Characterization of Pasteurella haemolytica strains isolated from goats in Hungary

Thirty-five Pasteurella haemolytica strains were isolated in Hungary from goat carcasses sent for postmortem examination from two farms with large goat flocks. All strains belonged to biotype A and with the exception of one strain of serotype A8 they belonged to serotype A2. No untypable strains were found by the indirect haemagglutination test.     

Natural hybridization between wheat (Triticum aestivum L.) and its wild relatives Aegilops geniculata Roth and Aegilops triuncialis L.

BACKGROUND

Cultivated bread wheat (Triticum aestivum L.) spontaneously hybridizes with wild/weedy related Aegilops populations, but little is known about the actual rates at which this hybridization occurs under field conditions. It is very important to provide reliable empirical data on this phenomenon in order to assess the potential crop–wild introgression, especially in the context of conducting risk assessments for the commercialization of genetically modified (GM) wheat, as gene flow from wheat to Aegilops species could transfer into the wild species genes coding for traits such as resistance to herbicides, insects, diseases or environmental stresses.

RESULTS

The spontaneous hybridization rates between wheat and A. geniculata and A. triuncialis, which are very abundant in the Mediterranean area, have been estimated for the first time in the northern part of the Meseta Central, the great central plateau which includes the largest area of wheat cultivation in Spain. Hybridization rates averaged 0.12% and 0.008% for A. geniculata and A. triuncialis, respectively. Hybrids were found in 26% of A. geniculata and 5% of A. triuncialis populations, at rates that can be ≤3.6% for A. geniculata and 0.24% for A. triuncialis.

CONCLUSION

The detection of Aegilops spp.–wheat hybrids in Aegilops populations indicates that gene flow can occur, although wheat is considered a crop with a low-to-medium risk for transgene escape. These data on field hybridization rates are essential for GM wheat risk assessment purposes. © 2023 Society of Chemical Industry.     

Application of an electronic nose to predict total volatile bases in capelin (Mallotus villosus) for fishmeal production

An electronic nose was used as a rapid technique to monitor changes in the headspace gas above capelin (Mallotus villosus) during storage at 0 and 5 degrees C. At both temperatures, refrigeration was compared with an ice/seawater cooling system. At 5 degrees C, the effect of added 0.2% acetic acid was also tested. Electronic nose measurements were compared to measurements of total volatile bases (TVB), gas chromatography of volatile compounds, and sensory analysis. TVB analysis indicated less spoilage in seawater/ice systems than in refrigeration, but the other measurements indicated more spoilage in the seawater system compared to refrigeration. The possibility of using only a few sensors in the electronic nose to predict TVB was studied using partial least squares regression and a saturated generalized linear model. The results reported herein indicate that rapid electronic nose measurements, which require no sample preparation, can be used to predict the TVB value of the raw material stored under different conditions.     

Technologies for the diagnosis and remediation of Fe deficiency

The objective of this paper is to review the developments in the last few years in two important issues related to Fe deficiency in plants. First, the current knowledge on the possible ways to carry out the diagnosis and prognosis of Fe deficiency in plants is discussed. This includes discussion on the best ways to carry out a meaningful analysis of Fe-containing compounds in different plant parts. We will also discuss other measurement techniques that can permit to assess the Fe nutritional status in plants, including leaf chlorophyll concentrations and others. Second, the new developments in management techniques to control and remediate iron deficiency are discussed. This includes possible improved ways to supply Fe compounds available to plants, both to the soil and to the irrigation water. We also discuss possible ways to supply directly the plant with Fe containing compounds, either to the foliage or to the stem. A particular emphasis is given throughout the paper to fruit tree crops growing in Mediterranean areas.     

Considering neighborhood effects improves individual dbh growth models for natural mixed-species forests in Mexico

Key message

More accurate diameter at breast height (dbh)-growth models are needed for developing management tools for mixed-species forests in Mexico. Individual distance-dependent dbh growth models that quantify local neighborhood effects have been developed for four species groups in such forests. The performance of the models is improved by distinguishing between inter- and intraspecific group competitions.

Context

The management of mixed-species forests in the northwest of Durango, Mexico, is mainly based on the selection method. Understanding the interspecific and intraspecific competition is critical to developing management tools for such mixed-species forests.

Aims

An individual-based distance-dependent modeling approach was used to model the growth of dbh and to evaluate neighborhood effects for four species groups in Mexican mixed-species stands.

Methods

Twenty-two species were classified into four groups: Pinus (seven species), other conifers (three species), other broadleaves (four species), and Quercus (eight species). Four methods were used to select neighboring trees and 12 competition indices (CIs) were calculated. Comparisons of the neighboring trees selection methods and CIs and tests of assumptions about neighborhood effects were conducted.

Results

Intra-species-group competition significantly reduced diameter growth for all species groups, except for the Quercus group. The Pinus, other conifers, and Quercus groups had significant and negative neighborhood effects on the other broadleaves species group, and not vice versa. The Quercus group also had negative neighborhood effect on the Pinus and other conifers species groups, and not vice versa. The Pinus and other conifers species groups had negative neighborhood effects on each other. All fitted age-independent dbh growth models showed a good of fit to the data (adjusted coefficient of determination larger than 0.977).

Conclusion

The growth models can be used to predict dbh growth for species groups and competition in mixed-species stand from Durango, Mexico.

