The Experts below are selected from a list of 208437 Experts worldwide ranked by ideXlab platform
Ralph E. J. Boerner - One of the best experts on this subject based on the ideXlab platform.
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Plant life span and response to inoculation with vesicular-arbuscular mycorrhizal fungi
Mycorrhiza, 1992Co-Authors: Ralph E. J. BoernerAbstract:To determine the relative responsiveness to and dependency on vesicular-arbuscular mycorrhizae (VAM) of annual and perennial plants, this study compared the responses of congeneric, sympatric pairs of species in the grass genera Panicum and Bromus to inoculation with two VAM fungal isolates from the genus Glomus . When inoculated with G. intraradices , the Perennials P. virgatum and B. inermus showed significantly greater response at both high and low phosphorus (P) than did the annuals P. capillare and B. secalinus . Responsiveness of Perennials was significant at both P levels, whereas annuals responded significantly only at low P. Neither Bromus species responded strongly to inoculation with G. etunicatum . Overall, the perennial grasses were more responsive and dependent than were the annuals. A survey of 26 studies including 84 plant-VAM fungus combinations yielded similar patterns of responsiveness in relation to P level and plant life span, especially for grasses. The greater responsiveness of perennial grasses to VAM infection must be considered within the suite of life history traits used to erect hypotheses concerning successional replacement of annuals by Perennials in graminoid-dominated ecosystems.
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Plant life span and response to inoculation with vesicular-arbuscular mycorrhizal fungi
Mycorrhiza, 1992Co-Authors: Ralph E. J. BoernerAbstract:To determine if annual and perennial species from weakly mycotrophic families exhibit the same differential patterns of responsiveness to vesicular-arbuscular mycorrhizae (VAM) as do members of the strongly mycotrophic grass family (Poaceae), this study examined the responses of congeneric, sympatric annual and Perennials species from the Caryophyllaceae and Solanaceae to inoculation with the VAM fungus Glomus intraradices . The perennial Solanum carolinense responded as positively to G. intraradices as did perennial grasses. The other Perennials examined, Solanum dulcamara and Silene nivea , were both relatively unresponsive to VAM inoculation and had mean responsiveness values below the typical level for annuals from strongly mycotrophic families. The annual Solanum nigrum exhibited a small positive response to inoculation, and was as responsive as many annuals from more mycotrophic families, especially at low P supply rates. The annual Silene noctiflora was strongly inhibited by inoculation. Mortality over 8 weeks was fivefold higher in VAM-inoculated Silene noctiflora than in uninoculated plants. Among the four herbaceous species examined, the species which persists longest in old-field succession in eastern North America was also the most responsive to VAM inoculation. Mechanisms are proposed for successional persistence and replacement based on VAM responsiveness and soil nutrient pool sizes.
Laurette Sonié - One of the best experts on this subject based on the ideXlab platform.
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Impact of atmospheric CO2 and plant life forms on soil microbial activities
Soil Biology and Biochemistry, 2007Co-Authors: Gilles Pinay, Laurette Sonié, Patricia Barbera, Alba Carreras-palou, Nathalie Fromin, Marie Madeleine Couteaux, Jacques Roy, Laurent Philippot, R. LensiAbstract:From the global change perspective, increase of atmospheric CO2 and land cover transformation are among the major impacts caused by human activities. In this study, we are addressing the combined issues of the effect of CO2 concentration increase and plant type on soil microbial activities by asking how annual and perennial plant groups affect soil microbial processes under elevated CO2. The experimental design used a mix of species of different growth forms for both annuals and Perennials. Our objective was: (1) to determine how two years of annual or perennial plant cover and CO2 enrichment could affect Mediterranean soil microbial processes; (2) to test the resistance and the resilience of these soil functional processes after a natural perturbation. We determined the effects of 2 years atmospheric CO2 enrichment on soil potential respiration (SIR), denitrification (DEA) and nitrification (NEA) activities. We could not find any significant effect of CO2 increase on SIR, DEA and NEA. However, we found a strong effect of the plant cover type, i.e. annuals versus Perennials, on the potential microbial activity related to N cycling. DEA and NEA were significantly higher in soil under annual plants while SIR was not significantly different. To determine whether these changes would survive a natural perturbation, we carried out a rain event experiment once the experimental treatments (i.e. different plant cover and atmospheric CO2 concentration) were stopped. The soil potential respiration, as expressed by the SIR, was not affected and remained stable. DEA rates converged rapidly under annuals and Perennials after the rain event. Under both annuals and Perennials NEA increased significantly after the rain event but remained significantly higher in the soil with annual plants. The relative change of the soil microbial processes induced by annual and perennial plants was inversely related to the density and the diversity of the corresponding microbial functional groups.
