Is the variability in my crop due to genetic or environmental factors? Using heritability to solve this question     

Peñuela  Mauricio  Viáfara-Vega  Ronald  Arias  Leidy Laura  Cifuentes-Silva  Héctor  López  José  Cárdenas  Heiber 《Journal of Crop Science and Biotechnology》2022,25(2):161-172

Journal of Crop Science and Biotechnology - Usually is common to see great differences among plants in our crops, this can allow us to think about selection of some plants with the best traits in...  相似文献   

Injection of the Diaphragmatic Crus With Methylene Blue for Coloration of the Canine Thoracic Duct     

Benjamin J. Bayer DVM  Diplomate ACVS  Mauricio Dujowich DVM  Diplomate ACVS  Alexander I. Krebs DVM  Timothy G. Leeds MD  FACOG  Gregory M. Anderson DVM  Diplomate ACVS  David F. Merkley DVM  Diplomate ACVS 《Veterinary surgery : VS》2014,43(7):829-833

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A Study on Al(III) and Fe(II) Ions Sorption by Cattle Manure Vermicompost     

Cláudio Pereira Jordão  Raphael Bragança A. Fernandes  Kamilla de Lima Ribeiro  Priscila M. de Barros  Mauricio Paulo F. Fontes  Francianny Maria de Paula Souza 《Water, air, and soil pollution》2010,210(1-4):51-61

Cattle manure vermicompost has been used for the adsorption of Al(III) and Fe(II) from both synthetic solution and kaolin industry wastewater. The optimum conditions for Al(III) and Fe(II) adsorption at pH?2 (natural pH of the wastewater) were particle size of ≤250?µm, 1 g/10 mL adsorbent dose, contact time of 4 h, and temperature of 25°C. Langmuir and Freundlich adsorption isotherms fitted reasonably well in the experimental data, and their constants were evaluated, with R ² values from 0.90 to 0.98. In synthetic solution, the maximum adsorption capacity of the vermicompost for Al(III) was 8.35 mg g^?1 and for Fe(II) was 16.98 mg g^?1 at 25°C when the vermicompost dose was 1 g 10 mL^?1, and the initial adjusted pH was 2. The batch adsorption studies of Al(III) and Fe(II) on vermicompost using kaolin wastewater have shown that the maximum adsorption capacities were 1.10 and 4.30 mg g^?1, respectively, at pH?2. The thermodynamic parameter, the Gibbs free energy, was calculated for each system, and the negative values obtained confirm that the adsorption processes were spontaneous.  相似文献   

Molecular characterization of Clostridium difficile isolates from horses in an intensive care unit and association of disease severity with strain type     

Magdesian KG  Dujowich M  Madigan JE  Hansen LM  Hirsh DC  Jang SS 《Journal of the American Veterinary Medical Association》2006,228(5):751-755

OBJECTIVE: To determine molecular characteristics, antimicrobial susceptibility, and toxigenicity of Clostridium difficile isolates from horses in an intensive care unit and evaluate associations among severity of clinical disease with specific strains of C difficile. DESIGN: Prospective study. ANIMALS: 130 horses. PROCEDURES: Feces were collected from horses admitted for acute gastrointestinal tract disease with loose feces and submitted for microbial culture and immunoassay for toxin production. Polymerase chain reaction assays were performed on isolates for toxins A and B genes and strain identification. RESULTS: Isolates were grouped into 3 strains (A, B, and C) on the basis of molecular banding patterns. Toxins A and B gene sequences were detected in 93%, 95%, and 73% of isolates of strains A, B, and C, respectively. Results of fecal immunoassays for toxin A were positive in 40%, 63%, and 16% of horses with strains A, B, and C, respectively. Isolates in strain B were resistant to metronidazole. Horses infected with strain B were 10 times as likely to have been treated with metronidazole prior to the onset of diarrhea as horses infected with other strains. Duration from onset of diarrhea to discharge (among survivors) was longer, systemic inflammatory response syndromes were more pronounced, and mortality rate was higher in horses infected with strain B than those infected with strains A and C combined. CONCLUSIONS AND CLINICAL RELEVANCE: Horses may be infected with a number of heterogeneous isolates of C difficile. Results indicated that toxigenicity and antimicrobial susceptibility of isolates vary and that metronidazole-resistant strains may be associated with severe disease.  相似文献   

