Newly identified host range of European mountain ash ringspot‐associated virus (EMARaV) and its distribution in the Czech Republic

It has been previously shown that European mountain ash ringspot‐associated virus (EMARaV), a multipartite, negative‐strand RNA plant virus, is pathogenic for European mountain ash (Sorbus aucuparia L.). However, its transmissibility to and replication in other host species remains poorly understood. In this work, we performed experimental inoculations of seventeen virus‐tested species and interspecies hybrids of subfamily Maloideae (family: Rosaceae) with buds from EMARaV‐infected S. aucuparia trees. Surprisingly, a majority of the graft‐inoculated tree species, for instance Sorbaronia, Aronia and Amelanchier, developed symptoms typical for EMARaV infection. These symptoms included chlorotic spots of various size and shape and mottling on leaves but not on flowers and fruits. The propagation of EMARaV in graft‐inoculated tree species was subsequently confirmed by molecular detection tools. Based on these results, we carried out a systematic survey throughout the Czech Republic and identified the presence of EMARaV in wild growing trees in all explored regions, with massive disease infestation in several locations. More importantly, EMARaV infection was newly detected in S. aucuparia subsp. moravica, S. aucuparia × Crataegus sanguinea cv. Granatnaja, (Sorbus aria × Aronia arbutifolia) × S. aucuparia cv. Burka, cv. Finskaja (a Sorbus hybrid of unknown origin) and Aronia melanocarpa; all these EMARaV‐infested trees were grown in production orchards. The sequencing of the nucleocapsid (NC)‐coding gene from several of these EMARaV isolates provided insight into the population structure and phylogenetic relationships of the EMARaV variants occurring in the Czech Republic. Together, our biological and molecular findings extend our knowledge on the host range of EMARaV and provide the first evidence of its natural occurrence in hosts dissimilar to S. aucuparia.     

Looking backward to move forward: early detection of neurodegenerative disorders

Early detection of neurodegenerative disorders would provide clues to the underlying pathobiology of these diseases and would enable more effective diagnosis and treatment of patients. Recent advances in molecular neuroscience have begun to provide the tools to detect diseases like Alzheimer's disease, Parkinson's disease, and others early in their course and potentially even before the development of clinical manifestations of disease. These genetic, imaging, clinical, and biochemical tools are being validated in a number of studies. Early detection of these slowly progressive diseases offers the promise of presymptomatic diagnosis and, ultimately, of disease-modifying medications for use early in disease and during the presymptomatic period.     

Genetic diversity,phylogenetic position and morphometric analysis of Astacus colchicus (Decapoda,Astacidae): a new insight into Eastern European crayfish fauna

The phylogeny of European crayfish fauna, especially with respect to Eastern European species, is still far from being completely resolved. To fill this gap, we analyzed most of the European crayfish species focusing on the phylogenetic position of the endemic crayfish Astacus colchicus, inhabiting Georgia. Three mitochondrial and one nuclear marker were used to study evolutionary relationships among European crayfish species, resulting in the unique phylogenetic position of A. colchicus indicating independent species status to A. astacus. Phylogenetic analyses revealed a deep molecular divergence of A. colchicus in comparison to A. astacus (6.5–10.9% in mtDNA and 1.1% in nDNA) as well as to Pontastacus leptodactylus and P. pachypus (5.5–10.0% in mtDNA and 1.4–2.4% in nDNA). Absent ventral process on second male pleopod and abdominal somites II and III with pleura rounded lacking prominent spines clearly indicate taxonomic assignment to the genus Astacus; however, the species is distributed almost in the middle of Ponto-Caspian area typical by occurrence of the genus Pontastacus. Several morphological indices linked to head length, carapace, and total body length and width were found to demonstrate apparent differences between A. colchicus and A. astacus. Although this study provides a novel insight into European crayfish phylogeography, we also point out the gaps in comprehensive study of the P. leptodactylus species complex, which could reveal details about the potential species status of particular species and subspecies within this genus.     

