Foliage‐applied sodium nitroprusside and hydrogen peroxide improves resistance against terminal drought in bread wheat

Terminal drought is threatening the wheat productivity worldwide, which is consumed as a staple food by millions across the globe. This study was conducted to examine the influence of foliage‐applied stress signalling molecules hydrogen peroxide (H₂O₂; 50, 100, 150 μm ) and nitric oxide donor sodium nitroprusside (SNP; 50, 100, 150 μm ) on resistance against terminal drought in two bread wheat cultivars Mairaj‐2008 and BARS‐2009. These stress signalling molecules were applied at anthesis stage (BBCH 61); drought was then imposed by maintaining pots at 35% water holding capacity. Terminal drought caused significant reduction in grain yield of both tested bread wheat cultivars; however, foliage application of both stress signalling molecules at either concentration improved the performance of both bread wheat cultivars. Maximum improvement in 100‐grain weight (12.2%), grains per spike (19.7%), water‐use efficiency (WUE; 19.8%), chlorophyll content index (10.7%), total soluble phenolics (21.6%) and free leaf proline (34.3%), and highest reduction in leaf malondialdehyde contents (20.4%) was recorded when H₂O₂ was foliage‐applied at 100 μm . Foliage application of SNP enhanced the grains per spike, 100‐grain weight and grain yield by 14.9%, 11.3% and 20.1%, respectively, than control. The foliage‐applied stress signalling molecules improved the accumulation of soluble phenolics, proline and glycine betaine with simultaneous reduction in malondialdehyde contents, which enabled wheat plants to sustain the biological membranes under stress resulting in better stay green (high chlorophyll contents) under drought. This helped improving the grain number, grain weight, grain yield, WUE and transpiration efficiency. In crux, foliage‐applied H₂O₂ and SNP, at pre‐optimized rate, may be opted to lessen the drought‐induced yield losses in bread wheat in climate change conditions.     

Molecular characterisation of Theileria equi and risk factors associated with the occurrence of theileriosis in horses of Punjab (Pakistan)

Theileria equi (T. equi) is an obligate intra- and extra-erythrocytic parasite that causes equine theileriosis (ET) in equids. Equine theileriosis is considered a notifiable disease of global significance, a major constraint to the international movement of horses, and endemic in many countries. This disease may be difficult to diagnose, as it can produce variable and nonspecific clinical signs. A cross-sectional study was designed for the molecular characterisation of T. equi and to investigate the associated risk factors of ET accompanied by its consequences on haematological and sero-biochemical parameters. A convenience sampling of 500 blood samples were collected from ET suspect horses from January to December 2017. PCR was performed on all blood samples targeting the 18S rRNA gene of T. equi followed by sequencing; 9% animals tested positive with confirmed sequences. The isolates of this study showed high homology with Cuban, Russian and Brazilian isolates of T. equi (accession numbers KY111762.2 , MG551915.1 and KY952237.1 , respectively). Based on multivariate analysis, the principal risk factors consisted of absence of dogs on the premises and presence of tick infestation. The haemato-biochemical parameters showed a decrease in granulocytes and erythrocytes, and an increase in lymphocytes, monocytes, mean corpuscular volume, mean corpuscular haemoglobin, mean platelet volume, glucose, phosphorus and aspartate aminotransferase in positive horses. This is the first study which identified ET in Punjab (Pakistan) using molecular techniques and risk factors together with the haemato-biochemical variations in horses.     

Development of a monoclonal antibody-based co-agglutination test to detect enterotoxigenic Escherichia coli isolated from diarrheic neonatal calves

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsa-stained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a co-agglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.     

Farmers' attitudes towards techniques for improving oestrus detection in dairy herds in South West England

Unidentified heats contribute to declining fertility rates in English dairy herds. Several techniques have been advocated to improve heat detection rates. Despite demonstrable technical efficacy and cost-effectiveness, uptake is low. A study in South West England used the Theory of Reasoned Action (TORA) to explore dairy farmers' attitudes and beliefs towards heat detection techniques. Few farmers were convinced that following prescribed observation times, milk progesterone testing and using pedometers would fit their system or improve on their current heat detection practices. Perceived difficulty of using a technique was not a constraint on adoption. Without promotion that addresses identified barriers and drivers to adoption, little change in current practice can be expected.     

