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The intercropping of two or more crop species on the same piece of land at a given time has been hypothesized to enhance crop yield stability. To address this hypothesis, we assessed the grain yield stability of various barley-pea and wheat-faba bean mixtures grown in seven experimental field trials (locations) across Europe during two years with contrasting weather (2017 and 2018). Three different yield stability measures were used, all based on the expected yield variability of the mixture components grown as sole crops, and the corresponding observed yield variability of the same components grown in 50:50 mixtures in a replacement design. Stability indices were calculated as ratios between the expected and observed variabilities, with values > 1 indicating greater stability of the intercrops. Mean grain yields tended to be higher in intercrops than sole crops. However, in contrast to our hypothesis, the observed (intercrop) yield stability was similar or lower than the expected (sole crop) stability in most locations except one. Furthermore, yield stability significantly increased with increasing mean yields when assessed across differentially productive locations. The results are relevant for the designing of intercropping systems as a means to increase yield stability and the resilience of cropping systems.
Martin Weih; Alison Karley; Adrian Newton; Lars Kiær; Christoph Scherber; Diego Rubiales; Eveline Adam; James Ajal; Jana Brandmeier; Silvia Pappagallo; Angel Villegas-Fernández; Moritz Reckling; Stefano Tavoletti. Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions. Agriculture 2021, 11, 255 .
AMA StyleMartin Weih, Alison Karley, Adrian Newton, Lars Kiær, Christoph Scherber, Diego Rubiales, Eveline Adam, James Ajal, Jana Brandmeier, Silvia Pappagallo, Angel Villegas-Fernández, Moritz Reckling, Stefano Tavoletti. Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions. Agriculture. 2021; 11 (3):255.
Chicago/Turabian StyleMartin Weih; Alison Karley; Adrian Newton; Lars Kiær; Christoph Scherber; Diego Rubiales; Eveline Adam; James Ajal; Jana Brandmeier; Silvia Pappagallo; Angel Villegas-Fernández; Moritz Reckling; Stefano Tavoletti. 2021. "Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions." Agriculture 11, no. 3: 255.
Cereal–legume intercropping increases the nitrogen (N) input from biological nitrogen fixation (BNF) and improves the exploitation of fertilizer and soil N, often leading to higher grain N content and higher productivity per unit land area compared to monocrops. Previous studies have found that these effects are more tangible under low soil and fertilizer N conditions compared to high N availability, and there is a need to assess the N uptake at critical crop development stages in order to time the N application for maximum uptake and use efficiency. The objective of this study was to assess the productivity of pea–barley intercropping compared to monocropping under 0 kg N ha−1 (0 N) and 100 kg N ha−1 (100 N). In 2017, a split plot experimental design was implemented with pea (Pisum sativum) sole crop (SC pea), barley (Hordeum vulgare) sole crop (SC barley), and pea–barley intercrop (IC total) as the main plots and 100 N applications in two 50 kg N ha−1 splits at 30 and 60 days after emergence as subplots within the main plots. The Land Equivalent Ratio (LER), based on grain dry matter (GDM) yields in the pea–barley intercrop (IC total), was higher (1.14 at 0 N and 1.10 at 100 N), indicating 10–14% greater radiation, nutrient, and water use efficiency compared to the sole crops and 4% greater resource use efficiency at 0 N compared to the 100 N; this illustrated greater total intercrop productivity compared to sole crops. The 100 N treatment decreased the SC pea and pea in intercrop (IC pea) GDM and grain dry matter N (GDMN) and increased the GDM and GDMN in SC barley and barley in the intercrop (IC barley). Intercropping increased the grain N content and therefore the protein content of the grains in 0 N and 100 N treatments. The highest fertilizer N yield, % nitrogen derived from fertilizer (%NDFF), and % nitrogen use efficiency (%NUE) were achieved in SC barley followed by IC total, indicating that intercropping improved the soil and fertilizer N use compared to SC pea. The IC pea increased the % nitrogen derived from atmosphere (%NDFA) from 67.9% in SC pea to 70.1% in IC pea. IC total increased the share of %NDFF, %NDFS, and %NDFA compared to the SC pea, which indicated a significant advantage of intercropping due to the complementarity of the component species under limited N supply in the field.
Reed Cowden; Ambreen Shah; Lisa Lehmann; Lars Kiær; Christian Henriksen; Bhim Ghaley. Nitrogen Fertilizer Effects on Pea–Barley Intercrop Productivity Compared to Sole Crops in Denmark. Sustainability 2020, 12, 9335 .
AMA StyleReed Cowden, Ambreen Shah, Lisa Lehmann, Lars Kiær, Christian Henriksen, Bhim Ghaley. Nitrogen Fertilizer Effects on Pea–Barley Intercrop Productivity Compared to Sole Crops in Denmark. Sustainability. 2020; 12 (22):9335.
