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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Viabilidade de aplicação da seleção precoce em batata-doce [Ipomoea batatas (L.) Lam.] e avaliação de caracteres relacionados à produção / Viability of application of early selection in sweet potato [Ipomoea batatas (L.) Lam.] and evaluation of traits related to production

Moreira, Glaucia Bethânia Rocha 23 August 2016 (has links)
A cultura da batata-doce assume papel importante no cenário agrícola nacional por ser considerada uma espécie altamente versátil, que consegue suprir as necessidades nutricionais da população, além de atualmente ser foco da cadeia de produção do etanol, pelo seu elevado teor de amido. Apesar da importância dessa cultura, ela é pouco estudada e, no que se refere ao melhoramento genético dessa espécie, os estudos são ainda mais escassos. Essa falta de informações acerca dos genótipos mais adaptados às condições de determinada região é um dos principais problemas enfrentados pelos produtores de batata-doce que não conseguem atingir o máximo de produtividade, pois as variedades utilizadas não conseguem expressar o seu potencial. Visando a aceleração dos programas de melhoramento, surge como alternativa a realização da seleção precoce, podendo-se realizar o descarte de materiais com características desfavoráveis nas primeiras gerações clonais. Para auxiliar na seleção precoce, a utilização de técnicas multivariadas como a análise GGE Biplot é de fundamental importância para se atingir sucesso na seleção. Dessa forma, os objetivos do presente trabalho foram (a) avaliar a eficiência da seleção precoce em batata-doce, bem como identificar possíveis correlações entre características morfológicas, para auxiliar na seleção de genótipos superiores; (b) identificar genótipos produtivos e que apresentem características de raiz favoráveis para o mercado e com elevado teor de amido para serem utilizados em futuros programas de melhoramento. Os experimentos foram realizados em casa de vegetação, onde foram avaliados em três épocas distintas, além de uma vez a campo para a mensuração dos caracteres relacionados à produção e ao teor de amido. Pelos resultados observados, nota-se que a utilização da técnica de seleção precoce em batata-doce pode não ser eficiente pelo comportamento que os genótipos assumiram no decorrer das avaliações, já que a correlação entre épocas foi muito baixa ou até mesmo inexistente, o que dificulta a seleção em etapas iniciais do programa. Porém, com relação às correlações entre as características em uma mesma época, nota-se que várias delas apresentaram correlações positivas, levando à interpretação de que se selecionarmos para uma determinada característica, automaticamente selecionaremos para outra correlacionada a esta. Os resultados para os caracteres produtivos indicam que existem genótipos que apresentam elevado potencial produtivo, superior à média nacional e também apresentam características desejáveis na forma e tamanho das raízes tuberosas. Além dessas características, algumas contêm elevado teor de amido, o que é altamente desejável para a indústria de biocombustíveis. Pode-se concluir que a técnica de seleção precoce não é recomendável para a cultura, mas existem características altamente correlacionadas em uma época específica. Existem genótipos que podem ser utilizados em programas de melhoramento, tanto pelo seu elevado potencial produtivo e características de raiz desejáveis quanto pela concentração de amido. / The culture of sweet potato plays an important role in the national agricultural scenario because it is considered a highly versatile species that can meet the nutritional needs of the population, in addition to currently being the focus of the ethanol supply chain, for their high starch content. Despite the importance of this crop, it is little studied and, in relation to the genetic improvement of this species, studies are still more scarce. This lack of information about the genotypes most adapted to the conditions of a given region is one of the main problems faced by sweet potato producers who fail to achieve maximum productivity, as the varieties used can not express their potential. Aiming at the acceleration of plant breeding programs, the alternative of performing early selection arises, and the disposal of materials with unfavorable characteristics can be carried out in the first clonal generations. And to assist in the early selection, using multivariate techniques such as GGE Biplot analysis is crucial to achieving success. Thus, the objectives of this study were (a) to evaluate the efficiency of early selection in sweet potatoes, as well as to identify possible correlations between morphological characteristics, in order to assist in the selection of superior genotypes; (b) to identifying productive genotypes that exhibit favorable root characteristics for the market and with high starch content for use in future breeding programs. The experiments were conducted both in greenhouse and in field conditions, where the traits related to production and starch content were assessed at three different times and one time, respectively. The results indicate that the use of the early selection technique in sweet potatoes may not be efficient, on the basis of the behavior shown by the genotypes in the assessments, since the correlation between assessment times was very low or even non-existent, making it difficult for selection to be applied in the initial stages of the program. However, regarding the correlations between the characteristics in the same assessment instance, it can be noted that several of them had positive correlations, implying that, if a particular feature is selected for, that automatically selects for others correlated to this. The results for the productive characters indicate that there are genotypes that have high yield potential, higher than the national average and that also have desirable characteristics regarding the shape and size of the tuberous roots. In addition to these features, some accessions have high starch content, which is highly desirable for the biofuel industry. It can be concluded that the early selection technique is not recommended for this crop, but there are nonetheless highly correlated characters at particular times. There are genotypes that can be utilized in breeding programs, both for their high yield potential associated to desirable root characteristics and for the concentration of starch.
72

