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131.
Hernandez JA Garbarino EJ Shearer JK Risco CA Thatcher WW 《Journal of the American Veterinary Medical Association》2007,230(1):89-93
OBJECTIVE: To assess the efficacy of prophylactic hoof health examination and trimming during midlactation at reducing the incidence of lameness during late lactation in dairy cows. DESIGN: Randomized field trial. ANIMALS: 333 Holstein cows. PROCEDURES: Cows without apparent lameness were randomly allocated into 1 of 2 groups approximately 204 days after calving. Cows allocated to the treatment group (n = 161) were examined on a tilt table for diagnosis and underwent hoof-trimming procedures, if needed, for treatment of hoof disorders or lesions. Cows in the control group (n = 172) were not examined. Cows were assigned a locomotion score weekly for 28 weeks after allocation to a group. The number of cows classified as lame during late lactation (approx 205 to 400 days after calving) was compared between groups to assess the efficacy of prophylactic examination and trimming. RESULTS: Incidence of lameness during late lactation was 24% in cows in the control group and 18% in cows in the treatment group. CONCLUSIONS AND CLINICAL RELEVANCE: The 25% decrease in number of new cases of lameness in cows undergoing prophylactic hoof health examination and trimming during midlactation may be relevant for the well-being of dairy cows and should not represent a major economic burden to producers. 相似文献
132.
Gimenez G Florin-Christensen M Belaunzarán ML Isola EL Suárez CE Florin-Christensen J 《Veterinary immunology and immunopathology》2007,119(3-4):171-179
Erythrocytes of bovines and other ruminants have a strikingly anomalous phospholipid composition, with low or absent phosphatidylcholine (PC) together with high sphingomyelin (SM) content. Here, we report the presence in normal bovine serum of high levels of anti-phospholipid antibodies of IgM isotype against, PC and the phosphono analogue of phosphatidylethanolamine, aminoethylphosphonolipid (AEPL), normally produced by rumen ciliates. In contrast, no antibodies were detected against SM or N-acyl-phosphatidylethanolamine (NAPE), the major components of bovine erythrocytes. In addition, we found that exposure of the ciliate Tetrahymena thermophila to bovine serum results in rapid lysis, an effect that was inhibited by adsorption of the serum with SM/AEPL liposomes. Furthermore, incubation with bovine serum had a similar effect on freshly obtained ruminal ciliates, and the lytic activity was eliminated by pre-adsorption of the serum with SM/PE liposomes. The ruminant mode of life with its concomitant ciliate fauna is hereby linked to the peculiar conformation of bovine erythrocyte membranes. We propose that the unique phospholipid composition of bovine erythrocytes appears as an evolutionary adaptation to tolerate the lytic effects of anti-phospholipid antibodies generated against AEPL, a membrane component of the huge mass of ruminal ciliates, necessary commensals of this group of mammals. 相似文献
133.
Fuensanta García‐Orenes Antonio Roldn Alicia Morugn‐Coronado Carlos Linares Artemi Cerd Fuensanta Caravaca 《Land Degradation \u0026amp; Development》2016,27(6):1622-1628
Soil microbial populations and their functions related to nutrient cycling contribute substantially to the regulation of soil fertility and the sustainability of agroecosystems. A field experiment was performed to assess the medium‐term effect of a mineral fertilizer and two organic fertilization systems with different nitrogen sources on the soil microbial community biomass, structure, and composition (phospholipid fatty acids, pattern, and abundance), microbial activity (basal respiration, dehydrogenase, protease, urease, β‐glucosidase, and total amount of phosphomonoesterase activities), and physical (aggregate stability) and chemical (total organic C, total N, available P and water‐soluble carbohydrates) properties in a vineyard under semiarid Mediterranean conditions after a period of 10 years. The three fertilization systems assayed were as follows: inorganic fertilization, addition of grapevine pruning with sheep manure (OPM), and addition of grapevine pruning with a legume cover crop (OPL). Both treatments, OPM and OPL, produced higher contents of total organic carbon, total N, available P, water‐soluble carbohydrates, and stable aggregates. The organic fertilization systems increased microbial biomass, shifted the structure and composition of the soil microbial community, and stimulated microbial activity, when compared with inorganic fertilization. The abundances of fungi and G+ bacteria were increased by treatments OPM and OPL, without significant differences between them. Organic and inorganic fertilization produced similar grapevine yields. The ability of the organic fertilization systems for promoting the sustainability and soil biological and chemical fertility of an agroecosystem under semiarid conditions was dependent of the organic N source. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
134.
Barbarita Companioni Mayda Arzola Yania Rodríguez Marais Mosqueda María Cristina Pérez Orlando Borrás José Carlos Lorenzo Ramón Santos 《Euphytica》2003,130(3):341-347
Banana and plantain are among the most important food crops in developing countries but production is threatened by increasing
virulent forms of Fusarium oxysporum f. sp. cubense. Chemical control is not economically effective and,therefore, breeding programs are necessary. Traditional field studies
of new genotype resistance to this disease are time-consuming and destructive. Therefore,we developed a rapid and non-destructive
procedure to differentiate field-grown banana resistant from susceptible clones. This procedure implicates application of
culture filtrates of Fusarium oxysporum f. sp. cubense race 1 onto banana leaves. The relationship between duration of the fungal in vitro incubation, and the fungal culture fresh mass, the culture filtrate absorbency, and the Gross Michel (susceptible cultivar)leaf
lesion area (after application of the culture filtrate) were similar and at 24day-incubation the highest values of the recorded
indicators were observed. A comparison between Gross Michel and FHIA-01(resistant) was also performed. The most relevant differences
between cultivars were observed at 48 hours after application of the culture filtrate, and in the middle-aged leaves. The
position of the culture filtrate application in the leaf limb (distal, middle, proximal) was not determinant. A wider comparison
among banana cultivars confirmed previous results informed by other researchers using different systems to study this plant-fungus
interaction. Such a confirmation validates the effectiveness of the procedure described here to select rapid and non-destructively
banana resistance to this disease at field level.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
135.
