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dc.contributor.advisorRivera-Vargas, Lydia I.
dc.contributor.authorFernández-García, Jessie
dc.description.abstractIncidence and characterization of Alternaria spp. associated with foliar lesions at different stages of the onion cycle were determined. The study was carried out at commercial and experimental fields in the southern area of Puerto Rico. Alternaria spp. incidence increased in sixty- day-old onion plants of cultivars ‘Mercedes’ and ‘Excalibur’. Sixty two percent of selected Alternaria isolates were placed within a “semi-arborescent” group, not described taxonomically. Other isolates were identified as: Alternaria alli, A. destruens, A. palandui, A. tenuissima and Pleospora eturmiuna. Pathogenicity tests conducted in vitro and in the field revealed that A. alli, A. tenuissima, Alternaria sp. “semi-arborescent” and Pleospora eturmiuna were pathogenic to onions, been A. alli the most virulent. Molecular characterization of Alternaria isolates was determined using RAPD-PCR, ITS1- 5.8S-ITS2 region of the ribosomal DNA, and sequences analysis of region ITS1-ITS4 of rDNA.en_US
dc.description.abstractSe determinό la incidencia y caracterizaciόn de Alternaria spp. asociadas con lesiones foliares en diferentes etapas del ciclo de vida de la cebolla. El estudio se realizó en predios comerciales y experimentales en el área sur de Puerto Rico. La incidencia de Alternaria spp. aumentό en plantas de cebollas de sesenta días de edad de los cultivares ‘Mercedes’ y ‘Excalibur’. El sesenta y dos porciento de los aislados de Alternaria seleccionados fueron colocados dentro de un grupo “semi-arborescentes”, no descrito taxonόmicamente. Otros aislados fueron identificados como: Alternaria alli, A. palandui, A. tenuissima, A. destruens y Pleospora eturmiuna. Las pruebas de patogenicidad en in-vitro y en campo revelaron que Alternaria alli, A. tenuissima, Alternaria sp. “semi- arborescentes” y P. eturmiuna fueron patogénicas a la cebolla siendo A. alli la más virulenta. La caracterizaciόn molecular de los aislados de Alternaria fue determinada utilizando RAPD-PCR, la regiόn de ITS1-5.8S- ITS2 del ADN ribosomal y el análisis de las secuencias de la regiόn de ITS1-ITS4 del rADN.en_US
dc.description.sponsorshipProyecto T-STAR-97 del Departamento de Agricultura federal (USDA)en_US
dc.subjectAlternaria spp.en_US
dc.subjectCiclo de vidaen_US
dc.titleIncidencia y caracterización: Morfológica, patogénica y genética de Alternaria spp. en cultivos de cebolla del sur de Puerto Ricoen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2005 Jessie Fernández Garcíaen_US
dc.contributor.committeeCantrell, Sharon
dc.contributor.committeeCabrera, Irma
dc.contributor.representativeAlameda, Myrna Protectionen_US
dc.contributor.collegeCollege of Agricultural Sciencesen_US
dc.contributor.departmentDepartment of Crops and Agro-Environmental Sciencesen_US

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