Data/hora: 11/06/2024 06:54:55

Provedor de dados: 	32	
País: 	Mexico	
Título: 	Búsqueda de portainjertos de aguacate tolerantes resistentes a Phytophthora cinnamomi Rands	
Autores: 	Castañeda González, Elba Lidia.	
Data: 	2012-09-08	
Ano: 	2009	
Palavras-chave: 	Persea americana Mill.; Portainjertos; PCR; Doctorado; Fitopatología; Rootstock.	
Resumo: 	México se considera el centro de origen del aguacate y mantiene diversidad genética  en  materiales criollos.  En este estudio, se realizaron colectas de semilla para  detectar  tolerancia o resistencia a Phytophthora cinnamomi Rands, principal patógeno de la raíz  del aguacate. El material se colectó en los estados de Querétaro, Puebla y Estado de  México, seleccionando árboles que no mostraban síntomas (árboles “escape”) aún  cuando los huertos están infestados con el patógeno. Además, se incluyeron en la  investigación semillas de 22 accesiones del Banco de Germoplasma (BG) de la  Fundación Salvador Sánchez Colín CICTAMEX S.C. y planta clonal del portainjerto  Duke-7 resistente a P. cinnamomi y utilizado como testigo. Se inocularon 5,200  plántulas con micelio de P. cinnamomi para hacer una selección masal recurrente;  treinta y ocho plantas mostraron potencial para utilizarse como portainjerto. Para  evaluar el polimorfismo entre genotipos, caracterizarlos y detectar la cercanía entre  individuos, de los 38 materiales seleccionados, se extrajo el ADN y se caracterizó  molecularmente con RAPD e ISSR; se incluyeron también los materiales: Topa-topa   (susceptible), Duke-7 (resistente) y Day resistente a P. cinnamomi y salinidad,  provenientes del BG y utilizados como referencia. Los dendogramas se elaboraron con  el programa FreeTree, versión 0.9.1.50, aplicando un método de remuestreo con 1,000  repeticiones. La similitud genética se estimó con el coeficiente Nei and Li, y para los  agrupamientos se utilizó el método UPGMA. Trece de los 25 iniciadores presentaron  polimorfismo; el promedio del contenido de información polimórfica (PIC) para RAPD e  ISSR fue de 0.9052 y 0.9054, respectivamente, con un total de 3,057 bandas. De forma  independiente se caracterizaron 16 accesiones de aguacate provenientes del BG, 14  de ellas con resistencia o tolerancia en campo a P. cinnamomi y dos con  susceptibilidad al patógeno. El análisis detectó un alto grado de polimorfismo entre los  materiales evaluados.________México is considered as the origin center of the avocado and maintain genetic diversity  in wild materials. Seed collections were carried out to find tolerance or resistance to  Phytophthora cinnamomi Rands, main pathogen of the avocado root. The collection  sites were the states of Queretaro, Puebla and state of Mexico, where “escape” trees  were selected in orchards infested whit the pathogen, likewise, in this research there  were included seeds of 22 accessions from the Germplasm Bank (GB) located in  Coatepec Harinas, state of Mexico, y clone plant Duke-7 as standard. After five years  from the beginning of the collection, the outcome was 5,200 seedlings that were  inoculated with P. cinnamomi through recurrent mass selection. From this selection, 38  plants survived and are considered as potential of rootstock. Likewise, there were  materials selected to water with salty water with concentrations up to 14.2 meq/L of Na+  and 4.52 meq/L of Cl-. From these 38 materials, the DNA was extracted and   characterized molecularly with RAPD and ISSR, which includes three materials from the  Germoplasm Bank used as reference: Topa-topa (susceptible), Duke-7 (resistant) and   Day resistant to P. cinnamomi and salinity as well. The objective was to evaluate the  polymorphism among genotypes, characterize them and detect a close relationship  among individuals. The Dendograms (trees) were constructed with the software  FreeTree, version 0.9.1.50 considering a re-sampling method with 1 000 replications.  The close genetic relationship was estimated by Nei and Li coefficient, and the cluster  analysis was analyzed by the UPGMA method. Only 13 of 25 primers showed  polymorphism; the average of the polymorphic information content for RAPD and ISSR  was 0.9052 and 0.9054, respectively, with a total of 3,057 bands. Other study was by  vegetal culture of 16 accessions from the GB, 14 resistant to P. cinnamomi in field, this  analysis detected a high degree of polymorphism among materials assessed.	
Tipo: 	Tesis	
Idioma: 	Espanhol	
Identificador: 	http://hdl.handle.net/10521/1334