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1	An Analysis of the Development of Shoot Apices in Excised Immature Zygotic Cotton Embryos (Gossypium hirsutum cv Texas Marker-1) Arnold, Marianne 2011 December 1900 (has links) Although cottonseed is an important source of oil and fiber, the development of cotton embryos has not been investigated as well as development of cotton fiber. The development of cotton embryos in late heart-stage and early cotyledonary stage is less well investigated than the first 10-14 days after anthesis, or the late stages of embryo development during seed-fill and desiccation. This analysis focused on cotton embryos in the late heart-stage and early cotyledonary stage of development (1.5-4.0 mm or about 13-18 DPA). In vitro analyses are important tools for studying embryos in isolation from the endosperm and fiber and when it is necessary to monitor the developing embryo continuously. The original goal of this work was to develop an in vitro culture method that would support continued development of excised zygotic embryos from the early cotyledonary stage into complete plants with true shoots, i.e. true leaves or visible buds and then to use this method to study aspects of developmental regulation during cotyledonary stage and the transition to later stages. Not all embryos were competent to develop true shoots (an apical bud or a leaf plus a bud) in culture. A number of cultural variables were tested and eliminated. Embryo maturity at the time embryos were excised and the presence or absence of light during the first 14 days of culture affected the competence of immature embryos to developed true shoots. The effect of light was verified in several large replicated experiments. Morphological changes occurring during in vivo development were examined microscopically. The transition from heart-stage to early cotyledonary stage and the development of the first leaf from initials to a large structure were identified. Embryonic shoot apices continued to grow in cultured 1-3 mm embryos. The size and shape of light-treated and dark-treated embryonic apices was compared. A germination test of mature seeds identified seedlings with a similar phenotype occurring at similar rates in seedlings and light-cultured embryos and possible causes were discussed. immature embryo embryo development cotyledonary stage embryo rescue tissue culture zygotic embryo shoot apical meristem photomorphogenesis
2	Embryo adoption : implications of personhood, marriage, and parenthood / McMillen, Brooke. January 2008 (has links) Thesis (M.A.)--Indiana University, 2008. / Department of Philosophy, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Peggy Zeglin Brand, Jason T. Eberl, Michael B. Burke. Includes vitae. Includes bibliographical references (leaves 79-84).
3	Exploitation of Solanum chilense and Solanum peruvianum in tomato breeding for resistance to Tomato yellow leaf curl disease Julián Rodríguez, Olga 07 April 2014 (has links) Among viral diseases affecting cultivated tomato, Tomato yellow leaf curl disease (TYLCD) is one of the most devastating. This disease is caused by a complex of viruses of which Tomato yellow leaf curl virus (TYLCV) is regarded as the most important species. Current control strategies to fight viral diseases in tomato are mainly based on genetic resistance derived from wild relatives. In the present thesis, resistance derived from S. chilense and S. peruvianum has been exploited in breeding for resistance to TYLCD. In a previous study, TYLCV-resistant breeding lines derived from LA1932, LA1960 and LA1971 S. chilense accessions were developed. Therefore, the first objective of this thesis was to study the genetic control of the resistance derived from these accessions. With this aim, response to viral infection was assayed in segregating generations derived from the aforementioned resistant lines. The results obtained were compatible with a monogenic control of resistance. Resistance levels were higher in LA1960- and LA1971-derived F2 generations, as shown by slighter symptoms in the resistant plants and a higher number of asymptomatic plants compared with the results obtained in the LA1932-derived F2 generation. It is noteworthy that the level of resistance present in our materials is comparable to or even higher than the levels found in tomato lines homozygous for Ty-1. The response in plants heterozygous for the resistance gene was comparable to the response in homozygous plants for all three sources employed. This implies that the resistance genes derived from all three sources seem to be almost completely dominant. This effect was stronger for LA1971-derived resistance. The results were similar when comparing viral accumulation, as was expected, since a positive correlation was found in these families between viral accumulation and symptom scores. This has important implications in breeding, since the resistance will be used mostly for hybrid development. Our second objective was to map the loci associated with the major resistance genes identified. A total of 263 markers were screened, 94 of them being polymorphic between both species. Recombinant analysis allowed the resistance loci to be localized on chromosome 6, in a marker interval of 25 cM. This interval includes the Ty-1/Ty-3 region, where two S. chilense-derived TYLCD resistance loci were previously mapped. In order to test if the resistance genes identified in our populations were allelic to Ty-1 and Ty-3, further fine mapping was carried out. A total of 13 additional molecular markers distributed on chromosome 6 allowed 66 recombinants to be identified, and the resistance region to be shortened to a marker interval of approximately 950 