Divergência genética em acessos de amendoim com base em descritores fenotípicos

Ramos, Jean Pierre Cordeiro 12 February 2015 (has links)
Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-03-09T14:02:43Z No. of bitstreams: 1 PDF - Jean Pierre Cordeiro Ramos.pdf: 743229 bytes, checksum: e79f51445e4907b6849b1bc46cf35e46 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:01:15Z (GMT) No. of bitstreams: 1 PDF - Jean Pierre Cordeiro Ramos.pdf: 743229 bytes, checksum: e79f51445e4907b6849b1bc46cf35e46 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:01:24Z (GMT) No. of bitstreams: 1 PDF - Jean Pierre Cordeiro Ramos.pdf: 743229 bytes, checksum: e79f51445e4907b6849b1bc46cf35e46 (MD5) / Made available in DSpace on 2016-07-21T21:01:24Z (GMT). No. of bitstreams: 1 PDF - Jean Pierre Cordeiro Ramos.pdf: 743229 bytes, checksum: e79f51445e4907b6849b1bc46cf35e46 (MD5) Previous issue date: 2015-02-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The peanut breeding programs are based on introducing or disponibilization of genetic variability by crossing, with further selection of lines showing robust descriptors as to agronomical, nutritional and physiological aspects. The multivariate analysis methodologies have been often used to estimating the inter-relationship between genotypes, based in several descriptors in order to indicate group of promising materials for further use in breeding programs. The objective of this study was to estimate the genetic diversity among peanut genotypes based on three clustering methodology, in order to selecting parents for oil and food markets. A germplasm collection containing 77 genotypes of peanut (var. fastigiata and vulgaris) was planted in field, using plots consisted of 5m-rows, in a spacing 0.7 m X 0.2 m. The following variables were evaluated: height of main stem, total dry weight of plant, weight of pods/plant, seed weight/plant, number of pods/ plant, number of seeds/pod, weight of 100 pods, weight of 100 seeds, percent of oil in seeds, pod length, harvest index, hairiness, color of the main stem, growth habit, color seed, color of leaves, inflorescence on the main stem, early flowering and Full maturation of pods. Three clustering methods were selected for divergence analysis: Tocher, UPGMA and principal components.. It was found that the three methodologies, when used together, were consistent in group establishing, revealing interesting combinations for further use in breeding programs, aiming generation of drought tolerant lines and indicated to food market. / Os programas de melhoramento do amendoim se baseiam na introdução ou disponibilização de variabilidade genética, seguidos de seleção de linhagens que apresentem descritores responsivos pelo desempenho das plantas nos aspectos nutricionais, fisiológicos e agronômicos. Técnicas de análise multivariada têm sido frequentemente utilizadas para estimar as interrelações entre genótipos, baseando-se em vários descritores com intuito de indicar quais genótipos são mais promissores para serem inseridos em programas de melhoramento. Objetivou-se, com este trabalho, proceder a uma análise da diversidade genética entre genótipos de amendoim baseando-se em diferentes métodos de agrupamento, visando seleção de genitores para os mercados de óleo e alimento. Foram utilizados 77 genótipos na fase de pré-melhoramento de amendoim da subespécie fastigiata, contendo as variedades fastigiata e vulgaris, da coleção de amendoim da Embrapa Algodão. A unidade experimental foi constituída por uma fileira de 5 m contendo 50 plantas, num espaçamento 0,7 m X 0,2 m. Foram avaliadas as seguintes variáveis: peso das vagens/planta, peso das sementes/planta, número de vagens/planta, número de sementes/vagem, peso de 100 vagens, peso de 100 sementes, teor de óleo nas sementes, comprimento da vagem, índice de colheita, peso seco total da planta, altura da haste principal, pilosidade, cor da haste principal, hábito de crescimento, cor das sementes, cor dos folíolos, inflorescência na haste principal, início da floração e Maturação completa da vagem. Três métodos de agrupamentos foram selecionados para analise da divergência: Tocher, UPGMA e componentes principais. As três metodologias usadas, em conjunto, mostraram-se concordantes na formação dos grupos estabelecidos, revelando combinações interessantes para serem usadas em programas de melhoramento visando obtenção de linhagens com tolerância ao ambiente semiárido e com padrão de sementes voltados para o mercado de alimentos.
73

