Thesis (Ph. D.)--University of Wisconsin--Madison, 1932. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes annotated, chronological bibliography (leaves 222-654) and indexes.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Sorghum (Sorghum bicolor [L.] Moench) is fifth among the major cereal crops in the world in terms of production area and total production. Grain sorghum can be successfully produced in a wide range of environments, its productivity is severely limited by pathogens, insects and abiotic stresses. One of these pathogens is Claviceps africana Frederickson Mantle & de Milliano, commonly known as ergot. As is the case with many sorghum diseases, the best long term approach to control ergot may be the use of genetic resistance. There is limited information about resistance to C. africana in sorghum, and the reported resistance in most lines is fertility-based. Dahlberg (1999) first reported the line IS8525 to have the most tolerance to ergot of any of the accessions screened in Puerto Rico. The specific objectives of this research are: (1) to confirm the presence of C. africana resistance in IS8525 germplasm, (2) to determine if the resistance in IS8525 is pollen mediated or ovule based, and (3) to determine if the resistance in IS8525 is heritable and stable across environments. Ergot vulnerability ratings were determined for two recombinant inbred line populations, IS8525D and IS8525J, in four locations during 2001. Also, ergot vulnerability ratings were evaluated in four test-cross populations (using as testers A3Tx623 and A3Tx623) in two locations. Evaluations of the original parents indicate that ergot tolerance in IS8525D parent was consistently better than that in IS8525J parent. As expected, neither parent provided complete resistance. The IS8525J recombinant inbred line population showed significantly more ergot susceptibility than the IS8525D recombinant inbred line population and this trend was consistent across environments. Variation for ergot vulnerability amo ng recombinant inbred lines for both populations was detected, but the amount of variability was environment dependent. In the testcross hybrids, all four populations were susceptible to ergot, primarily due to male sterility in the hybrids, confirming that the tolerance shown in IS8525 germplasm is mostly pollen mediated. However, a greater level of tolerance in the IS8525 hybrid checks confirmed the reports of tolerance by Dahlberg et al. (1998) and Reed et al. (2002).

Sorghum (Sorghum bicolor [L.] Moench) is fifth among the major cereal crops in the world in terms of production area and total production. Grain sorghum can be successfully produced in a wide range of environments, its productivity is severely limited by pathogens, insects and abiotic stresses. One of these pathogens is Claviceps africana Frederickson Mantle & de Milliano, commonly known as ergot. As is the case with many sorghum diseases, the best long term approach to control ergot may be the use of genetic resistance. There is limited information about resistance to C. africana in sorghum, and the reported resistance in most lines is fertility-based. Dahlberg (1999) first reported the line IS8525 to have the most tolerance to ergot of any of the accessions screened in Puerto Rico. The specific objectives of this research are: (1) to confirm the presence of C. africana resistance in IS8525 germplasm, (2) to determine if the resistance in IS8525 is pollen mediated or ovule based, and (3) to determine if the resistance in IS8525 is heritable and stable across environments. Ergot vulnerability ratings were determined for two recombinant inbred line populations, IS8525D and IS8525J, in four locations during 2001. Also, ergot vulnerability ratings were evaluated in four test-cross populations (using as testers A3Tx623 and A3Tx623) in two locations. Evaluations of the original parents indicate that ergot tolerance in IS8525D parent was consistently better than that in IS8525J parent. As expected, neither parent provided complete resistance. The IS8525J recombinant inbred line population showed significantly more ergot susceptibility than the IS8525D recombinant inbred line population and this trend was consistent across environments. Variation for ergot vulnerability amo ng recombinant inbred lines for both populations was detected, but the amount of variability was environment dependent. In the testcross hybrids, all four populations were susceptible to ergot, primarily due to male sterility in the hybrids, confirming that the tolerance shown in IS8525 germplasm is mostly pollen mediated. However, a greater level of tolerance in the IS8525 hybrid checks confirmed the reports of tolerance by Dahlberg et al. (1998) and Reed et al. (2002).

No description available.

Thesis (Ph. D.)--University of Michigan, 1930. / Cover title. "Reprinted from the American journal of botany, vol. XVIII, no. 1 ... January, 1931." "Literature cited": p. 76-78.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. / Made available in DSpace on 2012-10-18T21:10:14Z (GMT). No. of bitstreams: 0 / A identificação de Claviceps africana em sorgo, foi dividida em três distintas etapas, interligadas entre si. Na primeira fase, foram analisadas amostras de panículas frescas de sorgo (Sorghum bicolor [L.] Moench), provenientes de lavoura naturalmente infestada, coletadas nos municípios de Rio do Oeste e Ituporanga, no Estado de Santa Catarina; escleródios de Claviceps spp coletados em sorgo, provenientes do campo de produção de sementes, no município de Capinópolis no Estado de Minas Gerais e escleródios do fungo em estudo, provenientes de plantação em casa-de-vegetação realizada no Departamento de Ciência e Tecnologia de Alimentos, do Centro de Ciências Agrárias, da Universidade Federal de Santa Catarina, para a caracterização morfológica dos escleródios. Tendo sido esta realizada, com o emprego de técnicas de macroscopia para a observação da camada externa da estrutura fúngica, através de microscópio-estereoscópio e, de microscopia nos tecidos internos da estrutura, visualizados por microscópio óptico e microscópio eletrônico de varredura. Na segunda etapa do trabalho de identificação micológica e fitopatológica de C.africana em sorgo, foram aplicados métodos de germinação dos escleródios, com a finalidade de obtenção da fase teleomorfa do fungo. Também, a partir do isolamento da cultura pura das fontes de inóculo do fungo, aplicados no teste de patogenicidade em dois anos consecutivos, para a observação da doença e a comprovação do fungo em estudo. Na última etapa do trabalho, de análise bioquímica para a detecção do alcalóide principal, encontrado no escleródio do fungo, a dihidroergosina (DHE), com a utilização de métodos empregados na determinação de micotoxinas, realizadas com amostras provenientes das etapas anteriores. Os resultados foram submetidos à análise estatística descritas em duas etapas: estatística descritiva e análise de variância, através do programa Statistica TM da Star Soft TM. Como resultado final, foi possível o cruzamento de dados, provenientes de áreas afins complementares, para a confirmação do trabalho proposto, bem como, da experimentação das diferentes técnicas na identificação do fungo.

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains ix, 134 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Paul Hsiao-tseng Liang. / Ph.D.