Directional selection on initial flowering date in <i>Phlox drummondii</i> (Polemoniaceae)

Kelly, Martin G.; Levin, Donald A.

doi:10.2307/2656634

Cited by 30 publications

(20 citation statements)

References 66 publications

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“…Indeed, the flowering overlap and frequency of isolated individuals decreased and increased, respectively, with field infestation. Individual differences in the timing of flowering may be caused by several environmental factors, including plant density (Kelly & Levin, ). However, in the present study, we detected no strong effect of intrapopulation density variation (i.e.…”

Section: Discussionmentioning

confidence: 99%

How to escape from crop‐to‐weed gene flow: phenological variation and isolation‐by‐time within weedy sunflower populations

et al. 2012

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SummaryThe evolution of crop-related weeds may be constrained by recurrent gene flow from the crop. However, flowering time variation within weedy populations may open the way for weed adaptation by allowing some weeds to escape from this constraint. We investigated this link between phenology, gene flow and adaptation in weedy sunflower populations that have recently emerged in Europe from crop-wild hybridization.We studied jointly flowering phenology and genetic diversity for 15 microsatellite loci in six cultivated sunflower (Helianthus annuus) fields infested by weedy sunflower populations.The flowering overlap of cultivated and weedy sunflowers varied between and within populations: some weedy individuals were found to be completely isolated from the crop, the frequency of these plants being higher in populations from highly infested fields. Within weedy populations, we detected a pattern of isolation-by-time: the genetic divergence between individuals was positively correlated with their divergence in flowering period. In addition, earlier weeds, which flowered synchronously with the crop, were genetically more similar than lateflowering weeds to the cultivated varieties.Overall, our results suggest that crop-to-weed gene flow occurred, but was limited by divergent phenologies. We discuss the roles of weed adaptation and population history in the generation of this partial reproductive isolation.

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Section: Discussionmentioning

confidence: 99%

How to escape from crop‐to‐weed gene flow: phenological variation and isolation‐by‐time within weedy sunflower populations

et al. 2012

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“…Environmental factors include temperature (e.g., Schemske et al 1978;Primack 1980;McGuire and Armbruster 1991), light availability (e.g., Marquis 1988), attacks by herbivores (e.g., Augspurger 1981;Widé n 1991;EnglishLoeb and Karban 1992;Wright and Meagher 2003), etc. (review by Rathcke and Lacey 1985;Kelly and Levin 2000). It is likely that the flowering periods of gorse are also under both genetic and environmental control, but further studies are needed to ascertain this point.…”

Section: Introductionmentioning

confidence: 95%

Flowering phenology of Ulex europaeus: ecological consequences of variation within and among populations

et al. 2007

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Reproductive phenology of gorse (Ulex europaeus L., Genisteae, Fabaceae) is unusual in that the onset and duration of flowering vary greatly among individuals within populations: some plants initiate flowering in autumn or winter and continue flowering through spring, others initiate flowering in early spring. To understand the origin of this diversity and its ecological consequences, we investigated flowering phenology of randomly sampled individuals from five different natural populations in Brittany (France). Reproductive success was evaluated for individuals with contrasting flowering patterns, from 16 natural populations. Flower production, pod production, seed production and seed predation were estimated. Plants initiating flowering in spring produced larger numbers of flowers and pods over a shorter period than plants flowering from winter to spring, which produced few flowers and pods at a time but over a longer period. Pod production of longflowering plants did not differ significantly between winter and spring, but their pods were more intensively attacked by seed predators in spring than in winter. We discuss our results in relation to biotic and abiotic parameters. We postulate that long-flowering can be interpreted as a bet-hedging strategy, spreading the risk of pod failure (rotting or freezing) in winter and of seed predation in spring.

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“…Information about the timing of onset and duration of flowering in a population is of fundamental biological importance because of its influence on total seed production, and ultimately, fitness (Fenner 1998). The variation in flowering pheno logy among individuals in a population strongly influences the reproductive success of a plant (Rathcke and Lacey 1985, Kelly and Levin 2000).…”

Section: Significance Of Reproductive Phenology Studiesmentioning

confidence: 99%

Annual variation in floral phenology and pollen production in a 25‐year‐old plantation of Tectona grandis

Khanduri

2012

Nordic Journal of Botany

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Teak is a timber tree that is widely distributed in the tropics. Several studies on pollination and reproductive biology have been conducted, but generally information on flowering phenology and annual variation in total pollen production per tree is lacking. The reproductive phenology as well as flower‐ and pollen grain production of individuals in a population is important to theoreticians, field biologists and plant breeders, as they determine the distribution of genotypes within populations and influences the degree of differentiation among populations. This study reports flowering phenology and variation in total flower, fruit‐ and pollen production per tree in teak in a 25‐year‐old plantation across three consecutive years (2006–2008). The results show that the date of onset and end of flowering was highly variable across years. The longest flowering period of 93 days was observed in 2006. There was an asynchrony in the number of open flowers due to differences in time of anthesis among individuals (± 2 days) and inflorescences within individuals (± 6 h). The production of pollen grains per tree in 2007 was 33%, i.e. 16% more compared to 2006 and 2008. The fruit production per tree was 42% and 27% higher in 2007 compared to 2006 and 2008. Concentration of pollen grains (both on jelly‐coated microscopic slides and stigmas) were highest between noon and 2 pm. At this time, the stigmatic pollen load ranged between 4–8 pollen grains per stigma, which is sufficient for fruit development. The study concludes that the asynchronization of the flower opening might give rise to a high amount of self‐pollination in the stand, ultimately leading to poor fruit setting. Also, the large production of flowers and pollen per tree induced geitonogamy and decreased female fitness, as T. grandis is preferentially an out‐crossing species.

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Directional selection on initial flowering date in Phlox drummondii (Polemoniaceae)

Cited by 30 publications

References 66 publications

How to escape from crop‐to‐weed gene flow: phenological variation and isolation‐by‐time within weedy sunflower populations

How to escape from crop‐to‐weed gene flow: phenological variation and isolation‐by‐time within weedy sunflower populations

Flowering phenology of Ulex europaeus: ecological consequences of variation within and among populations

Annual variation in floral phenology and pollen production in a 25‐year‐old plantation of Tectona grandis

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