Nuclear and chloroplast diversity of Pacific Northwest wheat (Triticum aestivum) breeding germplasm

Edwards, Melanie Love 18 December 2002 (has links)
Wheat breeders must effectively maintain and manage existing genetic diversity in order to continue the development of superior genotypes. It is therefore fundamental that the genetic relationships and diversity within the germplasm pools be thoroughly characterized and understood. Recently, DNA-based markers have provided powerful tools for genetic diversity analysis. This study investigates the usefulness of nuclear and chloroplast simple sequence repeat (SSR) markers in characterizing Pacific Northwest wheat (Triticum aestivum) breeding germplasm, and explores the patterns of genetic relatedness revealed by these markers. The 15 chloroplast SSRs were effective in differentiating between B-type, D-type, and barley (Hordeum vulgare) cytoplasms. Genetic distance estimates were determined for each pair of lines studied and analyzed using UPGMA clustering. The markers revealed five plastomic types within the B-type cytoplasm studied. Several lines of wheat in this germplasm, including important PNW cultivars like Madsen, were found to contain D-type cytoplasm rather than the B cytoplasm of wheat. Nuclear SSR assays using 24 markers revealed three major clusters of germplasms: PNW soft white winter wheat, Western European-derived lines, and Great Plains accessions, as well as two clusters of more distantly related lines and genetic stocks. The primary defining characteristic of these clusters was regional adaptation. Subgroups of these major groups often clustered together on the basis of pedigree and market class. When nuclear and chloroplast SSR data was combined in analysis, the primary defining characteristic of the dendrogram became the type of cytoplasm rather than regional adaptation, with secondary divisions based on pedigree relationships. Cultivars released prior to 1950 were found to have a minimum of 20% of alleles in common for nuclear and chloroplast data combined, despite being unrelated via pedigree information. Heterogeneity was 2.3% for all marker/variety combinations. Overall, these sets of markers were found to be effective in characterizing the genetic relatedness of PNW wheat breeding germplasm. / Graduation date: 2003
74

Diversity of Low Chill Peaches (Prunus persica) from Asia, Brazil, Europe and the USA

Anderson, Natalie A. 2010 May 1900 (has links)
One hundred fifty-five peach (Prunus persica) cultivars, from Asia, Brazil, Europe, and the USA, were examined using eleven Simple Sequence Repeats (SSRs) to study the genetic relationships among low chill as compared to high chill peach germplasm. Data was analyzed by NTSYSpc to form a similarity matrix using Nei and Li’s Dice similarity coefficient. This similarity matrix was then subjected to a cluster analysis and a dendrogram was constructed using the UPGMA (Unweighted Pair-Group Method, Arithmetic Mean) method. A wide range of diversity was detected, from 0.33 coefficient of similarity amongst the Thai peaches to 0.97 between two Brazilian peaches. The most distant clusters were the low chill peaches from Thailand and Taiwan and the local cultivars (both fruit and ornamental types) from China. Among the improved germplasm, there were distinct clusters for the Chinese/Japanese cultivars, three clusters for the Brazilian cultivars and one for the cultivars from the USA and Europe. The Brazilian materials clustered according to breeding programs in São Paulo and Pelotas reflecting the different sets of local cultivars used in the breeding efforts. The largest group investigated was the European/USA peaches. This group subdivided into three distinct clusters, with a general clustering of the low chill germplasm. The low chill accessions from Asia were genetically distant from the improved low chill peaches from the USA or Brazil. The low chill peaches from the Americas were more closely related to the high chill peaches developed in the USA and China/Japan due to the introgression of this germplasm into a low chill background.
75

Estimating genetic variability in horticultural crop species at different stages of domestication /

Persson, Helena. January 2001 (has links)
Thesis (Ph. D.)--Swedish University of Agricultural Sciences, 2001. / Includes bibliographical references.
76

Conservation and in vitro propagation of Hong Kong Camellias

Siu, Lai-ping., 蕭麗萍. January 1992 (has links)
published_or_final_version / Botany / Master / Master of Philosophy
77

