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dc.contributor.advisorWessel-Beaver, Linda
dc.contributor.authorRosa-Valentín, Giseiry M.
dc.description.abstractTropical pumpkin (Cucurbita moschata) and watermelon (Citrullus lanatus) are the most important cucurbit crops in Puerto Rico (PR). Potyviridae is an important family of viruses that severely affects these crops in PR. Among these viruses are: Squash vein yellowing virus (SqVYV), Papaya ringspot virus (PRSV) and Zucchini yellow mosaic virus (ZYMV). An experiment was conducted with each of these viruses. In Experiment 1, USDA accessions not in the watermelon core collection were tested for SqVYV resistance. Accessions were inoculated, and disease severity and absorbance (ELISA) were evaluated in the field. In Experiment 2, the biological behavior of a collection of PRSV strains from PR were tested in susceptible and resistant lines of tropical pumpkin and in susceptible lines of watermelon. Plants were inoculated and severity of symptoms and absorbance were measured. In Experiment 3, accessions of C.lanatus and C. citroides previously identified as resistant to ZYMV were inoculated with the local ZYMV strain. Severity of ZYMV and absorbance were observed to determine if these accessions are also resistant to this strain. No watermelon accessions evaluated for SqVYV showed complete resistance (defined as symptom free and negative ELISA), but some demonstrated moderate levels of resistance, particularly PI277997 and PI526237. Strains 874 and 903 of PRSV caused more severe symptoms on pumpkin and watermelon than the standard strain 231. These strains were also able to infect Cucurbita moschata cv. Nigerian Local, a cultivar that has previously been always resistant to PRSV. Subsequently, tissues of these plants of Nigerian Local were able to infect susceptible genotypes of C. moschata cv. Waltham and Citrullus lanatus cv. Sugar Baby and Crimson Sweet. C. citroides PI537277 was highly resistance to the local strain of ZYMV, while C. lanatus accessions PIs 485580, 494528, 494529, 595200, 595201, and 595203 were moderately resistant to ZYMV.
dc.description.abstractEn Puerto Rico (PR) las cucurbitáceas de mayor importancia son calabaza (Cucurbita moschata) y sandía (Citrullus lanatus). Una importante familia de virus que afecta severamente este grupo de plantas en PR es la familia Potyviridae. Entre ellos están: Squash vein yellowing virus (SqVYV), Papaya ringspot virus (PRSV) y Zucchini yellow mosaic virus (ZYMV). Se realizó un experimento con cada uno de estos virus. En Experimento 1 se evaluaron accesiones de sandía de la colección de USDA para resistencia a SqVYV. Para esto se realizaron inoculaciones mecánicas y se tomaron medidas de severidad de síntomas y lecturas de absorbancia de una prueba ELISA de plantas en el campo. En Experimento 2 se estudió el comportamiento biológico de nuevas cepas de PRSV recolectadas en PR en cultivares de calabazas susceptibles y resistentes y sandías susceptibles. Se inocularon estas plantas y se tomaron medidas de severidad de síntomas y lecturas de absorbancia. En Experimento 3 se evaluaron accesiones de C. lanatus y C. citroides previamente identificadas como resistentes para ZYMV. Se inocularon estas accesiones con la cepa local de ZYMV. Se observó la severidad y absorbancia para determinar si estas accesiones también resultan resistentes a esta cepa. Ninguna accesión de sandía evaluada para SqVYV mostró resistencia completa (sin síntomas y con ELISA negativa), pero algunas mostaron niveles moderadas de resistencia, en particular PI277997 y PI526237. Las cepas 874 y 903 de PRSV fueron más severas que la cepa estándar 231. Estas fueron capaces de infectar Nigerian Local. Posteriormente tejido de estas plantas de Nigerian Local, identificado como resistente, fue capaz de infectar genotipos susceptibles de calabaza ‘Waltham’ y sandía ‘Sugar Baby’ y ‘Crimson Sweet’. La sandía PI537277 fue altamente resistente a la cepa local de ZYMV, mientras que PI485580, PI494528, PI494529, PI595200, PI595201 y PI595203 fueron moderadamente resistentes.
dc.description.sponsorshipA los proyectos USDA-NIFA-Tropical Subtropical Agricultural Research Program número 2008-34135-19505 y 2010-34135-21022 y USDA-NIFA-Hispanic Serving Institutions Educational Grants Program número 2006-38422-17106.en_US
dc.titleTres potyvirus que afectan las cucubitáceas en Puerto Rico: resistencia genética y comportamiento biolócoen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2012 Giseiry M. Rosa Valentín.en_US
dc.contributor.committeeVerle Rodríguez, Jose Carlos
dc.contributor.committeeEstévez de Jensen, Consuelo
dc.contributor.committeeVan Bloem, Skip
dc.contributor.representativeVélez Díaz, Ana
dc.contributor.collegeCollege of Agricultural Sciencesen_US
dc.contributor.departmentDepartment of Crops and Agro-Environmental Sciencesen_US

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