Effects of salinity on growth characteristics and osmoregulation of juvenile cobia,Rachycentron canadum (Linnaeus 1766), reared in potassium‐amended inland saline groundwater

The suitability of inland saline groundwater as a medium to culture juvenile cobia, Rachycentron canadum, was assessed. In the first experiment, juvenile cobia stocked in raw (unamended) saline groundwater at salinities of 5, 10, and 15 g/L exhibited complete mortality after 108, 176, and 195 hr, respectively. The second experiment evaluated the rearing of juvenile cobia (mean weight ~9.23 ± 0.12 g) in potassium (K⁺)‐amended saline groundwater (100% K⁺ fortified) and reconstituted seawater at salinities of 5, 10, and 15 g/L to assess growth and osmoregulation in distinct culture media. Following 60 days of culture, all fish survived the experimental period. Final mean bodyweight of cobia reared in K⁺‐amended saline groundwater (103.2–115.8 g) and seawater (111.2–113.8 g) of different salinities did not vary significantly (p > .05). No differences (p > .05) were observed in specific growth rate, weight gain (%), and feed conversion ratio between treatment groups. Serum osmolality increased with salinity and was significantly higher (p < .05) for fish in K⁺‐amended saline groundwater (353–361 mOsmol/Kg) than in reconstituted seawater (319–332 mOsmol/Kg), although differences were not observed between salinities by water type. Cobia stocked in saline groundwater of different salinities were osmoregulating normally, and the higher values observed may be because of variations in ionic composition and other interfering ions in saline groundwater. Trial results suggest that juvenile cobia can achieve optimal growth in K⁺‐amended saline groundwater of low and intermediate salinities.     

Effect of farm management on topsoil organic carbon and aggregate stability in water: A case study from Southwest England,UK

There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content (F = 8.500, p < .0001) or not (F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC_adj R² = .571, p < .0001) or not (SOC_unadj R² = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.     

SnToxA,SnTox1, and SnTox3 originated in Parastagonospora nodorum in the Fertile Crescent

The centre of origin of the globally distributed wheat pathogen Parastagonospora nodorum has remained uncertain because only a small number of isolates from the Fertile Crescent were included in earlier population genetic and phylogeographic studies. We isolated and genetically analysed 193 P. nodorum strains from three naturally infected wheat fields distributed across Iran using 11 neutral microsatellite loci. Compared to previous studies that included populations from North America, Europe, Africa, Australia, and China, the populations from Iran had the highest genetic diversity globally and also exhibited greater population structure over smaller spatial scales, patterns typically associated with the centre of origin of a species. Genes encoding the necrotrophic effectors SnToxA, SnTox1, and SnTox3 were found at a high frequency in the Iranian population. By sequencing 96 randomly chosen Iranian strains, we detected new alleles for all three effector genes. Analysis of allele diversity showed that all three effector genes had higher diversity in Iran than in any population included in previous studies, with Iran acting as a hub for the effector diversity that was found in other global populations. Taken together, these findings support the hypothesis that P. nodorum originated either within or nearby the Fertile Crescent with a genome that already encoded all three necrotrophic effectors during its emergence as a pathogen on wheat. Our findings also suggest that P. nodorum was the original source of the ToxA genes discovered in the wheat pathogens Phaeosphaeria avenaria f. sp. tritici 1, Pyrenophora tritici-repentis, and Bipolaris sorokiniana.     

Molecular identification of blast resistance genes in rice landraces from northeastern India

Rice blast disease caused by the fungus Magnaporthe oryzae is one of the most devastating diseases causing huge losses worldwide. In the present study, major blast resistance genes were investigated in landraces originating from northeastern India. Based on phenotypic evaluation, 288 landraces were classified into three distinct groups: resistant (75), moderately resistant (127) and susceptible (86). The genetic frequencies of the 18 major blast resistance genes were between 6.2% and 27.4%, with only two genotypes possessing a maximum of nine blast resistance genes. The cluster and population structure analysis grouped the landraces into two groups. Through principal coordinate analysis, the scatter plots partitioned the resistant and moderately resistant landraces into different groups. Analysis of molecular variance showed maximum (96%) diversity within populations and least (4%) diversity between populations. Association analysis identified six markers, CRG4_2, RM72, tk59-2, pi21_79-3, RM1233 and RM6648, that are significantly associated with blast disease and explained a phenotypic variance of 1.1–6.5%. The associated genes could be used in marker-assisted rice breeding programmes for gene pyramiding to develop rice varietal resistance against blast disease. The present study represents a valuable blast resistance genetic resource that could be used for identification of new R genes, donors for blast resistance, and genomic studies.     

Commuting distances to local non‐farm workplaces and out‐migration: The case of Northeast Thailand

The relationship between commuting distances and where people work has been studied for urban contexts in both developed countries and developing countries. However, few studies have examined the situation in rural areas, and none look at commuting distances to non‐farm workplaces in rural areas of developing countries. This paper investigates how commuting distance, and thus accessibility, to local non‐farm work influences non‐farm employment and out‐migration from rural villages in Northeast Thailand. The main issues examined are: (i) the distance that rural residents travel to work in local non‐farm jobs; and (ii) the influence that local non‐farm employment has on the number of outmigrants from rural villages. The study finds: (i) distance between villages and non‐farm work sites impact the number of villagers who are employed in regular wage work; (ii) beyond 20 km villagers are less likely to travel to non‐farm employment using their own means of transportation; and (iii) employment in regular wage work decreases outmigration. The findings from this study contribute to the debates over the drivers of rural out‐migration, rural livelihood changes, and agrarian changes that are taking place in Southeast Asia.     

