Rapid Population Differentiation in a Mosaic Environment. II. Morphological Variation in Anthoxanthum odoratum

Snaydon, R. W.; Davies, M. S.

doi:10.2307/2407014

Cited by 78 publications

(81 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Local genetic differentiation in response to selection has been studied extensively in populations of perennial, wind pollinated, outcrossing grasses (Jam and Bradshaw, 1966;McNeilly, 1968;Snaydon and Davies, 1972). Less attention has been paid, however, to the amount of genetic differentiation which arises in such populations in the absence of selection.…”

Section: Introductionmentioning

confidence: 99%

The mating system and genetic structure in a perennial grass, Cynosurus cristatus L.

Ennos

1985

Heredity

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

The mating system and genetic structure in a perennial grass, Cynosurus cristatus L.

Ennos

1985

Heredity

View full text Add to dashboard Cite

“…There is little indication of the extent to which ramet size has been held constant in most previous studies, though several workers (e.g., Bradshaw, 1959;Antonovics and Bradshaw, 1970;Snaydon and Davies, 1972) have clearly stated that they used a set number of tillers per ramet, when working with grasses. In species other than grasses, for example Potentilla glandulosa (Clausen et a!., 1940), Achillea mulefolium (Clausen eta!., 1948), and Clintonia borealis (Ashmun and Pitelka, 1985), it is usually more difficult to standardize the initial size of ramets.…”

Section: Resultsmentioning

confidence: 99%

“…The populations selected for study were collected from contrasting plots of the Park Grass Experiment at Rothamsted, which had received different fertilizer treatments annually for 120 years and different liming treatments for 70 years (Thurston, 1969;Williams, 1978). Previous studies have shown that populations of A. odoratum from the Park Grass Experiment differ morphologically (Snaydon and Davies, 1972), differ in their response to contrasting soils (Snaydon, 1970), and differ in their response to various mineral nutrients and toxins Snaydon, 1973, 1974).…”

Section: Introductionmentioning

confidence: 98%

An assessment of the spaced-plant trial technique

Davies

Snaydon

1989

Heredity

View full text Add to dashboard Cite

The study was designed to investigate the effects of ramet size, site conditions and fertilizer applications on the relative performance of plant populations, when grown in spaced-plant trials. The effects of other factors are also considered.Ten-fold differences in initial ramet size had little effect on the subsequent performance of eight contrasting genotypes of the grass species Anthoxanthum odoratum. Increasing the number of planted tillers per ramet from one to four slightly increased plant survival, but did not significantly affect plant height, plant yield or flowering date. Planting large tillers slightly increased plant yield but did not significantly affect plant survival, height or flowering date. The subsequent effects of initial ramet size were always small, compared with differences between genotypes, and there were no significant genotype x ramet size interactions.Six diverse populations of A. odoratum were grown in spaced-plant trials at three sites with contrasting soils, and with various additions of nitrogen and phosphorus fertilizer. There were large differences between populations in panicle height, vegetative height, shoot dry weight, flowering date and disease susceptibility. The]re were no significant population x N or population x P interactions, but there were significant population x site interactions for panicle height, shoot dry weight and mildew score, so that the performance of the various populations was not significantly correlated between sites.On the basis of this and other studies, we conclude that the relative performance of populations in spaced-plant trials is little affected by initial ramet size or by fertilizer applications. By contrast, relative performance is greatly affected by differences between sites in soil type and climate.The limitations of extrapolating the results of spaced-plant trials to the competitive conditions that normally exist in both natural and agricultural plant communities are briefly discussed.

show abstract

“…H 1 is founded on the fact that ruderal species reproduce early and have high fecundity and short lives (Grime 1979), which are all traits that increase r. H 2 is based on the observation that mating system is the primary determinant of genetic diversity (e.g., Charlesworth and Pannell 2001) and that local adaptation has been demonstrated to have occurred in at least one persistent-increase species (Anthoxanthum odoratum) at Park Grass (Snaydon and Davies 1972).…”

Section: Causes Of Population Trends: a Hypothesismentioning

confidence: 99%

“…More recent work in the PGE has confirmed that this rust infection is spatially density dependent (G. R. Edwards and M. J. Crawley, personal communication). We also know that, at least in the case of mildew, disease incidence does vary with plot treatment (N fertilizer) and that one outbreeding, increasing species (A. odoratum) has evolved increased resistance to this disease on some high nitrogen plots (Snaydon and Davies 1972). Pathogens provide a plausible explanation as to how mating system and genetic diversity may have ecological consequences (Burdon and Thrall 2001).…”

Section: Genetic Causes Of Population Maintenance or Declinementioning

confidence: 99%

Ecological and Genetic Correlates of Long‐Term Population Trends in the Park Grass Experiment

Silvertown¹,

McConway²,

Hughes³

et al. 2002

The American Naturalist

View full text Add to dashboard Cite

The Park Grass Experiment (PGE) is the longestobserved set of experimental plant communities in existence. Although the gross composition of the vegetation was at equilibrium over the 60-yr period from 1920 to 1979, annual records show that individual species exhibited a range of dynamics. We tested two hypotheses to explain why some species initially increased and why subsequently some of these (the outbreak species) decreased again. The study was designed around eight phylogenetically independent contrasts (PICs), each containing related species with different dynamics. Our first hypothesis was that persistent increasers and outbreakers have higher intrinsic rates of natural increase than control species (species without trends), allowing them to spread when interspecific competition is reduced by drought. This was tested by measuring establishment and seed production of species in field experiments, with and without interspecific competition. Seed production in outbreak species responded more strongly to release from interspecific competition than it did in either of the other groups of species. Our second hypothesis was that outbreak species eventually declined because they lacked the genetic variation necessary to adapt to the novel habitats to which they had initially spread. We tested this by measuring mating systems and genetic diversity in persistent and outbreak species in the PGE. In seven out of seven PICs tested, the outbreak species was more selfing than its persistent relative. There was a significant positive correlation between outcrossing rate and gene diversity. These results support roles for both ecological and genetic traits in long-term dynamics.

show abstract

Rapid Population Differentiation in a Mosaic Environment. II. Morphological Variation in Anthoxanthum odoratum

Cited by 78 publications

References 17 publications

The mating system and genetic structure in a perennial grass, Cynosurus cristatus L.

The mating system and genetic structure in a perennial grass, Cynosurus cristatus L.

An assessment of the spaced-plant trial technique

Ecological and Genetic Correlates of Long‐Term Population Trends in the Park Grass Experiment

Contact Info

Product

Resources

About