Chicago/Turabian StyleReed Cowden; Ambreen Shah; Lisa Lehmann; Lars Kiær; Christian Henriksen; Bhim Ghaley. 2020. "Nitrogen Fertilizer Effects on Pea–Barley Intercrop Productivity Compared to Sole Crops in Denmark." Sustainability 12, no. 22: 9335.
Floral resources are increasingly used in conservation biological control to support natural enemies of insect pests. However, the dietary value of floral resources in supporting predatory arthropods, including their effect on longevity and fecundity has not yet been systematically reviewed. To comprehensively evaluate this, the presented review summarizes published studies on the effect of various floral resources (flowers, pollen, and sugar solution (as a proxy for nectar)) on predatory arthropods. We identified 70 articles, including 628 trials, which measured predator longevity (347) and fecundity (281) when supplied with floral resources, as compared to a water only control. Across predator species, results showed that floral resources significantly increased predator longevity, especially whole flowers and sugar solution. Pollen could also prolong predator longevity but was less effective than sugar solution and flowers. The effect of flowers varied greatly among plant species, with those having open or exposed nectaries being more likely to prolong predator longevity, supposedly due to higher accessibility. Some predator species could oviposit on a diet consisting only of floral resources. The findings in the present study emphasize the value of floral resources on supporting predators. Predatory arthropods’ biological control services could be enhanced by choosing plants that favor them in conservation biological control programs.
Xueqing He; Lars Pødenphant Kiær; Per Moestrup Jensen; Lene Sigsgaard. The effect of floral resources on predator longevity and fecundity: A systematic review and meta-analysis. Biological Control 2020, 153, 104476 .
AMA StyleXueqing He, Lars Pødenphant Kiær, Per Moestrup Jensen, Lene Sigsgaard. The effect of floral resources on predator longevity and fecundity: A systematic review and meta-analysis. Biological Control. 2020; 153 ():104476.
Chicago/Turabian StyleXueqing He; Lars Pødenphant Kiær; Per Moestrup Jensen; Lene Sigsgaard. 2020. "The effect of floral resources on predator longevity and fecundity: A systematic review and meta-analysis." Biological Control 153, no. : 104476.
SummaryPlant root and shoot growth has been shown to depend on the relatedness of co-cultivated genotypes, implying the existence of ‘kin recognition’ mechanisms mediated by root exudates. If confirmed, this has important implications for crop breeding.We present the first large-sale investigation of kin recognition in a crop germplasm collection comprising 30 North-European cultivars and landraces of spring wheat, spanning 100 years of breeding history. In a full diallel in vitro bioassay, we compared root growth of seedlings when growing in pure substrate, or in substrate previously occupied by a donor seedling from the same (KIN) or another (NONKIN) genotype.Seedlings growing in KIN or NONKIN substrate generally had longer but not more roots than seedlings growing in pure substrate. Responses were generally larger in longer roots, suggesting that root elongation was promoted throughout the growth period. Responses to KIN and NONKIN substrates were found to range from positive to negative, with root length responses to kin being increasingly positive with year of release. Seedlings growing in KIN substrate generally had shorter but not fewer roots than seedlings growing in NONKIN substrate. This kin recognition ranged from positive to negative across the specific donor-receiver combinations and did not change systematically with year of release of either genotype. Root traits in both KIN and NONKIN substrate were affected by both donor and receiver genotype, and these effects were generally larger than the effect of specific combinations. Genotypes showing higher levels of kin recognition also tended to invoke larger responses in other genotypes. Kin recognition was reduced in most cases by the addition of sodiumorthovanadate, a chemical inhibitor, supporting the hypothesis that kin responses were mediated by changes in the chemical constitution of the substrate.The identified patterns of kin recognition across the germplasm collection were complex, suggesting a multigenic background and shared breeding history of the genotypes. We conclude that kin response represents a potential target for crop breeding which can improve root foraging and competitive interactions.
Lars Pødenphant Kiær; Jacob Weiner; Camilla Ruø Rasmussen. Effects of kin recognition on root traits of wheat germplasm over 100 years of breeding. 2020, 1 .
AMA StyleLars Pødenphant Kiær, Jacob Weiner, Camilla Ruø Rasmussen. Effects of kin recognition on root traits of wheat germplasm over 100 years of breeding. . 2020; ():1.
Chicago/Turabian StyleLars Pødenphant Kiær; Jacob Weiner; Camilla Ruø Rasmussen. 2020. "Effects of kin recognition on root traits of wheat germplasm over 100 years of breeding." , no. : 1.
