25 results on '"Anna Westerbergh"'
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2. Perennials as Future Grain Crops: Opportunities and Challenges
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Elizabeth A. Chapman, Hanne Cecilie Thomsen, Sophia Tulloch, Pedro M. P. Correia, Guangbin Luo, Javad Najafi, Lee R. DeHaan, Timothy E. Crews, Lennart Olsson, Per-Olof Lundquist, Anna Westerbergh, Pai Rosager Pedas, Søren Knudsen, and Michael Palmgren
- Subjects
Plant Science - Abstract
Perennial grain crops could make a valuable addition to sustainable agriculture, potentially even as an alternative to their annual counterparts. The ability of perennials to grow year after year significantly reduces the number of agricultural inputs required, in terms of both planting and weed control, while reduced tillage improves soil health and on-farm biodiversity. Presently, perennial grain crops are not grown at large scale, mainly due to their early stages of domestication and current low yields. Narrowing the yield gap between perennial and annual grain crops will depend on characterizing differences in their life cycles, resource allocation, and reproductive strategies and understanding the trade-offs between annualism, perennialism, and yield. The genetic and biochemical pathways controlling plant growth, physiology, and senescence should be analyzed in perennial crop plants. This information could then be used to facilitate tailored genetic improvement of selected perennial grain crops to improve agronomic traits and enhance yield, while maintaining the benefits associated with perennialism.
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- 2022
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3. Linking wheat nitrogen use to root traits: Shallow and thin embryonic roots enhance uptake but reduce conversion efficiency of nitrogen
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Hui Liu, Tino Colombi, Ortrud Jäck, Anna Westerbergh, and Martin Weih
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Soil Science ,Agronomy and Crop Science - Published
- 2022
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4. Evidence for magnesium–phosphorus synergism and co-limitation of grain yield in wheat agriculture
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Tino Colombi, Anna Westerbergh, Martin Weih, Thomas Keller, Pernilla Vallenback, Ortrud Jäck, and Hui Liu
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0106 biological sciences ,Ecophysiology ,Science ,Biomass ,chemistry.chemical_element ,01 natural sciences ,Article ,Crop ,Nutrient ,Yield (wine) ,Plant ecology ,Multidisciplinary ,Chemistry ,business.industry ,Phosphorus ,food and beverages ,04 agricultural and veterinary sciences ,Agronomy ,Agriculture ,040103 agronomy & agriculture ,Medicine ,0401 agriculture, forestry, and fisheries ,business ,Agroecology ,010606 plant biology & botany - Abstract
Modern crop production is characterized by high nitrogen (N) application rates, which can influence the co-limitation of harvested yield by other nutrients. Using a multidimensional niche volume concept and scaling exponents frequently applied in plant ecological research, we report that increased N and phosphorus (P) uptake in a growing wheat crop along with enhanced grain biomass is associated with more than proportional increase of other nutrients. Furthermore, N conversion efficiency and grain yield are strongly affected by the magnesium (Mg) to P ratio in the growing crop. We analyzed a field trial in Central Sweden including nine wheat varieties grown during two years with contrasting weather, and found evidence for Mg co-limitation at lower grain yields and P co-limitation at higher yields. We argue that critical concentrations of single nutrients, which are often applied in agronomy, should be replaced by nutrient ratios. In addition, links between plant P and Mg contents and root traits were found; high root number enhanced the P:N ratio, whilst steep root angle, indicating deep roots, increased the Mg:N ratio. The results have significant implications on the management and breeding targets of agriculturally grown wheat, which is one of the most important food crops worldwide.
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- 2021
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5. Increased Recovery of Green Doubled Haploid Plants from Barley Anther Culture
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Anna Westerbergh, Estelle Lerceteau-Köhler, Sridevy Sriskandarajah, and Mohammad Sameri
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fungi ,Stamen ,food and beverages ,Biology ,medicine.disease ,Microspore ,Germination ,Botany ,Shoot ,Albinism ,medicine ,Doubled haploidy ,Hordeum vulgare ,Cultivar ,Agronomy and Crop Science - Abstract
Albinism is a major limitation in the production of doubled haploid plants in cereals. As this trait is partly genetically controlled, the culture method has to be adapted to the plant genotype to reduce albinism. We have improved green plant recovery in the Northern barley ( Hordeum vulgare L.) spring cultivar Mitja from 6 to 42% by altering the culture method and composition of the culture media. In a new three-step protocol, the addition of casein hydrolysate to an inter - mediate regeneration medium gave the high - est number of green plants. The shoot and root growth medium used for germinated embryos was superior to the standard media reported in the literature for root formation and shoot growth. o ur modified method has merit for test - ing with other recalcitrant genotypes in anther and isolated microspore cultures.