kb, which overlaps with the Ty-1/Ty-3 region described previously by other authors. Therefore, the results obtained indicate that closely linked genes or alleles of the same gene govern TYLCV resistance in several S. chilense accessions. The third objective of the present thesis was to start the construction of a set of introgression lines (ILs) derived from Solanum peruvianum accession PI 126944 into the cultivated tomato genetic background. Once this collection of ILs is developed, it will represent a powerful tool for exploiting the resistance to different pathogens found in this particular accession in addition to other possible characters of interest. The starting plant material consisted of several segregating generations that were derived from two interspecific hybrids previously obtained by our group. Many crosses and embryo rescue were required to obtain subsequent generations due to the high sexual incompatibility that exists between tomato and PI 126944. Several mature fruits from the most advanced generations produced a few viable seeds, although embryo rescue was also employed to obtain progeny. As only a few plants were obtained by direct backcrossing, additional crosses were made in order to increase the number of descendants. A high degree of incompatibility was also found in crosses between sib plants. A total of 263 molecular markers were tested in some generations, 105 being polymorphic between tomato and PI 126944. Available generations were genotyped with these polymorphic markers in order to determine which alleles of S. peruvianum were already introgressed. On average, 79, 78 and 84 % of the S. peruvianum genome was represented in the pseudo-F2, pseudo-F4 and pseudo-F5 generations, respectively, for the markers analyzed. A reduction in the S. peruvianum genome was observed in more advanced generations, such as BC1 (56 %), pseudo-F2-BC1 (60 %) and pseudo-F3-BC1 (70 %). A greater reduction was observed in the pseudo-F3-BC2 generation (33 %). As a consequence of the reduction in the S. peruvianum genome, a loss of incompatibility was observed in some cases. The S. peruvianum genome was almost completely represented among the different plants of the most advanced generations. An evaluation for resistance to TYLCD and Tomato spotted wilt virus (TSWV) was carried out in some of the advanced generations, some of which were resistant to one or both viruses. In conclusion, we have conducted a successful and deeper exploitation of two wild species with proved resistance to TYLCD, S. chilense and S. peruvianum, identifying and fine mapping new genes of resistance. / Julián Rodríguez, O. (2014). Exploitation of Solanum chilense and Solanum peruvianum in tomato breeding for resistance to Tomato yellow leaf curl disease [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36867 Molecular markers Resistance Solanum chilense Tomato TYLCV Fine mapping Embryo rescue Solanum peruvianum Introgression lines GENETICA
4	Técnicas y estrategias de mejora para facilitar la hibridación interespecífica y el acortamiento del ciclo generacional en el género Capsicum Manzur Poblete, Juan Pablo Andrés 30 April 2014 (has links) Los pimientos, chiles y ajíes suponen uno de los productos de mayor importancia económica del mundo, ocupando la séptima posición en superficie entre las hortícolas. Bajo estas denominaciones se engloba un grupo de cinco especies cultivadas y más de veinte especies silvestres pertenecientes al género Capsicum. Entre las especies domesticadas, C. annuum es la más relevante económicamente y su cultivo se extiende por casi todo el mundo. C. chinense (Ej. Tipo Habanero) y C. frutescens (Ej. Tipo Tabasco) son filogenéticamente cercanos a C. annuum y los tres conforman el complejo annuum-frutescens-chinense. Las otras dos especies, menos conocidas son C. baccatum (Ej. Tipo Ají) y C. pubescens (Ej. Tipo Rocoto), siendo esta última la más alejada filogenéticamente del resto de las especies domesticadas. Dada la compleja cruzabilidad que presentan estas especies, la mejora del pimiento común (C. annuum) se ha restringido principalmente al germoplasma primario (intraespecie). Sin embargo, en diferentes estudios de cribado en especies relacionadas -germoplasma secundario- como C. chinense, C. frutescens y C. baccatum se han encontrado diversos genes de interés para estreses bióticos (resistencia a plagas y enfermedades) y abióticos (tolerancia a salinidad, estrés hídrico). Así, el desarrollo de estudios dirigidos a mejorar la eficiencia de la hibridación interespecífica, tales como determinar y superar barreras a la hibridación, aumentan en gran medida la variabilidad genética disponible para los mejoradores. Por otra parte, los principales métodos de mejora en pimiento (autofecundación, retrocruces, selección recurrente) requieren sucesivas generaciones de selección y fecundación (retrocruzamientos y/o autofecundaciones), requiriendo entre 7 y 8 años (asumiendo una generación por año) para desarrollar una nueva variedad. Así, estudiar y optimizar técnicas tales como el cultivo in vitro de embriones inmaduros, evitarían la espera de la maduración del fruto, lo que podría reducir el tiempo generacional y aceleraría el programa de mejora, reduciendo los costos para las empresas productoras de semillas. / Manzur Poblete, JPA. (2014). Técnicas y estrategias de mejora para facilitar la hibridación interespecífica y el acortamiento del ciclo generacional en el género Capsicum [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37197 Capsicum sp. Interspecific cross Genetic bridge Cycle shortening Embryo rescue In vitro culture GENETICA
