Selection in early generations and the occurrence of heterosis for the character root distribution

Crops of bean are sensible to climate changes, especially water stress. One way to minimize this instability is through genetic breeding of root system character. Thus, the objective of this study was to identify genotypes with superior root system in the first segregating generation at three depths in the soil profile and also verify the occurrence of heterosis for the root system character. Evaluations were performed using the method of Bohm (Methods studying root systems. Springer, Berlin 1979) at three different depths (0–10, 10–20 and 20–30 cm), in the experimental area of the Institute of Molecular Genetics and Breeding, at the State University of Santa Catarina UDESC Lages-SC. Twelve segregating populations and four parents (BAF 09, BAF 07, BAF 50 and IPR Uirapuru) were assessed by comparison. The favorable genotypes to the progress of generations are: two, seven and three for depths up to 20 cm and three for depths up to 30 cm. The cross between the parents BAF 07 (black group) and BAF 50 (carioca group) presented wide genetic divergence, providing significant increase in the root system revealed by the analysis of their progenies. The selection of superior genotypes in the layer of 20–30 cm was limited because most genotypes have similar and poorly distribution. Due to the strong effect of the dominance component, heterosis occurred for root distribution in early generation. This fact may interfere in the selection of autogamous species of bean related to this genetic character.     

Replacement levels of elephant grass by moist pineapple by-product silage in diets of Santa Inês crossbred sheep: performance and digestibility

The present study evaluated the effect of replacing elephant grass (EG) with moist pineapple by-product silage (PS) on the apparent digestibility, consumption of digestible nutrients and performance of 25 castrated male lambs Santa Ines crossbreds. The lambs had an initial body weight of 20.2?±?3.5 kg and were housed in individual pens in a completely randomised design with five treatments (replacement of EG by PS at five proportions of 0, 25, 50, 75 and 100 %) and five replicates during 74 days. There was no significant effect of PS replacement proportions on the intake of dry matter (DM), organic matter (OM), total carbohydrates (TC), non-fibrous carbohydrates or total digestible nutrients (TDN). The consumption of crude protein (CP) decreased linearly with the inclusion of PS in the diets. The digestibility of DM, OM and TCs as well as levels of TDN increased linearly with the addition of PS. The use of PS in the diets had no significant effect on the digestibility of CP and neutral detergent fibre corrected for ashes and protein (NDFom(n)). These results demonstrated that there was no difference in the performance of animals fed diets with or without PS.     

Multivariate analysis of CPMAS 13C-NMR spectra of soils and humic matter as a tool to evaluate organic carbon quality in natural systems

A series of humic and fulvic acids isolated from different sources, size‐fractions separated from a humic acid, and three soils of different origin were subjected to CPMAS ¹³C‐NMR spectroscopy to obtain the distribution of their carbon contents. The relative areas of chemical shift regions in NMR spectra were used to apply a principal component analysis (PCA) to the three sets of samples. The multivariate analysis was successful in efficiently differentiating samples on the basis of the quality of their organic carbon content. The PC biplots based on two principal components distinguished objectively among samples as accurately as it was possible to do by subjective qualitative evaluation of the original spectra. In the case of the soils, a discriminant analysis (DA) was applied to build a classification model that allowed the validation of the three soils according to their origin. Percentage of validation in the classification model is expected to increase when a large number of NMR spectra are accumulated and/or the concentration of organic carbon in samples is enhanced. The multivariate analyses described are likely to become a useful tool to increase the importance of CPMAS ¹³C‐NMR spectra in the appraisal of natural organic matter variations in heterogeneous natural systems.     

Biology of Thaumastocoris peregrinus in different eucalyptus species and hybrids

The bronze bug Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae), originating in Australia, has been rapidly spreading in eucalyptus plantations in the Southern Hemisphere, including South Africa, Zimbabwe, Argentina, Uruguay, Paraguay and Chile. In Brazil, it was detected in 2008 in the states of Sao Paulo and Rio Grande do Sul. Due to incomplete knowledge about the biology of this pest, the present study evaluated the bioecology of T. peregrinus in different eucalyptus species and hybrids. The genetic materials utilized were: Eucalyptus camaldulensis, E. urophylla, E. grandis, ??1277?? (Hybrid E. grandis x camaldulensis??HGC), ??VM-1?? (Hybrid E. urophylla x camaldulensis??HUC) and ??H-13?? (Hybrid E. urophylla x grandis??HUG). The experiment was conducted in a climate-controlled chamber at a temperature of 26?±?1°C, r.h. = 70%?±?10% and 12?h photophase. The biology of different genotypes indicated that the species E. urophylla and E. grandis are the most suitable for the development and reproduction of T. peregrinus, although all treatments enabled the bronze bug to develop and produce descendants. T. peregrinus developed and reproduced in the principal vegetal materials planted in the southern, central-west and northeastern regions of Brazil, constituting a potentially damaging insect pest to eucalyptus plantations.     

Preslaughter Anesthesia with Lippia alba Essential Oil Delays the Spoilage of Chilled Rhamdia quelen

This study evaluated whether anesthesia with essential oil (EO) of Lippia alba (300 mg L^?1 for 4 min) prior to electronarcosis (128 V m^?1 × 300 Hz for 5 s) or hypothermia (ice/water slurry) could delay fish spoilage during chilled storage of whole fish. Silver catfish (Rhamdia quelen) were subjected to two different pre-stunning treatments (water or anesthesia with EO of L. alba) followed by two different stunning procedures (hypothermia or electrical stunning), yielding four groups (n = 32/group): water (control) + hypothermia, water (control) + electrical stunning, EO of L. alba + hypothermia, and EO of L. alba + electrical stunning. After stunning, fish were slaughtered by percussion and stored in ice. Preslaughter anesthesia with the EO of L. alba extended fish shelf life by delaying the loss of freshness (nucleotide degradation), growth of Enterobacteriaceae, and fish deterioration (sensory evaluation). Such preservative effect was most remarkable for fish that were subsequently submitted to electrical stunning, as they had the lowest demerit scores and greatest shelf life in the sensory evaluation. Our results showed that preslaughter anesthesia with EO of L. alba followed by electrical stunning can delay the loss of freshness and extend fish shelf life during chilled storage.     

Effects of monensin on growth performance of beef heifers consuming warm-season perennial grass and supplemented with sugarcane molasses

Tropical Animal Health and Production - The objective of this study was to evaluate the effects of monensin on performance of beef heifers fed warm-season forages. Brangus heifers...