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Specific leaf area and leaf nitrogen concentration in annual and perennial grass species growing in Mediterranean old-fields
Oecologia, 1997Co-Authors: Eric Garnier, P. Cordonnier, J.-l. Guillerm, Laurette SoniéAbstract:Specific leaf area (the ratio of leaf area to leaf dry mass) and leaf nitrogen concentration were measured on ten annual and nine perennial grass species growing in two old-fields of southern France, under a sub-humid Mediterranean climate. Specific leaf area (SLA) was found to be significantly higher in annuals than in Perennials, but leaf nitrogen concentration expressed on a dry mass basis (LNCm) was similar in both life-forms; expressed on an area basis, leaf nitrogen concentration (LNCa) was significantly higher in Perennials. The correlation between SLA and LNCm was negative in annuals and positive in Perennials, while that between the inverse of specific leaf area (1/SLA) and LNCa was positive in annuals and not significant in Perennials. It is hypothesized that these contrasting patterns depend on whether the two components of SLA – leaf thickness and density – vary in opposite directions. For nine of the species studied (six annuals and three Perennials), relative growth rate data obtained in the laboratory under non-limiting nutrient supply were available; positive correlations were found between these values and both SLA and LNCm obtained in the field, suggesting that the interspecific differences in structural and chemical characteristics of leaves are maintained under a wide range of growing conditions.
Bruno Mary - One of the best experts on this subject based on the ideXlab platform.
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Changes in soil carbon stocks under perennial and annual bioenergy crops
Global Change Biology Bioenergy, 2016Co-Authors: Fabien Ferchaud, Guillaume Vitte, Bruno MaryAbstract:Bioenergy crops are expected to provide biomass to replace fossil resources and reduce greenhouse gas emissions. In this context, changes in soil organic carbon (SOC) stocks are of primary importance. The aim of this study was to measure changes in SOC stocks in bioenergy cropping systems comparing perennial (Miscan-thus 9 giganteus and switchgrass), semi-perennial (fescue and alfalfa), and annual (sorghum and triticale) crops, all established after arable crops. The soil was sampled at the start of the experiment and 5 or 6 years later. SOC stocks were calculated at equivalent soil mass, and d 13 C measurements were used to calculate changes in new and old SOC stocks. Crop residues found in soil at the time of SOC measurements represented 3.5–7.2 t C ha -1 under perennial crops vs. 0.1–0.6 t C ha -1 for the other crops. During the 5-year period, SOC concentrations under perennial crops increased in the surface layer (0–5 cm) and slightly declined in the lower layers. Changes in d 13 C showed that C inputs were mainly located in the 0–18 cm layer. In contrast, SOC concentrations increased over time under semi-perennial crops throughout the old ploughed layer (ca. 0–33 cm). SOC stocks in the old ploughed layer increased significantly over time under semi-Perennials with a mean increase of 0.93 AE 0.28 t C ha -1 yr -1 , whereas no change occurred under perennial or annual crops. New SOC accumulation was higher for semi-perennial than for perennial crops (1.50 vs. 0.58 t C ha -1 yr -1 , respectively), indicating that the SOC change was due to a variation in C input rather than a change in mineralization rate. Nitrogen fertilization rate had no significant effect on SOC stocks. This study highlights the interest of comparing SOC changes over time for various cropping systems.
