation of populations on male reproductive success.

  • patterns of Pollen Flow in a dense population of the insect pollinated canopy tree species castanopsis sieboldii
    Journal of Heredity, 2012
    Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Tohru Manabe, Masahiro Miura, Nobuhiro Tomaru, Shinichi Yamamoto
    Abstract:

    Insect pollinations of tree species with high-density populations have rarely been studied. Since the density of adults can affect effective Pollen dispersal, short-distance pollination, even by insects, may frequently occur in high-density populations. To test this prediction, we investigated pollination patterns in a high-density population of the insect-pollinated canopy tree species Castanopsis sieboldii by paternity analysis using genotypes at 8 microsatellite loci of 145 adult trees and 439 seeds from 11 seed parents in a 4-ha plot. We then explored their genetic effects on the population by calculating other population genetics parameters. Although C. sieboldii has high potential for long-distance dispersal of Pollen (as indicated by a fat-tailed dispersal kernel), the cumulative pollination at the local scale was spatially limited and strongly dependent on the distance between parents due to the high density of adults. Genetic diversity estimates for Pollen pools accepted by each seed parent converged on a maximum as the effective number of Pollen parents increased. The genetic diversity of Pollen pool bulked over all the seed parents from inside the plot did not differ from that of the total Pollen pools. Therefore, although Pollen Flow from distant Pollen parents may help to maintain the genetic diversity of offspring, Pollen parents neighboring seed parents may be the main contributors to the genetic diversity of the offspring at the seed stage.

  • Population differentiation and gene Flow within a metapopulation of a threatened tree, Magnolia stellata (Magnoliaceae)
    American Journal of Botany, 2007
    Co-Authors: Suzuki Setsuko, Yoshihiko Tsumura, Saneyoshi Ueno, Kiyoshi Ishida, Nobuhiro Tomaru
    Abstract:

    We examined genetic differentiation among eight local populations of a metapopulation of Magnolia stellata using 10 nuclear and three chloroplast microsatellite (nSSR and cpSSR) markers and evaluated the influence of historical gene Flow on population differentiation. The coefficient of genetic differentiation among populations for nSSR (FST ¼ 0.053) was less than half that for cpSSR (0.137). An isolation-by-distance pattern was detected for nSSRs, but not cpSSRs. These results suggest that Pollen Flow, as well as seed dispersal, has significantly reduced genetic differentiation among populations. We also examined patterns of contemporary Pollen Flow by paternity analysis of seeds from nine seed parents in one of the populations using the nSSR markers and found it to be greatly restricted by the distance between parents. Although most Pollen Flow occurred within the population, Pollen Flow from outside the population accounted for 2.5% of the total. When historical and contemporary Pollen Flows among populations were compared, the levels of Pollen Flow seem to have declined recently. We conclude that to conserve M. stellata, it is important to preserve the whole population by maintaining its metapopulation structure and the gene Flow among its populations.

  • Patterns of Pollen Flow and Genetic Differentiation Among Pollen Pools in Quercus salicina in a Warm Temperate Old–growth Evergreen Broad-leaved Forest
    Silvae Genetica, 2004
    Co-Authors: Atsushi Nakanishi, Hiroshi Yoshimaru, Tohru Manabe, Nobuhiro Tomaru, Takayuki Kawahara, Shinichi Yamamoto
    Abstract:

    Abstract Paternity analysis and analysis of molecular variance were used to determine patterns of Pollen Flow and genetic differentiation among Pollen pools in Quercus salicina in an 11.56-ha plot in a temperate old-growth evergreen broad-leaved forest. The genotypes at seven microsatellite loci were determined for 111 adult trees and 276 seeds collected from under eight seed parents. The proportion of Pollen Flow from outside the plot (further than 100 m) was 52.2%, indicating that long-distance Pollen Flow occurred frequently in this species, as observed in other Quercus species. The Pollen pools from inside and outside the plot differed genetically, and genetic structure was detected in the population of adult trees within the plot. Therefore, longdistance Pollen Flow from outside the plot may introduce new or low-frequent alleles, and increase genetic diversity in this population. However, the actual average distance of Pollen Flow within the plot was significantly shorter than the average potential distance, and negative exponential curves explained well the frequencies of matings as functions of the distance between parents, as found in other Quercus species. The genetic composition of Pollen pools differed among the eight seed parents. The genetic differentiation of Pollen pools between the seed parents showed significant positive correlation with the spatial distance between them, indicating that neighboring seed parents tend to accept similar Pollen pools, probably because matings are frequently mediated by Pollen transported over short distances

Hirofumi Yamaguchi - One of the best experts on this subject based on the ideXlab platform.

