Herbivory by Western Flower Thrips (Frankliniella occidentalis Pergande) (WFT) and drought-stress due to limited water availability are currently two major factors that can severely impact cotton (Gossypium hirsutum L.) production. This dissertation examines the effects of drought-stress on cotton and host-plant resistance (HPR) to WFT in laboratory conditions, and seeks to identify the physiological and morphological mechanisms that underlie drought-tolerance and HPR. A life-history systems-approach was developed that provides a new level of detail for understanding how environmental variation impacts adult female WFT. The approach was illustrated by investigating the combined effects of cotton genotype, periodic drought-stress, and prey availability on the adult female omnivorous thrips using a factorial design. Three treatment conditions were significantly different, none of which were predicted based on prevailing ecological-hypotheses. At the same time, the approach produced three novel insights about WFT life-history and reproductive strategy. The roles of negative photo-taxis and leaf biomechanical properties were investigated as potential mechanisms that influence WFT foraging-decisions on individual cotyledons. Results showed that WFT foraging-decisions could be considered adaptive, but there was limited support for either of the mechanisms investigated. The physiological responses to drought stress and drought recovery were investigated for three transgenic cotton cultivars and an untransformed wild-type (WT). At peak drought, ABA levels, stomatal area, and stomatal apertures in the transgenic isolone, AtRAV1-1 were 48% lower, 27.7%, and 16.3% smaller than WT. These results suggest that AtRAV1-1 was the most drought-tolerant and support the hypothesis that changes in stomatal morphology may have functionally contributed to drought-tolerance. Lastly, I investigated whether changes in phytohormone concentrations associated with periodic-drought stress in four cotton cultivars (three transgenic and WT) were correlated with WFT feeding, fitness and state-dependent reproductive responses (i.e., the relationship between initial weight and reproduction). Results showed that JA-Ile and JA were positively correlated with state-dependent egg viability and fecundity, respectively, and negatively correlated with total egg viability and fecundity, respectively, supporting the hypothesis that JA and JA-Ile underlie the negative effects on WFT reproduction and the associated shift to state-dependent reproduction.

Polyunsaturated fatty acids are major structural components of plant chloroplast and endoplasmic reticulum membranes. Two fatty acid desaturases (designated FAD2 and FAD3) desaturate 75% of the fatty acids in the endoplasmic reticulum. The w -6 fatty acid desaturase (FAD2) may be responsible for cold acclimation response, since polyunsaturated phospholipids are important in helping maintain plant viability at lowered temperatures. To study regulation of FAD2 gene expression in cotton, a FAD2 gene was isolated from two genomic libraries using an Arabidopsis FAD2 hybridization probe and a cotton FAD2 5¢ -flanking region gene-specific probe, respectively. A cotton FAD2 gene was found to be in two overlapping genomic clones by physical mapping and DNA sequencing. The cloned DNA fragments are identical in size to cotton FAD2 genomic DNA fragments shown by genomic blot hybridization. The cotton FAD2 coding region has 1,155 bp with no introns and would encode a putative polypeptide of 384 amino acids. The cotton FAD2 enzyme has a high identity of 75% with other plant FAD2 enzymes. The enzyme has three histidine-rich motifs that are conserved in all plant membrane desaturases. These histidine boxes may be the iron-binding domains for reduction of oxygen during desaturation. To confirm that this FAD2 enzyme is functional, a plasmid construct containing the cotton FAD2 coding region was transformed into Saccharomyces cerevisiae. The transformed yeast cells were able to catalyze the conversion of oleic acid (C18:1) into linoleic acid (C18:2). The FAD2 gene contains an intron of 2,967 bp in its 5¢ -flanking region, 11 bp upstream from the initiation codon. The intron could be essential for transcriptional regulation of FAD2 gene expression. Several putative promoter elements occur in the 5¢ -flanking region of this gene. A potential TATA basal promoter element occurs at 41 bp upstream from the cap site. Two presumptive helix-loop-helix (bHLH) motifs that may be seed-specific promoter elements are located at 109 bp and 135 bp upstream from the potential cap site.