Numerous studies have demonstrated that plant species diversity enhances ecosystem functioning in terrestrial ecosystems, including diversity effects on insects (herbivores, predators and parasitoids) and plants. However, the effects of increased plant diversity across trophic levels in different ecosystems and biomes have not yet been explored on a global scale. Through a global meta-analysis of 2,914 observations from 351 studies, we found that increased plant species richness reduced herbivore abundance and damage but increased predator and parasitoid abundance, predation, parasitism and overall plant performance. Moreover, increased predator/parasitoid performance was correlated with reduced herbivore abundance and enhanced plant performance. We conclude that increasing plant species diversity promotes beneficial trophic interactions between insects and plants, ultimately contributing to increased ecosystem services.
Nian-Feng Wan; Xiang-Rong Zheng; Li-Wan Fu; Lars P Kiær; Zhijie Zhang; Rebecca Chaplin-Kramer; Matteo Dainese; Jiaqi Tan; Shi-Yun Qiu; Yue-Qing Hu; Wei-Dong Tian; Ming Nie; Rui-Ting Ju; Jian-Yu Deng; Jie-Xian Jiang; You-Ming Cai; Bo Li. Global synthesis of effects of plant species diversity on trophic groups and interactions. Nature Plants 2020, 6, 503 -510.
AMA StyleNian-Feng Wan, Xiang-Rong Zheng, Li-Wan Fu, Lars P Kiær, Zhijie Zhang, Rebecca Chaplin-Kramer, Matteo Dainese, Jiaqi Tan, Shi-Yun Qiu, Yue-Qing Hu, Wei-Dong Tian, Ming Nie, Rui-Ting Ju, Jian-Yu Deng, Jie-Xian Jiang, You-Ming Cai, Bo Li. Global synthesis of effects of plant species diversity on trophic groups and interactions. Nature Plants. 2020; 6 (5):503-510.
Chicago/Turabian StyleNian-Feng Wan; Xiang-Rong Zheng; Li-Wan Fu; Lars P Kiær; Zhijie Zhang; Rebecca Chaplin-Kramer; Matteo Dainese; Jiaqi Tan; Shi-Yun Qiu; Yue-Qing Hu; Wei-Dong Tian; Ming Nie; Rui-Ting Ju; Jian-Yu Deng; Jie-Xian Jiang; You-Ming Cai; Bo Li. 2020. "Global synthesis of effects of plant species diversity on trophic groups and interactions." Nature Plants 6, no. 5: 503-510.
Wheat is the most commonly grown cereal crop in Europe and in major parts of Europe the most yield limiting disease is Septoria tritici blotch (STB) caused by Zymoseptoria tritici. Currently, the control of the disease depends on cultivar resistance and substantial input of fungicides. The impact of using mixtures of elite cultivars as an alternative was investigated through a meta-analysis based on trial data from the Danish national cultivar testing. The cultivar testing includes a four-way cultivar mixture every year and in these trials STB severity and yield have been monitored at multiple locations between 1995 and 2017. Results from 19 years of cultivar testing trials provided a data set for 406 trials from which the effect of mixtures was evaluated. The meta-analysis revealed that cultivar mixtures reduced STB severity with 10.6% and increased yields with 1.4% across all trials. The effects were greatest in untreated trials where STB severity was reduced with 17% and yields increased with 2.4%. The mixtures did not only perform better than the average of their component cultivars grown as pure stand, they also performed better than the average of the four most grown cultivars in a given year. No relationship was found between disease pressure or location and the performance of the mixtures. The mixtures included in the cultivar testing were not designed to control STB and the results are therefore perceived as a baseline to the attainable disease control from mixtures. The use of cultivar mixtures is relevant for low input farming systems, but can also contribute to disease control in intensive farming systems. Cultivar mixtures have the potential to minimise dependency on fungicides as an important element in integrated pest management.
Rose Kristoffersen; Lise Nistrup Jørgensen; Lars Bonde Eriksen; Ghita Cordsen Nielsen; Lars Pødenphant Kiær. Control of Septoria tritici blotch by winter wheat cultivar mixtures: Meta-analysis of 19 years of cultivar trials. Field Crops Research 2020, 249, 107696 .
AMA StyleRose Kristoffersen, Lise Nistrup Jørgensen, Lars Bonde Eriksen, Ghita Cordsen Nielsen, Lars Pødenphant Kiær. Control of Septoria tritici blotch by winter wheat cultivar mixtures: Meta-analysis of 19 years of cultivar trials. Field Crops Research. 2020; 249 ():107696.
Chicago/Turabian StyleRose Kristoffersen; Lise Nistrup Jørgensen; Lars Bonde Eriksen; Ghita Cordsen Nielsen; Lars Pødenphant Kiær. 2020. "Control of Septoria tritici blotch by winter wheat cultivar mixtures: Meta-analysis of 19 years of cultivar trials." Field Crops Research 249, no. : 107696.
