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1.
2.
As an alternative to ground-cover data collection by conventional and expensive sampling techniques, we compared measurements
obtained from very large scale aerial (VLSA) imagery for calibrating moderate resolution Landsat data. Using a grid-based
sampling scheme, 162 VLSA images were acquired at 100 m above ground level. The percent vegetation cover in each photo was
derived using SamplePoint (a manual inventory method) and VegMeasure (a reflectance based, automated method). Approximately
two-thirds of the VLSA images were used for calibrating Landsat data while the remainder was used for validation. Regression
models with Landsat bands accounted for 55% of the VegMeasure-based measurements of vegetation, whereas models that included
both Landsat bands and elevation data accounted for 67%. The relationship between the Landsat bands and the percent vegetation
cover measured by SamplePoint was lower (R
2 = 20%), highlighting the differences between the inventory and reflectance based protocols. Results from the model validation
indicated that the model’s predictive power was lower when the vegetation cover was either <20% or >55%. Additional work is
needed in these ecosystems to improve the calibration techniques for sites with low and high vegetation cover; however, these
results demonstrate the VLSA imagery could be used for calibrating Landsat data and deriving rangeland vegetation cover. By
adopting such methodologies the US Federal land management agencies can increase the efficiency of the monitoring programs
in Wyoming and in other western states of the US.
Mention of trade names is for information only and does not imply endorsement by USDA over comparable products or services. 相似文献
3.
R. Ramesh Kumar L. Prasanna Anjaneya ReddyJ. Vinay Kumar K. KomaraiahS. Purnanand K.P. Sastry 《Industrial Crops and Products》2012,35(1):199-202
Ashwagandha (Withania somnifera) is an important medicinal plant and its dried roots are used in traditional systems of medicine. The market price of roots is determined by physical (textural) quality. Brittle roots with high starch and low fiber are considered to be superior because of ease in grinding. Genetic diversity studies based on root textural parameters have not been done so far. So the present study was designed to assess genetic diversity for morphometric traits and root textural quality parameters among two morphologically distinct groups: Poshita and Nagore. The PCA separated the morphometric and root texture variables distinctly into two different principal components: PC-1 and PC-2 respectively, indicating that both are negatively associated. All the morphotypes in Poshita group showed high positive loadings in PC-1 indicating that component genotypes are high root yielding. Nagore morphotypes were low yielding but the root texture was good. Clustering of morphotypes grouped Poshita and Nagore separately with high inter-cluster distances indicating that both groups are highly divergent from each other, suggesting that there is sufficient scope for varietal improvement through hybridization. 相似文献
4.
Weeds PL Chakraborty S Fernandes CD d'A Charchar MJ Ramesh CR Kexian Y Kelemu S 《Phytopathology》2003,93(2):176-185
ABSTRACT Using molecular markers, this work compares the genetic diversity in Colletotrichum gloeosporioides infecting species of the tropical forage legume Stylosanthes at the center of origin in Brazil and Colombia with that of Australia, China, and India, where Stylosanthes spp. have been introduced for commercial use. There was extensive diversity in the pathogen population from Brazil, Colombia, China, and India. The Australian pathogen population was least diverse probably due to its geographical isolation and effective quarantine. The extensive diversity in China and India means that threats from exotic pathogen races to Stylosanthes pastures can potentially come from countries outside the South American center of origin. In Brazil and India, both with native Stylosanthes populations, a high level of genetic differentiation in the pathogen population was associated with sites where native or naturalized host population was widely distributed. There was limited genetic diversity at germplasm evaluation sites, with a large proportion of isolates having identical haplotypes. This contrasts recent pathogenicity results for 78 of the Brazilian isolates that show hot spots of complex races are more common around research stations where host germplasm are tested, but few are found at sites containing wild host populations. For a pathogen in which the same races arise convergently from different genetic backgrounds, this study highlights the importance of using both virulence and selectively neutral markers to understand pathogen population structure. 相似文献
5.
Pasnik DJ Vemulapalli R Smith SA Schurig GG 《Veterinary immunology and immunopathology》2003,95(1-2):43-52
A recombinant vaccine was constructed for piscine mycobacteriosis utilizing a Brucella abortus strain RB51 vector expressing a mammalian Mycobacterium sp. 85A antigen. Juvenile striped bass were inoculated with the resulting construct at doses equivalent to 10(6), 10(7), 10(8), 10(9), and 10(10) colony-forming units/fish. Blood and tissue samples from these fish demonstrated significant specific humoral and cell-mediated immune responses towards the 85A antigen in a dose-dependent manner. However, survival studies determined that inoculated fish failed to demonstrate cross-protective responses after live Mycobacterium marinum challenge 70 days post-inoculation. 相似文献
6.
