Resumen: Ante el cambio climático, las especies pueden perder representación de su nicho en el biotopo, viéndose afectado el riesgo de extinción. Esta breve revisión de la literatura pretende establecer las bases del estado del conocimiento sobre riesgo de extinción en función al nicho climático. Esto permitirá formular futuros abordajes tales como predicciones de riesgo en base al nicho climático. Según la literatura, la amplitud del nicho y la posición relativa de sus componentes determinan el riesgo de extinción. Esta información puede complementar el conocimiento sobre el riesgo de extinción relacionado a la distribución geográfica. También se puede utilizar para planificar estrategias de conservación específicas para cada situación. Las características de los nichos climáticos pueden interactuar con factores externos (amenazas, competencia) e intrínsecos (área ocupada, dispersión), afectando el riesgo de extinción. Aún persisten vacíos de información sobre los nichos climáticos y limitaciones en sus métodos de estudio. La literatura existente se ha enfocado en vertebrados paleárticos y nichos realizados. Por último, se presenta un caso de estudio que ilustra diferencias entre los nichos climáticos realizados de especies de aves según su riesgo de extinción, mediante la comparación de estadísticas descriptivas. Estas confirman en parte lo que menciona la literatura, pero requieren mejoras para garantizar que proporcionen información veraz. En el futuro, sería interesante explorar estas estadísticas como predictores climáticos para conocer el estado de especies poco conocidas y entender mejor el riesgo de extinción, agregando la dimensión climática a las evaluaciones de riesgo.

Abstract: Species could lose part of their niche representation in the biotope due to climate change, potentially affecting extinction risk. This brief review of the literature aims to establish the basic aspects of our current knowledge concerning extinction risk related to climatic niches. This will enable the formulation of future approaches such as predictions of extinction risk based on the climatic niche. The literature indicates that niche width and relative position of niche components determine extinction risk. This information could complement our knowledge of extinction risk based on geographic distributions. It could also be used to plan specific conservation strategies for each situation. Climatic niche characteristics may interact with external factors (threats and competition) and intrinsic factors (occupied area and dispersal), affecting extinction risk. Information gaps about climatic niches persist as well as limitations of their study methods. Most studies have focused on paleartic vertebrates and realized niches. Finally, a case study is presented in which differences among bird realized climatic niches according to their extinction risk are illustrated by comparing descriptive statistics. These partially confirm what is mentioned in the literature but should be improved to guarantee that they provide accurate information. In the future, it would be interesting to explore these descriptive statistics as climatic predictors of conservation status for data deficient species and to gain a better understanding of extinction risk by adding the climatic dimension to risk evaluations.

Abstract Corn is one of the most important economic, social and cultural agricultural products in Paraguay, being the main ingredient of several typical foods. Due to the cross-pollination of this plant, it can be contaminated with transgenic maize pollen found in nearby fields. The general objective of this research was to evaluate the presence of transgenic sequences in corn grains marketed in the Departments of Itapúa, Alto Paraná and Canindeyú for the preparation of flour for human consumption. We studied 18 samples of corn kernels marketed for the preparation of flour from the Departments of Itapúa, Alto Paraná and Canindeyú. The DNA was extracted using the Trimethyl Ammonium Bromide (CTAB) protocol. For the detection of the transgenic sequences, the polymerase chain reaction (PCR) method was used. The bands were analyzed visually and using the ImageJ program. The results showed the presence of 5 positive samples for the P-35S-CaMv promoter and 5 samples for the T-nos terminator, none of them presented both sequences sought in the same construction; this indicates that 10 of 18 samples were contaminated with transgenic sequences. These findings show that transgenic products are available in Paraguayan local markets without consumers being aware of this situation.

RESUMO A fusariose do trigo, ou giberela, causada por um complexo de Fusarium spp., é uma importante doença no Paraguai. Dentre as estratégias utilizadas para o seu controle, a resistência genética é considerada altamente eficiente e de baixo custo. Objetivou-se avaliar e comparar o efeito de F. graminearum em seis genótipos de trigo, incluindo duas variedades testemunha, em duas datas de semeadura. Os genótipos foram inoculados artificialmente na espiga, por meio da injeção de um pool de quatro isolados patogênicos de F. graminearum, na fase de floração. O desenvolvimento da fusariose foi avaliado pela pontuação da incidência e severidade da doença, porcentagem de espiguetas doentes e grãos danificados, bem como pela área sob a curva de progresso da doença. Além da infecção de grãos, foi determinado o seu impacto no desenvolvimento de micotoxinas (deoxinivalenol) e sua interação com os genótipos. Os resultados identificaram uma linhagem avançada (Lin 84), com nível de resistência à fusariose comparável ao das fontes universalmente conhecidas de resistência (Sumai 3 e Frontana). Os outros três genótipos (Caninde 11, Caninde 12 e Caninde 21), apesar de apresentarem maior potencial de rendimento de grãos, foram avaliados como moderadamente suscetíveis a suscetíveis. Esses resultados sugerem que, embora seja possível transferir a resistência da fusariose do trigo para um tipo agronômico melhorado, combinar a resistência com um maior potencial de rendimento de grãos continua sendo um desafio contínuo.