O presente trabalho teve por objetivo avaliar diferentes espaçamentos entre linhas e densidades de plantas em três cultivares de algodoeiro com diferentes arquiteturas de plantas. Os experimentos foram conduzidos no ano agrícola 2005/2006 no Centro Experimental Central, do Instituto Agronômico, em Campinas-SP, no Pólo Regional do Noroeste Paulista, da APTA, em Votuporanga-SP e na Fazenda de Ensino e Pesquisa da Unesp, Campus de Ilha Solteira, em Selvíria-MS. O delineamento experimental utilizado foi em blocos ao acaso, em esquema fatorial 2x2x3, com 4 repetições, sendo dois espaçamentos entre linhas (0,45 e 0,90 m), duas densidades de semeadura (6 e 10 plantas.m-1) e três cultivares (IAC 24, DeltaOpal e Fibermax 966). Em cada parcela experimental foram tomadas 4 plantas ao caso e avaliadas as seguintes variáveis: altura final das plantas, altura de inserção do 1° ramo frutífero, diâmetro do caule, número de ramos reprodutivos e número de capulhos por planta. Em Votuporanga foram determinadas a incidência de podridão de maçãs e a espessura do pericarpo de maçãs jovens. Amostras de 20 capulhos foram colhidas em cada parcela experimental, para a avaliação dos componentes da produção: massa de um capulho, massa de 100 sementes e porcentagem de fibra (apenas no experimento de Campinas); e para as análises das características tecnológicas da fibra: comprimento, uniformidade de comprimento, tenacidade, micronaire e maturidade. Em Campinas foi determinada a produção de algodão em caroço na área útil de cada parcela do experimento. De acordo com os dados obtidos, pôde-se concluir que: a utilização de espaçamentos mais largos acarreta maior altura final das plantas, maior diâmetro do caule, maior número de ramos reprodutivos e número de capulhos por planta; a utilização de espaçamentos entre 0,45 e 0,90 m e densidades de plantas entre 6 e 10 plantas.m-1 não acarreta em diferenças na produtividade do algodoeiro; em condições de menor competição entre plantas e maior penetração de luz no dossel, isto é, sob espaçamentos mais largos e/ou menor densidade de plantas na linha, o algodoeiro prioriza a produção de fibras; independente da cultivar e do espaçamento adotado, o índice micronaire pode aumentar com a redução do número de plantas na linha; a incidência de podridão de maçãs do algodoeiro, bem como sua severidade, estão relacionadas ao genótipo utilizado, quer seja pela arquitetura da planta como também pela espessura do pericarpo dos frutos. / The aim of this work was to evaluate different row spacings and plant population densities for three cotton cultivars with different plant architecture. The experiments were carried out in experimental areas belonging to Instituto Agronômico, in Campinas- SP, at Pólo Regional do Noroeste Paulista, from APTA, in Votuporanga-SP and at Unesp Campus de Ilha Solteira, in Selvíria-MS. A randomized block design was used, with four replicates, in a factorial 2x2x3 scheme, with two row spacings (0.45 and 0.90 m), two plant population densities (6 and 10 plants.m-1) and three cotton cultivars (IAC 24, DeltaOpal e Fibermax 966). Four plants per plot were labeled and analyzed for the plant height, insertion height of the first fruit branch, stem diameter, number of fruit branches and open bolls per plant. In Votuporanga were also analyzed the boll rot incidence and the pericarp thickness of young bolls. Samples of 20 open bolls randomized chosen per plot were analyzed for yield components: average open boll mass, 100 seeds mass, and fiber percentage, just on the Campinas experiment; and for fiber technological characteristics: length, length uniformity, strength, micronaire and maturity. In Campinas the cotton yield was determinated in the useful area of each plot. According to the experimental data obtained it was possible to conclude: the use of wider row spacing leads to a greater plant height, larger stem diameter, greater number of fruit branches and bolls per plant. The use of row spacing varying from 0.45 to 0.90 and plant densities varying from 6 to10 plants.m-1 do not affect cotton yield; under lower plant competition and higher light levels in the canopy, that is, in wider row spacing and/or lower plant population, the fiber production is prioritized by the cotton plant; independently of the cultivar and row spacing, the micronaire may increase with plant population reduction; the boll rot incidence, as well as its severity, are related to plant genotype, due to either plant architecture and pericarp thickness.