Aims Cultivar mixtures can increase productivity through complementarity in resource use, but reported results are often conflicting and the role of plasticity in shaping plant-plant interactions is poorly understood. We aim to determine if individual cultivars show different phenotypic responses when grown in a mixture, whether these responses depend on the neighboring cultivar identity, and how they contribute to variations in productivity and nitrogen (N) use. Methods Five spring barley cultivars were field-grown in pure stands and in mixtures during 2 years. Plant traits related to development, growth, N use, and reproduction were measured to identify temporal patterns of plastic responses to neighboring plants. Results Plants in mixtures were shorter and developed slower early in the season, but later on they grew faster and produced more grain than the corresponding pure stands. Some cultivars showed complementary N accumulation only when grown together with specific neighbors. Mechanisms of improved productivity differed between the individual mixtures. Conclusions Plastic plant-plant interaction between cultivars is an important driver behind the variability in mixing effects. Results contribute to a better understanding of how productivity in cultivar mixtures is affected by plastic adaptation and differentiation of plant traits, depending on the environment created by neighboring genotypes.
Iris Dahlin; Lars P Kiær; Göran Bergkvist; Martin Weih; Velemir Ninkovic. Plasticity of barley in response to plant neighbors in cultivar mixtures. Plant and Soil 2019, 447, 537 -551.
AMA StyleIris Dahlin, Lars P Kiær, Göran Bergkvist, Martin Weih, Velemir Ninkovic. Plasticity of barley in response to plant neighbors in cultivar mixtures. Plant and Soil. 2019; 447 (1-2):537-551.
Chicago/Turabian StyleIris Dahlin; Lars P Kiær; Göran Bergkvist; Martin Weih; Velemir Ninkovic. 2019. "Plasticity of barley in response to plant neighbors in cultivar mixtures." Plant and Soil 447, no. 1-2: 537-551.
Nian-Feng Wan; Xiang-Yun Ji; Jian-Yu Deng; Lars P Kiær; You-Ming Cai; Jie-Xian Jiang. Plant diversification promotes biocontrol services in peach orchards by shaping the ecological niches of insect herbivores and their natural enemies. Ecological Indicators 2019, 99, 387 -392.
AMA StyleNian-Feng Wan, Xiang-Yun Ji, Jian-Yu Deng, Lars P Kiær, You-Ming Cai, Jie-Xian Jiang. Plant diversification promotes biocontrol services in peach orchards by shaping the ecological niches of insect herbivores and their natural enemies. Ecological Indicators. 2019; 99 ():387-392.
Chicago/Turabian StyleNian-Feng Wan; Xiang-Yun Ji; Jian-Yu Deng; Lars P Kiær; You-Ming Cai; Jie-Xian Jiang. 2019. "Plant diversification promotes biocontrol services in peach orchards by shaping the ecological niches of insect herbivores and their natural enemies." Ecological Indicators 99, no. : 387-392.
According to coevolution theory, plant chemical defences are continually evolving in response to selection by herbivores. Unique to the Brassicales, a few species in the Barbarea genus produce triterpenoid saponins that are highly deterrent to some specialist insect herbivores. One species, B. vulgaris, has diverged into two chemotypes, the G- and P-type, of which the P-type seems to have lost the saponin-based insect resistance by producing different saponin structures; it also produces different glucosinolates and other potential defence traits. Here, we examined the preference and performance of a larger set of specialist and generalist herbivores on the two plant types, including three generalist mollusc (Arion vulgaris, Deroceras sp., Cepaea sp.) as well as three specialist (Phaedon cochleariae, Athalia rosae, Pieris napi oleraceae) and two generalist (Mamestra brassicae, Myzus persicae) insect herbivores. Five out of six herbivore species preferred leaves of the P-type for feeding, and most of them also survived and/or grew better on the P-type, or preferred it for oviposition. In contrast, larvae of M. brassicae showed no preference and performed equally well on the two plant types; the leaf beetle P. cochleariae preferred the G-type for oviposition, which was, however, not reflecting larval performance. Overall, the defences of the P-type against herbivores seem not to be as effective as those of the G-type, which is surprising given its large geographical distribution, overlapping with that of the G-type in Scandinavia and Finland. This suggests that additional ecological interactions determine the success of the two chemotypes.
Stina Christensen; Swantje Enge; Karen Rysbjerg Jensen; Caroline Müller; Lars P Kiær; Niels Agerbirk; Christine Heimes; Thure P. Hauser. Different herbivore responses to two co-occurring chemotypes of the wild crucifer Barbarea vulgaris. Arthropod-Plant Interactions 2018, 13, 19 -30.