A detailed study has been conducted to evaluate the residues of endosulfan and its principal metabolite (alpha-endosulfan, beta-endosulfan and endosulfan sulfate) which may have accumulated in environmental samples due to regular aerial spray application of endosulfan on cashew leaf plantation for a period of 20 years. Three months after the last spray of endosulfan 350 g litre-1 EC at 300 ml acre-1 (equivalent to 105 g AI acre-1 = 42.5 g ha-1), a total of 93 samples of cow milk, fish, water, soil and dried cashew leaf were collected from a village in Kasargode District, Kerala, India, where endosulfan contamination was likely to have occurred. All the samples were analyzed for total residues of endosulfan (comprising alpha- and beta-endosulfan), endosulfan sulfate and also the potential hydrolysis product endosulfan diol, using gas chromatography with electron capture detection. The minimum detection limits of total endosulfan was 0.001 microgram g-1. Analysis of soil samples showed the deposition of total endosulfan residues in the range < 0.001-0.010 microgram g-1, and dried leaf samples showed residues of endosulfan in the range < 0.001-3.43 micrograms g-1 dry weight. In cow milk, fish and water, endosulfan residues could not be detected above the minimum detection limit. Endosulfan diol was not observed in any sample. The data obtained was confirmed by GC-MS-EI using selective ion monitoring (SIM) mode. 相似文献
7.
Chanda Kushwaha Ramesh Chand Chandra Prakash Srivastava 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(3):323-330
Aeciospores in Uromyces fabae were found to be repeating spores and play an important role in pea rust outbreaks in the North Eastern Plain Zone (NEPZ) of India. Experiments conducted on pea rust from 2001 to 2004 revealed the dominance of aeciospores at all growth stages of pea in this region. Urediospore production was erratic and was only observed in a few samples of stems and tendrils (5–10%). Inoculation of pea plants either by aeciospores or urediospores resulted in the production of aeciospores. Production of aeciospores was observed at a temperature range of 10–25 °C, with a maximum at 25 ± 2 °C. Among the different growth stages of pea, the pod formation stage was highly susceptible and produced the maximum number (744) of aecidia/leaf at 20–25 °C. Significant effects of growth stages and temperature were also noticed for pustule number. Urediospore production mainly coincided with the senescence of the pea plants. Maximum germination (2%) of aeciospores was observed at 25 °C, whereas maximum urediospore germination (3.5%) was at 15 °C. Temperatures > 15 °C decreased urediospore germination. A relative humidity (RH) of 100% was favourable for aeciospore germination while 98% RH favoured urediospore germination. Typical histo-pathological behaviour of the aeciospores was observed. 相似文献
8.
K. Premkumar A. Pachiappan Suresh K. Abraham S. T. Santhiya P. M. Gopinath A. Ramesh 《Fitoterapia》2001,72(8):398-911
Spirulina fusiformis was tested for its possible in vivo protective effects against cyclophosphamide (CP) and mitomycin-C (MMC) induced genotoxicity and oxidative stress in mice. Pre-treatment with S. fusiformis (250, 500 and 1000 mg kg(-1), p.o., daily for 5 days) significantly reduced the chromosomal damage and lipid peroxidation with concomitant changes in antioxidants and detoxification systems. All the three tested doses were effective in exerting a protective effect against CP and MMC. 相似文献
9.
Sathanandam Pavithra N. Patil Prakash Rekha Ajitha Muthuvel Iyamperumal Patel Amrutlal R. Boggala Ramesh B. Shirol Adiveppa M. Ravishankar Kundapura V. 《Genetic Resources and Crop Evolution》2022,69(8):2787-2801
Genetic Resources and Crop Evolution - Manilkara zapota (L.) P. Royen, a widely adapted and popular tree meant for its appetizing fruits in tropics with no genomic resources like microsatellite... 相似文献
10.
S.?Vijayalakshmi Kusum?Yadav Chanda?Kushwaha S.?B.?Sarode C.?P.?Srivastava Ramesh?Chand B.?D.?SinghEmail author 《Euphytica》2005,144(3):265-274
Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm−2 leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC1F1 [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on
the parents, F1, F2, BC1F1 and BC1F2 generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant
gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase
chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant
analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately
tested with the 31 BC1F1 individuals. Two RAPD makers, viz., SC10-82360 (primer, GCCGTGAAGT), and SCRI-711000 (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified.
These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably. 相似文献