A ramulose, causada por Colletotrichum gossypii var. cephalosporioides, é uma das mais importantes doenças do algodoeiro no Brasil. O fungo é transportado e transmitido pela semente, que se constitui fonte de inóculo inicial. Os objetivos do presente trabalho foram i) estudar o efeito de inibidores de germinação sobre a germinação, comprimento da radícula e incidência do patógeno nas sementes; ii) avaliar o efeito de níveis de incidência na semente e do controle químico da parte aérea sobre o progresso da ramulose; iii) estudar a transmissão do patógeno planta-semente em função da incidência da doença. Com base nos resultados observou-se que os solutos Manitol e NaCl no potencial osmótico de -0,8 MPa reduziram a germinação, o comprimento da radícula e não interferiram na detecção do patógeno. A área abaixo da curva de progresso da incidência e severidade da ramulose foi maior, quanto maior foi o nível de incidência nas sementes, independente do número de pulverizações no ano de 2006. No ano de 2007, a área abaixo da curva de progresso da ramulose foi dependente do número de pulverizações, sendo maior, quanto maior foi o nível de incidência nas sementes, mas sendo reduzida de acordo com o número crescente de pulverizações. Não houve efeito da quantidade de doença sobre a produção nos anos estudados, mas no ano onde foi registrada maior intensidade de doença, a produção de algodão em caroço foi mais baixa. Houve correlação positiva e significativa entre o nível de inóculo inicial, 40 dias após a emergência, e a incidência da ramulose quando 70% das maçãs estavam formadas. Também houve correlação positiva e significativa entre a incidência da doença no campo e a incidência do patógeno nas sementes. / The ramulosis, caused by Colletotrichum gossypii var.cephalosporioides is one of the most important disease of cotton in Brazil. The fungus is transported and transmited by seeds and is an important initial inoculum source. The objectives of this research were i) to study the effect of germination inhibitors on the germination, length of radicle and incidence of the pathogen in the seeds; ii) to evaluate the effect of incidence levels in the seeds and the chemical control of canopy on the progress of ramulosis; iii) to study the transmission of the pathogen from plant to seeds in function of incidence of disease. Based on results it was observed that the Manitol and NaCl in the osmotic potential of -0,8 MPa reduced the germination, the length of radicle and did not caused decrease in the incidence of the pathogen in the seeds. The area under curve of progress of incidence and severity of ramulosis was higher, as much as the level of incidence in the seeds, independent of sprays number in the 2006 year. In the 2007 year the area under curve of progress of incidence and severity of ramulosis was dependent of sprays number. It was higher as much as the level of incidence in the seeds, but it was reduced according to the number of sprays was increased. There was not effect of disease intensity on the yield in the studied years, but in the year which the disease was more severe, the cottonseed yield was reduced. There was positive and significant correlation between the level of initial inoculum at 40 days after seedling emergence and the incidence of ramulosis when 70% of bolls were completely developed. There was positive and significant correlation between the incidence of disease in the field and the incidence of the pathogen in the seeds.

