catálogo para las regiones pampeana y delta del río parana

CATÁLOGO PARA LAS REGIONES PAMPEANA Y DELTA DEL RÍO PARANÁEl huerto semillero de plántulas, constituido por 93 individuos, mantiene el nivel de diversidad genéticade la población de mejoramiento, conservando el 99 % de los alelos originalmente presentes. La comparaciónde este huerto, respecto de un huerto construido solo en base a criterios fenotípicos, evidenció un decrecimientodel 20 % en el nivel de Similitud genética promedio y solo un 5 % de disminución en el ÍndiceFenotípico promedio. El huerto semillero clonal, integrado por 24 genotipos superiores no emparentados, tambiénmantiene el nivel de diversidad genética presente en la población de mejoramiento, a pesar de haberseestimado la pérdida de un 30 % de alelos raros (alelos con frecuencias menores al 5 %).La información generada por el empleo de marcadores moleculares le permitirá al mejorador disponer deotra herramienta de evaluación para la toma de decisiones a mediano y largo plazo, respecto de las estrategiasde mejora genética.PLAGAS EN PLANTACIONESREUNIONES446. Casaubón, E. (1); G. Cueto (2); K. Hodara (2); and A. González (1).Relations among the site, the plague (Platypus sulcatus Chapuis) and the trunk disease in acommercial plantation of Populus deltoides cv. Catfish-2 located in the low Delta of the Paranáriver (Argentina).XXI St Session International Poplar Commission – IPC 2000 – Poplar and Willow Culture: Meetingthe Needs of Society and the Environment. Portland, Oregon, USA. September 24-30.(1) Estación Experimental Agropecuaria Delta del Paraná, INTA, Campana, (Buenos Aires). ecasaubon@correo.inta.gov.ar(2) Departamento de Ciencias Biológicas. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Laboratorio104, 4º Piso, pabellón II, Ciudad Universitaria. (C1428EHA). Buenos Aires. khodara@bg.fcen.uba.arSUMMARYIn the Paraná delta area, poplar commercial plantations are placed in high lands and in low landssurrounded and protected by dams, occupying 14000 ha in the zone. The greatest wood volume is assigned tosawmills and veneering, and a less proportion of the volume is assigned to grinding. This work is aimed atstudying the relation between the plantation site quality with damages caused by “Taladro de los Forestales”(Platypus sulcatus Chapuis), and the relation with other diseases, such as cankers, which affect the trunk until 2m. high and reducing the wood quality and/or its quantity. The taladro is a small and cylindrical coleopterousappertaining to Platypodidae family. This insect burrows galleries within trunks affecting wood quality,decreasing its commercial value, and producing important volume loss in adult plantations when infected tressbreak with the wind effect. This is considered as the most important poplar pest in the region. We alsoanalyzed a disease incidence, which causes cracks in the poplar trunks and bark death. Consequently, thecommercial value of wood quality decreases and may promote volume loss due to the downfall of the infectedplants. We carried out the study in a 2 ha plantation of Populus deltoides cv. Catfish-2, which is the mostwidespread clone in the delta area. The plantation was 12 years old, the plants were placed at 3 x 4 mintervals, and a direct relation was found among the forest site, the pest and the disease. The taladro’s attackwas not at random because the most affected trees had greater diameter and height than those no infected,and they were placed in soil types of “albardón endicado”. These trees showed the most quantity of activeholes and cracks at galleries height, as a consequence of the wind effect. The percentage of infected plantsdue to this disease was greater in the best plantation site, probably because of physiological causes, although thepest affected to the plants with smaller diameters than the healthy ones. Low sites, typically from “bañados”protected by dams, presented lower volumetric yields, lower quantity of active holes, less plants broken by thewind at the height of galleries and less cracks in the trunks.- 169 -