Glycinebetaine Improves Chilling Tolerance in Hybrid Maize

Plant growth and development is hampered by various environmental stresses including chilling. We investigated the possibility of improving chilling tolerance in hybrid maize by glycinebetaine (GB) seed treatments. Maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 mg l^?1 (p.p.m.) aerated solution of GB for 24 h and were dried back. Treated and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Germination and seedling growth was significantly hindered under chilling stress. Moreover, chilling stress significantly reduced the starch metabolism and relative water contents (RWC), and increased the membrane electrolyte leakage. However, activities of antioxidants (catalase, superoxide dismutase and ascorbate peroxidase) were increased under stress conditions. Seed treatments with GB improved the germination rate, root and shoot length, seedling fresh and dry weights, leaf and root scores, RWC, soluble sugars, α‐amylase activity and antioxidants significantly compared with untreated seeds under optimal and stress conditions. Induction of chilling tolerance was attributed to maintenance of high tissue water contents, reduced membrane electrolyte leakage, and higher antioxidant activities and carbohydrate metabolism. Seed treatment with 100 mg l^?1 GB was the best treatment for improving the performance of hybrid maize under normal and stress conditions compared with control and other levels used.     

Inorganic and organic carbon dynamics in forested soils developed on contrasting geology in Slovenia—a stable isotope approach

Purpose

Soil carbon dynamics were studied at four different forest stands developed on bedrocks with contrasting geology in Slovenia: one plot on magmatic granodiorite bedrock (IG), two plots on carbonate bedrock in the karstic-dinaric area (CC and CD), and one situated on Pleistocene coalluvial terraces (FGS).

Materials and methods

Throughfall (TF) and soil water were collected monthly at each location from June to November during 2005–2007. In soil water, the following parameters were determined: T, pH, total alkalinity, concentrations of Ca²⁺ and Mg²⁺, dissolved organic carbon (DOC), and Cl^? as well as δ¹³C_DIC. On the other hand, in TF, only the Cl^? content was measured. Soil and plant samples were also collected at forest stands, and stable isotope measurements were performed in soil and plant organic carbon and total nitrogen and in carbonate rocks. The obtained data were used to calculate the dissolved inorganic carbon (DIC) and DOC fluxes. Statistic analyses were carried out to compare sites of different lithologies, at different spatial and temporal scales.

Results and discussion

Decomposition of soil organic matter (SOM) controlled by the climate can explain the ¹³C and ¹⁵?N enrichment in SOM at CC, CD, and FGS, while the soil microbial biomass makes an important contribution to the SOM at IG. The loss of DOC at a soil depth of 5 cm was estimated at 1 mol m^?2 year^?1 and shows no significant differences among the study sites. The DOC fluxes were mainly controlled by physical factors, most notably sorption dynamics, and microbial–DOC relationships. The pH and pCO₂ of the soil solution controlled the DIC fluxes according to carbonate equilibrium reactions. An increased exchange between DIC and atmospheric air was observed for samples from non-carbonate subsoils (IG and FGS). In addition, higher δ¹³C_DIC values up to ?19.4?‰ in the shallow soil water were recorded during the summer as a consequence of isotopic fractionation induced by molecular diffusion of soil CO₂. The δ¹³C_DIC values also suggest that half of the DIC derives from soil CO₂ indicating that 2 to 5 mol m^?2 year^?1 of carbon is lost in the form of dissolved inorganic carbon at CC and CD after carbonate dissolution.

Conclusions

Major difference in soil carbon dynamics between the four forest ecosystems is a result of the combined influence of bedrock geology, soil texture, and the sources of SOM. Water flux was a critical parameter in quantifying carbon depletion rates in dissolved organic and inorganic carbon forms.

     

Boron fertilization improves seed yield and harvest index of Camelina sativa L. by affecting source-sink

The impact of soil (1, 2 kg ha^?1) and foliar (100, 200 mg L^?1) boron (B) with control (no B) was evaluated on phenology and yield formation of Camelina each applied at stem elongation and flowering stages. Foliar (200 mg L^?1) or soil B (2 kg ha^?1) resulted in earlier flowering and maturity, increased fruit bearing branches (19.68%), number of siliqua, seeds per siliqua (4.6%), biological yield (15%), seed yield (24%), harvest index (11.4%) and oil contents (23%) than no B. Increased fruit bearing branches, seed filled siliqua or seed numbers, harvest index and oil quality can be attributed to changes in dry matter accumulated of stem with simultaneous increase in siliqua dry weight with foliar or soil applied B. In crux, foliar (200 mg L^?1) or soil applied (2 kg ha^?1) B seems promising to improve seed and oil yield, harvest index of Camelina sativa under B deficient condition.     

