RESUMO

Abstract Arbuscular mycorrhizae (AM) fungi play a crucial role in the growth of soybean; however, the planting system employed is thought to have an effect on AM fungal communities in the rhizosphere. This study was performed to explore the influence of continuous soybean cropping on the diversity of Arbuscular mycorrhizal (AM) fungi, and to identify the dominant AM fungus during the seedling stage. Three soybean cultivars were planted under two and three years continuous cropping, respectively. The diversity of AM fungi in the rhizosphere soil at the seedling stage was subsequently analyzed using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that an increase in cropping years improved the colonization rate of AM in all three soybean cultivars. Moreover, the dominant species were found to be Funneliformis mosseae and Glomus species. The results of cluster analysis further confirmed that the number of years of continuous cropping significantly affected the composition of rhizospheric AM fungal communities in different soybean cultivars.

Assuntos

RESUMO

Arbuscular mycorrhizae (AM) fungi play a crucial role in the growth of soybean; however, the planting system employed is thought to have an effect on AM fungal communities in the rhizosphere. This study was performed to explore the influence of continuous soybean cropping on the diversity of Arbuscular mycorrhizal (AM) fungi, and to identify the dominant AM fungus during the seedling stage. Three soybean cultivars were planted under two and three years continuous cropping, respectively. The diversity of AM fungi in the rhizosphere soil at the seedling stage was subsequently analyzed using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that an increase in cropping years improved the colonization rate of AM in all three soybean cultivars. Moreover, the dominant species were found to be Funneliformis mosseae and Glomus species. The results of cluster analysis further confirmed that the number of years of continuous cropping significantly affected the composition of rhizospheric AM fungal communities in different soybean cultivars.(AU)

RESUMO

Arbuscular mycorrhizae (AM) fungi play a crucial role in the growth of soybean; however, the planting system employed is thought to have an effect on AM fungal communities in the rhizosphere. This study was performed to explore the influence of continuous soybean cropping on the diversity of Arbuscular mycorrhizal (AM) fungi, and to identify the dominant AM fungus during the seedling stage. Three soybean cultivars were planted under two and three years continuous cropping, respectively. The diversity of AM fungi in the rhizosphere soil at the seedling stage was subsequently analyzed using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that an increase in cropping years improved the colonization rate of AM in all three soybean cultivars. Moreover, the dominant species were found to be Funneliformis mosseae and Glomus species. The results of cluster analysis further confirmed that the number of years of continuous cropping significantly affected the composition of rhizospheric AM fungal communities in different soybean cultivars.

Assuntos

RESUMO

Abstract Arbuscular mycorrhizae (AM) fungi play a crucial role in the growth of soybean; however, the planting system employed is thought to have an effect on AM fungal communities in the rhizosphere. This study was performed to explore the influence of continuous soybean cropping on the diversity of Arbuscular mycorrhizal (AM) fungi, and to identify the dominant AM fungus during the seedling stage. Three soybean cultivars were planted under two and three years continuous cropping, respectively. The diversity of AM fungi in the rhizosphere soil at the seedling stage was subsequently analyzed using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that an increase in cropping years improved the colonization rate of AM in all three soybean cultivars. Moreover, the dominant species were found to be Funneliformis mosseae and Glomus species. The results of cluster analysis further confirmed that the number of years of continuous cropping significantly affected the composition of rhizospheric AM fungal communities in different soybean cultivars.

RESUMO

Objetivo: Avaliar a relação entre variáveis meteorológicas e doenças respiratórias por faixa etária. Métodos: Trata-se de um estudo ecológico de séries temporais para o período compreendido entre 2008 e 2011. Primeiramente, as internações foram analisadas por grupo de faixa etária e, em seguida, relacionadas com informações climáticas, temperatura, precipitação, umidade relativa do ar e velocidade dos ventos, através da climatologia dinâmica e de parâmetros estatísticos, utilizando análise de regressão múltipla, teste qui-quadrado e distribuição normal. Resultados: Os resultados mostraram 12.067 registros de internações por doenças respiratórias e por faixa etária. As maiores médias de internação ocorreram na faixa etária de 1 a 4 anos, com média de 42,09%, (5.079) e acima de 60 anos, com média de 27,14% (3.274) para o período de estudo, sendo as pneumonias predominantes, com 81,0% (9.774) das internações. Verificou-se menor número de internações em janeiro e maior, em junho e julho. Conclusão: Com base nas investigações realizadas, observou-se correlação significativa entre os parâmetros climáticos e as internações por doenças respiratórias

Objective: To evaluate the relationship between the meteorological variables and respiratory diseases by age. Methods: This is an ecological time-series study, for the period comprised between 2008 and 2011. First, admissions were analyzed by age group and then related to climate information: temperature, precipitation, relative air humidity, and wind speed, through dynamic climatology and statistical parameters using multiple regression analysis, chi-square test and normal distribution. Results: The results showed 12,067 records of hospital admissions for respiratory diseases according to the age group. The highest average number of hospitalizations was found in the age range from 1 to 4 years, with a mean of 42.09% (5079), and over 60 years, with a mean of 27.14% (3274) for the study period. The highest prevalence was due to pneumonia, accounting for 81.0% (9,774) of admissions. The number of hospitalizations was lower in January and higher in June and July. Conclusion: Based on the investigations carried out, a significant correlation was observed between climate parameters and hospitalization for respiratory diseases.

Objetivo: Evaluar la relación entre variables meteorológicas y enfermedades respiratórias por franja de edad. Métodos: Se trata de un estudio ecológico de series temporales en el período entre 2008 y 2011. En primer lugar, los ingresos fueron analizados por franja de edad y, en seguida, relacionados con las informaciones climáticas, temperatura, precipitación, humidad relativa del aire y la velocidad de los vientos a través de la climatología dinâmica y parámetros estadísticos utilizándose del análisis de regresión múltiple, prueba del Chicuadrado y distribución normal. Resultados: Los resultados señalaron 12.067 registros deingresos por enfermedades respiratorias y franja de edad. Las mayores medias de ingreso se dieron en la franja de edad de 1 a 4 años con media del 42,09%, (5.079) y por encima de los 60 años con media del 27,14% (3.274) en el período del estudio, siendo las neumonías las más predominantes en el 81,0% (9.774) de los ingresos. Se verifico menos ingresos en enero y más en junio y julio. Conclusión: Basado en las investigaciones realizadas, se observó correlación significante entre los parámetros climáticos y los ingresos por enfermedades respiratorias.

Assuntos

RESUMO

Introgression of exotic maize (Zea mays L.) germplasm is an effective approach to broadening the genetic base of Chinese germplasm. America is the center of maize origin and germplasm diversity. By analyzing general combining ability effects and heterosis responses among maize populations from the U.S., International Maize and Wheat Improvement Center (CIMMYT), and Brazil studied by different authors, 24 elite maize populations from America region, including eight U.S. populations, eight CIMMYT populations, and eight Brazilian populations, were identified as having high potential in China. Based on adaptation improvement, we suggest to introgress BSSS(R)C10, BS10(FR)C14, BS13(S)C9, BSK(HI)C8 Syn 3, BR106, Pop44(C8), and Pop45(C3) into Chinese heterotic group A, and introgress BS11(FR)C14, BS16(S)C3 Syn 2, BS29(R)C3, BSCB1(R)C14, BR105, and Pop42(C4) into Chinese heterotic group B by forming semi-exotic populations or pools, respectively, in order to broaden the Chinese germplasm base.

Assuntos