Prospecting for biodiversity the search for legal and institutional frameworks /

Carrizosa, Santiago. January 1996 (has links)
Thesis (Ph. D.)--University of Arizona, 1996. / Includes bibliographical references (leaves 263-271).
78

Divergência genética em acessos de melão utilizando redes neurais artificiais / Genetic divergence in melon using artificial neural networks

Melo, Stefeson Bezerra de 20 March 2015 (has links)
Made available in DSpace on 2016-08-12T19:18:30Z (GMT). No. of bitstreams: 1 StefesonBM_TESE.pdf: 501527 bytes, checksum: 94d141004aa016dc604cc1543577c5ee (MD5) Previous issue date: 2015-03-20 / Melon (Cucumis melo L.) is a species economic importance to Brazilian northeast, especially in Mossoró-Assú agropolo. The study of genetic diversity allows in the preliminary selection of individuals with superior characteristics to produce hybrids with the high heterotic in breeding programs. The objective of this study was to evaluate the genetic divergence among 46 melon genotypes for 22 physicochemical and agronomic quantitative variables, evaluated by techniques artificial neural networks. Two experiments were conducted in Horta Experimental Department of Plant Sciences at the Universidade Federal Rural do Semi-Árido - UFERSA in the Mossoró, State of Rio Grande do Norte, in the periods 12/09/2006 to 05/12/2006 and 15/08/2007 to 17/10/2007. Through the techniques of artificial neural networks, was found four groups for both experiments, but also to average of two years. A discriminant analysis was used to check the consistency of groups formed and it was observed that considering the 22 variables, there was 100% hit, that is, for the discriminant function all genotypes were classified correctly. In addition was also observed distances between groups and group 1 was significantly distant from all other groups, more distant, genetically, Group 3. Group 2 are different with respect to group 3 and group similar to 4. The group 3 shows similarity to group 4. And so we suggest possible crosses between accessions 2, 13, 15, 16, 17, 27, 33, 36, 40, 43, 46 that would be most promising for new populations of work. Artificial neural networks have proved viable as a method of analysis of genetic divergence in melon and genetic divergence was found for all groups, and with that you can get new crossings in order to obtain improved populations / O meloeiro (Cucumis melo L.) é uma espécie de grande importância econômica para o nordeste brasileiro, em especial no agropólo Mossoró-Assú. O estudo da divergência genética possibilita uma seleção preliminar de indivíduos com características superiores para obtenção de híbridos com maior efeito heterótico para serem introduzidos em programas de melhoramento genético. O objetivo deste trabalho foi avaliar a divergência genética entre 46 acessos de meloeiro para 22 variáveis quantitativas físico-químicas e morfoagronômicas, avaliados por meio da aplicação das técnicas de Redes Neurais Artificiais. Foram conduzidos dois experimentos na Horta Experimental do Departamento de Ciências Vegetais da Universidade Federal Rural do Semi-árido - UFERSA, no município de Mossoró, Estado do Rio do Grande do Norte, nos períodos de 12/09/2006 a 5/12/2006 e de 15/08/2007 a 17/10/2007. Por meio das técnicas de Redes Neurais Artificiais, verificou-se a formação de quatro grupos para ambos os experimentos, como também para a média dos dois anos. Analisando os grupos constituídos das médias de 2006 e 2007. Em todos os grupos as variáveis do fruto foram as que obtiveram as maiores dispersões. Uma análise de discriminante foi utilizada para verificar a consistência dos grupos formados e observou-se que considerando as 22 variáveis houve 100% de acerto, isto é, para a função discriminante todos os acessos foram classificados corretamente. Adicionalmente também foi observada as distâncias entres os grupos, e o grupo 1 foi significativamente distante de todos os outros grupos, porém mais distante, geneticamente, do grupo 3. O grupo 2 é divergente em relação ao grupo 3 e similar ao grupo 4. O grupo 3 apresenta similaridade em relação ao grupo 4. E desta forma sugerimos possíveis cruzamentos entre os acessos 2, 13, 15, 16, 17, 27, 33, 36, 40, 43, 46 que seriam os mais promissores para novas populações de trabalho. As redes neurais artificiais se mostraram viáveis como método da análise da divergência genética no meloeiro e foi encontrada divergência genética para todos os grupos estudados, e com isso pode-se obter novos cruzamentos com o intuito de obter populações melhoradas
79

Adaptabilidade, estabilidade e tolerância de acessos de meloeiro à salinidade / Adaptability, stability and tolerance toof melon accessions to salinity