Submitted by (ana.araujo@ufrpe.br) on 2017-02-21T13:15:52Z No. of bitstreams: 1 Morganna Pollynne Nobrega Pinheiro.pdf: 878308 bytes, checksum: a4236d2ac8451c4536fac545f2b19b94 (MD5) / Made available in DSpace on 2017-02-21T13:15:52Z (GMT). No. of bitstreams: 1 Morganna Pollynne Nobrega Pinheiro.pdf: 878308 bytes, checksum: a4236d2ac8451c4536fac545f2b19b94 (MD5) Previous issue date: 2011-02-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The cotton crop is present in several sectors, from agriculture to the industry, generating about 70% of employment to level of primary production, putting the cotton as a major international commodities. The Brazil has been increasing in terms of production, currently the fifth largest world producer and exporter quarter. Despite this, the management of the crop is very high and the main costs for machinery and to control pests and diseases. With the advent of the current practices of modern biotechnology, biological strategies for the control of pests and diseases have been used, including the use of plants genetically modified to contain genes that defend these evils. These genes, often regulated by constitutive expression promoters provide protection throughout the plant, although the levels are different in appearance tissue. In this case, the use of tissue-specific promoters to drive the sequence codante allows more direct action to protect and lowest power plant to promote target protein. The cotton crop is vulnerable to various pests that affect the reproductive structures, especially lepidopters and coleopters. With a view to ascertaining genes expressed in flower buds to subsequently use them in the area of trangenics, a subtractive cDNA library from flower buds built.We generated 768 sequences, having been formed 168 clusters with 126 contigs and 42 singlets. The in silico analysis were performed against the database of cotton (CottonDB) and Bank of Arapidopisis thaliana (TAIR) and many genes have been identified. From this analysis we selected six genes related to the development of eggs, fibers, pollen tube and pistil (ANTIFIB010, ASH, OVU, FIB010, FIBEARLY and GLUCANASE) to studies of semiquantitative RT-PCR. The results showed that the selected genes are expressed in all tissues studied (button, stem, leaf and root), however we could observe a higher level of expression in flower buds. / A cultura do algodão está presente em vários setores, desde o agrícola até o industrial, gerando cerca de 70% de toda mão-de-obra em nível de produção primária. Isso coloca o algodão como uma das principais commodities internacionais. O Brasil vem se destacando no âmbito da produção, sendo atualmente o quinto maior produtor mundial e o quarto exportador. A despeito disso, o manejo da lavoura é muito elevado sendo os principais custos destinados com maquinários e controle de pragas e doenças. Com o advento das práticas atuais da biotecnologia moderna, estratégias biológicas visando o controle de pragas e doenças vêm sendo utilizadas, dentre elas o uso de plantas geneticamente modificadas expressando genes que a defendem desses males. Tais genes, frequentemente regulados por promotores de expressão constitutiva oferecem proteção em toda a planta, embora os níveis sejam diferenciados no aspecto tissular. Nesse caso, o uso de promotores tecido-específico para guiar a sequência codante possibilita ação mais direta de proteção e menor gasto de energia da planta para promover a proteína alvo. A lavoura do algodoeiro é vulnerável a várias pragas que incidem nas estruturas reprodutivas, especialmente lepidópteros e coleópteros. Com a finalidade de conhecer genes expressos nos botões florais, a fim de, posteriormente, utilizá-los na área de transgenia, uma biblioteca subtrativa de cDNA de botão floral construída. Foram geradas 768 sequências, tendo sido formado 168 agrupamentos com 126 singlets e 42 contigs. As análises in silico foram realizadas contra o banco de dados do algodão (CottonDB) e o banco de Arapidopisis thaliana (TAIR) e muitos genes foram identificados. A partir dessas análises foram selecionados seis genes relacionados ao desenvolvimento de óvulos, fibras, tubo polínico e pistilo (ANTIFIB010, ASH, OVU, FIB010, FIBEARLY e GLUCANASE) para estudos de RT-PCR semiquantitativo. Os resultados mostraram que os genes selecionados são expressos nos tecidos estudados (botão, haste, folha e raiz), no entanto pôde-se observar um maior nível de expressão nos botões florais.