A manually controlled TDR soil moisture meter operating with 300 ps rise-time needle pulse

Summary The principle of operation of a simple, manually controlled Time Domain Reflectometer (TDR meter) for soil moisture measurements, which operates with a needle pulse of 300 ps rise-time, is described. A block diagram and constructions are also given. Construction of a switchless multiple sensor probe, having an inherent delay reference, is presented. Results of measurements of the soil dielectric constant as related to water content, for soils having different bulk densities, textures and humus content show a high correlation. The results agree closely with other investigators measurements with different, more expensive, TDR instruments. The general principle of microprocessor-controlled TDR operated soil moisture meter is considered.Patent pending     

Barley yield response to irrigation and potential profits in the Texas High Plains

Summary Irrigated winter barley (Hordeum vulgare L.) can be a profitable alternative to some low profit major crops in the Texas High Plains. A six-year evaluation of yield response related to total spring irrigation water, applied by surface methods (furrow), and seasonal precipitation resulted in a multivariate function explaining 74% of the yield variation. Predicted yields varied from a low of 3.69 Mg ha^–1 to a maximum 6.18 Mg ha^–1 with 0 and 389 mm, respectively, based on average monthly precipitation quantities. Precipitation is skewed to less than average in th semi-arid Texas High Plains. Using modal precipitation amounts of 40% of average precipitation, yield estimates were reduced to 2.29 Mg ha^–1 with zero spring irrigation and to 5.63 Mg ha^–1 at the peak with 450 mm. A second multivariate yield response function related to alternative timings of single and multiple spring irrigations explained 76% of the variation in yields. Among all combinations of 1, 2, 3, and 4 spring irrigations, irrigation water-use efficiency was estimated to be highest with one application at the boot stage of development. All other single and combinations of multiple irrigations resulted in lower water-use efficiencies. A comparison of enterprise budgets of four irrigation timing alternatives and levels of application indicated highest profit over variable costs, $ 287 ha^–1, was attained by applying a total of 307 mm in three spring applications at the boot, head, and milk stages. A lower level of 217 mm applied at boot and milk stages was $ 12 ha^–1 less profitable and a higher level of 425 mm was $ 24 ha^–1 less profitable. When fixed costs of irrigation facilities, land, and machinery were considered, returns to management and risk were highest, $ 101 ha^–1, with 217 mm. Using 40% of average precipitation, profits were reduced $ 65 ha^–1 with 217 mm and $ 69 ha^–1 with 307 mm spring irrigation levels.Respectively, agricultural economist, research scientist, and research associate, Texas Agr. Exp. Station, Amarillo, Texas; Emeritus Extension agronomist, Texas Agr. Ext. Service, Amarillo, Texas; agricultural engineer, Texas Agr. Exp. Station, Amarillo, Texas     

Assessment of the impact of climate change on the latency period of leaf rust on triticale in Poland

ABSTRACT

Disease development in plants is strongly dependent on weather conditions, with temperature playing a particularly significant role by influencing latency period duration. Using two models describing the relationship between latency period and temperature, we performed simulations aimed at predicting changes in the latency period of leaf rust (Puccina recondita f. sp. tritici) on triticale in response to expected climate change. The simulations were based on meteorological data recorded in the period 1986–2005 at locations representing 16 provinces in Poland and based on values obtained after transformation of the observed data to reflect temperature changes under four scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) according to the giss_e2_r climate model. In all scenarios, the results for the two triticale cultivars studied, Witon (vulnerable to P. recondita) and Gniewko (less susceptible), showed a threat of faster development (shorter leaf rust latency period) on triticale triggered by climate change in south-east and south-central Poland than in other regions. The results also showed an increased probability of future regional diversification of leaf rust latency period duration on vulnerable triticale cultivars, opportunities for earlier start of leaf rust epidemics on triticale in Poland and an increase in ?nal disease severity in comparison with 1986–2005.     