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The fate of cumulative applications of N-15-labelled fertiliser in perennial and annual bioenergy crops
Agriculture Ecosystems and Environment, 2016Co-Authors: Fabien Ferchaud, Guillaume Vitte, Jean-marie Machet, Nicolas Beaudoin, Manuella Catterou, Bruno MaryAbstract:The fate of nitrogen (N) fertiliser applied to bioenergy crops is a key issue to allow high biomass production while minimising environmental impacts due to N losses. The aim of this study was to follow the fate in the soil-plant system of N fertiliser applied to perennial (Miscanthus x giganteus and switchgrass), "semi-perennial" (fescue and alfalfa) and annual (sorghum and triticale) bioenergy crops. Crops received N-15-labelled fertiliser (urea ammonium nitrate solution) during 4 or 5 successive years on the same subplots, at a rate varying from 24 to 120 kg N ha(-1) yr(-1). Biomass production, N and N-15 removal at harvest were measured each year. The N-15 recovery in crop residues, non-harvested crop parts and soil was measured at the end of the N-15-labelling period. Perennial crops had higher biomass production but generally lower N-15 recovery in harvested biomass than other crops, particularly when harvested late (end of winter). At the end of the 4 or 5-year period, the proportion of N-15 recovered in harvested biomass was 13-34% for Perennials, 23-38% for semi-Perennials and 34-39% for annual crops. Perennial crops stored large amounts of N in their belowground organs; the mean N-15 recovery in these organs was 12%, corresponding to a N storage flux of 14 kg N ha(-1) yr(-1). The N-15 recovery in soil (including crop residues) was higher for Perennials (average 36%) than semi-Perennials (28%) and annual crops (19%), corresponding to a N immobilisation rate of 43,15 and 12 kg N ha(-1) yr(-1) respectively. The mean overall N-15 recovery in the soil-plant system was 69% in Perennials, 61% in semi-Perennials to 56% in annual crops, suggesting that important fertiliser losses occurred through volatilisation and denitrification. Perennial bioenergy crops had the better efficiency by storing fertiliser-N in soil organic matter and living belowground biomass used as N reserves for succeeding years. (C) 2016 Elsevier B.V. All rights reserved.
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Drainage and nitrate leaching assessed during 7 years under perennial and annual bioenergy crops
BioEnergy Research, 2016Co-Authors: Fabien Ferchaud, Bruno MaryAbstract:Sustainable bioenergy crops must contribute not only to the production of renewable energy but also to maintaining or restoring water resource and quality. The aim of this study was to quantify water drainage and nitrate leaching under perennial (Miscanthus x giganteus and switchgrass), "semi-perennial" (fescue and alfalfa) and annual (sorghum and triticale) bioenergy crops managed with two N fertilisation rates. Soil water and mineral N contents were measured twice a year during 7 consecutive years. These measurements were used to initialize the STICS model which simulated in turn the amounts of drained water and nitrate leached below 210 cm. Semi-perennial crops produced less drainage than annual crops (64 vs. 133 mm year(-1)) despite a similar biomass production. Perennial crops resulted in an intermediate drainage (90 mm year(-1)) but a greater biomass production. The drainage was negatively correlated with biomass production for perennial and annual crops. Perennial crops exhibited much higher water use efficiency than the other species. Nitrate concentration in drained water was low for all crops, most often less than 20 mg NO3 l(-1). It was lower for Perennials than other crops, except for miscanthus on the first year of measurement. However, the comparison of model outputs with nitrate concentrations measured in subsoil after 5 years indicated that the peak of nitrate produced after miscanthus establishment was subsequently recovered by the crop in deep layers (below 210 cm). Perennial bioenergy crops have potential for restoring water quality but may decrease groundwater recharge in deep soils or dry climates.
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Soil water uptake and root distribution of different perennial and annual bioenergy crops
Plant and Soil, 2015Co-Authors: Fabien Ferchaud, Guillaume Vitte, Frédéric Bornet, Loic Strullu, Bruno MaryAbstract:Bioenergy crops are expected to provide biomass as a replacement for fossil resources, but their impact on the water cycle is still under question. This study aimed at both quantifying the ability of bioenergy crops to use soil water and analysing the relationship between their root systems and soil water uptake. Water content was monitored continuously for 7 years (2007-2013) under perennial (Miscanthus x giganteus and Panicum virgatum), semi-perennial (Festuca arundinacea and Medicago sativa) and annual (Sorghum bicolor and x Triticosecale) bioenergy crops. Root distribution was characterized in 2010 down to 3 m depth. Soil water deficit (SWD) was calculated as the difference between field capacity and actual water content. Maximal SWD (0-210 cm) during the growing season was higher for semi-Perennials, despite a lower biomass production than Perennials. Water capture in deep soil layers was greater under Perennials and semi-Perennials than under annual crops. A curvilinear asymptotic relationship was found between water capture and root density and described by a model the parameters of which varied between crops, indicating a variable soil water capture for a given root density. This study provides quantitative information required to simulate the impact of bioenergy crops on drainage and aquifer loading.