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-05-04T14:15:29Z No. of bitstreams: 1 PDF - Ruana Chagas da Silva.pdf: 1951311 bytes, checksum: ecb7f6c829485e06a3d3fdd70af43a7a (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-25T19:31:11Z (GMT) No. of bitstreams: 1 PDF - Ruana Chagas da Silva.pdf: 1951311 bytes, checksum: ecb7f6c829485e06a3d3fdd70af43a7a (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-25T19:33:41Z (GMT) No. of bitstreams: 1 PDF - Ruana Chagas da Silva.pdf: 1951311 bytes, checksum: ecb7f6c829485e06a3d3fdd70af43a7a (MD5) / Made available in DSpace on 2016-07-25T19:33:41Z (GMT). No. of bitstreams: 1 PDF - Ruana Chagas da Silva.pdf: 1951311 bytes, checksum: ecb7f6c829485e06a3d3fdd70af43a7a (MD5) Previous issue date: 2016-03-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aims to evaluate the effects of genotype x environment interaction by checking adaptability and stability, in addition to the grouping of environments through the AMMI methods (Additive Main effects and Multiplicative Interaction Analysis), GGE Biplot (Genotype and genotypes by Environment Interaction). The data were collected from the breeding program at Embrapa Cotton , referring to 16 cotton genotypes in eight locations (enviroment) in the state of Mato Grosso, Brazil. The analysis of individual and joint variance were carried out, then the analysis of adaptability and stability through the AMMI and GGE Biplot methods. Regarding the proportion of the capture of GE interaction in the first two axes, according to the two methodologies, a small superiority was noted of GGE (72.64%) compared to AMMI analysis (68.28%). The A4 and A6 environments were the main contributors to GE interaction, while the A2 and A3 environment the least influenced by GE interaction in both methods. The G4 genotypes (FMT 701) and G9 (LD CV 05) stood out as the most stable, combining broad adaptation and productivity, followed by G12 (Nuopal), G14 (CNPA MT 04 2080, G15 (CNPA MT 04 in 2088) and G16 (CNPA GO 03 -1947). The GGE methodology proved to be easier to interpret as well as less subjective to provide results than AMMI. / O presente estudo foi realizado com o objetivo de avaliar os efeitos da interação genótipo x ambiente, analisar adaptabilidade e estabilidade dos genótipos, além do agrupamento dos ambientes, por meio dos métodos AMMI (Additive Main effects and Multiplicative Interaction Analysis), GGE Biplot (Genotype and Genotypes by Environment Interaction). Foram utilizados dados obtidos junto ao programa de melhoramento genético da Embrapa Algodão, referentes a 16 genótipos de algodão, em oito locais (ambientes) distribuídos no Mato Grosso. Foram realizadas analises de variância individual e conjunta, em seguida, as analises de adaptabilidade e estabilidade por meio dos métodos AMMI e GGE Biplot. Em relação à proporção da captura da interação GxA nos dois primeiros eixos, pelas duas metodologias, notou-se uma pequena superioridade do GGE (72,64%) em relação à análise AMMI (68,28%). Os ambientes A4 e A6 foram os que mais contribuíram para a interação GxA, enquanto os ambiente A2 e A3 os que menos influenciaram pelos dois métodos. Os genótipos G4 (FMT 701) e G9 (LD CV 05) destacaram-se como mais estáveis, combinando ampla adaptação e produtividade, seguidos por G12 (Nuopal), G14 (CNPA MT 04 2080, G15 (CNPA MT 04 2088) e G16 (CNPA GO 03 -1947). A metodologia GGE mostrou-se ser de mais fácil interpretação e com resultados menos subjetivos do que AMMI.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-03-03T17:10:47Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Helton Pablo Moura Santos.PDF: 1447223 bytes, checksum: 5676806a271a7d14c8375994a1782651 (MD5) / Made available in DSpace on 2016-03-03T17:10:47Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Helton Pablo Moura Santos.PDF: 1447223 bytes, checksum: 5676806a271a7d14c8375994a1782651 (MD5) Previous issue date: 2015-02-26 / Water scarcity is a reality in many parts of the world and the demand for water for irrigated agriculture is quite significant, so the use of lower quality water is a viable alternative for these purposes. The objective of the present study to investigate the effects caused by irrigation with two types of water and nitrogen fertilization on growth, development and production of upland cotton (Gossipium hirsutum L), BRS TOPÁZIO. The experiment was conduced in the field in the period from March 25, 2014 to August 15, 2014 at Estação Experimental de Tratamentos Biológicos de Esgotos - EXTRABES, neighborhood of Tambor, in Campina Grande city, Paraíba. The experimental design was completely randomized and factorial 2x4, with three repetitions, totaling 24 units, the factors made up of four nitrogen rates (0, 20, 40 and 60 kg. Ha-1) and