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- 2015
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6. List of Contributors
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Miguel J. Beltran-García, Philip N. Benfey, Hermi F. Brito, Sylvie M. Brouder, Juan J. Camacho-Cristóbal, Carlos J. Ceacero, Maria C.F. Cunha Felinto, Ivan G.N. da Silva, Sylvia M. de Sousa, Paolo Di Mascio, Setyowati R. Djiwanti, Francisco Echaide-Aquino, Toru Fujiwara, Trevor Garnett, Agustín González-Fontes, Claudia T. Guimaraes, Wanli Guo, Xue He, María B. Herrera-Rodríguez, Aurora Huerta-Robles, Sameer Joshi, Surya Kant, Suresh Kaushik, Julia Kehr, Leon V. Kochian, Thomas Leustek, Damar L. López-Arredondo, Per-Olof Lundquist, Jonathan P. Lynch, Gloria Macedo-Raygoza, Jurandir V. Magalhaes, Hayato Maruyama, Marisa H.G. Medeiros, María T. Navarro-Gochicoa, Giao N. Nguyen, Yoshihiro Ohmori, Mamoru Okamoto, Darren Plett, Fernanda M. Prado, Katia R. Prieto, Martin Reich, Jesús Rexach, Lenin Sánchez-Calderón, Deepti Shankhdhar, Shailesh C. Shankhdhar, Ashish Sharma, Ryoung Shin, Erin E. Sparks, Wan Teng, Yiping Tong, Hellen P. Valério, Jeffrey J. Volenec, Qinglian Wang, Jun Wasaki, Martin Weih, Christian Weissert, Anna Westerbergh, James F. White, Kenji Yano, Lenin Yong-Villalobos, Baohong Zhang, Zhiyong Zhang, and Zhi-Liang Zheng
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- 2017
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7. Role of nutrient-efficient plants for improving crop yields: bridging plant ecology, physiology, and molecular biology
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Anna Westerbergh, Per-Olof Lundquist, and Martin Weih
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0106 biological sciences ,0301 basic medicine ,Food security ,Nutrient management ,Crop yield ,Scale (chemistry) ,Physiology ,Biology ,01 natural sciences ,Plant ecology ,03 medical and health sciences ,030104 developmental biology ,Nutrient ,Plant breeding ,010606 plant biology & botany - Abstract
The efficient use of nutrients underpins food security and reduces losses of nutrients to the environment. Different approaches have been applied to improve and evaluate the nutrient use efficiency (NUE) of plants, depending on the purpose to which the concept has been put. The various approaches differ greatly in the scale and target for NUE improvement and assessment. In this chapter, various approaches and conceptions for improving and evaluating NUE across different scales are discussed: (1) the investigation of the physiology and genetics of NUE at single tissue, cell and molecular scales, targeting understanding and improvement of NUE-related traits through, for example, plant breeding; and (2) the assessment of NUE and nutrient balances at whole plant, field, and regional scales for evaluating crops with NUE-improved traits. Appropriate methodologies are available to link the processes acting at molecular, individual plant, farm, and regional scales, but require increased collaborative efforts between the different disciplines.
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- 2017
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8. Cassava, a potential biofuel crop in (the) People’s Republic of China
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Jiaming Zhang, Christer Jansson, Xinwen Hu, Chuanxin Sun, and Anna Westerbergh
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Latin Americans ,Agroforestry ,Mechanical Engineering ,Tropics ,People's Republic ,Staple food ,Building and Construction ,Management, Monitoring, Policy and Law ,Pulp and paper industry ,Starch production ,General Energy ,Geography ,Biofuel ,China ,Guanxi - Abstract
Cassava ranks fifth among crops in global starch production. It is used as staple food in many tropical countries of Africa, Asia and Latin America. In (the) People’s Republic of China, although not yet a staple food, cassava is of major economic importance for starch for a large area of southern (the) PRC, especially in the provinces of Guangdong, Guanxi, Yunnan and Hainan. Recently, cassava-derived bioethanol production has been increasing due to its economic benefits compared to other bioethanol-producing crops in the country. We discuss here the possible potentials of cassava for bioethanol production.
