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51.
52.
Supradip Saha K.A. Gopinath Banshi Lal Mina Hari Shankar Gupta 《European Journal of Soil Biology》2008,44(5-6):521
To explore long-term impact of organic and inorganic fertilizers on soil health and grain quality, we monitored the enzyme activities and chemical properties of soil; and chemical composition of grain from eight treatments at an experimental field site established in 1996. There were eight treatments applied to both wheat and maize seasons: a control; four inorganic fertilizers, that is, nitrogen and phosphorus (NP), nitrogen and potassium (NK), phosphorous and potassium (PK) and nitrogen, phosphorus and potassium (NPK); farm yard manure alone (FYM) and addition of FYM at two different doses (100 and 50% of recommendation) to NPK that is, NPK + FYM and ½ NPK + FYM. After 11 years of the experiment the NPK + FYM and ½ NPK + FYM treatments had the highest yields, about 5 Mg maize ha−1 and 2 Mg wheat ha−1 with about 2 and 0.5 Mg ha−1, respectively more than the NPK treatments. The dehydrogeanse activity of soils increased significantly in FYM and ½ NPK + FYM. Except urease all other enzymatic activities were increased in those treatments, which received manure. Urease activity was higher in mineral-N applied plots. Grain protein content of both maize and wheat was highest in mineral fertilized plots. Test weight also increased significantly on application of mineral fertilizer. Plots treated with half dose of recommended mineral fertilizer along with FYM were higher in urease, phosphomono and diesterase activities than that of NPK + FYM treated plots. Long-term application of inorganic nutrients along with FYM improved grain mineral composition and yield. Inhibition of few enzymatic activities were also observed upon application of inorganic nutrients either alone or in combination. 相似文献
53.
54.
Establishment of persistent avian infectious bronchitis virus infection in antibody-free and antibody-positive chickens 总被引:2,自引:0,他引:2
Avian infectious bronchitis virus (IBV) causes a highly contagious and economically significant disease in chickens. Establishment of a carrier state in IBV infection and the potential for the persistent virus to undergo mutations and recombination in chicken tissues have important consequences for disease management. Nevertheless, whether chickens can maintain persistent IBV infection in the absence of reinfection from exogenous sources or the presence of antibody in the host can modulate virus persistence remains unclear. Indeed, whether or not IBV genome can undergo genetic changes during in vivo infection has not been demonstrated experimentally. In the present study, IBV shedding and tissue persistence were monitored in individual chickens maintained under strict isolation that precluded reinfection from exogenous sources. In the first of two experiments, intranasal exposure of 6-wk-old antibody-free chickens to IBV vaccine virus resulted in intermittent shedding of the virus from both trachea and cloaca of individual birds for up to 63 days. Also, the virus was recovered from the internal organs (spleen, gonad, kidney, lung, cecal tonsil, and cloacal bursa) of six of eight birds killed at various intervals between 27 and 163 days postinoculation (DPI). In the second experiment, IBV exposure of 1-day-old maternal antibody-positive chicks led to periodic virus shedding from the trachea and cloaca in all chickens until 77 days; however, internal organs (lungs and kidneys) of only one of seven birds (killed at 175 DPI) were virus positive, suggesting that presence of antibody at the time of infection protects internal organs from IBV infection. When the lung and kidney isolates of IBV from the latter experiment were compared with the parent-vaccine virus, no changes in their antigenicity, tissue tropism, or the nucleotide sequence of the S1 glycoprotein gene were observed. These findings indicate that, unlike the mammalian coronaviruses, propensity for frequent genetic change may not be inherent in the IBV genome. 相似文献
55.
We used slot blot hybridization of the hypervariable regions of the S1 subunit of spike peplomer gene to identify and characterize infectious bronchitis virus (IBV) strains. Template DNA was created from six reference strain IBVs of different serotypes and immobilized on a nitrocellulose membrane. We synthesized digoxigenin-labeled probes from reference and unknown field viruses and hybridized them to template DNA. All reference strains could be distinguished and isolates identified by serotype if they were at least 95% identical to a reference strain. This slot blot hybridization procedure was specific and reproducible, and strain typing was consistent with the S1 sequencing of the IBV genome. This study thus provides a simple and rapid method for typing of IBV. 相似文献
56.
Victor Stalinraj Koyadan Kizhakedath Vijayan Mohandas Sanjuktha Changaramkumarth Paran Balasubramanian Shankar Vinayakarao Alavandi Thairiyam Chinnappan Santiago 《Aquaculture Research》2009,40(2):129-138
The objective of this study was to investigate the reason for variation in the virulence of white spot syndrome virus (WSSV) from different shrimp farms in the Southeast coast of India. Six isolates of WSSV from farms experiencing outbreaks (virulent WSSV; vWSSV) and three isolates of WSSV from farms that had infected shrimps but no outbreaks (non‐virulent WSSV; nvWSSV) were collected from different farms in the Southeast coast of India. The sampled animals were all positive for WSSV by first‐step PCR. The viral isolates were compared using histopathology, electron microscopy, SDS‐PAGE analysis of viral structural proteins, an in vivo infectivity experiment and sequence comparison of major structural protein VP28; there were no differences between isolates in these analyses. A significant observation was that the haemolymph protein profile of nvWSSV‐infected shrimps showed three extra polypeptide bands at 41, 33 and 24 kDa that were not found in the haemolymph protein profile of vWSSV‐infected shrimps. The data obtained in this study suggest that the observed difference in the virulence of WSSV may not be due to any change in the virus, rather it could be due to the shrimp defence system producing certain factors that help it to accommodate the virus without causing any mortality. 相似文献
57.
