Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In this study chicken embryos were exposed at the air cell on embryonic day 6 to 19.8 or 9.9 mg / Kg egg mass of glyphosate in Roundup or glyphosate only. Chickens treated with 19.8 and 9.9 mg / Kg glyphosate in Roundup showed significant reduction in survivability compared to glyphosate alone treatments and controls. On embryonic day 18, embryos were sacrificed for evaluation of developmental toxicity using wet embryo mass, dry embryo mass, and yolk mass as indicators. Morphology measurements were taken on liver mass, heart mass, tibiotarsus length and beak length. Embryos treated with 19.8 mg / Kg glyphosate and 9.9 mg / Kg glyphosate in Roundup showed significant reductions in wet and dry embryo mass and yolk mass. Tibiotarsus length in 9.9 mg / Kg glyphosate in Roundup treatments were significantly reduced compared to 9.9 mg / Kg glyphosate treatments. Beak length was significantly reduced in 9.9 mg /Kg glyphosate in Roundup treatments compared to all other groups.

Efficient plant regeneration and transformation procedures and the stability of the transgene are important to the success of the cotton and soybean biotechnology industry. Engineering herbicide resistance into plants will provide the potential solution to effective weed control in agriculture and reduce loss in crop yields due to weeds. It will also provide cheaper control and decrease environmental hazards. The aims of this study were to develop efficient regeneration and transformation protocols for commercially grown soybean and cotton in South Africa and to use tobacco as a model plant to study the stability of the pat gene through seed generations, successive generations and high temperature and drought stress regimes. Tobacco (Nicotiana tabacum cv. Samsun) leaf disks were successfully transformed with the pat gene. PCR analysis confirmed the integration of the pat gene in all nine transgenic plants and T1, T2 and T3 progeny. Successive generations, high temperatures and drought stress had no adverse effect on the stability and expression of the pat gene in the transgenic tobacco plants. In view of the economic importance of soybean (Glycine max) and cotton (Gossypium hirsutum) in South Africa and the potential to improve commerciallygrown cultivars by genetic transformation, a regeneration and transformation protocol using the shoot apical meristem and Agrobacterium-mediated DNA transfer was successfully developed, to obtain herbicide (Basta) resistant commercially-grown South African soybean and cotton plants for the first time. The frequencies of regenerated plants per meristem were 66% for Talana, 52% for Ibis, 90% for Sabie, 74.6% for LRCC 101, 69.5% for Palala and 70% for 107/1. Prior to transformation experiments, Talana and Ibis were screened for susceptibility to virulent Agrobacterium tumefaciens sis 43. Both cultivars produced tumours in response to infection and were therefore compatible hosts for Agrobacterium-mediated DNA transfer. Transformation of Talana, Sabie and 107/1 with the pat gene, was successfully achieved following wounding of the shoot apical meristem and injecting with Agrobacterium in the presence of acetosyringone. Transformed explants and shoots grew in the presence of kanamycin and PPT, indicating that the integrated pat gene was producing the enzyme PAT which was successfully detoxifying the herbicide PPT. Final transformation frequencies from the initial transformed meristems to regenerated plants were 1.06% for Talana, 2.3-3% for Sabie and 1.2-2.3% for 107/1. These transformation frequencies were higher than those reported in the literature. PCR analysis of the extracted DNA from transgenic soybean and cotton shoots confirmed the presence of the 558 bp pat coding region in the transformed plants. The success of this study on the regeneration and transformation of soybean and cotton indicates that South African agriculture now has available techniques for plant regeneration and recombinant DNA technology for crop improvement of soybean and cotton.

