Effects of the lack of forest management on spatiotemporal dynamics of a subalpine Pinus cembra forest

Knowledge about the stand structure and dynamics of subalpine forests is crucial to preserve their multifunctionality. In the present study, we reconstructed the spatiotemporal dynamics of a subalpine Pinus cembra forest in the eastern Italian Alps in response to natural disturbances and forest management. We adopted a concurrent point pattern, dendroecological and growth dominance (GD) analysis. We mapped and measured all trees of Pinus cembra and Larix decidua in a 1?ha plot. We analyzed intra- and interspecific spatial patterns and spatial autocorrelation of tree size and age. We explored establishment dynamics and shifts in competition by analyzing growth suppression/release patterns and GD trends. Results showed a clumped, uneven-aged, multilayered structure where pine was dominant. The synergic action of ecological and human-induced factors is discussed to explain the prevalence of pine over time. Spatial pattern and autocorrelation analyses suggest a different colonization strategy of the two species, in which pine established after small-scale perturbations and experienced a stronger inter- and intra-specific competition. The interruption of tree establishment and shift in GD toward large trees resulting from the lack of forest management are the most important findings of this research. This highlights the importance of an active management to avoid the homogenization of the forest structure that is generally associated with a reduction in biodiversity and protective ability of forests.     

Correction to: RNAi,what is its position in crop protection?

Journal of Pest Science - A correction to this paper has been published: https://doi.org/10.1007/s10340-021-01393-0     

Genetic gain and correlations among traits for stink bug resistance in soybeans

An experiment was carried out at the State University of Londrina School Farm in a randomized complete blocks design with three replications; the plots underwent natural stink bug attacks to check correlations existing among agronomic traits and stink bug damage in 33 F₈ pure lines soybean. The seed size trait was measured by the weight of a hundred seeds (WHS) and the percentage of stink bug damage seeds (PDS) was measured by staining the seeds with tetrazolium at 0.01%. Seeds were considered damaged with at least one puncture and or with marks characteristic of stink bug. The phenotypic and genotypic correlations between the WHS and the PDS seeds were positive, being 0.51 and 0.67 ± 0.19, respectively. The relationship between the visual pod width (VPW) and PDS was also significant, being 0.41 and 0.54 ± 0.19 for phenotypic and genotypic correlations, respectively. Thus the breeder can select lines for stink bug resistance indirectly either by WHS or VPW. These two traits are very easy to assess when compared with the assessment of PDS damage, allowing the use of larger populations. However, in this case, the genetic gains by selection were smaller than those obtained by direct selection, but even so they were considered noteworthy. The VPW may be an efficient way of selection in large populations for stink bug resistance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Prevalence and risk factors associated with swine gastrointestinal nematodes and coccidia in the semi-arid region of northeastern Brazil

Tropical Animal Health and Production - In northeastern Brazil, with has a predominantly dry climate, farmers seek alternative sources of income and livelihood by the rearing pigs. The...     

Soil organic matter and nutrient accumulation in areas under intensive management and swine manure application

Purpose

Land use change and soil management are frequently associated to land degradation and soil organic matter (SOM) losses in tropical regions. In Brazil, in order to avoid this process, different management strategies have been applied, such as no-tillage and agricultural disposal of swine manure (SM). This study was carried out to evaluate the quantity and quality of SOM, as well as the occurrence of nutrient accumulation in soils of areas under contrasting management systems that have received consecutive applications of SM over the last decades in Brazil.

Materials and methods

Five land uses were sampled: native vegetation (NV), pasture with SM application (PA + SM), no-tillage with SM application (NT + SM), no-tillage (NT), and conventional tillage with SM application (CT + SM). Soil organic carbon (SOC), N, labile C, C management index (CMI), P, Ca²⁺, Mg²⁺, K⁺, Al³⁺, Fe, Zn, Mn, Cu, and H + Al were quantified.

Results and discussion

Except for PA + SM, the agricultural land uses caused decreases in SOC contents comparing to NV. PA + SM showed the highest C stocks, 138.9?±?3.4 Mg ha^?1 down to 0.4 m. The application of SM can be associated to the greater C stocks in PA + SM, NT + SM, and CT + SM and to the higher N contents in all land uses under this practice. Land uses which receive higher rates of swine manure application (PA + SM and CT + SM) have shown CMI greater than 100. However, this practice is associated to the accumulation of P, Cu, Na, and Zn in these soils.

Conclusions

The SM application is associated to improvement on C stocks and SOM quality in area under pasture, no-tillage, and conventional tillage in Paraná State, Brazil. However, this practice is the main driver of nutrient accumulation in these areas.

