Absorption, distribution and accumulation of nitrogen applied at different phenological stages in southern highbush blueberry (Vaccinium corymbosum interspecific hybrid)

Southern highbush blueberry has an early harvesting and then a long period of vegetative growth until dormancy, compared to highbush and rabbiteye blueberries. Nitrogen requirements could be different because of this specific early harvesting. Absorption of 15N enriched ammonium sulfate was compared at five phenological stages from bud swell to pre-dormancy in two years old plants of the cultivars Star and ÓNeal. Plants grown in pots were irrigated with ammonium sulfate solution (15N). Five plants for each application date were excavated and separated in parts (roots, canes, leaves, flowers, fruits or floral buds). Samples were taken three weeks after application from bud swell to pre-harvest treatment, and three month after for post-harvest and pre-dormancy treatment. Each tissue were dried and weighed before and after, and analyzed for 15N content, N content and N %….N%, and in leaves were also determined macro and micro nutrients. Nitrogen fertilization at bud swell is effective, even for the ÓNeal cultivarthat present floral bud break in absence of leaves. Post-harvest fertilization contribute N for summer vegetativegrowth which would influence the floral buds development next year, Nitrogenstorage at this time would led to the improved floral behavior next year. Nitrogen losses risk is lower at post-harvestfertilization.Fil: Pescie, María A.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Borda, Marcela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Ortiz, Daniela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Landriscini, María Rosa. Universidad Nacional del Sur. Departamento de Agronomía. Área Suelos y Aguas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin

Inoculation with <i>Oidiodendron maius</i> BP Improves Nitrogen Absorption from Fertilizer and Growth of <i>Vaccinium corymbosum</i> during the Early Nursery Stage

Blueberry roots are inefficient in taking up water and nutrients, a fact partially related to their scarcity of root hairs, but they improve nutrient uptake by associating with ericoid mycorrhizal and endophytic fungi. However, the benefits of this association are both cultivar- and fungus-dependent. Our objective was to assess the effect of inoculation with three native fungal strains (Oidiodendron maius A, O. maius BP, and Acanthomyces lecanii BC) on plantlet growth, plantlet survival, and nitrogen (N) absorption of the southern highbush blueberry (SHB) cultivars Biloxi and Misty. The fungal strains were inoculated into the peat-based substrate for growing blueberry cultivars, and plantlets produced by micropropagation were transplanted and grown for four months. The three inoculated strains positively affected the survival percentage in at least one of the cultivars tested, whereas O. maius BP positively affected plant biomass, N derived from fertilizer absorption, N content, and plant N recovery (%) in both Biloxi and Misty. Our results show that the O. maius BP strain may prove useful as a bio-inoculant to improve blueberry production during the nursery stage

Endophytic fungi in blueberry cultivars, in three production areas of Argentina

Blueberries develop a shallow and fibrous root system, with sparse root hairs, normally colonized by mycorrhizal fungi. The presence of endophytic fungi in blueberry roots has been studied mainly in the area of origin of each species. The aims of the present study were to determine the occurrence of endophytic fungi in the roots of southern highbush blueberry (SHB) cultivars, in the three most important blueberry production areas of Argentina, and identify them. Soil samples with blueberry rootlets were obtained and endophytic fungi were isolated from them. Some of them by classical taxonomy identification, and, when this was not possible, PCR amplified material were sequenced (Macrogen laboratory), DNA fragments were analyzed with the Basic Local Alignment Search Tool (BLAST) and identified, through GenBank. Blueberry roots were found to be colonized by a large number of fungal genera, which varied greatly among locations and cultivars. Some of the endophytic fungi identified have pathogenic function, others are only plant hosts, and some of them have mycorrhizal function as is the case of genus Oidiodendron where we found O. maius and O. echinulatum. We may conclude that SHB is associated with local ericoid fungi, some of which are mycorrhizal and some dark septate endophytes, which, in most cases, do not match with those found in production regions of their native area, but same of them are important to promote blueberry growth.Fil: Pescie, María A.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Fradkin, Maia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación en Producción Agropecuaria Ambiente y Salud. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigación en Producción Agropecuaria Ambiente y Salud; ArgentinaFil: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Chiocchio, Viviana Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin