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51.
Rhizobia were isolated from Albizia lebbek (L) Benth. seed-lings collected from six different places, tested against the nodulation test and inoculated into 45 day old Albizia lebbek seedlings in steri... 相似文献
52.
A. Kumari A. Das B. N. Devanna S. Thakur P. K. Singh N. K. Singh T. R. Sharma 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(1):55-65
The rice blast resistance gene Pi54 (formerly Pi-k h ) isolated from indica rice line Tetep confers broad spectrum resistance to different strains of Magnaporthe oryzae in India. In this study, we performed PCR based allele mining for blast resistance gene Pi54 from six cultivated rice lines and eight wild rice species to understand its structural variation and its impact on the phenotypes. Sequence analysis indicates presence of more variation between cultivated and wild species (35–90 %) than variation found among cultivated species (1–20 %). Structural analysis of alleles showed presence of variable number of Open Reading Frames (0–2) principally having point mutations in the leucine rich repeats (LRR) regions. The Ka/Ks ratio of LRR region was >1, which shows the effect of selection pressure at this domain. The Pi54 alleles have 142 polymorphic sites with average nucleotide diversity of 0.04522. The Ka/Ks ratio of coding region ranged from 0 to >1 and Tajima’s D test showed negative as well as Darwinian selection within the alleles, which corresponded well with their phenotypic reaction to M. oryzae. The results obtained in this study shows divergent nature of Pi54 allele in wild species and land races of rice. The resistance alleles identified in this study can be used in effective management of rice blast disease through gene pyramiding. 相似文献
53.
54.
Field experiments were conducted in Bhubaneswar, Orissa, India, during the dry season (January–May) in 2008 and 2009 to investigate
whether practices of the System of Rice Intensification (SRI), including alternate wetting and drying (AWD) during the vegetative
stage of plant growth, could improve rice plants’ morphology and physiology and what would be their impact on resulting crop
performance, compared with currently recommended scientific management practices (SMP), including continuous flooding (CF)
of paddies. With SRI practices, grain yield was increased by 48% in these trials at the same time, there was an average water
saving of 22% compared with inundated SMP rice. Water productivity with AWD-SRI management practices was almost doubled (0.68 g l−1) compared to CF-SMP (0.36 g l−1). Significant improvements were observed in the morphology of SRI plants in terms of root growth, plant/culm height, tiller
number per hill, tiller perimeter, leaf size and number, leaf area index (LAI), specific leaf weight (SLW), and open canopy
structure. These phenotypic improvements of the AWD-SRI crop were accompanied by physiological changes: greater xylem exudation
rate, crop growth rate, mean leaf elongation rate (LER), and higher light interception by the canopy compared to rice plants
grown under CF-SMP. SRI plants showed delayed leaf senescence and greater light utilization, and they maintained higher photosynthetic
rates during reproductive and grain-filling stages. This was responsible for improvement in yield-contributing characteristics
and higher grain yield than from flooded rice with SMP. We conclude that SRI practices with AWD improve rice plants’ morphology,
and this benefits physiological processes that result in higher grain yield and water productivity. 相似文献
55.
Sen Chauhan Indra Gupta Ashok K. Khate Keviletsu Chauhan Anuj Krishna Shankar Rao Thakur Pathak Shivendra Hazra Ritwik Singh Maneesh 《Tropical animal health and production》2010,42(8):1809-1815
The objective of the study was to evaluate the effects of genetic and non-genetic factors on production of breeding bulls
and semen quality parameters in Karan Fries crossbred male by fitting least squares analysis. Genetically, the animals were
divided into three subclasses. The non-genetic factors were season of birth, period of birth, and age group with three subclasses
each for season of birth and period of birth. Age group was classified into four subclasses. The traits generated in the study
were number of males reaching semen donation stage (AFSC) and first freezing (AFSF), age at last semen collection (ALSC) and
last freezing (ALSF), age at disposal (AD), and lifetime semen production traits (up to 1 year after first freezing). The
effect of period of birth was significant for AFSC, AFSF, ALSC, and AD. It was also significant for total ejaculates produced
in a year. The age group had significant effect on AFSF. Effect of genetic group was significant for freezable ejaculates
produced in a year, for frozen semen doses produced in a year, and for number of ejaculates cryoprocessed in a year. Season
had no statistically significant effect on any of the traits studied. The influence of period revealed that the most of the
traits of breeding bulls improved after intermediate period, which could be due to better care, training, feeding, and other
management practices in the latter years. However, no consistent trend could be established for the effects of genetic groups
and other non-genetic causes on the traits considered. 相似文献
56.
