Controle de pragas na cultura do feijão (Phaseolus vulgaris L.) e avaliação econômica

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Cluster and meta-analyses of genetic parameters for feed intake traits in growing beef cattle

A data set based on 50 studies including feed intake and utilization traits was used to perform a meta-analysis to obtain pooled estimates using the variance between studies of genetic parameters for average daily gain (ADG); residual feed intake (RFI); metabolic body weight (MBW); feed conversion ratio (FCR); and daily dry matter intake (DMI) in beef cattle. The total data set included 128 heritability and 122 genetic correlation estimates published in the literature from 1961 to 2012. The meta-analysis was performed using a random effects model where the restricted maximum likelihood estimator was used to evaluate variances among clusters. Also, a meta-analysis using the method of cluster analysis was used to group the heritability estimates. Two clusters were obtained for each trait by different variables. It was observed, for all traits, that the heterogeneity of variance was significant between clusters and studies for genetic correlation estimates. The pooled estimates, adding the variance between clusters, for direct heritability estimates for ADG, DMI, RFI, MBW and FCR were 0.32 +/- 0.04, 0.39 +/- 0.03, 0.31 +/- 0.02, 0.31 +/- 0.03 and 0.26 +/- 0.03, respectively. Pooled genetic correlation estimates ranged from -0.15 to 0.67 among ADG, DMI, RFI, MBW and FCR. These pooled estimates of genetic parameters could be used to solve genetic prediction equations in populations where data is insufficient for variance component estimation. Cluster analysis is recommended as a statistical procedure to combine results from different studies to account for heterogeneity.

Replacement of dicalcium phosphate by rock phosphate in cattle diets: nutrients digestibility, plasma parameters, ruminal fermentation and microbial synthesis efficiency

Este estudo foi conduzido para avaliar os efeitos da substituição do fosfato bicálcico pelo fosfato de rocha na dieta de bovinos em crescimento. Foram determinados a digestibilidade aparente das dietas, a absorção aparente do fósforo, cálcio e flúor, o pH ruminal, a concentração de amônia ruminal, a eficiência microbiana e o fósforo no plasma utilizando-se cinco bovinos da raça Holandesa Preto-e-Branco, fistulados, pesando entre 275 e 283 kg. O delineamento estatístico foi um quadrado latino 5 × 5 e as dietas consistiram de 0, 25, 50, 75 e 100% de substituição do fosfato bicálcico pelo fosfato de rocha no suplemento mineral. A adição de fosfato de rocha nas dietas ocasionou aumento linear na ingestão, no fluxo omasal, no fluxo fecal e no desaparecimento total do flúor. As dietas não diferiram quanto à absorção aparente do cálcio, assim como em relação à ingestão, excreção, digestão e digestibilidades aparentes parcial e total da matéria seca, matéria orgânica, proteína bruta, fibra em detergente neutro e carboidratos não-fibrosos. O fósforo no plasma não foi influenciado pelos tratamentos e a média foi de 5,93 mg/dL. Não houve diferença para o pH ruminal e concentração de amônia ruminal. A substituição do fosfato bicálcico não afetou a síntese microbiana aparente e verdadeira de proteína. A total substituição do fosfato bicálcico pelo fosfato de rocha em suplementos minerais em bovinos em crescimento não afetou o ambiente ruminal e a síntese de proteína no rúmen. Assim, a substituição do fosfato bicálcico em dietas para bovinos em crescimento diminui a absorção de fósforo e deveria ser vista com cuidado dependendo dos requerimentos.

Genetic variation in growth traits and yield of rubber trees (Hevea brasiliensis) growing in the Brazilian state of São Paulo

Analysis of variance and covariance was preformed on growth traits (stem girth, bark thickness, total height gain and rubber yield) of 22 open-pollinated progenies of the rubber tree Hevea brasiliensis from an Asian Hevea collection introduced to Agronomic Institute (Instituto Agronômico, Campinas, São Paulo, Brazil; IAC) in 1952. This progeny trial was replicated at three sites in São Paulo state and it was found that at three years from sowing there was statistically significant variation for girth, bark thickness, height and rubber yield. An individual test sites, values of individual plant heritability for girth ranged from ĥ i 2 = 0.36 to ĥ i 2 = 0.89 whereas values for heritability for progeny means ranged from ĥ i 2 = 0.77 to ĥ i 2 = 0.87. These moderate and high heritabilities suggest that a combination of progeny and within-progeny selection would be effective at increasing girth in this population at individual sites. Across sites, values of individual-plant heritability for girth ranged from ĥ i 2 = 0.36 to ĥ i 2 = 0.47, whereas values for heritability of progeny means girth ranged from ĥ x̄ 2 = 0.77 to ĥ x̄ 2 = 0.87. There were high positive genetic correlations between increased girth and bark thickness suggesting that breeding aimed at increasing girth would also increase bark thickness and possibly height. Copyright by the Brazilian Society of Genetics.

Indicators of soil degradation in urban forests: Physical and chemical parameters

The fragmentation of forest habitats in urban areas has aroused increasing interest in recent years according to the growing environmental problems. The fragmentation of theses ecosystems is caused, in general, by the pressure of housing, agriculture and industry, causing losses in biodiversity and problems of soil degradation in the border areas of theses remnants. The establishment of indicators of soil degradation becomes essential for the implementation of conservation and reclamation. This study analyzes physical and chemical characteristics of soil under different forms of vegetation in the forest surrounding the Quilombo Forest, located in Campinas/SP - Brazil, and examines the possibility of using these indices as indicators of environmental degradation in urban remnants. The parameters analyzed were: specific weight natural (γn), specific weight of solids (γs) Ca, P, K, Mg, pH, organic matter, H + Al, Sum of Base (SB) Percent Base Saturation (V%), Cation Exchange Capacity (CEC). The study shows that in general the different forms of land used in the study area significantly changed (or according to) the physical aspects of soil The porosity and voids of the soil stood out as the best indicators of soil physical degradation in the layer 0-20 cm deep. In relation to chemical indices, the soil under the cultivation of cane sugar had a significantly higher pH, K, Ca, Mg and sum of bases. The areas of forest showed higher levels of phosphorus, organic matter and CEC, indicating the importance of maintaining vegetation and replacement for the cycling of organic matter.