Sangram Ketan Sahoo Shajahan Ferosekhan Shiba Shankar Giri Kalidoss Radhakrishnan Debabrata Panda Murugesan SriHari Bindu R. Pillai 《Aquaculture Research》2019,50(5):1431-1437
Length–weight relationship (LWR) of 661 numbers of hatchery‐produced magur, Clarias magur of all the life stages such as hatchlings, fry, fingerlings, juveniles and adults, was studied. The LWR of all the life stages of magur was estimated and the equations are as follows, hatchlings W = 0.0052*L1.282 (r2 = 0.8784), fry W = 0.0088*L3.028 (r2 = 0.8113), fingerlings W = 0.0065*L3.226 (r2 = 0.8906), juveniles W = 0.0028*L3.420 (r2 = 0.8175) and adults W = 0.0017*L3.491 (r2 = 0.8310). A positive allometric growth (b > 3) was observed in all the life stages except hatchlings. The annual growth rate of magur was observed with the body length and weight of 24 ± 1 cm and 115 ± 17 g, respectively, under the commercial production system. This is the first kind of study that describes about the LWR and growth performance of all the life stages of hatchery‐produced C. magur catfish from hatchlings to adults under commercial production system. This study will be more useful to the hatchery managers and fish growers to optimize the resources and husbandry practices to improve the growth, survival, and biomass production. 相似文献
58.
Genotype by Environment (G×E) Interaction Study on Yield Traits in Different Maturity Groups of Rice
Jadhav Swapna Balakrishnan Divya Shankar V Gouri Beerelli Kavitha Chandu Gowthami Neelamraju Sarla 《Journal of Crop Science and Biotechnology》2019,22(5):425-449
Journal of Crop Science and Biotechnology - Rice production is affected by emerging problems of climate change and over-utilization of resources. To obtain consistent yield across diverse... 相似文献
59.
The usual practice of estimating association and direct and indirect effects among various traits in Gossypium hirsutum is with ungrouped genetic material based on staple length and strength. During 2003–2004 and 2004–2005 genotypic and phenotypic
association among ten characters were estimated in G. hirsutum genotypes: (i) set-1: 10 genotypes of low fibre strength (≤196.2 mN/tex) and medium staple length (≤25.0 mm), (ii) set-2:
10 genotypes of high fibre strength (≥235.44 mN/tex) and long staple length (≥28 mm) and (iii) set-3: 20 genotypes of set-1
and 2. The differences in the estimates of associations, direct and indirect effects for different characters in fibre quality
groups were examined. The complete analysis of variance for the characters under study viz; days to 50% flowering, plant height
(cm), number of monopodial and sympodial branches per plant, seed cotton yield per plant (g), boll weight (g), total number
of bolls per plant, lint %, 2.5% span length (mm) and fibre strength (mN/tex) indicated highly significant genotypic differences
for genotypes, years and genotype × years interaction. Variation within medium staple length and low strength (set-1), high
staple length and high strength genotypes (set-2) and their interaction with year were also significant. Medium staple length
and low strength (set-1) versus high staple length and high strength component (set-2) was significant for all the traits
indicating significant variability between the sets. A true relationship and direct selection were observed for days to 50%
flowering, number of monopodial and sympodial branches per plant with seed cotton yield in the three sets suggesting that
separation of genetic material based on staple length and fibre strength for improvement of seed cotton yield through these
traits is not required. Magnitude and direction of direct effect and association with yield of the other traits; plant height,
number of total bolls per plant, boll weight, lint %, staple length and fibre strength differed between the sets. This study
concluded that more successful planning of a breeding programme can be made through path coefficient analysis if the genetic
material is grouped based on staple length and fibre strength.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
60.
Shiba Shankar Giri Sangram Ketan Sahoo Satyendra Nath Mohanty 《Aquaculture International》2010,18(4):539-544
An 84-day feeding trial was conducted to study the effect of replacing dietary fishmeal with dried chicken viscera meal (CVM)
on the growth (net biomass gain, specific growth rate, SGR), feed acceptability, feed conversion ratio (FCR), protein efficiency
ratio (PER) and carcass composition of Clarias batrachus fingerlings. Triplicate groups of fingerlings with mean initial body weight of 13.35 g were fed on six iso-nitrogenous and
iso-lipidic diets. The control diet (CVM0) used marine by-catch fishmeal as the sole source of animal protein. In the other
five diets (CVM100–CVM500), 20–100% of fishmeal was substituted by dried CVM at 20% increments. The highest body weight gain,
SGR and PER, and the lowest FCR were observed in fish fed a diet containing 300–500 g CVM kg−1. The fish accumulated increasing quantities of lipids and decreasing levels of ash in their carcasses with increasing levels
of dietary CVM. 相似文献