Colibri Colección : Reúne artículos de publicaciones periódicas en donde por lo menos uno de sus autores pertenece a la Facultad de Agronomía.

Short-term effectiveness of Ulex europaeus control measures in Uruguay

Wed, 01 Jan 2025 00:00:00 GMT

Título: Short-term effectiveness of Ulex europaeus control measures in Uruguay Autor: Bresciano, Daniella; Borges, Alejandra; Olano Ibarra, Rodrigo Agustín; Santiago, Fernanda de; Pérez Güida, Lucía; Munka, Carolina Editor: Enloe, Stephen F. Resumen: Gorse (Ulex europaeus L.) is a leguminous shrub native to western Europe, voluntarily introduced into Uruguay for ornamental purposes. It is considered among the 100 most problematic invasive species in the world. In Uruguay, it seriously affects both livestock and forestry systems. We evaluated different weed management techniques on a cattle farm invaded by U. europaeus, in the region of Lavalleja. In spring 2020, three treatments were applied— cutting only (C); cutting and grazing (CG); and cutting, applying herbicide, and grazing (CHG)—to 18 plots ranging from 25 m2 to 50 m2. Following treatment, U. europaeus regrowth and the height and the perimeter of five plants per plot, as well as seedling recruitment, were assessed over 16 mo. The livestock were cattle (Bos sp.) and sheep (Ovis sp.). The CHG treatment was the most effective in inhibiting the regrowth of U. europaeus, while grazed plants grew less in height compared with those excluded from grazing (CG = 62.3 cm ± 1.9, C = 84.8 cm ± 2.0, P < 0.05). However, by the end of the study, seedling recruitment was lower in the C treatment (C = 0.3 ± 0.3, CG = 3.1 ± 1.8, CHG = 8.6 ± 4.6 seedlings m−2, P< 0.05), where increased height of herbaceous vegetation may have reduced the success of the emergence and establishment of regenerants. These results encourage further long-term study of this invasive species’ response, as well as an evaluation of the potential impacts of these control measures on non-target species.

Development of nuclear microsatellite markers in Yerba mate (Ilex paraguariensis A. St. Hil.) from whole-genome sequence data

Sun, 01 Jan 2023 00:00:00 GMT

Título: Development of nuclear microsatellite markers in Yerba mate (Ilex paraguariensis A. St. Hil.) from whole-genome sequence data Autor: Tassano Sabino, Carolina; Olano Ibarra, Rodrigo Agustín; Gaiero Guadagna, Paola; Vaio Scvortzoff, Magdalena; Speranza Gastaldi, Pablo Rafael Resumen: Ilex paraguariensis A. St.-Hil. ( yerba mate) (Aquifoliaceae Bercht. & J. Presl) is a plant species with great economic and cultural importance because its leaves are processed and ground to make infusions like mate or tereré. The species is distributed in a continuous area that includes Southern Brazil, and part of Paraguay and Argentina. Uruguay represents the Southern distribution limit of the species, where small populations can be found as part of ravine forests. Although there are previous reports of molecular markers for this and other species in the genus, the available markers were not informative enough to represent the intra and interpopulation genetic diversity in marginal Uruguayan populations. In this study, we developed highly informative nuclear polymorphic microsatellite markers to be applied in genetic studies in I. paraguariensis. Markers were identified in contigs from the genome sequence of two individuals and then tested for amplification and polymorphism content in a diverse panel. Markers which passed these filters were tested on populations from Uruguay. They detected higher diversity within populations (in terms of number of alleles and heterozygosity) than previously reported, and levels of heterozygosity similar to those reported for two Brazilian populations. This subset of seven markers were successfully multiplexed, substantially reducing the costs of the analysis. Combined with previously reported nuclear and plastid markers, they can be used to evaluate the genetic diversity of rear-edge populations, identify genotypes for paternity studies and provide relevant information for the conservation and management of germplasm.

Explaining how diversified crop rotation systems reduce soybean yield gap : the case of Uruguay

Wed, 01 Jan 2025 00:00:00 GMT

Título: Explaining how diversified crop rotation systems reduce soybean yield gap : the case of Uruguay Autor: Álvarez Durán, Santiago; Ernst, Oswaldo Resumen: The increase in cultivated area in Uruguay’s main cropping systems (CS) has been achieved through a shift from crop-pasture rotation systems to continuous annual cropping systems with a high frequency of soybean. Evidence suggests eliminating perennial pastures and reducing crop sequence diversification may gradually reduce soil quality, limiting the actual crop productivity and generating adverse environmental effects.

Field assessment of sequential herbicide mixtures on nitrogen cycle-related functions in soybean production

Wed, 01 Jan 2025 00:00:00 GMT

Título: Field assessment of sequential herbicide mixtures on nitrogen cycle-related functions in soybean production Autor: García Carriquiry, Isabel; Silva, Vera; Inchausti, Pablo; Trasante, Tania; Niell, Silvina; Azziz de los Santos, Julio Gastón; Berro Pizzarossa, A.; Saracho, W.; Fernández, Gabriela; Geissen, Violette Resumen: Herbicide applications worldwide generally intend to protect crop yields from weed interference while avoiding mechanical disturbance in the topsoil layer. Their intensive use often leads to cocktails of chemicals in soils, which may interfere with natural soil functions, and productivity. The effects of a sequence of herbicides typi cally used in soybean crops were tested on different endpoints related to the nitrogen cycle. The field experiment was repeated in 2020–2021 and 2021–2022, from fallow to harvest time of the soybean crop. The treatments were: a control without herbicides, a sequence of three herbicide applications at the label recommended rate, all the six possible combinations of the three herbicide applications, and a treatment with the typical, complete scheme but at twice the recommended rate. The first application was a mixture of glyphosate, dicamba, and clethodim; the second was a mixture of glyphosate, S-metolachlor, and flumioxazin, and the third herbicide application moment included fomesafen only. All the treatments remained weed-free, either by herbicides or manual removal. Significant negative effects were detected for nodulation in some treatments at the vegetative stage compared to the control, but no dose-dependent response was observed. Plant biomass and nodulation were not significantly related to herbicide mixtures at the reproductive stage, nor was the soybean yield at harvest time. These results engender a complex scenario for farmers to fully grasp the potential risks associated with the use of herbicides. However, potential nitrification was affected after the third herbicide application moment in the first year of the experiment, in all the treatments exposed to at least one herbicide application, while the abundance of ammonia oxidizers showed no effects. This comprehensive field assessment is relevant to evaluate herbicide environmental risks, accounting for plantmicrobiome interactions under real pedo-climatic conditions and stress factors.