Determinants of barley grain yield in a wide range of Mediterranean environments

Barley grain yield in rainfed Mediterranean regions can be largely influenced by terminal drought events. In this study the ecophysiological performance of the ‘Nure’ (winter) × ‘Tremois’ (spring) barley mapping population (118 Doubled Haploids, DHs) was evaluated in a multi-environment trial of eighteen site–year combinations across the Mediterranean Basin during two consecutive harvest years (2004 and 2005). Mean grain yield of sites ranged from 0.07 to 5.43 t ha⁻¹, clearly dependent upon both the total water input (rainfall plus irrigation) and the water stress index (WSI) accumulated during the growing season. All DHs were characterized for possessing molecular marker alleles tagging four genes that regulate barley cycle, i.e. Vrn-H1, Vrn-H2, Ppd-H2 and Eam6. Grain yield differences were initially interpreted in terms of mean differences between genotypes (G), environments (E), and for each combination of genotype and environment (GE) through a “full interaction” ANOVA model. Variance components estimates clearly showed the greater importance of GE over G, although both were much lower than E. Alternative linear and bilinear models of increasing complexity were used to describe GE. A linear model fitting allelic variation at the four genes explained genotype main effect and genotype × environment interaction much better than growth habit itself. Adaptation was primarily driven by the allelic constitution at three out of the four segregating major genes, i.e. Vrn-H1, Ppd-H2 and Eam6. In fact, the three genes together explained 47.2% of G and 26.3% of GE sum of squares. Grain yield performance was more determined by the number of grains per unit area than by the grain weight (phenotypic correlation across all genotypic values: r = 0.948 and 0.559, respectively). The inter-relationships among a series of characters defining grain yield and its components were also explored as a function of the length of the different barley developmental phases, i.e. vegetative, reproductive, and grain filling stages. In most environments, the best performing (adapted) genotypes were those with faster development until early occurrence of anthesis. This confirmed the crucial role of the period defining the number of grains per unit area in grain yield determination under Mediterranean environments.     

Effects of nitrogen and phosphorus fertilization on mycorrhizal formation of two poplar clones (Populus trichocarpa and P. tremula x tremuloides)

Mineral fertilization is a common management practice in short rotation forestry. The mycorrhizal formation of trees can be affected by fertilizer applications, however, very little is known on such effects in arable soils. The effects of a nitrogen (N) and phosphorus (P) fertilization on mycorrhizal formation of two poplar clones (Populus trichocarpa and P. tremula x tremuloides) were investigated at the plantation Abbachhof (South Germany). We determined the ectomycorrhizal colonization and the abundance of VAM spores in the soil during three years, and the species richness of sporocarps during one growing season. Approximately 26 to 73% of the fine roots of P. trichocarpa and 41 to 82% of the fine roots of P. tremula x tremuloides were colonized with ectomycorrhizal fungi. The percentage of ectomycorrizal colonization on P. tremula x tremuloides was significantly reduced after both fertilization treatments. On P. trichocarpa only the P‐fertilization reduced the ectomycorrhizal colonization. The composition of ectomycorrhizal morphotypes was significantly affected by the N and P fertilization on P. tremula x tremuloides, but not on P. trichocarpa. Sporocarps of 12 ectomycorrhizal fungi species were found at the plantation. Cortinarius uliginosus, Lactarius controversus and Krombholziella aurantiaca produced sporocarps only on control plots, whereas Cortinarius croceocaeruleus, Inocybe umbrina, Laccaria tortilis, Paxillus involutus and Rhizopogon roseolus produced sporocarps only on fertilized plots. Inocybe geophylla, I. glabripes, Laccaria laccata and Tuber borchii produced sporocarps on both control and fertilized plots. The density of VAM spores was lower in the rooting zone of Populus trichocarpa than under P. tremula x tremuloides. In an efficient management of these short rotation plantations mineral fertilizer applications must be low enough to avoid undesired suppressions of mycorrhizal formation.     

Nitric oxide emissions from black soil, northeastern China: A laboratory study revealing significantly lower rates than hitherto reported

Nitric oxide (NO) is an important component of biogeochemical cycling of nitrogen, produced via biologically mediated processes of nitrification and denitrification in soils. The production and consumption processes of NO in black soils are not fully understood. We established how moisture and temperature affect NO dynamics for black soil samples of maize land in the temperate zone of northeastern China. The optimum soil moisture for the maximum NO production and emission was determined to be 41% water-filled pore space (WFPS), based on laboratory experiments and modeling. For a given moisture, NO fluxes increased exponentially with soil temperature at any given soil moisture. The optimum soil moisture for the maximum NO emission was constant and independent of soil temperature. The NO consumption rate constant (k) in the studied soil (range 9.31 × 10⁻⁶-15.1 × 10⁻⁶ m³ kg⁻¹ s⁻¹) was in the middle of the range of similar k values published to date. The maximum NO emission potential for black soils at 25 °C and 15 °C were about 18.6 and 9.0 ng N m⁻² s⁻¹, respectively. Based on laboratory results and field monitoring data of soil water content and soil temperature, the average NO fluxes from black soils in the region were estimated to be 10.7 ng N m⁻² s⁻¹ for an entire plant growth period. NO emissions likely occur principally in July, associated with optimum soil moisture. The present study suggests that NO fluxes from black soil are much lower than the previous reports from cropland in southern parts of China.     

Fractal dimension and shape parameters of asexual Fusarium spores from selected species: Which species can be distinguished?

Journal of Plant Diseases and Protection - Fungi of the genus Fusarium are prominent plant pathogens producing various toxic secondary metabolites. Digital microscopic images were taken from the...     