Orientador: Julio Cezar Durigan / Banca: Pedro Luís da Costa Aguiar Alves / Banca: Dagoberto Martins / Resumo: O presente trabalho foi conduzido em Jaboticabal, SP, no ano agrícola de 2000/01. Objetivou-se estudar a possibilidade de redução na dosagem da mistura herbicida (fluazifop-p-butil + fomesafen), aplicada em pós-emergência, no controle de plantas daninhas. Foram instalados três experimentos de campo em novembro, dezembro e janeiro, sobre Latossolo Vermelho eutrófico típico, de textura argilosa. O delineamento foi de blocos ao acaso, num esquema de parcelas sub-divididas, com quatro repetições. Os cultivares IAC- Foscarin31 e o MG/BR46-Conquista, respectivamente, constituíram as parcelas e as dosagens de 100% (1,6 l p.c./ha.), 75% e 50% do herbicida, juntamente com as testemunhas infestada e capinada, as sub-parcelas. A distância entrelinhas foi de 0,45 m. Na aplicação do herbicida utilizou-se pulverizador costal, à pressão constante de 35 lbf.pol-2, com consumo de calda de 200 l/ha. Na semeadura da soja em novembro, obteve-se baixa densidade de plantas (11/m). No entanto, devido ao grande desenvolvimento, para ambos os cultivares, características de produção analisadas, como número de vagens/planta, número de grãos/vagem e massa de 100 grãos, não foram significativamente afetadas pela presença de plantas daninhas. O cultivar IAC- Foscarin31 foi mais sensível à ação fitotóxica do herbicida, baseando-se nos sintomas visuais de intoxicação. Para os experimentos com semeaduras mais tardias, verificou-se influência do fotoperíodo, além das plantas daninhas, proporcionando reduções no crescimento e produtividade da cultura. Nestas épocas, o cultivar IAC- Foscarin31 mostrou maior sensibilidade ao fotoperíodo e à interferência de plantas daninhas. Em todos os experimentos constataram-se produções semelhantes entre os manejos químicos e o com capinas. / Abstract: The research was carried out in Jaboticabal, SP, in 2000/01 crop year. The aim was study the possibility of reduction in doses of herbicide mixture, in postemergence to weed control. The tests were installed in November, December and January, on Red Latossoil eutrofic of clayish texture. It was used a randomized blocks experimental design with four replications, in split-plot scheme. Cultivars, IAC- Foscarin31 and MG/BR46-Conquista, constituted the plot and the herbicide doses at 100% (1.6 l p.c.ha-1), 75% and 50%, together with the checks (with and without weeds), the split-plot. The row spacing was 0,45 m. The herbicide application was done using knapsack sprayer, with constant pressure (35 lbf.pol-2 ), and volume of application of 200 l.ha-1. When soybean was sowned in November, low stand of plants (11/m) was obtained. Due the great plants development, the agronomic characteristics analyzed as number of pods.plant-1, number of grains.pod-1 and weight of 100 grains were not affected by weed interference. The cultivar IAC- Foscarin31 was more susceptible to fitotoxicity action, estimated by visual symptoms. The tests sowned late were influenced by fotoperiod and weeds, causing reduction in growth and yield. At this time, cultivar IAC-Foscarin31 showed higher sensibility to fotoperiod and weed interference. For all the tests were possible to obtain same yields among chemicals managements and check without weeds. / Mestre

Typescript (photocopy) / Bibliography :leaves 310-329. / ix, 329 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1994

Bibliography: leaves 143-161. / xi, 161 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Pot exmeriments are undertaken during the winter growing season to examine Paraquat and Diquat resistance in the grass weed species Hordeum leporinum Link., H. glaucum Steud. and Vulpia bromoides SF Gray, and in the broadleaf weed Arctotheca calendula (L.) Levyns. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1994

Bibliography: leaves 143-161. Pot exmeriments are undertaken during the winter growing season to examine Paraquat and Diquat resistance in the grass weed species Hordeum leporinum Link., H. glaucum Steud. and Vulpia bromoides SF Gray, and in the broadleaf weed Arctotheca calendula (L.) Levyns.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 35-40). Also available on the World Wide Web.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 22, 2010). Thesis advisor: Dr. Reid J. Smeda. Includes bibliographical references.

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