Fabien Ferchaud - One of the best experts on this subject based on the ideXlab platform.
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Changes in soil carbon stocks under perennial and annual bioenergy crops
Global Change Biology Bioenergy, 2016Co-Authors: Fabien Ferchaud, Guillaume Vitte, Bruno MaryAbstract:Bioenergy crops are expected to provide biomass to replace fossil resources and reduce greenhouse gas emissions. In this context, changes in soil organic carbon (SOC) stocks are of primary importance. The aim of this study was to measure changes in SOC stocks in bioenergy cropping systems comparing perennial (Miscan-thus 9 giganteus and switchgrass), semi-perennial (fescue and alfalfa), and annual (sorghum and triticale) crops, all established after arable crops. The soil was sampled at the start of the experiment and 5 or 6 years later. SOC stocks were calculated at equivalent soil mass, and d 13 C measurements were used to calculate changes in new and old SOC stocks. Crop residues found in soil at the time of SOC measurements represented 3.5–7.2 t C ha -1 under perennial crops vs. 0.1–0.6 t C ha -1 for the other crops. During the 5-year period, SOC concentrations under perennial crops increased in the surface layer (0–5 cm) and slightly declined in the lower layers. Changes in d 13 C showed that C inputs were mainly located in the 0–18 cm layer. In contrast, SOC concentrations increased over time under semi-perennial crops throughout the old ploughed layer (ca. 0–33 cm). SOC stocks in the old ploughed layer increased significantly over time under semi-Perennials with a mean increase of 0.93 AE 0.28 t C ha -1 yr -1 , whereas no change occurred under perennial or annual crops. New SOC accumulation was higher for semi-perennial than for perennial crops (1.50 vs. 0.58 t C ha -1 yr -1 , respectively), indicating that the SOC change was due to a variation in C input rather than a change in mineralization rate. Nitrogen fertilization rate had no significant effect on SOC stocks. This study highlights the interest of comparing SOC changes over time for various cropping systems.
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The fate of cumulative applications of N-15-labelled fertiliser in perennial and annual bioenergy crops
Agriculture Ecosystems and Environment, 2016Co-Authors: Fabien Ferchaud, Guillaume Vitte, Jean-marie Machet, Nicolas Beaudoin, Manuella Catterou, Bruno MaryAbstract:The fate of nitrogen (N) fertiliser applied to bioenergy crops is a key issue to allow high biomass production while minimising environmental impacts due to N losses. The aim of this study was to follow the fate in the soil-plant system of N fertiliser applied to perennial (Miscanthus x giganteus and switchgrass), "semi-perennial" (fescue and alfalfa) and annual (sorghum and triticale) bioenergy crops. Crops received N-15-labelled fertiliser (urea ammonium nitrate solution) during 4 or 5 successive years on the same subplots, at a rate varying from 24 to 120 kg N ha(-1) yr(-1). Biomass production, N and N-15 removal at harvest were measured each year. The N-15 recovery in crop residues, non-harvested crop parts and soil was measured at the end of the N-15-labelling period. Perennial crops had higher biomass production but generally lower N-15 recovery in harvested biomass than other crops, particularly when harvested late (end of winter). At the end of the 4 or 5-year period, the proportion of N-15 recovered in harvested biomass was 13-34% for Perennials, 23-38% for semi-Perennials and 34-39% for annual crops. Perennial crops stored large amounts of N in their belowground organs; the mean N-15 recovery in these organs was 12%, corresponding to a N storage flux of 14 kg N ha(-1) yr(-1). The N-15 recovery in soil (including crop residues) was higher for Perennials (average 36%) than semi-Perennials (28%) and annual crops (19%), corresponding to a N immobilisation rate of 43,15 and 12 kg N ha(-1) yr(-1) respectively. The mean overall N-15 recovery in the soil-plant system was 69% in Perennials, 61% in semi-Perennials to 56% in annual crops, suggesting that important fertiliser losses occurred through volatilisation and denitrification. Perennial bioenergy crops had the better efficiency by storing fertiliser-N in soil organic matter and living belowground biomass used as N reserves for succeeding years. (C) 2016 Elsevier B.V. All rights reserved.