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- 2009
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9. The genetic basis of hairlessness in Silene dioica (Caryophyllaceae)*
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Anna Westerbergh
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biology ,Botany ,Genetics ,Caryophyllaceae ,General Medicine ,biology.organism_classification ,Silene dioica - Published
- 2008
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10. Quantitative trait loci controlling cyanogenic glucoside and dry matter content in cassava (Manihot esculenta Crantz) roots
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Martin A. Fregene, Ann-Christin Rönnberg-Wästljung, Anna Westerbergh, Urban Gullberg, Thomas Egwang, and Elizabeth Balyejusa Kizito
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education.field_of_study ,Population ,Manihot esculenta ,food and beverages ,Overdominance ,General Medicine ,Biology ,Heritability ,Quantitative trait locus ,chemistry.chemical_compound ,chemistry ,Agronomy ,Cyanogenic Glucoside ,Molecular marker ,Botany ,Genetics ,Dry matter ,education - Abstract
Cassava (Manihot esculenta Crantz) is a starchy root crop grown in the tropics mainly by small-scale farmers even though agro-industrial processing is rapidly increasing. For this processing market improved varieties with high dry matter root content (DMC) is required. Potentially toxic cyanogenic glucosides are synthesized in the leaves and translocated to the roots. Selection for varieties with low cyanogenic glucoside potential (CNP) and high DMC is among the principal objectives in cassava breeding programs. However, these traits are highly influenced by the environmental conditions and the genetic control of these traits is not well understood. An S1 population derived from a cross between two bred cassava varieties (MCOL 1684 and Rayong 1) that differ in CNP and DMC was used to study the heritability and genetic basis of these traits. A broad-sense heritability of 0.43 and 0.42 was found for CNP and DMC, respectively. The moderate heritabilities for DMC and CNP indicate that the phenotypic variation of these traits is explained by a genetic component. We found two quantitative trait loci (QTL) on two different linkage groups controlling CNP and six QTL on four different linkage groups controlling DMC. One QTL for CNP and one QTL for DMC mapped near each other, suggesting pleiotrophy and/or linkage of QTL. The two QTL for CNP showed additive effects while the six QTL for DMC showed additive effect, dominance or overdominance. This study is a first step towards developing molecular marker tools for efficient breeding of CNP and DMC in cassava.
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- 2007
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11. Genetic diversity and variety composition of cassava on small-scale farms in Uganda: an interdisciplinary study using genetic markers and farmer interviews
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Thomas Egwang, Elizabeth Balyejusa Kizito, Linley Chiwona-Karltun, Anna Westerbergh, and Martin A. Fregene
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Genetic Markers ,Rural Population ,Manihot ,Genotype ,Plant Science ,Biology ,Crop ,Genetic variation ,Genetics ,Uganda ,Alleles ,Plant Proteins ,Genetic diversity ,Models, Statistical ,Polymorphism, Genetic ,Models, Genetic ,business.industry ,Genetic Variation ,food and beverages ,General Medicine ,Variety (linguistics) ,Biotechnology ,Agriculture ,Genetic marker ,Insect Science ,Africa ,Genetic structure ,Animal Science and Zoology ,Agricultural biodiversity ,business - Abstract
Cassava is a tropical crop and grown for its tuberous starchy roots. In Africa it is mainly cultivated by small-scale farmers who observe, select and name their cassava varieties based on morphology, food, social and economic interest. Here we have used an interdisciplinary approach involving farmer interviews, genetic markers and morphological descriptors to study the composition of cassava varieties on small-scale farms in 11 villages located in three districts in Uganda, the genetic structure within and between these varieties and their morphology. The composition of local, newly introduced and improved varieties differed widely between villages and districts. The Ugandan farmers in our study seemed to adopt improved varieties to a greater extent when there was a nearby market, prevalence of disease epidemics and good extension service. We found considerable genetic variation both within and between cassava varieties though the variation was larger between varieties. However, most local and improved varieties showed predominating genotypes at many loci. Accessions of commonly grown varieties meeting farmers' preferences could therefore be selected and implemented in future breeding programmes involving development, dissemination and adoption. The like-named varieties in different villages were genetically similar, demonstrating farmers' ability to differentiate and maintain the same variety over large areas. However, some varieties with different names in different villages showed both genetic and morphological similarity, suggesting that farmers may rename plants when they are introduced into their fields. The large differences found in variety and genetic composition between villages and districts in Uganda may be a result of the diverse needs and growing conditions characteristic for traditional farming system. This suggests that efforts to conserve and increase the genetic diversity in farmers' fields will require policies tailored to each area.
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- 2006
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12. Quantitative trait loci controlling phenotypes related to the perennial versus annual habit in wild relatives of maize
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John Doebley and Anna Westerbergh
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Genetic Markers ,Perennial plant ,Quantitative Trait Loci ,Environment ,Quantitative trait locus ,Biology ,Zea mays ,Chromosomes, Plant ,Genotype ,Genetics ,Poaceae ,Crosses, Genetic ,Plant Stems ,Homozygote ,Chromosome Mapping ,food and beverages ,Chromosome ,General Medicine ,Phenotype ,Trait ,Habit (biology) ,Seasons ,Restriction fragment length polymorphism ,Edible Grain ,Agronomy and Crop Science ,Biotechnology - Abstract
We used quantitative trait locus/loci (QTL) mapping to study the inheritance of traits associated with perennialism in a cross between an annual (Zea mays ssp. parviglumis) and a perennial (Z. diploperennis) species of teosinte. The most striking difference between these species is that Z. diploperennis forms rhizomes, whereas Z. mays ssp. parviglumis lacks these over-wintering underground stems. An F2 population of 425 individuals was genotyped at 95 restriction fragment length polymorphism marker loci and the association between phenotype and genotype was analyzed by composite interval mapping. We detected a total of 38 QTL for eight traits. The number of QTL found for each trait ranged from two for rhizome formation to nine for tillering. QTL for six of the traits mapped near each other on chromosome 2, and QTL for four traits mapped near each other on chromosome 6, suggesting that these regions play an important role in the evolution of the perennial habit in teosinte. Most of the 38 QTL had small effects, and no single QTL showed a strikingly large effect. The map positions that we determined for rhizome formation and other traits in teosinte may help to locate corresponding QTL in pasture and turf grasses used as forage for cattle and for erosion control in agro-ecosystems.