AMA StyleStina Christensen, Swantje Enge, Karen Rysbjerg Jensen, Caroline Müller, Lars P Kiær, Niels Agerbirk, Christine Heimes, Thure P. Hauser. Different herbivore responses to two co-occurring chemotypes of the wild crucifer Barbarea vulgaris. Arthropod-Plant Interactions. 2018; 13 (1):19-30.
Chicago/Turabian StyleStina Christensen; Swantje Enge; Karen Rysbjerg Jensen; Caroline Müller; Lars P Kiær; Niels Agerbirk; Christine Heimes; Thure P. Hauser. 2018. "Different herbivore responses to two co-occurring chemotypes of the wild crucifer Barbarea vulgaris." Arthropod-Plant Interactions 13, no. 1: 19-30.
Julie Borg; Lars P Kiær; C. Lecarpentier; I. Goldringer; A. Gauffreteau; S. Saint-Jean; S. Barot; J. Enjalbert. Unfolding the potential of wheat cultivar mixtures: A meta-analysis perspective and identification of knowledge gaps. Field Crops Research 2018, 221, 298 -313.
AMA StyleJulie Borg, Lars P Kiær, C. Lecarpentier, I. Goldringer, A. Gauffreteau, S. Saint-Jean, S. Barot, J. Enjalbert. Unfolding the potential of wheat cultivar mixtures: A meta-analysis perspective and identification of knowledge gaps. Field Crops Research. 2018; 221 ():298-313.
Chicago/Turabian StyleJulie Borg; Lars P Kiær; C. Lecarpentier; I. Goldringer; A. Gauffreteau; S. Saint-Jean; S. Barot; J. Enjalbert. 2018. "Unfolding the potential of wheat cultivar mixtures: A meta-analysis perspective and identification of knowledge gaps." Field Crops Research 221, no. : 298-313.
Enhancing ground cover vegetation is an important agricultural practice that regulates herbivore and predator insects in agricultural landscapes. However, the effects of ground cover on the spatial distributions of these organisms have scarcely been explored. Our goal was to measure the effects of ground cover on the spatial aggregation and association of insect herbivores and predators, which might contribute to the control of herbivorous pests. We conducted our experiments in peach orchards at two sites in eastern China. The two sites have experimental units with ground cover treatments that created a heterogeneous landscape. We conducted a 2-year experiment to investigate the abundance and distribution of herbivores (leafhoppers) and predators (ladybirds), using geostatistics to analyze their spatial aggregation and association. The abundance of predators increased and that of herbivores decreased in ground cover orchards compared to control orchards without ground cover. The proportion of spatial structure was greater than 0.75 for both herbivores and predators in the control orchards, indicating a lack of spatial aggregation, and less than 0.75 in peach orchards with ground cover, indicating spatial aggregation. The correlation of spatial aggregation between herbivores and predators was significantly positive in the ground cover treatment, indicating association of the two insect guilds. In control orchards, on the other hand, this was not significant. The presence of ground cover increased predator abundance, spatial aggregation of herbivores and predators as well as their spatial association, suggesting a mechanism for more efficient control of herbivorous pests in peach orchards.
Nian-Feng Wan; Xiang-Yun Ji; Lars P Kiær; Shuang-Shuang Liu; Jian-Yu Deng; Jie-Xian Jiang; Bo Li. Ground cover increases spatial aggregation and association of insect herbivores and their predators in an agricultural landscape. Landscape Ecology 2018, 33, 799 -809.
AMA StyleNian-Feng Wan, Xiang-Yun Ji, Lars P Kiær, Shuang-Shuang Liu, Jian-Yu Deng, Jie-Xian Jiang, Bo Li. Ground cover increases spatial aggregation and association of insect herbivores and their predators in an agricultural landscape. Landscape Ecology. 2018; 33 (5):799-809.
Chicago/Turabian StyleNian-Feng Wan; Xiang-Yun Ji; Lars P Kiær; Shuang-Shuang Liu; Jian-Yu Deng; Jie-Xian Jiang; Bo Li. 2018. "Ground cover increases spatial aggregation and association of insect herbivores and their predators in an agricultural landscape." Landscape Ecology 33, no. 5: 799-809.
Alberto Canarini; Lars P Kiær; Feike A. Dijkstra. Soil carbon loss regulated by drought intensity and available substrate: A meta-analysis. Soil Biology and Biochemistry 2017, 112, 90 -99.
AMA StyleAlberto Canarini, Lars P Kiær, Feike A. Dijkstra. Soil carbon loss regulated by drought intensity and available substrate: A meta-analysis. Soil Biology and Biochemistry. 2017; 112 ():90-99.
