Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 55-57).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 11, p. 1991. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 34-37).

Many seedsmen have observed that lima bean seed of a variety like Early Thorogreen, which has green cotyledons, often fades in color during harvesting. This fading of color is known as bleaching. A variety which has green cotyledon and hence green seed, should retain this green color during harvest. Bleached seeds are likely to emerge slowly when planted. Also, the final field stand from a planting of bleached seed is likely to be poor.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 183-192). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 183-192). Also available on the Internet.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Thomas A. Evans, Dept. of Plant & Soil Sciences. Includes bibliographical references.

No description available.

The effects of Rhizoctonia solani on the hypocotyls of resistant and susceptible lines of lima bean were studied . The fungus attacks lima bean at one or more stages during host development and causes pre-and -postemergence damping-off, root rot, and foliage blight. The isolate of the fungus used in this study was obtained from infected radishes grown in Salt Lake County. Utah. The formation of infection cushions and modes of penetration by this fungus was no different on the resistant and susceptible lima bean hypocotyls . The infection process was studied under laboratory conditions . Differential staining showed that the fungal hyphae were closely appressed to the host surface , and at first along the longitudinal axis o f the epidermal cells. Later, hyphal branches grew in oblique and transverse directions . Aggregated hyphal tips formed infection cushions , which gave rise to one or more infection pegs that penetrated the host directly . Following penetration, both intercellular and intracellular hyphae were formed. The build-up of masses of hyphae occurred as club-shaped structures in the cortex of the susceptible lima bean hypocotyls , but were not observed in the resistant hypocotyls . The extents of infection in the resistant and susceptible lima bean hypocotyls were different at 7 days after inoculation. The hyphae in the susceptible hypocotyl had penetrated into vascular bundles and pith , whereas the hyphae had penetrated the cortex and pith of the resistant hypocotyl but were not observed in the vascular tissue. Stomatal penetration from individual hyphal side branches was rare and apparently of minor importance as a means of penetration by this isolate .

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-14T12:51:13Z No. of bitstreams: 1 Jeferson Araujo Silva.pdf: 166823 bytes, checksum: 6c389068c6abcff8459db563807d3eb8 (MD5) / Made available in DSpace on 2017-03-14T12:51:13Z (GMT). No. of bitstreams: 1 Jeferson Araujo Silva.pdf: 166823 bytes, checksum: 6c389068c6abcff8459db563807d3eb8 (MD5) Previous issue date: 2011-02-22 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The collar rot caused by Sclerotium rolfsii, is an important disease that causes an incidence in lima bean (Phaseolus lunatus L.) at the Northeastern of Brazil. Aiming to select genotypes with potential to be used in a disease management, there were 50 genotypes of lima bean evaluated in relation to an isolate of S. rolfsii. Plants with 10 days old were inoculated by an injury into their base and deposited the sclerotia of the pathogen. The evaluation occurred at the 10th day after the inoculating, by calculating the percentage of the number of plants with symptoms in relation to the total of plants per pot. Most part of the genotypes (58%) behaved as highly susceptible to the pathogen while 28% were classified as susceptible, 10% as moderately resistant. Only two genotypes (F-2 and F-25) behaved as extremely resistant, corresponding to 4% of the total. The stability of resistance of these two genotypes was evaluated in relation to 10 isolates of S. rolfsii. Both genotypes showed a good level of resistance, thus demonstrating the potential of its use as a strategy for management of collar rot of the lima bean crop. / A podridão do colo, causada por Sclerotium rolfsii, é uma importante doença que pode incidir em fava (Phaseolus lunatus L.) no Nordeste brasileiro. Visando selecionar genótipos com potencial de utilização no manejo da doença, foram avaliados 50 genótipos de fava, em relação a um isolado de S. rolfsii. Plantas com 10 dias de idade foram inoculadas pelo método de ferimento do colo e deposição do escleródio do patógeno. A avaliação ocorreu aos 10 dias após a inoculação pela mensuração da incidência da doença, considerando a porcentagem de plantas com sintomas em relação ao total de plantas por vaso. A maioria dos genótipos (58%) se comportou como altamente suscetível ao patógeno, enquanto que 28% foram classificadas como suscetíveis e 10% como medianamente resistentes. Somente dois genótipos (F-2 e F-25) se comportaram como altamente resistentes, correspondendo a 4% do total. A estabilidade da resistência destes dois genótipos foi avaliada em relação a 10 isolados de S. rolfsii. Ambos os genótipos apresentaram um bom nível de resistência, demonstrando potencial de utilização como estratégia de manejo da podridão do colo na cultura da fava.

As sessile organisms, plants evolved a plethora of defenses against their attackers. Given the role of plants as a primary food source for many organisms, plant defense has important implications for community ecology. Surprisingly, despite the potential to alter entire food webs and communities, the factors determining plant investment in defense are not well-understood, and are even less understood considering the numerous symbiotic interactions in the same plant. Legume-rhizobia symbioses engineer ecosystems by fixing nitrogen from the atmosphere in trade for plant photosynthates, yet connecting symbiotic resource exchange to food web interactions has yet to be established. Here I test how rhizobia influence plant defense and tritrophic interactions in lima bean (Fabaceae - Phaseolus lunatus L.): a model plant in chemical ecology research characterized by a broad range of different defenses. Examining suites of traits among lima bean genotypes, highly cyanogenic cultivars and wild type plants (high cyanotypes) produce more hook-shaped trichomes, as a putative combined approach of chemical and mechanical defenses, forming defense syndromes to protect against multiple feeding guilds (Chapter 2). Testing costs that may have contributed to forming tradeoffs among strategies, high cyanotypes show reduced fitness under plant-plant competition relative to low cyanotypes, but when challenged with herbivory, high cyanotypes fitness reductions are no longer evident (Chapter 3). Young leaves, not reproductive organs, are the most cyanogenic lima bean organ, and removal quantitatively decreases fitness, supporting assumptions that the most valuable tissues will be most highly defended (Chapter 4). Testing the degree to which nitrogen-fixing rhizobia contribute to cyanogenesis, high cyanotypes form more nodules than low cyanotypes. Quantitative relationships between nodule number and plant traits highlight the role symbiotic investment plays a role in plant defense and nutritive phenotype, while simultaneously, genotypically-determined levels of defense shape plant investment in symbiosis (Chapter 5). Interestingly, traits that trade off by cyanotype (i.e. high cyanogenesis but low indirect defense) reflect the patterns in plants with nitrogen-fixing rhizobia. Rhizobia-inoculated lima beans show reduced indirect defenses, recruiting fewer parasitoid wasps (Chapter 6) and predatory ants (Chapter 7). Examining plant-ant attraction in greater detail, ants prefer headspace regions above EFN droplets, corresponding with species-specific differences in suites of volatiles, indicating EFN, like floral nectar, can be scented to manipulate insect behavior (Chapter 8). Overall, understanding when investing in traits to recruit predators is more effective than investing in defensive chemistry, and how particular ecological contexts, such as symbioses can influence the outcome of defense allocation strategies remains a fascinating area of research. Determining the mechanisms underlying why rhizobia and other belowground microbial symbionts influence their host plants' above ground interactions, whether plants traits affected by symbiotic microbes are simply a function of the costs and benefits from resource exchange, or whether symbionts can influence the success of primarily direct versus indirectly defended plants is an important question for understanding complex trophic systems and connecting to agricultural implications for more effective biological pest control.