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- 2004
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13. An interaction between a specialized seed predator moth and its dioecious host plant shifting from parasitism to mutualism
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Anna Westerbergh
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Mutualism (biology) ,Pollination ,Obligate ,Pollinator ,Ecology ,Dioecy ,Parasitism ,Biology ,biology.organism_classification ,Predator ,Ecology, Evolution, Behavior and Systematics ,Silene dioica - Abstract
Seed predator/pollinator and host plant interactions, which may be considered as antagonistic, have the potential to provide good model systems for the study of the early stages of evolution towards mutualism. I describe a relationship between a seed predator, the geometrid moth Perizoma affinitatum, and the dioecious plant Silene dioica. The moth is an obligate seed predator on its host plant. The searching and ovipositing behaviour of the female moths, number of eggs deposited per flower, the pollinating ability of the moths and the seed consumption by the larvae are described as different parameters and studied in two Finnish coastal populations. A high pollinating ability and limited seed consumption by the predator was found and discussed in relation to fitness models of P. affinitatum and S. dioica. In a mutualistic relationship there must be a balance between the costs and benefits so that the seed production by the moths is larger than the seed consumption by the larvae, given a net seed output larger than zero. The data of the parameters included in a seed production/consumption model give a positive seed output when the proportion of S. dioica flowers pollinated by other non-predating insects is less than 60%. Accordingly, even if P. affinitatum would become the exclusive pollinator it would not endanger the survival of the host plant and both partners would benefit from this interaction. Limited seed consumption, high pollinating ability and host specificity as seen in the P. affinitatum and S. dioica interaction are considered to have been important pre-existing qualities in the evolution of the obligate mutualisms between yucca and yucca moths and fig and fig wasps. In isolated serpentine populations where the gene flow is restricted and co-pollinators are rare the interaction between P. affinitatum and S. dioica has the potential to shift from parasitism to mutualism.
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- 2004
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14. Evidence for parallel evolution and site‐specific selection of serpentine tolerance in Cerastium alpinum during the colonization of Scandinavia
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Anna Westerbergh, Sverre Dahlgren, and Anna Britt Nyberg Berglund
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Hybrid zone ,biology ,Physiology ,Alpine plant ,Cerastium alpinum ,Soil water ,Botany ,Randomized block design ,Caryophyllaceae ,Cerastium ,Colonization ,Plant Science ,biology.organism_classification - Abstract
Summary •The effects of Ni and Mg, two factors involved in the infertility of serpentine soils, were studied in the alpine plant Cerastium alpinum. Root growth of plants from adjacent serpentine and non-serpentine populations in Scandinavia, representing an eastern and western postglacial immigration lineage and the hybrid zone between them, were compared to study the adaptation of C. alpinum populations. •Seedlings were placed in solutions with low or high concentrations of Ni and Mg in a full factorial experiment according to a randomized block design. The growth of roots was analyzed and discussed in relation to the soil content. •The serpentine populations showed higher tolerance to Ni and Mg stress than non-serpentine populations. The degree of metal tolerance differed among the serpentine populations and was related to the effective concentrations of Ni and Mg in the soil at each site. •The results suggest that serpentine tolerance is locally evolved in C. alpinum and that tolerance has arisen in parallel during the postglacial colonization of Scandinavia on serpentine soils with similar composition.
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- 2003
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15. Interactions between seed predators/pollinators and their host plants: a first step towards mutualism?