     

Selection for feed efficiency does not change the selection for growth and carcass traits in Nellore cattle

The objectives were to conduct a genetic evaluation of residual feed intake (RFI) and residual feed intake adjusted for fat (RFIFat) and to analyse the effect of selection for these traits on growth, carcass and reproductive traits. Data from 945 Nellore bulls in seven feed efficiency tests in a feedlot were analysed. Genetic evaluation was performed using an animal model in which the feed efficiency test and age of the animal at the beginning of the test were considered as a systematic effect. Direct additive genetic and residual effects were considered as random effects. Correlations and genetic gains were estimated by two‐trait analysis between feed efficiency measures (RFI and RFIFat) and other traits. Feed conversion showed low heritability (0.06), but dry matter intake (DMI), average daily gain, RFI, RFIFat, metabolic body weight and scrotal circumference measured at 450 days of age (SC450) showed moderate to high heritability (0.49, 0.28, 0.33, 0.36, 0.38 and 0.80, respectively). Similarly, ribeye area, backfat thickness, rump cap fat thickness, marbling score and subcutaneous fat thickness also had high heritability values (0.46, 0.37, 0.57, 0.51 and 0.47, respectively). Genetic correlations between RFI and SC450 were null, and between RFIFat and SC450 were strongly positive. Genetic and phenotypic correlations of RFI and RFIFat with carcass traits were not different from zero, as correlated responses for carcass traits were also not different from zero. The Nellore selection for feed efficiency by RFI or RFIFat allows the recognition of feed efficient animals, with DMI reduction and without significant changes in growth and carcass traits. However, because of the observed results between RFIFat and SC450, selection of animals should be analysed with caution and a preselection for reproductive traits is necessary to avoid reproductive impairments in the herd.     

Effects of day length on flowering and yield production of Salicornia and Sarcocornia species

Salicornia is a new vegetable crop that can be irrigated with highly saline water, even at salt concentrations equivalent to full-strength seawater. During leafy vegetable cultivation, the onset of the reproductive phase is an undesired phenomenon that reduces yield and quality and prevents year-round cultivation. Knowledge about the regulation of floral induction in the members of the tribe Salicornieae, however, is lacking. To establish year-round cultivation, we studied the flower induction of five Salicornia and two Sarcocornia varieties. Plants were grown under two day lengths, 13.5 h and 18 h, and harvested by a repetitive harvest regime. A 13.5-h day length prevented flower induction in the Israeli Salicornia varieties, but a longer day length was required to prevent flower induction in two species originating from more northern latitudes. The onset of the reproductive phase under suboptimal short day length conditions severely reduced vegetative growth and yields in Salicornia. In Sarcocornia, the repetitive harvest regime prevented flowering, making it a promising candidate for year-round cultivation. Irrigating the plants with full-strength seawater (electrical conductivity 48 dS m⁻¹) vs. water with moderate salinity (electrical conductivity 10 dS m⁻¹) did not change the general flowering pattern of the studied Salicornieae members.     

Transmission of hypovirulence agents among some Cryphonectria parasitica strains from Italy

Six hypovirulent (H) strains of Cryphonectria parasitica collected in Italy were tested for dsRNA content, virulence, and conversion ability. Nine converts were also checked for dsRNA. In inoculation trials, H and converted (C) strains showed reduced pathogenicity. Most H and C strains were able to convert strains from various v-c groups. DsRNA banding patterns were similar in five of the H strains and in their converts, while the last one and its converts showed no evidence of dsRNA. The broad conversion ability of H strains seems to be responsible for the natural recovery of Italian chestnut trees.     

Delayed Lung Maturation of Foetus of Diabetic Mother Rats Develop with a Diminish,but Without Changes in the Proportion of Type I and II Pneumocytes,and Decreased Expression of Protein D‐Associated Surfactant Factor

Newborn children of diabetic mothers have an increased morbidity and mortality because of respiratory distress syndrome. We study lung histogenesis during intrauterine development of offspring of diabetic Sprague‐Dawley rats at 18, 19 and 21 days of gestation (DG). Pregnant rats were grouped into diabetic (streptozotocin‐induced), citrate, and control groups; five female and five male offspring were selected randomly from each group at 18, 19 and 21 DG, and a biopsy of the lung was taken and processed in paraffin for histological examination. The biopsy for the transmission electron microscopy (TEM) analysis was taken at 21 days. A delay in alveolization of the offspring at 18, 19 and 21 days of the diabetic group was observed, which was confirmed at TEM level, and also less quantity of protein D associated to surfactant in diabetic group was detected (P < 0.001). The foetuses of the diabetic group presented a delay in lung histogenesis and in differentiation of the type II pneumocytes cells, but conserved the proportion with a decrease in 50% of pneumocytes, accompanied by a diminish of protein D associated to surfactant factor.