Chicago/Turabian StyleAlberto Canarini; Lars P Kiær; Feike A. Dijkstra. 2017. "Soil carbon loss regulated by drought intensity and available substrate: A meta-analysis." Soil Biology and Biochemistry 112, no. : 90-99.
Northern Europe supports large soil organic carbon (SOC) pools and has been subjected to high frequency of land‐use changes during the past decades. However, this region has not been well represented in previous large‐scale syntheses of land‐use change effects on SOC, especially regarding effects of afforestation. Therefore, we conducted a meta‐analysis of SOC stock change following afforestation in Northern Europe. Response ratios were calculated for forest floors and mineral soils (0–10 cm and 0–20/30 cm layers) based on paired control (former land use) and afforested plots. We analyzed the influence of forest age, former land‐use, forest type, and soil textural class. Three major improvements were incorporated in the meta‐analysis: analysis of major interaction groups, evaluation of the influence of nonindependence between samples according to study design, and mass correction. Former land use was a major factor contributing to changes in SOC after afforestation. In former croplands, SOC change differed between soil layers and was significantly positive (20%) in the 0–10 cm layer. Afforestation of former grasslands had a small negative (nonsignificant) effect indicating limited SOC change following this land‐use change within the region. Forest floors enhanced the positive effects of afforestation on SOC, especially with conifers. Meta‐estimates calculated for the periods 30 years since afforestation revealed a shift from initial loss to later gain of SOC. The interaction group analysis indicated that meta‐estimates in former land‐use, forest type, and soil textural class alone were either offset or enhanced when confounding effects among variable classes were considered. Furthermore, effect sizes were slightly overestimated if sample dependence was not accounted for and if no mass correction was performed. We conclude that significant SOC sequestration in Northern Europe occurs after afforestation of croplands and not grasslands, and changes are small within a 30‐year perspective.
Teresa G. Bárcena; Lars P Kiær; Lars Vesterdal; H. M. Stefánsdóttir; P. Gundersen; B. D. Sigurdsson. Soil carbon stock change following afforestation in Northern Europe: a meta‐analysis. Global Change Biology 2014, 20, 2393 -2405.
AMA StyleTeresa G. Bárcena, Lars P Kiær, Lars Vesterdal, H. M. Stefánsdóttir, P. Gundersen, B. D. Sigurdsson. Soil carbon stock change following afforestation in Northern Europe: a meta‐analysis. Global Change Biology. 2014; 20 (8):2393-2405.
Chicago/Turabian StyleTeresa G. Bárcena; Lars P Kiær; Lars Vesterdal; H. M. Stefánsdóttir; P. Gundersen; B. D. Sigurdsson. 2014. "Soil carbon stock change following afforestation in Northern Europe: a meta‐analysis." Global Change Biology 20, no. 8: 2393-2405.
Thure Pavlo Hauser; Stina Christensen; Christine Heimes; Lars P Kiær. Combined effects of arthropod herbivores and phytopathogens on plant performance. Functional Ecology 2013, 27, 623 -632.
AMA StyleThure Pavlo Hauser, Stina Christensen, Christine Heimes, Lars P Kiær. Combined effects of arthropod herbivores and phytopathogens on plant performance. Functional Ecology. 2013; 27 (3):623-632.
Chicago/Turabian StyleThure Pavlo Hauser; Stina Christensen; Christine Heimes; Lars P Kiær. 2013. "Combined effects of arthropod herbivores and phytopathogens on plant performance." Functional Ecology 27, no. 3: 623-632.
Varietal seed mixtures tend to increase and stabilize crop yields, yet their application is sparse. Large-scale cultivation of variety mixtures may require a better understanding of how inter-varietal interactions and their interaction with the environment may influence the grain yield of variety mixtures relative to their component varieties. For this purpose, six variety mixtures of spring barley and 14 component varieties were grown in each of 17 trial environments. A total of 28 observed and a priori plant characteristics, including grain yield, disease severity and weed competitiveness, were derived for each component variety in each trial. The relationship between inter-varietal diversity of each characteristic and the mixing effect on grain yield was analysed. Additionally, various types of yield stability were estimated and compared among mixtures and component varieties. One mixture out-yielded all of its component varieties in almost half of the trial environments. Inter-varietal diversity in grain yield potential correlated significantly with mixing effect, as did straw length diversity when weighted with weed pressure. The grain yields of most mixtures were more stable across environments than their component varieties when accounting also for the general response to environmental productivity. Hence, most mixtures adapted slightly better to environmental productivity and were less sensitive to environmental stress than their component varieties. We conclude that the efficacy of variety mixtures may be enhanced by mixing relatively high-yielding varieties differing in responsiveness to environmental productivity.