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Drainage and nitrate leaching assessed during 7 years under perennial and annual bioenergy crops
BioEnergy Research, 2016Co-Authors: Fabien Ferchaud, Bruno MaryAbstract:Sustainable bioenergy crops must contribute not only to the production of renewable energy but also to maintaining or restoring water resource and quality. The aim of this study was to quantify water drainage and nitrate leaching under perennial (Miscanthus x giganteus and switchgrass), "semi-perennial" (fescue and alfalfa) and annual (sorghum and triticale) bioenergy crops managed with two N fertilisation rates. Soil water and mineral N contents were measured twice a year during 7 consecutive years. These measurements were used to initialize the STICS model which simulated in turn the amounts of drained water and nitrate leached below 210 cm. Semi-perennial crops produced less drainage than annual crops (64 vs. 133 mm year(-1)) despite a similar biomass production. Perennial crops resulted in an intermediate drainage (90 mm year(-1)) but a greater biomass production. The drainage was negatively correlated with biomass production for perennial and annual crops. Perennial crops exhibited much higher water use efficiency than the other species. Nitrate concentration in drained water was low for all crops, most often less than 20 mg NO3 l(-1). It was lower for Perennials than other crops, except for miscanthus on the first year of measurement. However, the comparison of model outputs with nitrate concentrations measured in subsoil after 5 years indicated that the peak of nitrate produced after miscanthus establishment was subsequently recovered by the crop in deep layers (below 210 cm). Perennial bioenergy crops have potential for restoring water quality but may decrease groundwater recharge in deep soils or dry climates.
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Water, nitrogen and carbon balance of bioenergy crops : impact of crop species and cropping practices
2015Co-Authors: Fabien FerchaudAbstract:Second generation biofuels could provide renewable energy to the transportation sector while mitigating climate change. However, their greenhouse gas, energy and environmental balances will probably depend on the feedstock used for their production. Bioenergy crops that could be used for second generation biofuels will have to fulfil several requirements, including high productivity, low input requirements, and low environmental impacts. The objective of this work was to assess the water, N and C balances at the plot scale for various bioenergy crops with different management. The study is based on a long term field experiment, called “Biomass & Environment”, established at the INRA experimental station in Estrées-Mons, northern France. This experiment includes two perennial C4 crops (Miscanthus × giganteus and switchgrass), two semi-perennial forage C3 crops (fescue and alfalfa) and two annual C4/C3 crops (fibre sorghum and triticale). It compares two nitrogen treatments and two dates of harvest of perennial crops: early (October) or late harvest (February). Measurements have been carried out on: i) biomass production; ii) soil water stocks, monitored continuously during 7 years; iii) root depth and density; iv) drainage and nitrate concentration in drained water, assessed from soil water and mineral N content measurements (in mid-autumn and late winter) and using the STICS model; v) soil organic carbon (SOC) stocks in 2006 and 2011-2012; vi) the fate of 15N-labelled fertiliser applied during 4 or 5 successive years.Thanks to their deep rooting system, perennial and semi-perennial crops consumed more water than annual crops. The amount of drained water was lower under semi-perennial than annual crops (64 vs. 133 mm yr-1 average over 7 years), despite an equivalent biomass production. It was intermediate under perennial crops (56-137 mm yr-1) and negatively correlated to biomass production, itself depending on crop species and N rate. Nitrate concentration in drained water varied between 2 and 23 mg l-1. It was generally lower under perennial than other crops, except for miscanthus on the first year of measurement. SOC stocks increased markedly over time under semi-perennial crops (+0.93 t C ha-1 yr-1), whereas no significant change occurred under perennial and annual crops. The 15N recovery in the harvested biomass was lower for perennial than other crops, particularly when harvested late, but compensated by a higher 15N recovery in belowground organs and soil. The overall 15N recovery in the soil-plant system was 69% in Perennials, 61% in semi-Perennials and 56% in annual crops, suggesting that important fertiliser losses occurred through volatilisation and denitrification. In our pedo-climatic conditions, the C4 perennial crops performed best in terms of production, water and nitrogen use efficiency, and nitrogen losses towards the groundwater and the atmosphere. However, only semi-perennial crops yielded in SOC sequestration.