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Johan Westerbergh and Anna Westerbergh
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Mutualism (biology) ,Seed dispersal syndrome ,Pollinator ,Ecology ,Seed predation ,Parasitism ,Biology ,Predator ,Ecology, Evolution, Behavior and Systematics ,Coevolution ,Predation - Abstract
The mutualisms between fig trees and their pollinator fig wasps and between yucca plants and yucca moths are spectacular examples of coevolution. The characteristics of these independently evolved mutualisms have resulted from long-term processes, the first stages of which are unknown. A fundamental question in the study of mutualism is how these interactions evolve. Seed predator/pollinator and host plant interactions, which may initially be considered as mainly antagonistic, have the potential to provide good model systems for the study of the first stages of evolution towards mutualism. We present here theoretical models assessing the consequences of interactions between specialized seed predator insects and their host plants. These models describe the parameters that affect the fitness of an individual female seed predator and her influence on the fitness of the host plant. In an optimal strategy for the seed predator, the number of eggs laid in each flower depends on the interaction between the adult and larva survival. Along with a growing predation pressure on adults and larvae several eggs must be laid in each flower by the female seed predator to enhance her fitness. However, in a situation where the host plant selectively aborts flowers with a high number of eggs the fitness of the seed predator will seriously decrease. If the cost of selective abortion is less than the cost of seed predation the host plant will maintain fitness. In a mutualistic relationship a balance between the cost and the benefit of the parameters in the fitness models of the seed predator and the host plant has to occur so that the net seed output is larger than zero (0). Any unselfish behaviour or quality of the seed predator that would benefit the host plant in such a way that the net seed output increases might be a first stage in an interaction becoming mutualistic. The models presented here will not only provide a platform for empirical studies on interactions that may swing from parasitism to mutualism, but also for seed predator/pollinator and host plant interactions in general.
- Published
- 2001
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16. Serpentine and non-serpentine Silene dioica plants do not differ in nickel tolerance
- Author
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Anna Westerbergh
- Subjects
Silene ,biology ,fungi ,food and beverages ,Soil Science ,Caryophyllaceae ,Plant Science ,Herbaceous plant ,biology.organism_classification ,Silene dioica ,Germination ,Serpentine soil ,Shoot ,Soil water ,Botany - Abstract
Serpentine soils are hostile to plant life. They are dry, contain high concentrations of nickel and have an unfavorable calcium/magnesium ratio. The dioecious plant Silene dioica (L.) Clairv. (Caryophyllaceae) is the most common herb on serpentine soils in the Swedish mountains. It also commonly grows on non-serpentine soils in the subalpine and coastal area. I have compared the germination frequency, plant establishment and growth of serpentine and subalpine non-serpentine populations in serpentine soil under greenhouse conditions. Further more I have studied the specific effect of nickel on root and shoot growth of serpentine and non-serpentine plants from the subalpine and coastal area in solutions with different concentrations of nickel. Plants from serpentine and non-serpentine populations grew well and in a similar fashion in serpentine soil. Moreover, S. dioica plants, irrespective of original habitat, tolerated enhanced concentrations of nickel when grown in solutions. An analysis of metal content in serpentine plants from natural populations shows that S. dioica has a higher nickel concentration in the roots than in the shoots. The growth studies show that S. dioica is constitutively adapted to serpentine, and that all populations have the genetic and ecological tolerance to grow on serpentine.
- Published
- 1994
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17. Genetic differentiation in endemicSilene(Caryophyllaceae) on the Hawaiian Islands
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Anna Westerbergh and Anssi Saura
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Silene ,biology ,Lava ,Ecology ,Context (language use) ,Plant Science ,biology.organism_classification ,Gene flow ,Genetic drift ,Genetic structure ,Genetic variation ,Genetics ,geographic locations ,Ecology, Evolution, Behavior and Systematics ,Founder effect - Abstract
Endemic Hawaiian Silene colonize new lava flows and are outcompeted as the ground ages. They illustrate the genetic processes operating in the evolution of pioneering island plants. The volcanic history of the Hawaiian Islands allows an estimation of the age of these plant populations. In this study, populations of S. struthioloides from Maui and the older part of the island of Hawaii, and S. ha aliensis from the youngest volcanoes of the island of Hawaii were analyzed by enzyme electrophoresis. The genetic structures of these populations were placed in a geographic and geologic context. Silene is much more polymorphic on the older island, Maui. Genetic variation appears to have been lost in the colonization of the youngest island, Hawaii. Interestingly, some loci for populations on the younger volcanoes of the island of Hawaii are monomorphic for alleles not found in populations on the older part of Hawaii. Recurrent colonizations are accompanied with founder effects, and restricted gene flow among populations has led to isolation and genetic drift. This has resulted in genetic and morphological differentiation of Silene populations on the youngest volcanoes.