Lars P Kiær; Ib M. Skovgaard; Hanne Østergård. Effects of inter-varietal diversity, biotic stresses and environmental productivity on grain yield of spring barley variety mixtures. Euphytica 2012, 185, 123 -138.
AMA StyleLars P Kiær, Ib M. Skovgaard, Hanne Østergård. Effects of inter-varietal diversity, biotic stresses and environmental productivity on grain yield of spring barley variety mixtures. Euphytica. 2012; 185 (1):123-138.
Chicago/Turabian StyleLars P Kiær; Ib M. Skovgaard; Hanne Østergård. 2012. "Effects of inter-varietal diversity, biotic stresses and environmental productivity on grain yield of spring barley variety mixtures." Euphytica 185, no. 1: 123-138.
Lars P Kiær; Ib M. Skovgaard; Hanne Østergård. Grain yield increase in cereal variety mixtures: A meta-analysis of field trials. Field Crops Research 2009, 114, 361 -373.
AMA StyleLars P Kiær, Ib M. Skovgaard, Hanne Østergård. Grain yield increase in cereal variety mixtures: A meta-analysis of field trials. Field Crops Research. 2009; 114 (3):361-373.
Chicago/Turabian StyleLars P Kiær; Ib M. Skovgaard; Hanne Østergård. 2009. "Grain yield increase in cereal variety mixtures: A meta-analysis of field trials." Field Crops Research 114, no. 3: 361-373.
Spontaneous gene flow between wild and cultivated chicory, Cichorium intybus L., may have implications for the genetic structure and evolution of populations and varieties. One aspect of this crop-wild gene flow is the dispersal of transgenes from genetically modified varieties, e.g. gene flow from GM chicory to natural chicory could have unwanted consequences. With the purpose to identify and quantify crop-wild gene flow in chicory, we analysed introgression in 19 wild chicory populations and 16 accessions of chicory varieties and landraces distributed across Northern, Central and Mediterranean Europe. The analysis used 281 AFLP markers and 75 SSAP markers giving a total of 356 polymorphic markers. Results from model based assignments with the program STRUCTURE indicated many incidents of recent gene flow. Gene flow was observed both between cultivars and wild populations, between landraces and wild populations, between different wild populations as well as between cultivars. Population structure visualized by distance-based clustering showed a North–South geographical structuring of the wild populations, and a general grouping of the cultivars corresponding to known origin. The results indicated, however, that the structuring between the two groups of wild and cultivated types was weak. As crop and wild recipients are genetically close and genes are transferred between the two types rather frequently, focus on mitigating crop-wild gene flow should be increased, before transgenic varieties are cultivated openly.
Lars P Kiær; François Felber; A. Flavell; R. Guadagnuolo; D. Guiatti; Thure Pavlo Hauser; A. M. Olivieri; I. Scotti; N. Syed; M. Vischi; Clemens Van De Wiel; R. B. Jørgensen; C. Wiel. Spontaneous gene flow and population structure in wild and cultivated chicory, Cichorium intybus L. Genetic Resources and Crop Evolution 2008, 56, 405 -419.
AMA StyleLars P Kiær, François Felber, A. Flavell, R. Guadagnuolo, D. Guiatti, Thure Pavlo Hauser, A. M. Olivieri, I. Scotti, N. Syed, M. Vischi, Clemens Van De Wiel, R. B. Jørgensen, C. Wiel. Spontaneous gene flow and population structure in wild and cultivated chicory, Cichorium intybus L. Genetic Resources and Crop Evolution. 2008; 56 (3):405-419.
Chicago/Turabian StyleLars P Kiær; François Felber; A. Flavell; R. Guadagnuolo; D. Guiatti; Thure Pavlo Hauser; A. M. Olivieri; I. Scotti; N. Syed; M. Vischi; Clemens Van De Wiel; R. B. Jørgensen; C. Wiel. 2008. "Spontaneous gene flow and population structure in wild and cultivated chicory, Cichorium intybus L." Genetic Resources and Crop Evolution 56, no. 3: 405-419.