  • natural hybridization in wild soybean glycine max ssp soja by Pollen Flow from cultivated soybean glycine max ssp max in a designed population
    Weed Biology and Management, 2002
    Co-Authors: Yuichiro Nakayama, Hirofumi Yamaguchi
    Abstract:

    The frequency of hybridization through Pollen Flow from the cultivated soybean to the wild soybean was evaluated for the purpose of assessment of the ecological risk of genetically modified crops. The Flowering habits of three soybean cultivars and one wild soybean accession were monitored on an experimental farm. A cultivar and a wild accession, both of which Flowered at a similar period, were then planted alternately in 5 × 12 arrays with 50 cm spacing on the farm. The seedlings of progeny seeds gathered from individual plants of the wild accession were used for an isozyme analysis to identify whether they were hybrid or not. In 23 plants of the wild accession, four plants produced hybrids (the incidence of hybridization = 17.4%). There was no directionality in hybridization. The hybridization rate per maternal plant varied from 0 to 5.89% with a mean of 0.73% for all maternal plants. The results indicate that natural hybrids are easily produced in a certain frequency by Pollen Flow from the cultivated soybean to the wild soybean under their simultaneous Flowering with adequate pollinators.

  • Diffusion of Paraquat Resistant Gene by Pollen Flow in the Natural and Designed Populations of Erigeron philadelphicus L..
    Journal of Weed Science and Technology, 1996
    Co-Authors: Hirofumi Yamaguchi, Sachiho Nakai, Hiroaki Watanabe
    Abstract:

    The diffusion of genes by Pollens was analyzed in a natural population of Erigeron philadelphicus that had paraquat resistant genotypes and in an experimental population designed with 4 resistant plants as center, 36 susceptible plants as surroundings and two susceptible satellite blocks. Pollen Flow occurs generally in leptokurtic fashion, while our observation indicated a bimodal distribution of diffusion within a 1.2m distance by bees and syrphids in the natural population. Experimental results indicated that although predominant pollinators fly in a near-neighbor fashion, the pattern of gene diffusion over 3m by Pollen may be affected by patchy distribution of individual plants in this outbreeding species.

I. Magnier - One of the best experts on this subject based on the ideXlab platform.

Alexandre M. Sebbenn - One of the best experts on this subject based on the ideXlab platform.

  • Contemporary Pollen Flow, mating patterns and effective population size inferred from paternity analysis in a small fragmented population of the Neotropical tree Copaifera langsdorffii Desf. (Leguminosae-Caesalpinioideae)
    Conservation Genetics, 2012
    Co-Authors: Ricardo O. Manoel, Patrícia F. Alves, Cecília L. Dourado, Ana P. S. C. Gaino, Miguel L. M. Freitas, Mário L. T. Moraes, Alexandre M. Sebbenn
    Abstract:

    Pollen Flow and dispersal patterns were investigated in a small, isolated forest fragment of the Neotropical insect pollinated tree Copaifera langsdorffii , using paternity analysis and eight microsatellite loci. We also investigated the coancestry and effective population size of progeny arrays for conservation and environmental restoration purposes. Open-pollinated seeds were collected from 15 seed trees within the forest fragment, in which all adult trees were mapped, measured and genotyped. Twenty seeds were also collected from the nearest neighbor tree located 1.2 km from the forest fragment. Our results show that levels of genetic diversity were significantly higher in adults than offspring and significant levels of inbreeding were detected in offspring ( F  = 0.226). From paternity analysis, we observed low levels of selfing ( s  = 8%) and Pollen immigration ( m  = 8%) in the fragment, but very high levels were detected for the isolated tree ( s  = 20%; m  = 75%), indicating that the population and the tree are not reproductively isolated and are connected by patterns of long distance Pollen dispersal (maximum detected 1,420 m). Within the forest fragment, the pattern of Pollen dispersal was a near neighbor pattern with 49% of the Pollen being dispersed within 50 m. The effective population size of the progeny array was low, indicating the need to collect seeds from a large number of seed trees (at least 76) for conservation purposes. The results show that the spatial isolation of the population and isolated tree due to forest fragmentation has not disrupted genetic connectivity; however, spatial isolation does seem to increase selfing and correlated mating.