- Published
- 1994
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18. Quantitative trait loci controlling cyanogenic glucoside and dry matter content in cassava (Manihot esculenta Crantz) roots
- Author
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Elizabeth, Balyejusa Kizito, Ann-Christin, Rönnberg-Wästljung, Thomas, Egwang, Urban, Gullberg, Martin, Fregene, and Anna, Westerbergh
- Subjects
Manihot ,Quantitative Trait Loci ,Chromosome Mapping ,Glycosides ,Plant Roots ,Chromosomes, Plant - Abstract
Cassava (Manihot esculenta Crantz) is a starchy root crop grown in the tropics mainly by small-scale farmers even though agro-industrial processing is rapidly increasing. For this processing market improved varieties with high dry matter root content (DMC) is required. Potentially toxic cyanogenic glucosides are synthesized in the leaves and translocated to the roots. Selection for varieties with low cyanogenic glucoside potential (CNP) and high DMC is among the principal objectives in cassava breeding programs. However, these traits are highly influenced by the environmental conditions and the genetic control of these traits is not well understood. An S(1) population derived from a cross between two bred cassava varieties (MCOL 1684 and Rayong 1) that differ in CNP and DMC was used to study the heritability and genetic basis of these traits. A broad-sense heritability of 0.43 and 0.42 was found for CNP and DMC, respectively. The moderate heritabilities for DMC and CNP indicate that the phenotypic variation of these traits is explained by a genetic component. We found two quantitative trait loci (QTL) on two different linkage groups controlling CNP and six QTL on four different linkage groups controlling DMC. One QTL for CNP and one QTL for DMC mapped near each other, suggesting pleiotrophy and/or linkage of QTL. The two QTL for CNP showed additive effects while the six QTL for DMC showed additive effect, dominance or overdominance. This study is a first step towards developing molecular marker tools for efficient breeding of CNP and DMC in cassava.
- Published
- 2007
19. Electrophoretic evidence for disomic inheritance and allopolyploid origin of the octoploid Cerastium alpinum (Caryophyllaceae)
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Anna-Britt Nyberg Berglund, Anna Westerbergh, and Anssi Saura
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Genetics ,education.field_of_study ,Heterozygote ,Alpine plant ,Population ,Locus (genetics) ,Caryophyllaceae ,Biological Sciences ,Biology ,biology.organism_classification ,Loss of heterozygosity ,Polyploidy ,Cerastium alpinum ,Genetic structure ,Biologiska vetenskaper ,Electrophoresis, Polyacrylamide Gel ,Allele ,education ,Molecular Biology ,Inbreeding ,Genetics (clinical) ,Biotechnology - Abstract
The mode of inheritance of six enzyme markers in the octoploid alpine plant Cerastium alpinum was analyzed. Offspring from crosses between heterozygotes showed fixed heterozygosity at malate dehydrogenase-2, phosphoglucoisomerase-2, triosephosphate isomerase-2, and triosephosphate isomerase-3. Phosphoglucomutase-1 also showed fixed heterozygosity except in offspring from one cross. Fixed heterozygosity in five enzyme systems suggests that C. alpinum has originated through at least some allopolyploidization. Offspring from plants heterozygous for two alleles at the menadione reductase-1 (Mr-1) locus did not deviate significantly from a 1:2:1 ratio. The large proportion of homozygotes suggests disomic inheritance because any kind of polysomic inheritance would result in a substantially increased proportion of heterozygotes relative to disomic inheritance. Assuming a diploid model for Mr-1, this locus was used to analyze the population genetic structure within C. alpinum populations. Inbreeding was found in many alpine populations. This may help explain the large genetic distances found among alpine populations in a previous study. The analysis is only based on one segregating locus, and the results should therefore be treated with caution. However, by establishing the mode of inheritance through crosses, we have been able to use a codominant marker in population genetic analysis of an octoploid plant.
- Published
- 2006
20. The effect of cassava mosaic disease on the genetic diversity of cassava in Uganda
- Author
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Martin A. Fregene, Urban Gullberg, Anton Bua, Elizabeth Balyejusa Kizito, Anna Westerbergh, and Thomas Egwang
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Germplasm ,Genetic diversity ,biology ,business.industry ,Agroforestry ,food and beverages ,Introgression ,Plant Science ,Horticulture ,biology.organism_classification ,Biotechnology ,Crop ,African cassava mosaic virus ,Genetic marker ,parasitic diseases ,Genetic variation ,Genetics ,Gene pool ,business ,human activities ,Agronomy and Crop Science - Abstract
Cassava (Manihot esculenta) is a tropical crop that is grown in Africa, Latin America and Southeast Asia. Cassava was introduced from Latin America into West and East Africa at two independent events. In Uganda a serious threat to cassava's survival is the cassava mosaic disease (CMD). Uganda has had two notable CMD epidemics since the introduction of cassava in the 1850s causing severe losses. SSR markers were used to study the effect of CMD on the genetic diversity in five agroecologies in Uganda with high and low incidence of CMD. Surprisingly, high gene diversity was detected. Most of the diversity was found within populations, while the diversity was very small among agroecological zones and the high and low CMD incidence areas. The high genetic diversity suggests a mechanism by which diversity is maintained by the active involvement of the Ugandan farmer in continuously testing and adopting new genotypes that will serve their diverse needs. However, in spite of the high genetic diversity we found a loss of rare alleles in areas with high CMD incidence. To study the effect of the introgression history on the gene pool the genetic differentiation between East and West Africa was also studied. Genetic similarities were found between the varieties in Uganda and Tanzania in East Africa and Ghana in West Africa. Thus, there is no evidence for a differentiation of the cassava gene pool into a western and an eastern genetic lineage. However, a possible difference in the genetic constitution of the introduced cassava into East and West Africa may have been diminished by germplasm movement.