When planning optimal conservation strategies for wild and cultivated types of a plant species, a number of influencing biological and environmental factors should be considered from the outset. In the present study Brassica rapa was used to illustrate this: to develop Scandinavian conservation strategies for wild and cultivated B. rapa, DNA-marker analysis was performed on 15 cultivated and 17 wild accessions of B. rapa plus 8 accessions of the cross compatible B. napus. The B. rapa cultivars were bred in Sweden and Finland in 1944–1997 and the wild B. rapa material was collected from Denmark, Sweden and United Kingdom. The B. napus accessions were bred within the last 20 years in the Scandinavian countries. Results were based on scoring of 131 polymorphic ISSR markers in the total plant material. A Bayesian Markov chain Monte Carlo (MCMC) approach implemented in NewHybrids demonstrated a clear distinction of B. rapa and B. napus individuals except for three individuals that seemed to be backcrosses. The backcrossed hybrids descended from two Swedish populations, one wild and one escaped. The overall pattern of genetic variation and structure in B. rapa showed that cultivated and wild B. rapa accessions formed two almost separated clusters. Geographical origin and breeding history of cultivars were reflected in these genetic relationships. In addition, wild populations from Denmark and Sweden seemed to be closely related, except for a Swedish population, which seemingly was an escaped cultivar. The study point to that many processes, e.g. spontaneous introgression, naturalisation, breeding and agricultural practise affected the genetic structure of wild and cultivated B. rapa populations.
Naja Steen Andersen; Gert Poulsen; Bente Anni Andersen; Lars P Kiær; Tina D’Hertefeldt; Mike J. Wilkinson; Rikke Bagger Jørgensen. Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa. Genetic Resources and Crop Evolution 2008, 56, 189 -200.
AMA StyleNaja Steen Andersen, Gert Poulsen, Bente Anni Andersen, Lars P Kiær, Tina D’Hertefeldt, Mike J. Wilkinson, Rikke Bagger Jørgensen. Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa. Genetic Resources and Crop Evolution. 2008; 56 (2):189-200.
Chicago/Turabian StyleNaja Steen Andersen; Gert Poulsen; Bente Anni Andersen; Lars P Kiær; Tina D’Hertefeldt; Mike J. Wilkinson; Rikke Bagger Jørgensen. 2008. "Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa." Genetic Resources and Crop Evolution 56, no. 2: 189-200.
Hybridization and its possible impacts is a subject of increased attention in connection with the risk of unintended gene flow from cultivated (including genetically modified) plants to wild relatives. Whether such gene flow by hybridization is likely to take place depends among other things on the persistence of the hybrids in a natural environment over time. To evaluate this, we studied an experimental hybridizing population of wild and cultivated chicories (Cichorium intybus) relative to a previous study on the same population 2 years earlier. We compared the genetic composition, morphology and fitness traits of plants from 2004 to the plants in the same plot in 2002. The majority of the plants in 2004 was more morphologically and genetically intermediate than in 2002. This indicates that no selection towards being wild-like or cultivar-like was present over the period of 2 years. Furthermore, no distinct fitness differences existed between the plants of 2004, probably due to most of the plants being intermediate. No hybridization barriers appeared to be present between wild and cultivated chicories beyond the F1 generation, since F2 hybrids and backcrosses were in abundance; in fact, hybrids of probably fourth or fifth generation were present. In conclusion, all results indicate that no barriers exist to the temporal persistence of chicory hybrids in a natural environment.
B. S. Sørensen; Lars P Kiær; R. B. Jørgensen; Thure Pavlo Hauser. The temporal development in a hybridizing population of wild and cultivated chicory (Cichorium intybus L.). Molecular Ecology 2007, 16, 3292 -3298.
AMA StyleB. S. Sørensen, Lars P Kiær, R. B. Jørgensen, Thure Pavlo Hauser. The temporal development in a hybridizing population of wild and cultivated chicory (Cichorium intybus L.). Molecular Ecology. 2007; 16 (16):3292-3298.
Chicago/Turabian StyleB. S. Sørensen; Lars P Kiær; R. B. Jørgensen; Thure Pavlo Hauser. 2007. "The temporal development in a hybridizing population of wild and cultivated chicory (Cichorium intybus L.)." Molecular Ecology 16, no. 16: 3292-3298.
An official journal of the Genetics Society, Heredity publishes high-quality articles describing original research and theoretical insights in all areas of genetics. Research papers are complimented by News & Commentary articles and reviews, keeping researchers and students abreast of hot topics in the field.
Lars P Kiær; M Philipp; R B Jørgensen; T P Hauser; M Philipp L P Ki. Genealogy, morphology and fitness of spontaneous hybrids between wild and cultivated chicory (Cichorium intybus). Heredity 2007, 99, 112 -120.
AMA StyleLars P Kiær, M Philipp, R B Jørgensen, T P Hauser, M Philipp L P Ki. Genealogy, morphology and fitness of spontaneous hybrids between wild and cultivated chicory (Cichorium intybus). Heredity. 2007; 99 (1):112-120.
Chicago/Turabian StyleLars P Kiær; M Philipp; R B Jørgensen; T P Hauser; M Philipp L P Ki. 2007. "Genealogy, morphology and fitness of spontaneous hybrids between wild and cultivated chicory (Cichorium intybus)." Heredity 99, no. 1: 112-120.