ABSTRACT Fusarium head blight (FHB), or scab, caused by a Fusarium spp. complex, is an important wheat disease in Paraguay. Among the strategies used to control it, the genetic resistance is considered highly efficient and cost effective. This study aimed to evaluate and compare the effects of F. graminearum on six wheat genotypes, including two comparison varieties, in two seeding dates. The genotypes were artificially inoculated in the spike, at the flowering stage, by injecting a pool of four pathogenic F. graminearum isolates. The FHB development was evaluated by scoring the disease incidence and severity, percentage of diseased spikelets and damaged kernels, as well as using the area under the disease progress curve. Besides the kernel infection, its impact on the development of mycotoxins (deoxynivalenol) and interactions with the genotypes were also evaluated. The results identified an advanced breeding line (Lin 84) with a resistance level to FHB comparable to that of the universally known resistance sources (Sumai 3 and Frontana). The other three genotypes (Caninde 11, Caninde 12 and Caninde 21), in spite of presenting a higher grain yield potential, were evaluated as moderately susceptible to susceptible. These results suggest that, although it is possible to transfer the FHB resistance to a higher agronomic type, combining such resistance with a higher grain yield potential remains an ongoing challenge.

Abstract Wheat Blast disease is caused by the fungus Pyricularia oryzae pathotype Triticum. The disease has been endemic to tropical South American region for over 30 years until 2016, when it occurred in Bangladesh, opening the possibility of its expansion to other regions. Considering the limited availability of known sources of resistance in wheat and the synthetic hexaploid wheats are known to be a source of resistance to multiple type of stresses, the objective of this research was to evaluate a collection of synthetic hexaploid wheats for their resistance to Wheat Blast. The experiments were carried out in the Hernando Bertoni Research Center, Paraguayan Institute of Agricultural Technology, Paraguay. Test spikes were inoculated, concentration of 5.104 conidios.mL-1. The reaction was evaluated 15 days after inoculation and observed for next 15 days to calculate the disease-progress. Sixty-four synthetic hexaploid wheats, provided by the International Maize and Wheat Improvement Center, Mexico, were subjected to infections by isolate (P14ATae039) of P. oryzae, 18 materials were selected based on their maximum values of reaction, to be reevaluated with two different isolates P14ATae039 and P14YTae031. TS29, TS49 synthetic wheat were identified as new sources of resistance to wheat blast and TS73 wheat that is moderately susceptible, but of different genetic origin. To our best knowledge, this is the first report of synthetic hexaploid wheats selected as new sources of genetic resistance to wheat blast disease.

Resumen La enfermedad Brusone en trigo es causada por el hongo Pyricularia oryzae patotipo Triticum. Desde hace 30 años, esta enfermedad ha sido endémica de Sudamérica hasta su aparición en Bangladés en el año 2016, abriendo la posibilidad de su expansión a otras regiones. Considerando poca disponibilidad de las fuentes de resistencia conocida en trigo y conociendo la resistencia de los trigos sintéticos hexaploides (TSHs) a distintos tipos de estrés, el objetivo de este trabajo fue evaluar una colección por su resistencia a la Piricularia. Los ensayos fueron realizados en el Centro de Investigación Hernando Bertoni, Instituto Paraguayo de Tecnología Agraria, Paraguay. Las infecciones fueron realizadas en espigas, concentración 5.104 conidios.mL-1. La reacción se evaluó a los 15 días después de la inoculación y observada durante los próximos 15 días para calcular el avance de la enfermedad. Sesenta y cuatro TSHs proporcionados por el Centro Internacional de Mejoramiento de Maíz y Trigo, México, fueron sometidos a infecciones por un aislado (P14ATae039) de P. oryzae., donde 18 materiales fueron seleccionados por su valor máximo de reacción, para una reevaluación con dos aislados P14ATae039 y P14YTae031. Los trigos TS29, TS49 fueron identificados como nuevas fuentes de resistencia a Brusone, al igual que TS73 que es moderadamente susceptible, pero de distinto origen genético. Para nuestro conocimiento este es el primer reporte de selección de los trigos sintéticos hexaploides como nuevas fuentes de resistencia genética para Brusone de trigo.