     

An association between the kinship and fertility of human couples

Previous studies have reported that related human couples tend to produce more children than unrelated couples but have been unable to determine whether this difference is biological or stems from socioeconomic variables. Our results, drawn from all known couples of the Icelandic population born between 1800 and 1965, show a significant positive association between kinship and fertility, with the greatest reproductive success observed for couples related at the level of third and fourth cousins. Owing to the relative socioeconomic homogeneity of Icelanders, and the observation of highly significant differences in the fertility of couples separated by very fine intervals of kinship, we conclude that this association is likely to have a biological basis.     

Seasonal and temporal changes in species use of the landscape: how do they impact the inferences from multi-scale habitat modeling?

Context

Multi-scale approaches to habitat modeling have been shown to provide more accurate understanding and predictions of species-habitat associations. It remains however unexplored how spatial and temporal variations in habitat use may affect multi-scale habitat modeling.

Objectives

We aimed at assessing how seasonal and temporal differences in species habitat use and distribution impact operational scales, variable influence, habitat suitability spatial patterns, and performance of multi-scale models.

Methods

We evaluated the environmental factors driving brown bear habitat relationships in the Cantabrian Range (Spain) based on species presence records (ground observations) for the period 2000–2010, LiDAR data on forest structure, and seasonal estimates of foraging resources. We separately developed multi-scale habitat models for (i) each season (spring, summer, fall and winter) (ii) two sub-periods with different population status: 2000–2004 (with brown bear distribution restricted to the main population nuclei) and 2005–2010 (with expanding bear population and range); and (iii) the entire 2000–2010 period.

Results

Scales of effect remained considerably stable across seasonal and temporal variations, but not the influence of certain environmental variables. The predictive ability of multi-scale models was lower in the seasons or periods in which populations used larger areas and a broader variety of environmental conditions. Seasonal estimates of foraging resources, together with LiDAR data, appeared to improve the performance of multi-scale habitat models.

Conclusions

We highlight that the understanding of multi-scale behavioral responses of species to spatial patterns that continually shift over time may be essential to unravel habitat relationships and produce reliable estimates of species distributions.

     

Weeds,aphids, and specialist parasitoids and predators benefit differently from organic and conventional cropping of winter cereals

The aphid–natural enemy interaction in winter wheat fields constitutes a complex system that has been frequently studied because of its implication for biological control. However, not all of the aphids living in cereal fields are crop pests, as there are also aphids living on weeds that may serve as alternative hosts or prey for aphid parasitoids or predators. In this context, a concomitant survey of the plant and insect communities was conducted to understand how different plant communities affect the abundance and richness of aphids and the interactions with their natural enemies. The plant community was split into functional groups (grasses, legumes and forbs), and the aphid community was divided into feeding groups according to their host preferences (specialists in grasses or forbs). The grass aphids, which dominated the total aphid catches, responded positively to grass cover, which was particularly enhanced in the conventional fields. Conversely, the forb aphids, which mainly conditioned the total species richness of the aphids, were closely correlated with the local abundance of legumes. The system of cereal aphid-parasitoids was enhanced in the conventional fields, where the abundance of grasses was higher, whereas the legumes of the organic fields indirectly played a key role in enhancing the richness of the parasitoids and the abundance of predators. Our findings indicate that a bottom-up effect exists throughout the plant community, aphids, and aphidophagous insects and that plant community characteristics should be considered to better understand cereal aphid control.     

Analysis of a site x year experiment with timothy polycross progeny

Summary Results from a cooperative breeding programme with timothy for the northern areas of Scandinavia are presented. The main aim of the programme was to identify genotypes for synthetic populations that are high yielding, adapted over the whole area and stable over years. A polycross comprising 12 genotypes from each of five sites within the region was formed. The subsequent 60 half-sib families and four reference varieties were then compared under sward conditions at the same sites. The trials lasted for three years and results for total dry matter yields are presented.Significant differences in yield between lines were found. There were also significant two and three factor interactions between lines, sites and years. A new two-step procedure is presented to select the genotypes to make up a synthetic variety. Firstly, a superiority measure (Q-value) is used to select a group of genotypes that are high yielding and stable over sites and years. Secondly, the GxE part of the Q-value is split into two terms. One measures adaptation to predictable environmental conditions. The other one measures stability to unpredictable changes in the environment. A plot of these two measures provides a tool for discarding unstable or poorly adapted genotypes. The statistical properties of the selection parameters are discussed.     

Soil organic‐C accumulation and N availability under improved pastures established in Mediterranean oak woodlands

Long‐term effects of improved pasture establishment (with high proportion of legumes) on soil organic‐C status and N availability in Mediterranean cork oak (Quercus suber L.) woodlands were assessed. Soils were sampled beneath scattered crowns and in open areas, considering two systems: unmanaged and managed woodlands where improved pastures were installed 26 and 32 years ago. Total and labile C and N pools were measured and C and N mineralization were determined over 24 weeks laboratory incubation. Soils under improved pastures showed higher organic‐C, total‐N and net N mineralization than those under unmanaged pasture, mainly when established beneath trees. Potentially mineralizable C, C mineralization rate and microbial C were not statistically different between the unmanaged and improved pasture sites, but were higher closer to the tree than in the open area (1.8, 1.2 and 1.2 times, respectively). The qCO₂ was higher in improved pastures (1.7 times). Labile pool of C and N extracted with hot water increased under improved pasture (3.4 and 1.7 times, respectively). Results indicate that soil quality amelioration by improved pastures is stronger in the presence of oak trees. Management systems that favour oak tree maintenance and regeneration should be taken into account to reverse soil degradation.