An analysis of the effects of water stress on leaf growth and yield of three barley cultivars

The main objective of the study was to evaluate the sensitivity of Iraqi local barley cultivar (Black) to soil water deficit as compared to other barley cultivars, namely: CM-72 and Arivat. The local cultivar proved to be susceptible during germination and emergence, but it developed resistance during the vegetative growth and yield formation stages. Growth analysis of individual leaves clearly showed that Black barley produced leaves of long growth duration which could affect the growth processes especially cell division. Thus, the reduction in the number of cells composing those leaves was small in the cultivar Black. Leaf growth rates as soil matric potential decreased, were reduced considerably, although, no clear trends were observed between cultivars. On the other hand, the smaller cell volume of local cultivar may have a role in its ability to tolerate water deficit. Some evidence that the local cultivar is post-flowering resistant is discussed.     

Agronomic traits at the seedling stage,yield, and fiber quality in two cotton (Gossypium hirsutum L.) cultivars in response to phosphorus deficiency

ABSTRACT

Cotton is critical for phosphorus demands and very sensitive for its deficiency. However, identifying the effect of low-phosphorus tolerance on cotton growth, yield, and fiber quality by reducing phosphorus consumption. This may help to develop phosphorus-tolerant high-yielding cotton cultivars. In a two-year repeated (2015 and 2016) hydroponic experiment (using 0.01 and 1 mM KH₂PO₄), two cotton cultivars with phosphorus sensitivity (Lu 54; a low-phosphorus sensitive and Yuzaomian 9110; a low-phosphorus tolerant) were screened on the base of agronomic traits and physiological indices through correlation analysis, cluster analysis and principal component analysis from 16 cotton cultivars. Low phosphorus nutrition reduced the plant height, leaf number, leaf area, phosphorus accumulation and biomass in various organs of seedlings. The deficiency negatively affected the morphogenesis of seedlings, as well as yield and fiber quality. Further, these screened cultivars were tested in a pot experiment with 0, 50, 100, 150, 200 kg P₂O₅ ha^?1 during 2016 and 2017. It was found to have a significant (P< 0.05) difference in boll number, lint yield, fiber strength, and micronaire at the harvest. Furthermore, after collectively analyzed the characteristics of Lu 54 and Yuzaomian 9110, there were six key indices that could improve the low phosphorus tolerance of cotton cultivars. These were root phosphorus accumulation, stem phosphorus accumulation percentage, leaf and total biomass of seedlings, seed cotton weight per boll and fiber length.     

Efficacy of an orally administered modified-live porcine-origin rotavirus vaccine against postweaning diarrhea in pigs

A commercially available, porcine-origin rotavirus vaccine was evaluated for efficacy against postweaning diarrhea due to rotavirus infection in pigs. Weight gains were compared at 5 intervals after weaning. Visual scoring was used to evaluate fecal consistency. Rectal swab specimens were cultured for hemolytic E coli and evaluated for rotaviral antigen by use of enzyme-linked immunosorbent assay. Milk from dams and sera from pigs and dams were evaluated for rotavirus-neutralizing antibodies by use of a plaque-reduction test. Significant differences between vaccinates and controls were not found in the determinants evaluated. Selected rotavirus-positive fecal and rectal swab specimens were examined for double-stranded (ds) RNA by use of direct electropherotyping, and the results were compared with the dsRNA pattern of rotavirus propagated from the vaccine. Only electropherotypes typical of field strain virus were found in the fecal and rectal swab specimens evaluated. Sera from guinea pigs and from a gnotobiotic pig immunized against the field strain rotavirus neutralized Ohio State University strain rotavirus (homologous to the vaccine rotavirus strain), but did not neutralize the Gottfried strain of rotavirus. This indicated that, although the dsRNA electropherotypes of the field and vaccine strains of the virus were different, the serotypes were similar, if not identical.     

Antibody titers against bovine coronavirus and shedding of the virus via the respiratory tract in feedlot cattle

OBJECTIVE: To describe patterns of seroconversion to bovine coronavirus (BCV) and shedding of BCV from the respiratory tract in feedlot cattle. ANIMALS: 1,074 calves in feedlots in Ohio, Texas, and Nebraska. PROCEDURE: Nasal swab specimens were obtained at time of arrival (day 0) and at various times during the initial 28 days after arrival at feedlots. Specimens were tested for BCV, using an antigen-capture ELISA. Serum samples were obtained at time of arrival and again 28 days after arrival; sera were analyzed for antibodies to BCV, using an antibody-detection ELISA. RESULTS: Samples from 12 groups of cattle entering 7 feedlots during a 3-year period revealed that 78 of 1,074 (7.3%) cattle were shedding BCV (range, 0 to 35.9% within specific groups). At time of arrival, 508 of 814 (62.4%) cattle had low (< 50) or undetectable BCV antibody titers. Seroconversion to BCV during the initial 28 days after arrival was detected in 473 of 814 (58%) cattle tested (range, 20.3 to 84.1 % within specific groups). In cattle shedding BCV from the nasal passages, 49 of 68 (72.1 %) seroconverted, and 472 of 746 (63.3%) cattle that were not shedding the virus seroconverted. CONCLUSIONS AND CLINICAL RELEVANCE: Bovine coronavirus can be detected in populations of feedlot cattle in the form of viral shedding as well as seroconversion to the virus. Although only a few cattle were shedding the virus at the time of arrival at a feedlot, most of the cattle seroconverted to BCV by 28 days after arrival.     

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.     

Comparative studies on three isolates of Breda virus of calves

Three isolates of Breda virus of calves were compared morphologically and antigenically. The isolates demonstrated similar morphology and shared common antigens, as determined by enzyme-linked immunosorbent assay and immunoelectron microscopy. On the basis of results of the hemagglutination-inhibition test, enzyme-linked immunosorbent assay, and immunoelectron microscopy, the 3 isolates were further subdivided into 2 serotypes: serotype 1 (Breda virus 1) represented by the Iowa isolate 1; and serotype 2 (Breda virus 2), by the Ohio isolate and the Iowa isolate 2. The 3 isolates caused diarrhea in gnotobiotic calves.     

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.     

Detection of antibodies against Bordetella avium in turkeys by avidin-biotin enhancement of the enzyme-linked immunosorbent assay and the dot-immunobinding assay.

An avidin-biotin-enhanced enzyme-linked immunosorbent assay (AB-ELISA) and an avidin-biotin-enhanced dot-immunobinding (AB-DIB) assay for detecting antibody to Bordetella avium in turkey sera were developed and compared with the microagglutination (MA) test. Whole-cell antigen, biotin-labeled goat anti-turkey IgG conjugate, and horseradish-peroxidase-labeled streptavidin were used in the AB-ELISA and AB-DIB assay. The AB-ELISA and AB-DIB assay were sensitive, specific, and reproducible. These assays were superior to the MA test for measuring acquired and maternal antibodies against B. avium. All MA-positive sera were positive by two assays, but some sera negative by MA test had titers in the AB-ELISA and AB-DIB assay. AB-ELISA and AB-DIB titers showed a positive correlation (r = 0.866), and AB-ELISA was more sensitive than the AB-DIB assay.