Family × Environment interactions in the growth and survival of Arctic charr (Salvelinus alpinus) grown in brackish and fresh water

We investigated whether Fraser strain Arctic charr Salvelinus alpinus L. reared in fresh water (FW) differed in survival and growth from full siblings transferred to brackish water (BW) and whether family performance was consistent throughout 1 year of commercial growth. Fish were grown communally (n = 3600) in either FW or BW from May 2008 to May 2009. Mean family survival in BW was moderately correlated with mean family survival in FW (r = 0.342; P = 0.032). Fish which survived until the conclusion of the experiment were significantly heavier in body weight at the baseline assessment than their full‐sibs which died. Family by treatment interactions were detected for body weight, condition factor and specific growth across all measurement dates (May 2008, October 2008 and May 2009) and growth intervals. Despite the varied response of families to treatment, mean family body weight in FW was correlated phenotypically with BW body weight in October 2008 (r = 0.633, P < 0.0001) and marginally correlated in May 2009 (r = 0.289, P = 0.061). These data suggest that body weight in FW and body weight in BW should be analysed as separate, but correlated traits in Arctic charr breeding programs.     

Superior bio-efficacy of a combined formulation of carbendazim and mancozeb in inducing defense responses in chilli seedlings against Sclerotium rolfsii Sacc. in comparison with methyl jasmonate

The objective of this work was to investigate the efficacy of a prepackaged combined formulation, Companion (carbendazim 12% + mancozeb 63% WP), sole application of carbendazim 50% WP, manozeb 75% WP and methyl jasmonate (MeJA), an inducer of systemic acquired resistance on disease severity and their role in post-infectional defense responses in chilli seedlings against Sclerotium rolfsii. Seeds were treated for 8 h with MeJA (2.5 mM and 5.0 mM) and each of fungicides (500 ppm), and were sown in pots containing soil and fungal inocula (95:5 w/w). At 15 days after sowing maximum defense against fungal infection was exhibited by Companion comparably followed by the sole application of carbendazim and mancozeb. MeJA reduced percent mortality of S. rolfsii-infected chilli seedlings significantly as compared to the inoculated control. Assessment of peroxidase (POX) and esterase (EST) at 15 days after sowing revealed the increased activity under inoculated condition. Highest POX activity in MeJA treatments (5 mM > 2.5 mM) was followed by the Companion treatment. Highest EST activity was registered in Companion treatment. The zymogram of POX isozymes showed over-expression of POX 2 and POX 4 isoforms, and induction of POX 1 isoform in inoculated treatments. On the other hand, that of EST isozymes showed induction of EST 1 isoform in Companion, carbendazim and MeJA treatments. All EST isoforms were over-expressed in Companion-treated seedlings. Both fungicides and MeJA showed significant effects on disease severity, induction of defense enzymes and isozyme pattern in S. rolfsii-infected chilli seedlings. Contact and systemic fungicides under the experiment demonstrated differential responses. The combination formulation was superior in disease control to application of the fungicide components individually. They compared favourably with MeJA in induction of defense-related enzyme activities. All these findings are new with respect to the chilli-S. rolfsii host–pathogen interaction system, S. rolfsii representing the sclerotial basidiomycetes in particular.     

Field efficacy of a biopesticide prepared from <Emphasis Type="Italic">Clerodendrum viscosum</Emphasis> Vent. (Verbenaceae) against two major tea pests in the sub Himalayan tea plantation of North Bengal,India

The toxicity of four concentrations (1, 5, 10 and 20% w/v) of an aqueous extract from the weed, Clerodendrum viscosum Ventenat (Verbenaceae) was investigated under field conditions of the North Bengal University, Darjeeling, West Bengal, India for managing two major pests of tea, Camellia sinensis (L), namely the tea mosquito bug, Helopeltis theivora Waterhouse, (Heteroptera: Miridae) and the tea red spider mite, Oligonychus coffeae Nietner, (Acarina: Tetranychidae). Four field trials, two for red spider mite and two for tea mosquito bug, were conducted during April–May 2008 and October–November 2009 following a Randomized Block design. The aqueous extract of C. viscosum effectively and significantly reduced the mite population as well as infestation of tea mosquito bug by 68–95% and 73–86%, respectively, and their bioefficacy is comparable to synthetic and neem pesticides. No phytotoxic effect (score 0–5% and grade 1) was observed in the tea bushes sprayed with different doses of aqueous extract of C. viscosum in the field. Made tea samples were taint free. Organoleptic test revealed leaf-infusions and liquor strength as good, scoring 6.5–7.0 on a 10 point scale. Availability and distribution of this weed (C. viscosum) in and around tea-growing areas of sub Himalayan region, along with its processing for the feasibility of including C. visosum extracts in the current IPM programme is discussed.     

Molecular characterization of a new isolate of phytoplasma associated with malformation and twisting of floral spikes of <Emphasis Type="Italic">Gladiolus</Emphasis> in India

In 2007–2009, severe virescence, malformation and twisting of flower spikes and yellowing of entire plants were observed in various Gladiolus cultivars growing in the gardens of the National Botanical Research Institute, Lucknow, India. The disease symptoms were very similar to symptoms in Gladiolus caused by the Aster yellows phytoplasma identified from Poland. Disease incidence was low (1.1–3.4%), but the severity of symptoms was high. A phytoplasma infection was detected in nine of 13 cultivars by PCR followed by nested PCR using universal phytoplasma primers P1/P6 or R16F2n/R16R2, respectively. An amplicon of ~1.2 kb obtained from the nested PCR was cloned and sequenced. Sequence analysis of the PCR amplicon revealed high (94–98%) identities and the closest phylogenic relationships with several isolates of Aster yellows phytoplasma of ‘Candidatus Phytoplasma asteris’ (16SrI group). Thus, the phytoplasma isolate of Gladiolus was identified as a new isolate of ‘Ca. P. asteris’ (16SrI group). In silico analysis of the phytoplasma isolate clearly indicated that the isolate was distinct from other Indian isolates of this phytoplasma.     

Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US

The foraging activities of nonindigenous feral hogs (Sus scrofa) create widespread, conspicuous soil disturbances. Hogs may impact forest regeneration dynamics through both direct effects, such as consumption of seeds, or indirectly via changes in disturbance frequency or intensity. Because they incorporate litter and live plant material into the soil, hogs may also influence ground cover and soil nutrient concentrations. We investigated the impacts of exotic feral hogs in a mixed pine-hardwood forest in the Big Thicket National Preserve (Texas, USA) where they are abundant. We established sixteen 10 m × 10 m plots and fenced eight of them to exclude feral hogs for 7 years. Excluding hogs increased the diversity of woody plants in the understory. Large seeded (>250 mg) species known to be preferred forage of feral hogs all responded positively to hog exclusion, thus consumption of Carya (hickory nuts), Quercus (acorns), and Nyssa seeds (tupelo) by hogs may be causing this pattern. The only exotic woody species, Sapium sebiferum (Chinese tallow tree), was more than twice as abundant with hogs present, perhaps as a response to increased disturbance. Hogs increased the amount of bare soil by decreasing the amounts of plant cover and surface litter. Plots with hogs present had lower soil C:N, possibly due to accelerated rates of nitrogen mineralization. These results demonstrate that hogs may influence future overstory composition and reduce tree diversity in this forest. Management of hogs may be desirable in this and other forests where large-seeded species are an important component of the ecosystem. Further, by accelerating litter breakdown and elevating nitrogen in the soil, hogs have the potential to impact local vegetation composition via nitrogen inputs as well.     

Comparative effect of root-knot nematode on severity of verticillium and fusarium wilt in cotton

The effect of root-knot nematode (RKN) (Meloidogyne incognita) onVerticillium dahliae andFusarium oxysporum f.sp.vasinfectum in cotton (Gossypium hirsutum) was investigated. Two different inoculation methods were used, one in which inoculum was added to the soil, so that nematode and fungal inoculum were in close proximity; the other, inoculation into the stem, whereby the two inocula were spatially separated. Invasion of the roots by RKN enhanced disease severity, as measured by the height of vascular browning in the stem, following inoculation with either wilt pathogen. The effect of RKN on Fusarium wilt was more pronounced than that on Verticillium wilt. Nematode-enhanced infection byF. oxysporum is a well known effect but there are few reports of enhanced infection byVerticillium due to RKN. Relative resistance of a number of cotton cultivars to both wilt diseases, as measured by height of vascular browning, was similar to the known field performance of the cultivars. The use of vascular browning as an estimate of disease severity was therefore validated. http://www.phytoparasitica.org posting Feb. 3, 2003.     

Effects of litter size and light regimen imposed during lactation on ovarian follicular population at weaning in third-parity sows

Sixteen third-parity sows maintained under two photoperiod treatments (16 h light: 8 h dark [16 h] or 4 h light: 20 h dark [4 h]) were assigned to be unilaterally ovariectomized (left ovary) at weaning on d 28 after farrowing a small litter (12 or fewer piglets; S) or a large litter (more than 12 piglets; L). Antral follicles were classified as atretic or nonatretic and divided into six size classes. The right ovary was obtained at slaughter, 16 d after estrus was detected. Number of antral follicles in the left ovary was greater (P less than .05) for L sows (540) than for S sows (427). Sows exposed to 16 h of light with large litters had a higher number of atretic follicles than all other groups (litter size x photoperiod interaction, P less than .05). Number of nonatretic follicles were similar between groups. However, when nonatretic follicles were classed by size (1 = smallest; 6 = largest), their distribution differed. In Class 1, L sows had more follicles than S sows (P less than .05). For Classes 3 and 4, photoperiod interacted with litter size to decrease the number of follicles in L 16 h sows (litter size x photoperiod interaction, P less than .05). These lower numbers of nonatretic follicles were related to a higher rate of follicular atresia in L 16 h sows. In Classes 2, 3 and 4, L 16 h sows had more atretic follicles than any other group (litter size x photoperiod interaction, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of titanium endoprostheses on bone mineral density measurements, using quantitative computed tomography.

Quantitative computed tomography has been used extensively to measure bone mineral density; particularly in the vertebral column and in the proximal portion of the femur in human beings with osteoporosis. Other potential applications of this technique include evaluation of bone adjacent to metallic endoprostheses and evaluation of fractures as they heal. Unfortunately, metal causes severe image degradation, principally seen as starburst streaking. One method used to decrease these artifacts is by imaging less-attenuating materials, such as titanium alloy. Titanium decreases image degradation sufficiently to allow accurate determination of the geometric properties of cadaveric bone. In our study, the effect of a titanium segmental endoprosthesis on bone mineral density measurement was determined by use of bone specimens from dogs and calibration standards. Titanium decreased the bone mineral density of calibration solutions from 6.8 (500 mg/cm3) to 17.7% (250 mg/cm3), and increased bone mineral density of cortical bone by 5.3%. Titanium did not affect the repeatability of these scans, indicating that the error caused by titanium was systematic and can be corrected. Our data were suggestive that quantitative computed tomography can be used to measure bone mineral density of cortical bone adjacent to titanium endoprostheses, with a predictable increase in density measurement.