Izumi Washitani - One of the best experts on this subject based on the ideXlab platform.

  • Effects of density and floral morph on Pollen Flow and seed reproduction of an endangered heterostylous herb, Primula sieboldii
    Journal of Ecology, 2006
    Co-Authors: F. Ishihama, S. Ueno, Y. Tsumura, Izumi Washitani
    Abstract:

    Summary 1 We assessed the effects of population density and the spatial arrangement of genetically compatible mates on the seed set and Pollen Flow of a heterostylous, bumblebee-pollinated perennial, Primula sieboldii E. Morren (Primulaceae), by using an experimental population under natural pollination conditions. 2 We also examined the intermorph differences in the Pollen dispersal distance and the frequency of self- and intramorph fertilization. 3 Seed set was significantly correlated with the number of opposite-morph Flowers within 2 m in short-styled genets, and within 3 m in long-styled genets. 4 Mean Pollen dispersal distance within the experimental population was 5.4 m, which was slightly shorter than that in a low-density population measured in a previous study (7.2 m). 5 The proportions of seedlings sired by the same morph or selfed were 10.2% and 3.0%, respectively, in long-styled mothers, compared with 1.9% and 0.0% among short-styled mothers. However, these differences were not statistically significant and no marked differences in Pollen dispersal distances were observed between the two morphs. 6 Our results suggest that the presence of opposite-morph genets within several metres is essential for success of seed reproduction in P. sieboldii, irrespective of population density, and that stochastic deviation of the morph ratio in small populations is therefore likely to cause considerable reduction in seed set.

  • Effect of Flowering phenology on Pollen Flow distance and the consequences for spatial genetic structure within a population of Primula sieboldii (Primulaceae)
    American Journal of Botany, 2006
    Co-Authors: Naoko Kitamoto, Saneyoshi Ueno, Akio Takenaka, Yoshihiko Tsumura, Izumi Washitani, Ryo Ohsawa
    Abstract:

    To evaluate the effects of Flowering phenology on Pollen Flow distance and spatial genetic structure in a population of a bumblebee-pollinated herb, Primula sieboldii, we investigated the Flowering phenology of 1712 Flowers of 97 genets in a population in Nagano Prefecture, Japan, and constructed a mating model based on the observed mating pattern, which was revealed by paternity analysis using 11 microsatellite markers. The effects of Flowering phenology were inferred by comparing estimated Pollen Flow distance and the level of heterozygosity in the next generation between two scenarios. In the first scenario, both the intergenet distance and Flowering phenology influenced mating opportunity, while in the second scenario only intergenet distance influenced mating opportunity. Although the frequency distribution of Pollen Flow distance at the population level did not differ significantly between the two scenarios, the mean Pollen Flow distance of several Flowers increased by more than 10 m as a result of variation in Flowering phenology. Furthermore, accounting for Flowering phenology predicted change in heterozygosity in the next generation from -0.04 to 0.07. The results showed that Flowering phenology can affect Pollen Flow distance and spatial genetic structure.

  • Seed set and gene Flow patterns in an experimental population of an endangered heterostylous herb with controlled local opposite-morph density
    Functional Ecology, 2003
    Co-Authors: Fumiko Ishihama, Yoshihiko Tsumura, S. Ueno, C. Nakano, M. Ajima, Izumi Washitani
    Abstract:

    Summary 1Seed reproduction of a plant species is strongly affected by the spatial structures of its population through gene Flow patterns. We assessed the effects of the spatial arrangement of genetically compatible mates on the seed set and gene Flow of a heterostylous perennial species, Primula sieboldii E. Morren (Primulaceae), using a patchy experimental population. 2Seed set was significantly higher in patches containing opposite-morph genets than in patches without opposite-morph genets. Pollen Flow within patches explained 76·9% of total Pollen Flow, while 13·5% was ascribed to Pollen Flow between patches. Mean and maximum Pollen dispersal distances within the experimental population were 7·23 and 89 m, respectively. 3Mean and maximum seed dispersal distances were 10·4 and 23·0 cm, respectively. 4Our results suggest a profound effect of the spatial arrangement of compatible mates within the patchy population on seed set and gene Flow. Investigations using experimental populations in combination with molecular markers will provide highly effective means for evaluating the influences of spatial structures on plant gene Flow and reproduction, and will also provide valuable information for conservation efforts.