- Published
- 2005
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21. Two postglacial immigration lineages of the polyploid Cerastium alpinum (Caryophyllaceae)
- Author
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Anna Westerbergh and Anna Britt Nyberg Berglund
- Subjects
Lineage (evolution) ,Disorders of Sex Development ,Caryophyllaceae ,Biology ,Polyploidy ,Soil ,Hybrid zone ,Polyploid ,Gene Frequency ,Cerastium alpinum ,Genetics ,Cluster Analysis ,Glacial period ,Finland ,Demography ,Sweden ,Polymorphism, Genetic ,Ecology ,Norway ,Altitude ,Taiga ,Genetic Variation ,General Medicine ,Emigration and Immigration ,Plants ,biology.organism_classification ,Plant Leaves ,Plant cover - Abstract
The plant cover of Fennoscandia is young because of the recent glaciation. This study covers the early stages of diversification and the genetic consequences of postglacial migration of a hermaphroditic polyploid plant, Cerastium alpinum. It has a continuous distribution in the alpine region, where it grows on alpine heaths and serpentine soils that are rich in heavy metals. Within the boreal forest C. alpinum has a scattered distribution on serpentine, dolomite and steep slopes. Plants from 31 populations in Norway, Sweden and Finland were subjected to enzyme electrophoresis. Analyses of the enzyme phenotypes suggest that C. alpinum has colonized Fennoscandia through two postglacial immigration events resulting in a southeastern and a southwestern lineage. These two lineages seem to meet in a hybrid zone in northern Sweden. Large genetic differences were found among most populations in both the southeastern and the southwestern lineages. This suggests that the populations are effectively isolated from each other.
- Published
- 2001
22. MORPHOLOGICAL TRAITS DEFINING SPECIES DIFFERENCES IN WILD RELATIVES OF MAIZE ARE CONTROLLED BY MULTIPLE QUANTITATIVE TRAIT LOCI
- Author
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Anna Westerbergh and John Doebley
- Subjects
Genetic Markers ,Genetic Linkage ,Population ,Tassel ,Biology ,Quantitative trait locus ,Zea mays ,Zea diploperennis ,Quantitative Trait, Heritable ,Family-based QTL mapping ,Species Specificity ,Pleiotropy ,Genetics ,Allele ,education ,Crosses, Genetic ,Ecology, Evolution, Behavior and Systematics ,education.field_of_study ,Reproduction ,food and beverages ,Chromosome Mapping ,biology.organism_classification ,Fixation (population genetics) ,Seeds ,General Agricultural and Biological Sciences - Abstract
We analyzed the genetic basis of morphological differences between two wild species of teosinte (Zea diploperennis and Z. mays ssp. parviglumis), which are relatives of maize. These two species differ in a number of taxonomically important traits including the structure of the tassel (male inflorescence), which is the focus of this report. To investigate the genetic inheritance of six tassel traits, quantitative trait locus (QTL) mapping with 95 RFLP markers was employed on a population of 425 F2 plants. Each trait was analyzed by interval mapping (IM) and composite interval mapping (CIM) to identify and characterize the QTL controlling the differences in tassel mor- phology. We detected two to eight QTL for each trait. In total, 30 QTL with IM and 33 QTL with CIM were found for tassel morphology. QTL for several of the traits mapped near each other, suggesting pleiotropy and/or linkage of QTL. The QTL showed small to moderate magnitudes of effect. No QTL of exceptionally large effect were found as seen under domestication and in the case of some other natural species. Thus, the model involving major QTL of large effect seems not to apply to the traits and species analyzed. A mixture of QTL with positive and negative allelic effects was found for most tassel traits and may suggest a history of periodic changes in the direction of selection during the divergence of Z. diploperennis and Z. mays ssp. parviglumis or fixation of QTL alleles by random genetic drift rather than selection.