Cotton Genetic Resources in the Western States of Mexico: In situ Conservation Status and Germplasm Collection for ex situ Preservation     

Mauricio Ulloa  James McD. Stewart  Enrique A. Garcia-C.  Salvador Godoy-A.  Arturo Gaytan-M.  N. Sebastián Acosta 《Genetic Resources and Crop Evolution》2006,53(4):653-668

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Genetic diversity and mating system of <Emphasis Type="Italic">bracatinga</Emphasis> (<Emphasis Type="Italic">Mimosa scabrella</Emphasis>) in a re-emergent agroforestry system in southern Brazil     

Priscila Ambrósio Moreira  Walter Steenbock  Nivaldo Peroni  Mauricio Sedrez dos Reis 《Agroforestry Systems》2011,83(2):245-256

Bracatinga (Mimosa scabrella) is a legume tree species common in the early stages of succession in Araucaria angustifolia forests in southern Brazil. Bracatinga can form high-density monospecific stands called bracatingais. Its traditional management for charcoal production involves maintenance of the seed bank. Our objective was to analyze the genetic diversity and structure of bracatingais to understand the mechanisms by which intraspecific diversity of M. scabrella is created and maintained in landscapes managed by family farmers in their agroforestry mosaics. We analyzed 14 bracatingais using 8 allozyme loci. We compared parental and progeny generation indices (7 loci) and described the mating system (9 loci) of two progenies. Overall diversity was high: A = 2.69, H _o = 0.257, H _e = 0.382 and similar between populations. Overall fixation (F = 0.364) was similar to the fixation index (f = 0.329). The genetic divergence among populations was low (Θ_p = 0.052) but significant. The progenies’ genetic diversity values were similar to those of the previous generation (H _{e pop11} = 0.342 vs. 0.420/H _{e pop10} = 0.432 vs. 0.400). Progenies were compatible with half-sib and full-sib crossing expectations (θ _xy  = 0.204 and 0.194). Our data showed that there is a tendency for genetic structuring caused not only by the reproductive system but also by genetic drift. It is very likely that the high genetic diversity is amplified by internal migration within each bracatingal. This study showed that current landscape management can contribute to maintaining high levels of bracatinga genetic diversity, which contributes to its regional conservation.  相似文献   

Spectral and time-resolved fluorescence signature of four weed species as affected by selected herbicides     

Mauricio Hunsche  Kathrin Bürling  Georg Noga 《Pesticide biochemistry and physiology》2011,101(1):39-47

In the present study we show for the first time the suitability of the laser-induced fluorescence technique to evaluate in vivo herbicide-induced damages as revealed by changes of fluorescence spectra and lifetime. Four herbicides of different modes of action (glyphosate, bromoxynil, mesotrione, and amitrole) were selected and applied to four weed species (Stellaria media, Setaria viridis, Chenopodium album, and Viola arvensis). Modifications of the fluorescence signature depended on the agrochemical – plant species interaction as well as on the time after application. Measurements in the red and far-red spectral region reveal disturbances in the functionality of the photosynthetic apparatus and chlorophyll concentration, e.g. after application of bromoxynil or mesotrione. Recordings in the blue and green spectral regions indicate changes of both amount and composition of specific fluorophores, i.e. after application of glyphosate and amitrole. In all spectral measurements, the position of peak maxima was not affected by herbicide application. The fluorescence lifetime, expressed as LTmean or as lifetime 1 (LT1, short-duration) and LT2 (long-duration) fractions, provided additional information to the spectrally resolved data. Thereby, significant alterations of the lifetime duration and fractional characteristics were observed at specific wavelengths, e.g. after application of bromoxynil, mesotrione, or amitrole.  相似文献   

Spinosad as an effective larvicide for control of Aedes albopictus and Aedes aegypti, vectors of dengue in southern Mexico     

Marina CF  Bond JG  Casas M  Muñoz J  Orozco A  Valle J  Williams T 《Pest management science》2011,67(1):114-121