Mammary carcinoma arising in an adenoma in a ewe

A large, firm, multi-cystic mammary gland mass grew slowly over 4 y in a 12-y-old, female Finn–Shetland cross sheep. A diagnosis of epithelial malignancy was suspected following fine-needle aspiration cytology at 30 mo after initial observation. The sheep was euthanized when the flock was downsized 18 mo later. A field postmortem examination revealed a large mammary mass, but an absence of metastases to internal organs. Imprint cytology of the mammary tissue supported a benign proliferative process. Histologically, mammary tissue was obliterated by cystic, tubular, and papillary adenomatous arrangements of mammary epithelium, with an anaplastic component, consistent with mammary carcinoma arising in an adenoma. IHC showed strong nuclear positivity to the antibody against progesterone receptor and minimal positivity to the antibody against estrogen receptor alpha expression. Intrinsic subtyping for basal or luminal epithelial origin was attempted through adaptation of companion animal IHC classification panels; high- and low-molecular-weight cytokeratins (CK5, CK8, CK18) failed to stain, but p63 expression for basal epithelium was positive.     

Temporal and spatial progress of the diseases caused by the crinivirus tomato chlorosis virus and the begomovirus tomato severe rugose virus in tomatoes in Brazil

Efficient management of whitefly-borne diseases remains a challenge due to the lack of a comprehensive understanding of their epidemiology, particularly of the diseases tomato golden mosaic and tomato yellowing. Here, by monitoring 16 plots in four commercial fields, the temporal and spatial distribution of these two diseases were studied in tomato fields in Brazil. In the experimental plots these diseases were caused by tomato severe rugose virus (ToSRV) and tomato chlorosis virus (ToCV), respectively. The incidence of each virus was similar in the plots within a field but varied greatly among fields. Plants with symptoms for both diseases were randomly distributed in three of four spatial analyses. The curves representing the progress of both diseases were similar and contained small fluctuations, indicating that the spread of both viruses was similar under field conditions. In transmission experiments of ToSRV and ToCV by Bemisia tabaci MEAM1 (former biotype B), these viruses had a similar transmission rate in single or mixed infections. It was then shown that primary and secondary spread of ToCV were not efficiently controlled by insecticide applications. Finally, in a typical monomolecular model of disease progress, simulation of the primary dissemination of ToSRV and ToCV showed that infected plants were predominantly randomly distributed. It is concluded that, although the manner of vector transmission differs between ToSRV (persistent) and ToCV (semipersistent), the main dispersal mechanisms are most probably similar for these two diseases: primary spread is the predominant mechanism, and epidemics of these diseases have been caused by several influxes of viruliferous whiteflies.     

Survey on Bactrocera spp. (Tephritidae,Diptera) in Austria

Fruit fly species (Diptera: Tephritidae) of the genus Bactrocera are among the most serious orchard pests worldwide but are not native to Austria. The unexpected finding of one Bactrocera zonata adult in Vienna in 2011 initiated increasing survey efforts in Austria since 2012. Traps with male attracting lures were employed at several sites during the fruiting periods and catches were analysed. At sites in Vienna (urban area) Bactrocera specimens were trapped between 2012 and 2018, whereas no Bactrocera specimens were caught in agricultural areas or commercial orchards outside the city. Twelve specimens were identified as B. zonata and nine specimens as B. dorsalis sensu lato, though for the latter it was not possible to distinguish between B. dorsalis s.l. and B. carambolae using molecular analysis (ITS1). Molecular sequencing showed that the specimens caught were genetically different (with only a few exceptions), indicating genetically different origins. It is evident that the repeated findings of Bactrocera specimens in Vienna, where winter temperatures do not allow the establishment of tropical fruit flies, are linked to repeated entries of juveniles with infested fruits (in luggage or consignments). The results of our study reveal the need to strengthen phytosanitary import requirements for fruit commodities and travellers’ luggage in order to protect fruit production in Austria and probably in other countries.     

Ectomycorrhizal fungal resources of Inner Mongolia Autonomous Region: above ground macrofungi and belowground ectomycorrhizae

New Forests - Desertification and land use pressures reduced forest cover in Inner Mongolia by 3% between 1992 and 2001. These forests primarily form symbioses with ectomycorrhizal fungi, and...     

Projecting the suitability of global and local habitats for myrtle rust (Austropuccinia psidii) using model consensus

Myrtle rust (caused by Austropuccinia psidii) affects more than 500 known host species in the Myrtaceae family. Three different modelling approaches (CLIMEX, MaxEnt and Multi-Model Framework) were used to project the habitat suitability for myrtle rust at both global and local scales. Current data on the global occurrence of myrtle rust were collected from online literature and expert solicitation. Long-term averages of climate data (1960–1990) were sourced from WorldClim and CliMond websites. Recent reports of myrtle rust in New Zealand were used for validation of model outputs but not in model training and testing. The model outputs were combined into a consensus model to identify localities projected to be suitable for myrtle rust according to two or three models (hotspots). In addition to the locations where the pathogen is currently present, all models successfully projected independent occurrence data in New Zealand suitable for establishment of the pathogen. Climate suitability for the pathogen was primarily related to temperature followed by rainfall in MaxEnt and the CLIMEX model. The results confirmed the optimum temperature range of this pathogen in the literature (15–25 °C). Additional analysis of the precipitation variables indicated that excessive rain (more than 2000 mm in warmest quarter of the year) combined with high temperatures (>30 °C) constrain pathogen establishment. The results of the current study can be useful for countries such as New Zealand, China, South Africa and Singapore where the pathogen has not fully spread or established.