Thesis (Ph. D.)--University of Adelaide, Dept. of Agronomy, Waite Agricultural Research Institute, 1986. / Includes bibliographical references (leaves 96-112).

Thesis (Ph. D.)--University of Adelaide, Dept. of Plant Pathology, 1984. / Includes bibliographical references (129-139).

Thesis (Ph. D.)--University of Adelaide, Dept. of Crop Protection, 1995? / Copy of author's previously published article inserted. Includes bibliographical references (leaves 60-75).

Thesis (Ph. D.)--University of Adelaide, Dept. of Plant Science, 1996? / Includes bibliographical references (leaves 121-141).

Thesis (M.S.)--Michigan State University. Dept. of Entomology, 2006. / Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 82-87). Also issued in print.

Plant parasitic nematodes are pests that cause significant economic losses. Due to ineffective chemical protection and its environmental demands, new ways of protection against the aforementioned nematodes are being developed. Nematophagous fungi studied in this thesis seem to be one of the possible ways of biological protection. Their effectiveness, however, is not entirely clear, because the slide culture of the surveyed fungi species (Dactylella oviparasitica, Lecanicillium muscarium Pleurotus ostreatus, Stropharia rugosoannulata, and a mixture of Arthrobotrys oligospora isolates, isolates A. oligospora A5/10 and A10/10, and the Gliorex preparation containing conidia Clonostachys rosea and Trichoderma harzianum) proved as effective organisms in regulating the beet cyst nematode (Heterodera schachtii), as all species showed a statistically significant difference in mortality of the hatched J2 larvae compared to the control variant. The pot experiment, however, showed no statistically significant difference in reducing the number of cysts, and in the species Dactylellaoviparasitica and a mixture of Arthrobotrysoligospora isolates, the number of cysts increased in comparison with the control variant. In practice, this method of protection is not sufficiently reliable, and it is necessary to continue the research before its possible introduction into practice.

Fusarium virguliforme, the causal agent of sudden death syndrome (SDS) in North America, and Heterodera glycines, soybean cyst nematode (SCN), are significant threats to the production of soybean. In 2014, two field trials were established to evaluate seed treatments and their efficacy in managing SDS and SCN. The locations were selected because each has a history of SDS and SCN. Plots were 3.04 meters wide by 6.1 meters in length with row spacing of 0.76 meters. Each plot received 2.45 grams of infested sorghum per 30.5 centimeters of row. At each location, two soybean varieties and ten different seed treatments were tested in 2014. In 2015, twelve seed treatments were tested on the same two varieties at the same two locations. Seed treatments were evaluated for phytotoxicity, vigor, stand count, SDS foliar ratings and soybean yield. Soil samples were collected at planting and at harvest to determine SCN reproduction. Root samples were collected from each plot to quantify the amount of F. virguliforme DNA in the soybean roots using a real-time quantitative polymerase chain reaction (qPCR) protocol. ANOVA and Fisher’s LSD Test were used to separate treatment means. Analysis of the qPCR was done by comparing the quantification cycle (Cq) values and separating means using ANOVA. There were significant differences between varieties for soybean yield and disease index. Treatments containing fluopyram had more phytotoxicity than treatments lacking fluopyram at both locations. Several treatments allowed for higher SCN reproduction than treatments with Clariva. At Ina, a fluopyram treatment and one of the Clariva treatments had higher soybean yield than the non-treated control. At Shawneetown, one fluopyram treatment had higher soybean yield than all other treatments. In the qPCR analysis, seed treatments with fluopyram had a lower amount of F. virguliforme DNA in the roots than the non-treated control.