Optimization of Phosphorus Fertilizer in Supplemental Feed‐Fed Based Nile Tilapia (Oreochromis niloticus) Ponds
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Moe Thidar Oo A M Shahabuddin Dhirendra P Thakur Aye Aye Mon Amararatne Yakupitiyage Amrit N Bart Ram C Bhujel Jim S Diana 《Aquaculture Research》2015,46(12):2859-2870
An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost‐benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week?1. Nitrogen fertilization rate was fixed at 28 kg N ha week?1 for all the treatments. Sex‐reversed Nile tilapia were stocked at 3 fish m?2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment. 相似文献
57.
This paper presents a new tool, developed with the aim of assessing the environmental impact from industrial effluents and sewage systems in Hanumante River and to recommend the finest procedures to control water pollution so as to improve the water quality of Hanumante River using environmental system analysis. Hanumante River is heavily polluted due to inefficient management resulting in water-associated problems. The time horizon for this study is from 2000 to 2030, yearly, and the spatial boundary is considered to be Hanumante River, Bhaktapur, Nepal. The stakeholder, function, and scenario analyses are employed as three tools for study. The participation of main stakeholders aids in resolving their various conflicting interests in Hanumante River, thus creating a common understanding about the crisis under study. A complete functional analysis illustrates various functions fulfilled by the river and their associated services. Based on the interests of the stakeholders and their priorities, two alternatives resulting in four scenarios are identified and ranked against four selected criteria. A combination of improved industrial technology and efficient municipal waste management gives the best solution to the pollution problem in Hanumante River. Different alternative themes have corresponding effects on the selected criteria. The choice is in the hands of the decision makers of Bhaktapur City. The outcome of this paper will ultimately help decision and policy makers to analyze the environmental impact of river systems and find efficient and better-quality decision making for water resource management incorporating the knowledge and experiences of various stakeholders. 相似文献
58.
Abstract Wodlly apple aphid Eriosoma lanigerum (Hsm.) is widely distributed in India. It reproduces all year round on apple and crab apple. Alates are produced from July to November and lay nymphs with degenerate mouth parts. The infestation is spread by nursery plants and air currents. The pest is controlled in the nursery either by dip-treatment with fenitrothion (0.025%) or dichlorvos (0.088%) or by soil application of phorate granules (2.5–3.0 g a.i.) during spring. Subterranean populations can be controlled with granules of dimethoate (15 g a.i.), aldicarb (5.0 g a.i.) or carbofuran (3.0 g a.i.). Aerial populations are controlled by autumn sprays of fenitrothion + dichlorvos + demeton-methyl (0.05%), vamidothion (0.025%), phosophamidon (0.035%) or dimethoate (0.03%). Banding of the trunk base with granules has been found useful in reducing reinfestation by checking the first instar nymphs, which migrate between the aerial and subterranean parts. Resistant root stocks of the ‘M.M.’ series are recommended against the pest. 相似文献
59.
60.
In this work, a series of fibrous electrets was prepared by applying electrostatic charge onto a polypropylene nonwoven fabric using corona charging process. The charging process parameters were systematically varied and their effects on charge decay were examined. A double exponential function composed of two exponentials of very different characteristics explained the charge decay characteristics very well. It was hypothesized that two charges of different nature were present in corona-charged fibrous electrets. One of the charges could be ascribed to deposition of ions onto the electret surface and the other charge could be attributed to internal polarization caused by ionic displacement. The overall charge decay could be then explained by the quick decay of the surface charge in addition to the slow decay of the bulk charge. The slow-decay component was found to contribute more to the overall charge decay with respect to a change in applied voltage. With a decrease in applied voltage, the contribution of the slow-decay component was increased. The rate of quick-decay component as well as the rate of slow-decay component was found to increase with the increase in applied voltage. With respect to a change in charging time, the quick-decay and slow-decay components were found to contribute almost equally to the overall charge. This was also true with respect to a change in distance between electrodes, except at a very high distance. With an increase in charging time, the rate of quick-decay component as well as the rate of slow-decay component started decreasing till the minimum values were obtained and increased thereafter. A similar observation was made on the role of distance between electrodes in determining the rate of quick-decay as well as the rate of slow-decay components. 相似文献