EXPLORING PHYTOPHTHORA PALMIVORA PARTIAL RESISTANCE IN CARICA PAPAYA FOR CROP IMPROVEMENT

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dc.contributor.advisorKantar, Michael
dc.contributor.authorDomingo, Ryan S.
dc.contributor.departmentTropical Plant and Soil Sciences
dc.date.accessioned2025-02-20T22:36:41Z
dc.date.available2025-02-20T22:36:41Z
dc.date.issued2024
dc.description.degreePh.D.
dc.identifier.urihttps://hdl.handle.net/10125/110193
dc.subjectPlant sciences
dc.subjectPlant pathology
dc.titleEXPLORING PHYTOPHTHORA PALMIVORA PARTIAL RESISTANCE IN CARICA PAPAYA FOR CROP IMPROVEMENT
dc.typeThesis
dcterms.abstractPapaya root rot caused by Phytophthora palmivora is a destructive disease threatening Hawaii’s papaya industry, resulting in crop damage, decreased production, and plant death. The surveillance of P. palmivora isolates from commercial papaya farms through the use of molecular techniques and evaluation of root rot resistance of commercially grown papaya cultivars will help estimate how much variation exists for potential use in breeding programs. This will help examine the geographic distribution of pathogen diversity, identify alternative cultivars with increased root rot resistance, and aid in developing new cultivars with increased resistance to P. palmivora. Extensive production loss and mortality of Carica papaya is associated with Phytophthora palmivora in Hawaii and other papaya growing regions of the world. Currently no commercial papaya cultivar is fully resistant to Phytophthora root rot. However, it is important to identify those that show partial resistance. Partial resistance is defined as reduced pathogen proliferation and spread in a plant, while tolerance is the ability of a plant to maintain yield in the presence of disease. Here we present a novel rapid papaya phenotyping assay with three quantification methods to assess P. palmivora resistance. Three papaya varieties of varying resistance (i.e., ‘Waimanalo’, RS-1, and ‘SunUp’) were used to validate the assay, which confirmed that the ‘Waimanalo’ cultivar exhibited increased resistance over RS-1, and the susceptible ‘SunUp’. Differential responses to P. palmivora infection were observed as early as three days post-inoculation. This assay will help to shorten the breeding process by quickly and cheaply identifying potential sources of resistance genes in seedlings, thus expediting the selection process compared to current conventional phenotyping protocols.
dcterms.extent78 pages
dcterms.languageen
dcterms.publisherUniversity of Hawai'i at Manoa
dcterms.rightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.typeText
local.identifier.alturihttp://dissertations.umi.com/hawii:12373

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Ph.D. - Tropical Plant and Soil Sciences