5	Interspecific hybridization in Leucadendron : capacity building and phylogenetic insights Liu, Hui January 2007 (has links) Flowers from members of the genus Leucadendron have colourful bracts and long vase life that make them highly desirable cut-flowers. Breeding programs based on interspecific hybridization would encounter difficulty if pre- or post-fertilization barriers exist in the distant crosses. Embryo rescue is one of the commonly used approaches to overcome post-fertilization barriers in wide hybridization. In this study, intersectional and intersubsectional hybridization of Leucadendron was attempted. Observation of pollen-pistil interactions revealed that post-zygotic rejection was the main reason for the incompatibility of the crosses, therefore embryo rescue was adopted and a protocol was developed to raise the hybrids. To better understand the genome structure in the genus, karyotypes of selected species were analyzed. Chromosome examination indicated that all (27) Leucadendron species examined were diploid and had a chromosome number of 2n = 26. The chromosomes were small in size and had predominantly median to submedian centromeres. The karyotypes of the species were rather symmetrical and seemed to be primitive according to Stebbins' karyotype classification. DNA based PCR-RFLP and RAMP markers were developed to identify Leucadendron hybrids at an early age. RAMP analysis showed more discrimination in identifying Leucadendron hybrids than did PCR-RFLP. The occurrence of PCR recombination also proved to be a troublesome issue when using the PCR-RFLP method, whereas the clarity of the interpretion of the RAMP method was not influenced by PCR recombination. Interspecific hybridization in a breeding program can provide valuable information on grouping of the species for systematic purposes. Regression analysis between cross success rate and cpDNA character difference revealed that there was a highly significant correlation between them. Patterns of success for intersectional hybridizations in Leucadendron were generally consistent with current taxonomic hypotheses regarding the sectional division of the genus. Success was generally lower for intersectional crosses than for intrasectional crosses. Cut flowers Proteaceae -- Breeding Leucadendron -- Breeding Leucadendron -- Molecular genetics Phylogeny Hybridization Interspecific hybridization Karyotype Embryo rescue Hybrid identification Phylogenetic relationship Leucadendron
6	Embryo Adoption: Implications of Personhood, Marriage, and Parenthood McMillen, Brooke Marie 14 April 2008 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / One’s personal claims regarding personhood will influence his moral belief regarding embryo adoption. In Chapter One, I consider the personhood of the human embryo. If the human embryo is a person, we are morally obligated to permit the practice of embryo adoption as an ethical means to save human persons. However, for those who do not claim that an embryo is a person at conception, embryo adoption is not a necessary practice because we have no moral obligation to protect them. There are still others who claim that personhood is gained at some point during gestation when certain mental capacities develop. I offer my own claim that consciousness and sentience as well as the potential to be self-conscious mark the beginning of personhood. Embryo adoption raises several questions surrounding the institution of marriage. Due to its untraditional method of procreation, embryo adoption calls into question the role of procreation within marriage. In Chapter Two, I explore the nature of the marriage relationship by offering Lisa Cahill’s definition of marriage which involves both a spiritual and physical dimension, and then I describe the concept of marriage from different perspectives including a social, religious, and a personal perspective. From a personal perspective, I explore the relationship between marriage and friendship. Finally, I describe how the concept of marriage is understood today and explore the advantages to being married as opposed to the advantages of being single. Embryo adoption changes the way we customarily think about procreation within a family because in embryo adoption, couples are seeking an embryo from another union to be implanted into the woman. This prompts some philosophers to argue that embryo adoption violates the marriage relationship. In Chapter Three, I further consider the impact of embryo adoption on the family as an extension of the marital relationship as well as the impact of embryo adoption on the traditional roles of motherhood and fatherhood. I examine motherhood by looking at how some philosophers define motherhood and when these philosophers claim a woman becomes a mother. After considering these issues regarding motherhood, I examine the same issues surrounding fatherhood. Peg Brand, PhD., Chair Embryo adoption Embryo rescue Embryo Adoption Rescue Motherhood Fatherhood Marriage Personhood Gestation Conception Reproductive technology Reproduction Surrogacy Conscious Consciousness Sentience Person Self-conscious Self-consciousness Procreation Conjugal union Marriage relationship Procreate Pregnancy Genetic motherhood Gestational motherhood Social motherhood Genetic father Social father Mother Motherhood Father Fatherhood IVF In vitro In vitro fertilization Pregnancy Postnatal adoption Althaus Aquinas Conee Crosby DeGrazia Finnis Ford Locke Lovering McMahan Parfit Quinn Singer Sumner Thomson Tooley Warren Cahill Moller Landau Mill Catholic Lutheran Calvinist Calvinism Aristotle Catholicism Kant Parsons Primoratz Feldman Firestone Tonti-Filippini Watt Geach Human embryo -- Transplantation Adoption -- Religious aspects Motherhood Fatherhood Marriage

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