BACKGROUND: Field trials were conducted during the wet and dry seasons in periurban and semi‐rural cemeteries in southern Mexico to determine the efficacy of a suspension concentrate formulation of spinosad (Tracer 480SC) on the inhibition of development of Aedes albopictus L. and Ae. aegypti Skuse. For this, oviposition traps were treated with spinosad (1 or 5 mg L^?1), Bacillus thuringiensis israelensis (Bti, VectoBac 12AS), a sustained release formulation of temephos and a water control. RESULTS: Ae. albopictus was subordinate to Ae. aegypti during the dry season, but became dominant or codominant during the wet season at both sites. The two species could not be differentiated in field counts on oviposition traps. Mean numbers of larvae + pupae of Aedes spp. in Bti‐treated containers were similar to the control at both sites during both seasons. The duration of complete absence of aquatic stages varied from 5 to 13 weeks for the spinosad treatments and from 6 to 9 weeks for the temephos treatment, depending on site, season and product concentration. Predatory Toxorhynchites theobaldi Dyar and Knab suffered low mortality in control and Bti treatments, but high mortality in spinosad and temephos treatments. Egg counts and percentage of egg hatch of Aedes spp. increased significantly between the dry and wet seasons, but significant treatment differences were not detected. CONCLUSION: Temephos granules and a suspension concentrate formulation of spinosad were both highly effective larvicides against Ae. aegypti and Ae. albopictus. These compounds merit detailed evaluation for inclusion in integrated control programs targeted at Ae. aegypti and Ae. albopictus in regions where they represent important vectors of human diseases. Copyright © 2010 Society of Chemical Industry  相似文献   

Evaluation of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate in Two Chilean Soils     

Mauricio Molina Roco  Rodrigo Ortega Blu 《Journal of plant nutrition》2013,36(3):521-534

ABSTRACT

Two Chilean soils were used to evaluate the performance of the nitrification inhibitor 3,4-dimetilpirazol phosphate (DMPP) added to ammonium-sulfate-nitrate (ASN) in comparison with traditional nitrogen (N) sources and different N-application forms. Two experiments were conducted: In the first, broccoli (Brassica oleracea var. italica) plants were cultivated in pots under greenhouse conditions, and received a N-fertilization equivalent to 150 Kg N ha^?1 as ASN+DMPP (one application), urea (two splits), and sodium-potassium nitrate (three splits). In the second, ryegrass (Lolium spp.) plants were grown in pots under shading conditions. In this case, ASN+DMPP and urea were applied at N rates equivalent to 150 and 300 Kg N ha^?1 in a single application. In the first experiment, ASN+DMPP increased dry-matter production, maintained a higher N content in the soil (at least until the middle of the growing period), and improved fertilizer N-use efficiency (FUE) in one soil. There were no significant differences in N-leaching losses. In the ryegrass experiment, ASN+DMPP increased dry-matter production and FUE, while N-leaching losses were reduced. Treatments with ASN+DMPP maintained higher N levels in soil throughout the growing period, and there were no significant differences in the available N fraction between the two N rates. The use of DMPP-containing fertilizers may be a good alternative for increasing FUE.  相似文献   

The influence of cultivar and plant age on the chemical composition of field-grown cassava leaves and roots     

Guillermo Gómez  Mauricio Valdivieso  Amy T. Noma 《Plant foods for human nutrition (Dordrecht, Netherlands)》1985,35(2):109-119

The chemical composition, including the proximal composition, cyanide and amino acid concentrations of leaves and root tissues, as well as the starch and sugar concentrations of root peel and parenchyma, of low-(M Col 113), intermediate-(M Col 22 and the hybrid CM 342-170) and high-(M Col 1684) cyanide-containing cassava cultivars at four plant ages (6, 8, 10 and 12 months) is presented. The local cultivar (M Col 113) showed lower leaf and root parenchyma dry matter contents, lower crude fiber and crude protein levels in root peel, a higher sugar content and lower cyanide concentration in root tissues, than the other three cultivars (M Col 22, CM 342-170 and M Col 1684). Most of the parameters studied were affected by the cultivar as well as by plant age. Less variability was observed for all criteria in the root parenchyma than in the leaves and root peel. The sulfur-containing amino acids were low in all tissues analyzed and a high concentration of arginine was found in the root tissue samples. The cyanide concentration of root parenchyma was less variable than that of leaves and root peel; the cultivar M Col 1684 showed a higher cyanide concentration in the parenchyma (900 to 1000 mg/kg DM) than the other three cultivars, which ranged from 100 to 200 mg/kg DM. The local cultivar (M Col 113) was the only one in which the cyanide concentration in leaves was higher than that of the root peel. The hybrid CM 342-170 produced roots with the highest dry matter and starch concentrations.  相似文献