Trace Metal Fluxes in a Sphagnum Peatland – Humic Lake System as a Consequence of Drainage

The study was conducted in a small (7.4 ha) peatland system with a humic lake concentrically surrounded by Sphagnum mat (Caricetum limosae) and Sphagnum bog (Ledo-Sphagnetum) in the Mazurian Lakeland in North-Eastern Poland. The peatland was situated in a forested catchment with a total area of 16.25 ha, and was influenced by surface drainage, artificially designed for forestry purposes. The content of zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu) and hydrogen (H) ions was analysed in waters from precipitation, humic lake, mat, bog and surface outflow. The yearly budget of these ions, expressed as difference between atmospheric inflow and surface outflow, for the whole catchment was presented. The drainage of the peatland system over three years was accompanied by an increase in pH of lake, mat and bog waters. The whole catchment retention of H⁺ and trace metals studied decreased yearly in absolute values under these conditions. The peatland system began to leach Pb into surface waters and lost its ability to intercept Cd. These effects could be caused by intensity of outflow of water and sulphates and lowering of water storage. However, the potential to retain Zn and Cu ions was preserved.     

Characterization of flowering time and SSR marker analysis of spring and winter type Brassica napus L. germplasm

Flowering dates and life forms of all available Brassica napus accessions conserved at the North Central Regional Plant Introduction Station (NCRPIS) were characterized, and a survey of molecular variation was conducted by using simple sequence repeats (SSR) in order to support better management of accessions with diverse life forms. To characterize flowering phenology, 598 B. napus accessions from the NCRPIS collection were planted in Iowa and Kansas field sites together with a current commercial cultivar and observed for days to flowering (first, 50% and 100% flowering) in 2003. Days from planting to 50% flowering ranged from 34 to 83 in Iowa and from 53 to 89 in Kansas. The mean accumulated growing degree days (GDD) to 50% flowering were 1,997 in Iowa, and 2,106 in Kansas. Between locations, the correlation in flowering time (r = 0.42) and the correlation in computed GDD (r = 0.40) were both significant. Differences in flowering-time rank were observed for several accessions. Accessions that failed to flower in Iowa in a single growing season comprised 28.5% of the accessions; of the flowering accessions, 100% plant flowering was not always achieved. Accessions were grouped according to flowering time. A stratified sample of 50 accessions was selected from these groups, including 10 non-flowering and 40 flowering accessions of diverse geographic origins and phenological variation. The flowering time observed in the sampled accessions when grown in the greenhouse were found to be significantly correlated to the flowering time observed in the field locations in Iowa (r = 0.79) and Kansas (r = 0.49). Thirty SSR markers, selected across 18 Brassica linkage groups from BrassicaDB, and 3 derived from Brassica expressed sequence tags (ESTs) were scored in the stratified sample. An average of three bands per SSR primer pair was observed. Associations of SSR marker fragments with the life forms were determined. Analysis of molecular variation by using cluster analysis and ordination resulted in recognizable, distinct groups of annual and biennial life-form types, which may have direct applications for planning and management of future seed regenerations. Mention of commercial brand names in this paper does not constitute an endorsement of any product by the U.S. Department of Agriculture or cooperating agencies.     

Reproductive season and male effect on quantitative and qualitative traits of individually collected Muscovy duck (Cairina moschata) semen

Males of Muscovy duck (Cairina moschata) are mainly used for mule duck production via artificial insemination of females originated from wild mallard duck (Anas platyrhynchos); therefore, the quantity and quality of drake semen play a crucial role. The assessment results of male reaction to sexual stimulation by dummy female and basic semen characteristic (ejaculate volume, sperm concentration and morphology) of 12 individually kept Muscovy drakes carried out during the entire reproductive season are described. The male and period of the reproductive season effect on scored semen traits are documented. In total, 792 individual semen collections and evaluations were performed. The average of positive reaction in the entire reproductive season varied from 90.6% in December and April to 50.0% in July, while for individual males, it varied between 97.1% and 29.0%. Throughout the season, the ejaculate volumes ranged from 0.05 to 2.45 ml, sperm concentration from 0.15 × 10⁹ ml⁻¹ to 4.44 × 10⁹ ml⁻¹, total number of live spermatozoa from 68.0% to 100% and live normal (properly formed, with any deformations) from 51.0% to 99.0%. Our study indicates the necessity of male breeders pre-selection before the onset of the reproductive season, and the need to leave an appropriate number of males to ensure adequate amount of semen for female insemination, especially when using Muscovy drakes (Cairina moschata) for interspecies crossing with Anas platyrhynchos ducks.