The secretory pathway of G. max performs a prominent role in its defense to H. glycines parasitism, a finding reinforced by the identification of the SNARE-associated gene ALPHA-SNAP-5 being rhg1. Other proteins performing important roles in secretion are Sec61-ALPHA, Sec61-BETA and Sec61-GAMMA which bind to form a trimeric complex that imports proteins into the ER for their eventual secretion. Comparative analyses to the Saccharomyces cerevisiae Sec61ALPHA, Sec61BETA and Sec61GAMMA proteins, respectively, shows G. max has 4 Sec61-ALPHA, 9 Sec61-BETA and4 Sec61-GAMMA proteins. At least one paralog from each gene family is expressed in H. glycines-parasitized root cells in G. max, but while undergoing a defense process. The overexpression of one selected Sec61-ALPHA, Sec61-BETA and Sec61-GAMMA in the H. glycines-susceptible genotype G. max[Williams 82/PI 518671] leads to an engineered defense response. In contrast, RNAi of the same selected Sec61-ALPHA, Sec61-BETA and Sec61-GAMMA genes in the H. glycines-resistant genotype G. max[Peking/PI 548402] leads to an engineered susceptible response. The combined opposite outcomes of the Sec61-ALPHA, Sec61-BETA and Sec61-GAMMA gene overexpression and RNAi provides evidence that they function in the defense process, consistent with the hypothesis that the G. max secretion system plays a role in its defense to H. glycines parasitism.

Made available in DSpace on 2017-07-10T17:37:32Z (GMT). No. of bitstreams: 1 Anna Paula Comerlato.pdf: 310606 bytes, checksum: 263346497f6f6a5c056dbda7677bb798 (MD5) Previous issue date: 2009-05-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate the effect of liquid waste, produced by the cassava industry in Western Paraná, on the soybean cyst nematode Heterodera glycines Ichinohe through in vitro and in vivo essays. In vitro and in vivo essays were performed in randomized experimental designs with 5 replications for each treatment as follows: water (positive control), nematicide (negative control) and cassava waste at 5%, 10%, 15%, 20%, 25%, 50%, 75% and 100% for the in vitro test and cassava waste at 10%, 25%, 50%, 75% and 100% for the in vivo test. The in vitro tests were performed with eggs, J2 and cysts of H. glycines, which were immersed into each solution for 24 hours and then inoculated into pots containing soybean plants with two mature leaves. The evaluation occurred 30 days after inoculation (dai). The in vivo essays were carried out with one application and two applications of cassava waste. The in vivo essays started with the inoculation of 5,000 eggs and/or J2 of H. glycines on soybean plants. Forty five dai, liquid waste was applied in the pots and soybean plants had their shoot cut. Twenty four hours after the first application, new soybean plants were transplanted to the pots. To the essay with two applications of liquid waste, the second one was run 75 dai but keeping the same plants after application. The evaluation for the in vivo essays occurred 60 days after the transplanting. The variables assessed were plant height, shoot length, root length, number of cysts, number of females and eggs per root system, fresh weight and dry weight of plants and the reproduction factor of H. glycines on soybean plants. The cyanide content for the cassava waste was determined as 40 mg.L-1 in manipueira 100%, using the kit Microquant (Merck). The in vitro essays showed that the number of J2 decreased significantly and progressively (R2=0,82) from cassava waste 15% to 100%. For eggs and cysts, the cassava waste treatments from 10% to 100% were more efficient than the control water. Moreover, cassava waste at 25% concentration showed the lowest values for number of eggs and cysts for the in vitro essays. For the in vivo essays, two applications of cassava residue allowed a better development of soybean plants, allied to a decrease on the number of females and cysts of H. glycines, when compared to one application alone. The treatments cassava waste at 50%, 75% and 100% were superior to the others but cassava waste at 50% showed the lowest values for the number of females and cysts / Objetivou-se com o presente estudo avaliar o efeito de manipueira industrial, coletada em fecularia do oeste do Paraná, sobre o nematóide de cisto da soja Heterodera glycines Ichinohe, mediante ensaios in vitro e in vivo. Os ensaios in vitro e in vivo foram realizados no delineamento experimental inteiramente casualisado com os tratamentos água (controle positivo), nematicida (controle negativo) e manipueira a 5%, 10%, 15%, 20%, 25%, 50%, 75% e 100% para o ensaio in vitro e manipueira a 10%, 25%, 50%, 75% e 100% para o ensaio in vivo em 5 repetições cada. Os ensaios in vitro foram realizados com ovos, J2 e cistos de H. glycines, os quais permaneceram imersos nas diferentes soluções por 24 horas, sendo posteriormente inoculados em vasos contendo plantas de soja com duas folhas definitivas. A avaliação ocorreu aos 30 dias após a inoculação (dai). No tratamento in vivo, foram realizados ensaios com uma aplicação e duas aplicações de manipueira. Para o ensaio com uma aplicação, plantas de soja foram inoculadas com 5.000 ovos e/ou J2 de H. glycines com aplicação de manipueira aos 45 dai. Após 24 horas da aplicação, a parte aérea das plantas foi cortada, tendo sido plantada nova muda de soja. Para o ensaio com duas aplicações, manipueira foi aplicada aos 45 e aos 75 daí, mantendo-se as plantas após a segunda aplicação. A avaliação dos ensaios in vivo ocorreu 60 dias após a última aplicação de manipueira. As variáveis avaliadas para os ensaios realizados foram altura de plantas, comprimento da parte aérea, comprimento do sistema radicular, número de cistos, fêmeas e ovos por sistema radicular, massa seca e massa fresca de plantas e fator de reprodução (FR). O teor de cianeto em manipueira 100% foi de 40 ppm, o qual foi determinado antes de cada ensaio. Para J2 tratados in vitro, houve redução significativa e progressiva (R2=0,82) a partir de manipueira a 15% de concentração. Para ovos e cistos tratados in vitro, manipueira a partir de 10% de concentração foi superior à testemunha somente água, sendo que manipueira 25% apresentou os valores mais baixos para número de ovos e cistos. Para os ensaios in vivo, manipueira em duas aplicações permitiu um melhor desenvolvimento das plantas de soja com maior redução de fêmeas e cistos por planta, quando comparado ao ensaio com apenas uma aplicação. Os tratamentos manipueira 50%, 75% e 100% foram significativamente superiores aos demais quando aplicados via solo em tubetes, sendo que manipueira 50% apresentou os valores mais baixos para número de fêmeas e cistos