Ferreira, Alex Rodrigues 26 February 2016 (has links)
Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2016-11-17T14:28:50Z No. of bitstreams: 1 AlexRF_DISSERT.pdf: 1133764 bytes, checksum: 8e61e6e8abd029e3d77b37b914fbc39a (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-02-15T15:00:40Z (GMT) No. of bitstreams: 1 AlexRF_DISSERT.pdf: 1133764 bytes, checksum: 8e61e6e8abd029e3d77b37b914fbc39a (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-02-15T15:00:54Z (GMT) No. of bitstreams: 1 AlexRF_DISSERT.pdf: 1133764 bytes, checksum: 8e61e6e8abd029e3d77b37b914fbc39a (MD5) / Made available in DSpace on 2017-03-21T14:58:02Z (GMT). No. of bitstreams: 1 AlexRF_DISSERT.pdf: 1133764 bytes, checksum: 8e61e6e8abd029e3d77b37b914fbc39a (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the adaptability and stability of melon accessions to salinity. Thirteen accessions and three commercial hybrids in four saline conditions in a randomized complete block design with three replications and the plot of a row of eight plants spaced 2.0 x 0.4 m. The environments are differentiated as the electrical conductivity of irrigation water, and set four salt levels (S1: 0.91 dS m-1, S2: 2.14 dS m -1, S3: 2.90 dS m-1, and S4: 3.92 dS m-1). The variables analyzed were: average fruit weight, number of fruits, productivity, pulp thickness, firmness of soluble solids and pulp. We utilized the GGE Biplot methodology for identifying adaptability and stability genotypes. We used the production efficiency index to identify tolerant genotypes salinity. Accessions A-29, A-50, A-13, A-14, A-39, Najd I and A-7 are tolerant to salinity and have features such as prolificacy, pulp thickness and firmness pulp for use in breeding programs or as rootstock for cultivation in high salinity conditions / O objetivo desse estudo foi verificar a adaptabilidade e estabilidade de acessos de melão a salinidade. Foram avaliados 13 acessos e três híbridos comerciais em quatro condições salinas em blocos completos casualizados com três repetições sendo a parcela constituída por uma linha de oito plantas no espaçamento 2,0 x 0,4 m. Os ambientes se diferenciaram quanto à condutividade elétrica da água de irrigação, sendo definidos quatro níveis salinos (S1 = 0,91 dS m-1, 2,14 dS m -1, 2,90 dS m-1 e 3,92 dS m-1). As variáveis analisadas foram: peso médio do fruto, número de frutos, produtividade, espessura da polpa, firmeza da polpa e sólidos solúveis. Utilizou-se a metodologia GGE Biplot para identificar os genótipos adaptados e estáveis. Também se utilizou o índice de eficiência de produção para classificar os acessos quanto à tolerância à salinidade. Os acessos/cultivares A-29, A-50, A-13, A-14, A-39, Najd I e A-7 são tolerantes à salinidade e possuem características como prolificidade, espessura da polpa e firmeza da polpa para serem utilizados em programas de melhoramento genético ou como porta-enxertos para cultivo em condições de salinidade elevada / 2016-11-17
80

Značení a izolace primordiálních gonocytů jeseterů / Identification and isolation of primordial gonocytes in sturgeon

DVOŘÁK, Matěj January 2014 (has links)
Primordial gonocytes (PGCs) in some animals, including fish arise after fertilization in extragonadal region from maternally inherited germline cytoplasm, and migrate to the future gonads region during embryogenesis, where differentiate into gametes. PGCs formation and migration patterns have been studied in several species models, and it is known that these patterns differ from each other. Sturgeons belong to class ray-finned fishes(Actinoptergii), in which the sturgeon phylogenetic position is an out-group to teleost fishes, the sturgeon development pattern is more similar to amphibians than teleost fishes. In this study, we demonstrate an injection technique for sturgeon PGCs visualization by GFP nos1 3'UTR mRNA. We found that the Sterlet(A. ruthenus) PGCs are specified in the vegetative pole of the embryo. Subsequently, we reported the PGCs migration route. The arisen PGCs actively migrated on the yolky cell mass, yolky extension, and after that passively moved to gonadal ridge. This study provides evidence that the PGCsare specified by maternally inherited germplasm, located in the vegetative part of the embryo. Sturgeon PGCs specification was similar to that of anuras, but the migration pattern resembled that of teleost. Furthermore, we successfully isolated PGCs to next needed studies.

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