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Soil water uptake and root distribution of different perennial and annual bioenergy crops
Plant and Soil, 2015Co-Authors: Fabien Ferchaud, Guillaume Vitte, Frédéric Bornet, Loic Strullu, Bruno MaryAbstract:Bioenergy crops are expected to provide biomass as a replacement for fossil resources, but their impact on the water cycle is still under question. This study aimed at both quantifying the ability of bioenergy crops to use soil water and analysing the relationship between their root systems and soil water uptake. Water content was monitored continuously for 7 years (2007-2013) under perennial (Miscanthus x giganteus and Panicum virgatum), semi-perennial (Festuca arundinacea and Medicago sativa) and annual (Sorghum bicolor and x Triticosecale) bioenergy crops. Root distribution was characterized in 2010 down to 3 m depth. Soil water deficit (SWD) was calculated as the difference between field capacity and actual water content. Maximal SWD (0-210 cm) during the growing season was higher for semi-Perennials, despite a lower biomass production than Perennials. Water capture in deep soil layers was greater under Perennials and semi-Perennials than under annual crops. A curvilinear asymptotic relationship was found between water capture and root density and described by a model the parameters of which varied between crops, indicating a variable soil water capture for a given root density. This study provides quantitative information required to simulate the impact of bioenergy crops on drainage and aquifer loading.
John H Willis - One of the best experts on this subject based on the ideXlab platform.
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Dissecting the role of a large chromosomal inversion in life history divergence throughout the Mimulus guttatus species complex
Molecular Ecology, 2018Co-Authors: Jennifer M. Coughlan, John H WillisAbstract:: Chromosomal inversions can play an important role in adaptation, but the mechanism of their action in many natural populations remains unclear. An inversion could suppress recombination between locally beneficial alleles, thereby preventing maladaptive reshuffling with less-fit, migrant alleles. The recombination suppression hypothesis has gained much theoretical support but empirical tests are lacking. Here, we evaluated the evolutionary history and phenotypic effects of a chromosomal inversion which differentiates annual and perennial forms of Mimulus guttatus. We found that Perennials likely possess the derived orientation of the inversion. In addition, this perennial orientation occurs in a second perennial species, M. decorus, where it is strongly associated with life history differences between co-occurring M. decorus and annual M. guttatus. One prediction of the recombination suppression hypothesis is that loci contributing to local adaptation will predate the inversion. To test whether the loci influencing perenniality pre-date this inversion, we mapped QTLs for life history traits that differ between annual M. guttatus and a more distantly related, collinear perennial species, M. tilingii. Consistent with the recombination suppression hypothesis, we found that this region is associated with life history in the absence of the inversion, and this association can be broken into at least two QTLs. However, the absolute phenotypic effect of the LG8 inversion region on life history is weaker in M. tilingii than in Perennials which possess the inversion. Thus, while we find support for the recombination suppression hypothesis, the contribution of this inversion to life history divergence in this group is likely complex.
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major qtls for critical photoperiod and vernalization underlie extensive variation in flowering in the mimulus guttatus species complex
New Phytologist, 2013Co-Authors: Jannice Friedman, John H WillisAbstract:Summary Species with extensive ranges experience highly variable environments with respect to temperature, light and soil moisture. Synchronizing the transition from vegetative to floral growth is important to employ favorable conditions for reproduction. Optimal timing of this transition might be different for semelparous annual plants and iteroparous perennial plants. We studied variation in the critical photoperiod necessary for floral induction and the requirement for a period of cold-chilling (vernalization) in 46 populations of annuals and Perennials in the Mimulus guttatus species complex. We then examined critical photoperiod and vernalization QTLs in growth chambers using F2 progeny from annual and perennial parents that differed in their requirements for flowering. We identify extensive variation in critical photoperiod, with most annual populations requiring substantially shorter day lengths to initiate flowering than perennial populations. We discover a novel type of vernalization requirement in perennial populations that is contingent on plants experiencing short days first. QTL analyses identify two large-effect QTLs which influence critical photoperiod. In two separate vernalization experiments we discover each set of crosses contain different large-effect QTLs for vernalization. Mimulus guttatus harbors extensive variation in critical photoperiod and vernalization that may be a consequence of local adaptation.