Growth and fatty acid composition of sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) genotypes as influence by planting dates and nitrogen fertilization in semiarid region of Northwest,Pakistan

A field experiment was conducted on silty clay loam soil in the years 2011–2012. Two sesame (Sesamum indicum L.) cultivars (Local Black and Local White) were evaluated using various 3 different sowing dates (20th June, 10th and 30th July) and four agrotechnical level (0, 40, 80 and 120 kg N ha^–1) at New Developmental Farm The University of Agriculture, Peshawar, Pakistan. The objective of this study was to evaluate the effects of sowing dates on growth, yield and oil fatty acid composition of two sesame cultivars grown under different nitrogen fertilization. Results showed that cv. Local Black was characterized by significantly higher content of oil (47%), seed yield (696 kg ha^–1) and oil yield (335 kg ha^–1) while cv. Local White had higher palmitic acid (8%) and linoleic acid (38.7%). Yield and its main components were positively affected by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds. Intensive technology of cultivation (120 kg N ha^–1), compared to the economical technology (40 kg N ha^–1), significantly increased the seed yield of both sesame cultivars. This was due to higher number of branches, Capsules m^–2, capsules plant^–1, seeds capsule^–1 and 1000 seed weight (g). The intensive technology of cultivation had a beneficial effect on the content of palmitic acid, linolenic acid and oleic acid in sesame seed.     

Farm and socio-economic characteristics of smallholder milk producers and their influence on technology adoption in Central Mexico

In order to identify the factors influencing adoption of technologies promoted by government to small-scale dairy farmers in the highlands of central Mexico, a field survey was conducted. A total of 115 farmers were grouped through cluster analysis (CA) and divided into three wealth status categories (high, medium and low) using wealth ranking. Chi-square analysis was used to examine the association of wealth status with technology adoption. Four groups of farms were differentiated in terms of farms' dimensions, farmers' education, sources of incomes, wealth status, management of herd, monetary support by government and technological availability. Statistical differences (p < 0.05) were observed in the milk yield per herd per year among groups. Government organizations (GO) participated little in the promotion of the 17 technologies identified, six of which focused on crop or forage production and 11 of which were related to animal husbandry. Relatives and other farmers played an important role in knowledge diffusion and technology adoption. Although wealth status had a significant association (p < 0.05) with adoption, other factors including importance of the technology to farmers, usefulness and productive benefits of innovations together with farmers' knowledge of them, were important. It is concluded that the analysis of the information per group and wealth status was useful to identify suitable crop or forage related and animal husbandry technologies per group and wealth status of farmers. Therefore the characterizations of farmers could provide a useful starting point for the design and delivery of more appropriate and effective extension.     

Mapping the QTLs underlying drought stress at developmental stage of sorghum (Sorghum bicolor (L.) Moench) by association analysis

This study was conducted to identify quantitative trait loci (QTLs) for drought tolerance in sorghum (Sorghum bicolor (L.) Moench) by association mapping using a simple sequence repeat (SSR)-marker-based diversity research set. Genotypic data for 98 SSR marker loci on ten chromosomes were used for the association analysis. The experiment was conducted under control (well-watered) and drought stress conditions, and the phenotypic values of 23 morphological traits were recorded. Drought tolerance was assessed by using a leaf drying score as a parameter of the tolerance/susceptibility: scores were assigned on a scale from 1 (most tolerant) to 9 (most susceptible). Under the control conditions, 17 QTLs associated with 12 traits were identified on chromosomes 1, 2, 4, 8, 9, and 10, with ?Log₁₀ (P) ranging from 2.5 to 7.6 and explaining 9.5–57.5 % of the total phenotypic variance for the traits. Under the drought stress conditions, nine QTLs associated with 8 traits were identified on chromosomes 1, 2, 3, and 10 that explained 9–61.2 % of the total phenotypic variance for the traits, with ?Log₁₀ (P) ranging from 2.5 to 3.5. QTLs for some traits were detected only under the drought stress condition, suggesting that these traits are important in drought tolerance. These QTLs could be used to further dissect the genetic and physiological basis of drought tolerance in sorghum.