Hierarchical genetic organization of human cortical surface area

Surface area of the cerebral cortex is a highly heritable trait, yet little is known about genetic influences on regional cortical differentiation in humans. Using a data-driven, fuzzy clustering technique with magnetic resonance imaging data from 406 twins, we parceled cortical surface area into genetic subdivisions, creating a human brain atlas based solely on genetically informative data. Boundaries of the genetic divisions corresponded largely to meaningful structural and functional regions; however, the divisions represented previously undescribed phenotypes different from conventional (non-genetically based) parcellation systems. The genetic organization of cortical area was hierarchical, modular, and predominantly bilaterally symmetric across hemispheres. We also found that the results were consistent with human-specific regions being subdivisions of previously described, genetically based lobar regionalization patterns.     

Network modeling of BVD transmission

ABSTRACT: Endemic diseases of cattle, such as bovine viral diarrhea, have significant impact on production efficiency of food of animal origin with consequences for animal welfare and climate change reduction targets. Many modeling studies focus on the local scale, examining the on-farm dynamics of this infectious disease. However, insight into prevalence and control across a network of farms ultimately requires a network level approach. Here, we implement understanding of infection dynamics, gained through these detailed on-farm modeling studies, to produce a national scale model of bovine viral diarrhea virus transmission. The complex disease epidemiology and on-farm dynamics are approximated using SIS dynamics with each farm treated as a single unit. Using a top down approach, we estimate on-farm parameters associated with contraction and subsequent clearance from infection at herd level. We examine possible control strategies associated with animal movements between farms and find measures targeted at a small number of high-movement farms efficient for rapid and sustained prevalence reduction.     

Global internet trade of plants – legality and risks

Internet trade of plants has been investigated in a short study that focused on plants for planting imported into Germany from third countries worldwide. Internet trade of plants may pose a high phytosanitary risk when commodities are infested with non‐native pests including quarantine pests. The offers of 1097 internet traders, in particular non‐European traders, have been checked. One hundred and seventeen consignments of plants were purchased from 70 different internet traders and investigated in detail. As only individual plants were purchased the study shows in particular what is available for purchase to private consumers. The study revealed that 89% of the consignments did not comply with phytosanitary import requirements for one or more reasons. In all these cases the phytosanitary certificate was missing and in 68% of the consignments the customs declaration was missing or wrong. Wrong customs declarations indicate that these internet traders ignored the import requirements or provided incorrect information to the import authorities. Prohibited plants could be easily bought via the internet. In addition, harmful organisms were found in 13% of the consignments and 2% of these were quarantine pests. All consignments that were accompanied by the required phytosanitary certificate issued by the National Plant Protection Organisation of the exporting country (11%) complied with the EU and German, respectively, import requirements.     

Flavonoids in horse chestnut (Aesculus hippocastanum) seeds and powdered waste water byproducts

Horse chestnut extracts are widely used in pharmacy and cosmetic industries. The main active constituents are saponins of oleane type, but seeds of horse chestnut also contain flavonoids, being glycosides of quercetin and kaempferol. Their contribution to the overall activity of the extracts was not clear. In the present work, the main flavonoids from horse chestnut seeds were isolated and their structures established with spectral methods. Seven glycosides were isolated, out of which six ( 2, 3, 4, 7, 11, 13) were previously reported and one ( 9) was identified as a new tamarixetin 3- O- [beta- d-glucopyranosyl(1-->3)]- O-beta- d-xylopyranosyl-(1-->2)- O-beta- d-glucopyranoside. The structures of three additional compounds 1, 10, and 12, not previously reported, were deduced on the basis of their LC-ESI/MS/MS fragmentation characteristics. A new ultraperformance liquid chromatographic (UPLC) method has been developed for profiling and quantitation of horse chestnut flavonoids. The method allowed good separation over 4.5 min. Thirteen compounds could be identified in the profile, out of which di- and triglycoisdes of quercetin and kaempferol were the dominant forms and their acylated forms occurred in just trace amounts. The total concentration of flavonoids in the powdered horse chestnut seed was 0.88% of dry matter. The alcohol extract contained 3.46%, and after purification on C18 solid phase, this concentration increased to 9.40% of dry matter. The flavonoid profile and their content were also measured in the horse chestnut wastewater obtained as byproduct in industrial processing of horse chestnut seeds. The total flavonoid concentration in the powder obtained after evaporation of water was 2.58%, while after purification on solid phase, this increased to 11.23% dry matter. It was concluded that flavonoids are present in a horse chestnut extract in a relatively high amount and have the potential to contribute to the overall activity of these extracts. Industrial horse chestnut wastewater can be used to obtain quercetine and kaempferol glycosides for cosmetic, nutraceutical, and food supplement industries.     

The use of Thymi Herba as feed additive (0.1%, 0.5%, 1.0%) in weanling piglets with assessment of the shedding of haemolysing E. coli and the detection of thymol in the blood plasma

Thymi Herba (Thymus vulgaris, rubbed) was given as feed additive to weanling piglets. 3 concentrations (0.1%, 0.5%, 1%) were tested against a control group. Rectal swabs were collected weekly and were sent in for bacterial testing. The shedding of haemolysing E. coli was evaluated. There was no significant difference in the shedding of haemolysing E. coli between the 4 groups. Neither was there a difference in the distribution of the various serotypes. Thymol was detected in the blood plasma in all thyme groups. The increase in thymol level with greater amounts of thyme herb was significant. Three days after withdrawal of the feed additive no thymol levels were detected. The study results did not reveal any effects on haemolysing E. coli in the gut.