- Published
- 2002
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23. Selective Grazing of Hairless Silene dioica Plants by Land Gastropods
- Author
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Anna Britt Nyberg and Anna Westerbergh
- Subjects
education.field_of_study ,Arianta arbustorum ,biology ,Arion fasciatus ,Arion ,Population ,biology.organism_classification ,Gene flow ,Silene dioica ,Seedling ,Botany ,Gastropoda ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
Silene dioica (Caryophyllaceae) has evolved different morphotypes that vary in hairiness in different habitats in the Swedish mountains. A hairy form, var. serpentinicola and a hairless (glabrous) form, var. smithii grow on serpentine, i.e. a dry soil rich in heavy metals. Var. lapponica is a densely hairy morphotype on subalpine meadows. Crosses between these varieties showed that glabrousness has a simple Mendelian inheritance and that glabrousness is determined by a recessive allele. The crosses further suggested that the recessive allele has been present in the original population that invaded the mountain area. Glabrous plants have, however, never been found on subalpine meadows, even though an earlier study has shown that gene flow is relatively common among serpentine and nearby meadow populations. In addition to the genetic background of glabrousness, we studied the grazing on glabrous smithii and hairy serpentinicola and lapponica plants by the slugs Arion fasciatus and Arion subfuscus and the snail Arianta arbustorum in greenhouse and in nature. Arion slugs, abundant on subalpine meadows, preferred glabrous plants and, in particular, A. fasciatus consumed high amounts of S. dioica. Arianta snails, however, consumed irrespective of morphotype. The selective behaviour was seen both at the seedling stage and the adult plant stage. Arion slugs were more choosy when they were given a choice of glabrous smithii and densely hairy lapponica plants then when they were served smithii and the less hairy variety serpentinicola. This study implies that the Arion slugs are important agents of selection on subalpine meadows. The selective grazing seems to counteract the flow of the recessive allele that determines glabrousness, from serpentine into meadow populations. Gastropods are rare in the dry serpentine habitat. The evolution of a distinct glabrous morphotype on serpentine is therefore rather due to relaxation of selection than to adaptation to serpentine stress.
- Published
- 1995
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24. Gene Flow and Pollinator Behaviour in Silene dioica Populations
- Author
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Anssi Saura and Anna Westerbergh
- Subjects
Silene ,Habitat fragmentation ,biology ,Habitat ,Pollinator ,Ecology ,Seed dispersal ,fungi ,Caryophyllaceae ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Silene dioica ,Gene flow - Abstract
Silene dioica (L.) Clairv. (Caryophyllaceae) is an insect pollinated and obligately cross-fertilising herb commonly found on serpentine, i.e. soils rich in heavy metals, and on cultivated meadows. Groups of Silene populations were studied in two areas in the Scandinavian mountains. In a northern area Silene populations grow in an open pine and birch forest while in the south, populations are surrounded by a continuous and dense spruce forest. Gene flow, estimated on the basis of allele frequencies, is highly restricted in the south in comparison to the north. This has led to an extensive genetic differentiation among populations. The pollinator guilds (Thricops flies, syrphid flies and bumblebees) are similar in the northern and southern populations and can therefore not account for the difference in gene flow. The flowering in nearby populations overlaps broadly and is also not the reason for the genetic differentiation in the south. The differentiation is more likely due to vegetation that limits pollinator movement. The level of gene flow differs in the two habitats both in the north and in the south. The gene flow is restricted among serpentine populations but common among meadow populations. Pollen dispersal, and in particular, anthropogenic seed dispersal mediate gene flow among meadows. Serpentine populations are unaffected by human activity. Pollinators are therefore the main agent of gene flow on serpentine. This study shows the importance of the surrounding vegetation in influencing gene flow patterns among populations as well as that habitat fragmentation affects the genetic properties of plant populations. In addition, we have also observed a restricted gene flow within populations. Enzyme allele frequencies show an excess of homozygotes within most of the populations. This can be explained through limited pollen dispersal and differences in male and female flowering density.
- Published
- 1994
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25. The Effect of Serpentine on the Population Structure of Silene dioica (Caryophyllaceae)
- Author
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Anna Westerbergh and Anssi Saura
- Subjects
0106 biological sciences ,0301 basic medicine ,education.field_of_study ,Natural selection ,biology ,Population ,Population genetics ,Caryophyllaceae ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Silene dioica ,03 medical and health sciences ,030104 developmental biology ,Genetic drift ,Genetic distance ,Botany ,Genetic structure ,Genetics ,education ,General Agricultural and Biological Sciences ,Ecology, Evolution, Behavior and Systematics - Abstract
Serpentine soils are rich in heavy metals and have a distinctive flora. Silene dioica is a member of the Scandinavian serpentine plant community but is also widespread outside serpentine soils. To study the population genetic consequences of serpentine stress and the origin and evolution of serpentine populations we analyzed the isozyme genetic structure of S. dioica. Seventeen pop- ulations located in the mountains of Vaisterbotten and Jamtland, central Sweden, were investigated by starch gel enzyme electrophoresis. About one half of the populations grow in serpentine soils and the rest on adjacent non-serpentine sites. Analyses of allele frequencies show that both ser- pentine and non-serpentine populations in the northern part of the studied area (Vaisterbotten) are genetically similar. Evidently serpentine does not exert strong selection acting upon isozyme loci. In the south (Jaimtland), however, the serpentine populations exhibit genetic differentiation. This allozyme divergence is probably not due to direct selection but rather represents the effects of isolation and genetic drift. The results suggest that S. dioica has colonized serpentine repeatedly and that the tolerant populations have a multiple origin.
- Published
- 1992
- Full Text
- View/download PDF
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