Master of Science / Department of Agronomy / William T. Schapaugh Jr / The soybean cyst nematode (Heterodera glycines) (SCN) is an important pathogen of soybean in the United States. Annual yield losses from SCN are estimated to be over $2 billion worldwide. However, SCN virulence or the ability of a nematode to grow on resistant soybean genotypes varies widely among SCN populations. Fortunately there are several genetic sources of resistance to decrease the virulence of the pathogen on soybean. The objectives of this research were to: 1) characterize the genetic diversity of soybean cyst nematode populations in Kansas, 2) determine the frequency of Kansas SCN populations virulent on PI88788, 3) determine which plant introductions used in the HG Type Test provide the best level resistance, and 4) compare the performance of commercial soybean cultivars to the plant introduction from which their SCN resistance was derived. Soil samples were collected from SCN-infested fields across the state. Each soil sample was taken to the greenhouse and planted to a susceptible soybean cultivar to increase SCN population. Following an SCN population increase, a HG Type Test was planted. H. glycines field populations were highly variable, not only in population densities, but also in their abilities to develop on soybean genotypes. Collected from a diverse range of environments, ten HG types were identified. About 50% of the H. glycines populations were virulent on PI 88788, and most of the populations were virulent on commercial SCN resistant lines which derived their resistance from PI 88788. The commercial lines tended to be more susceptible to SCN than the lines from which they derived their resistance, but few HG populations were virulent on PI 437654 or the commercial line that derived its resistance from PI 437654. These results suggest that sources other than PI 88788 should be used in the development of H. glycines resistant cultivars for Kansas. One possible source of resistance is PI 437654. Information about SCN diversity in Kansas will improve decisions regarding cultivar development and selection for SCN management.