two types of water (sewage sanitary treated in a UASBH reactor and artesian wellwater). In plants that received the treatment with treated sewage, given its nutrient richness, then the observed increase in stem diameter and height of the subjects, larger leaf area and higher yield, as compared with the irrigated with wellwater. The 40 kg. ha - ¹ nitrogen dose associated with treated sewage water had the highest production rate. / A escassez de água é uma realidade em diversas regiões do mundo e a demanda de água pela agricultura irrigada é bastante significativa, sendo assim, a utilização de água de qualidade inferior é uma alternativa viável para estes fins. Objetivou-se, com o presente estudo, investigar os efeitos causados pela irrigação com dois tipos de água e adubação nitrogenada, no crescimento, desenvolvimento e produção do algodão herbáceo (Gossipium hirsutum L), cultivar BRS TOPÁZIO. O experimento foi conduzido em campo no período de 25 de março de 2014 a 15 de agosto de 2014 na Estação Experimental de Tratamentos Biológicos de Esgotos - EXTRABES, bairro do Tambor, no município de Campina Grande, estado da Paraíba. O delineamento experimental foi inteiramente casualizado e com arranjo fatorial 2x4, com três repetições, totalizando 24 unidades, sendo os fatores constituídos de quatro doses de nitrogênio (0, 20, 40 e 60 kg. ha -1 ) e dois tipos de água (esgoto sanitário tratado em um reator UASBH e água de poço artesiano). Nas plantas que receberam o tratamento com esgoto sanitário tratado, dado a sua riqueza em nutrientes, observou-se então o aumento no diâmetro caulinar e altura dos indivíduos, maior área foliar e maior produção, quando comparadas com as irrigadas com água de poço. A dose de nitrogênio de 40 kg. ha -1 associada à água de esgoto sanitário tratado apresentou o maior índice de produção.

Lintroduction commerciale des cotonniers génétiquement modifiés (CGM), produisant les toxines insecticides de Bacillus thuringiensis (Bt), dans les pays en développement et notamment en Afrique, suscite des craintes de la part de la société civile au sujet de leur impact sur lenvironnement et léconomie des petits paysannats. Lobjectif de la thèse est de proposer, sur la base dune revue bibliographique et dune série détudes originales réalisées en Afrique du Sud et publiées par lauteur dans des revues scientifiques, un outil daide à la décision basé sur des critères techniques et scientifiques permettant de juger lintérêt de ladoption des variétés de cotonniers Bt en paysannat africain. Dans un premier temps nous présentons un état des lieux de la production cotonnière à léchelle mondiale ainsi que les modalités de la culture en Afrique. Cet inventaire permettra par la suite détablir un état des besoins nécessaire à lélaboration du cadre de décision. Dans un deuxième temps, limportance des cotonniers Bt dans lagriculture, leur efficacité agronomique et leurs effets sur lenvironnement sont discutés. Nous mettons en exergue le risque potentiel dune réduction de lefficacité de ces CGM sous linfluence de facteurs abiotiques tels que la sécheresse. Les recherches effectuées sur limpact environnemental des cotonniers Bt montrent que ceux-ci nont pas deffet direct sur la biodiversité. Cependant les pratiques agricoles mal adaptées en conjonction avec lusage de cette innovation peuvent entraîner des modifications de la diversité et de labondance de lentomofaune des agrosystèmes cotonniers. Concernant les flux de gènes et la probabilité de mélange non intentionnel de semences entre cultures Bt et non-Bt, huit sources potentielles de mélange ont été identifiées et leurs conséquences sont discutées. Limpact agroéconomique de lintroduction des cotonniers Bt est étudié dans un troisième temps. Les études entreprises en Afrique du Sud suggèrent que ces effets sont parfois discutables et la réussite de ladoption repose fortement sur la solidité économique de la filière, sur lorganisation de lencadrement technique, sur lefficacité du réseau de distribution dintrants agricoles et sur le niveau de rendement de la culture avant lintroduction de linnovation. La dernière partie de la thèse propose un cadre provisoire dévaluation de lopportunité dadoption des cotonniers Bt en petit paysannat africain. Ce cadre se fonde sur la formulation des problèmes à résoudre dans le paysannat et sur lévaluation des options techniques disponibles. Les conditions préalables à une introduction réussie des cultivars Bt sont identifiées et des mesures daccompagnement sont suggérées pour lusage durable de cette technologie.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 6 uppsatser.