Evaluación de la heredabilidad y selección combinada en un población de Solanum phureja Juz et Buk por resistencia a Spongospora subterranea (Wallr) Lagerh f. sp. subterranea Tomlinson y Phytophthora infestans (Mont) de Bary

Abstract

Resumen: Las dos enfermedades más importantes del cultivo de la papa en Colombia son la sarna polvosa y la gota, producidas por los patógenos Spongospora subterranean f. sp. subterranea y Phytophthora infestans, respectivamente. Para estas enfermedades, el mejoramiento genético es una de las principales estrategias para su manejo. Se sabe que en Solanum phureja existen niveles diferenciales de respuesta de resistencia y/o susceptibilidad a la sarna polvosa y la gota de la papa. El objetivo de este estudio consistió en estimar la heredabilidad de la característica de resistencia a sarna polvosa y gota de la papa en una población de papa criolla y establecer si la resistencia a ambas enfermedades está correlacionada, con el fin de realizar una selección combinada de los mejores materiales. En dos localidades del municipio de La Unión, se evaluó la severidad de la sarna polvosa en raíces y en el caso de gota en hojas, usando escalas diagramáticas. La heredabilidad depende de la población en estudio y de la unidad de selección que se utilice. Así, la heredabilidad se evaluó bajo los métodos de selección entre familias, entre y dentro de familias, masal estratificada y masal simple. Para el caso de sarna polvosa no se presentaron diferencias estadísticamente significativas entre las heredabilidades obtenidas para los diferentes métodos de selección, ni entre las localidades, variando la estimación de la heredabilidad entre 0.29 y 0.11. Por su parte para la resistencia a gota no se presentaron diferencias estadísticamente significativas entre las heredabilidad obtenidas para los diferentes métodos de selección, pero si entre las localidades, así en la vereda La Cabaña la estimación de la heredabilidad varió entre 0.35 a 0.54 y en la vereda San Juan la estimación de la heredabilidad varió entre 0.05 a 0.08. No se presentó correlación fenotípica, familiar y/o individual para la característica de resistencia entre ambas enfermedades. La estrategia de niveles independientes de selección permitió encontrar en la población los genotipos con mejor para resistencia S. subterranean f. sp. subterranea y P. infestans./ Abstract. Powdery scab and late blight are the most important and destructive diseases in potato in Colombia. These diseases are caused by the pathogens Spongospora subterranea f. sp. subterranea and Phytophthora infestans. Plant resistant breeding is an important tool for an integrated disease management for both pathogens. In Solanum phureja species resistance genes for Powdery scab and late blight are found. The objective of this study was to determinee the resistance heritability to S.subterranea f. sp. subterranea and P. infestans and to establish whether the resistance of both diseases is correlated to perform a combined selection of the best materials in a Solanum phureja population. This research took place in two farms near to La Unión (Antioquia, Colombia). The plants were evaluated for severity of the powdery scab in roots and severity of the late blight in leaves, using a diagrammatic scale. The heritability depended on the population and unit selection used. Heritability was tested with different methods, between families, within families and using, stratified mass and simple mass selection. For Spongospora subterranea f. sp. subterranea case there were not statistically significant differences among the heritability from the different selection methods or the different locations, the estimates of the heritability were between 0.29 and 0.11. For P. infestans no statistically significant differences among the heritability from the different selection methods were found, but there were significant differences between the different locations. The estimates of the heritability for La Cabaña were between 0.35 and 0.54 and, for San Juan between 0.05 and 0.08. There wasn´t phenotypic, familiar or individual correlation for the resistance characteristic between the two diseases. Independent levels strategy allowed finding the best genotypes with resistance to S. subterranean f. sp. subterranea and P. infestans.

Abstrac: Powdery scab and late blight are the most important and destructive diseases in potato in Colombia. These diseases are caused by the pathogens Spongospora subterranea f. sp. subterranea and Phytophthora infestans. Plant resistant breeding is an important tool for an integrated disease management for both pathogens. In Solanum phureja species resistance genes for Powdery scab and late blight are found. The objective of this study was to determinee the resistance heritability to S.subterranea f. sp. subterranea and P. infestans and to establish whether the resistance of both diseases is correlated to perform a combined selection of the best materials in a Solanum phureja population. This research took place in two farms near to La Unión (Antioquia, Colombia). The plants were evaluated for severity of the powdery scab in roots and severity of the late blight in leaves, using a diagrammatic scale. The heritability depended on the population and unit selection used. Heritability was tested with different methods, between families, within families and using, stratified mass and simple mass selection. For Spongospora subterranea f. sp. subterranea case there were not statistically significant differences among the heritability from the different selection methods or the different locations, the estimates of the heritability were between 0.29 and 0.11. For P. infestans no statistically significant differences among the heritability from the different selection methods were found, but there were significant differences between the different locations. The estimates of the heritability for La Cabaña were between 0.35 and 0.54 and, for San Juan between 0.05 and 0.08. There wasn´t phenotypic, familiar or individual correlation for the resistance characteristic between the two diseases. Independent levels strategy allowed finding the best genotypes with resistance to S. subterranean f. sp. subterranea and P. infestans.