Grisela L. Botta María P. Dimarco Alicia L. Melegari Marcelo A. Huarte Carlos A. Barassi 《Euphytica》1994,80(1-2):63-69
Summary
Fusarium solani f.sp. eumartii Carp. Snyder and Hansen (Fusarium eumartii) is a soil inhabitant that induces the so-called Potato Wilt and Stem End Rot disease. Prior to wilting, the pathogen induces peculiar small bronze spots on the leaflets. Failure to isolate F. eumartii from infected leaflets suggests the involvement of a toxin in the disease. The fungus was grown in liquid Richard's medium and thereafter a filtrate was obtained dialyzing (MW cutoff 12,000–14,000) and sterilizing the culture by filtration (0.22 m). Potato leaves treated with both the pathogen or the filtrate showed symptoms of bronze spots and significantly higher electrolyte leakage when compared to controls. Tomato leaves showed neither bronze spots nor electrolyte leakage after plant inoculation with the pathogen or with the filtrate treatment. Both, the absence of visible symptoms and the lack of electrolyte leakage in tomato could be associated to a certain degree of host specificity of the F. eumartii filtrate towards potato. The filtrate also induced symptoms similar to infections by F. eumartii in adult plants and in vitro plantlets of cultivars Huinkul MAG and Kennebec. Callus responses to the filtrate were related to responses of the cultivars to the pathogen in greenhouse. These results show the potential of the culture filtrate of F. eumartii for use in screening for wilting resistance. 相似文献
136.
Effect of incubation temperature regimes and culture medium on broccoli microspore culture embryogenesis 总被引:8,自引:0,他引:8
João Carlos da Silva Dias 《Euphytica》2001,119(3):389-394
Conditions for reliable induction of embryogenesis from isolated microspores were studied in ten genotypes of broccoli. Embryo
yields were significantly increased in almost all of the broccoli genotypes by the incubation at 32.5 °C for 1 day, than when the standard incubation at 30 °C for 2 days was used. Treatments of 48 hours at 32.5 °C produced less than optimal results suggesting that broccoli microspores are more sensitive to high temperatures than those
of B. napus. The use of the 1/2 NLN-13 medium yielded greater number of embryos than the standard NLN-13. The magnitude of the response to the redution of
the concentration of major salts by half in the NLN medium varied with the different genotypes. High embryogenic broccoli
cultivars, such as ‘Shogun’, ‘SDB9’, and ‘Green Valiant’, presented a better response to the reduction of the concentration
of major salts by half in NLN-13. Reduction never produced a detrimental effect on embryo yield and seems not to have any
effect in the subsequent development of embryos in plants.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
137.
José F. Barbosa-Neto Carlos M. Hernández Louise S. O’Donoughue Mark E. Sorrells 《Euphytica》1997,98(1-2):59-67
Genetic progress through selection is directly related to the amount of variability present in the population and the quality
of genes contributed by the parents. Genetic relationships between lines were studied using DNA marker-based estimates of
genetic similarity. A statistical methodology using the width of a confidence interval was developed to determine the number
of probes to be surveyed and the precision in the estimation of genetic distance between pairs of cultivars. Precision was
affected by type of genetic distance used, the number of cultivars, and amount of genetic diversity present in the studied
group. The width of a (1-α)% confidence interval decreased as the number of RFLP fragments increased. Oat and wheat diversity
studies were used to illustrate the methodology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
138.
Yields of large-seeded Andean (A) common bean (Phaseolus vulgaris L.) cultivars of Chile and Nueva Granada races are 40 to 60% lower compared to their Middle American (M) counterparts of small-seeded Mesoamerica and medium-seeded Durango races. Our objective was to use the concept of congruity backcrossing between Andean x Middle American inter-gene pool [AM 11833 = A 483 (A)///// A 686 (M) //// PVA 800A(A)/// ‘Carioca’ (M)// Carioca (M)/ G 19833 (A)] and between races within Andean gene pool [i.e., intra-gene pool Andean, AA 11834 = A483 (A)//// ‘Cardinal’(A) /// ‘Blanco Español’(A) // BlancoEspañol (A) / ‘Taylor’ (A)] to compare selection for seed yield improvement of large-seeded Andean beans. Seven hundred sixty seven F2-derived F3 (F2:3) families were produced for each population. Visual appraisal for total plant performance, combined with seed yield from non-replicated plots was used for selection of 551 families in F2:3, 182 families in F2:4, and 91 families in F2:5 in each population. Eight hundred twenty three F5:6 lines were developed from the 91 F2:5 families in each population. Visual selection, combined with seed yield in non-replicated plots was again used to select 294 lines in F5:6 in each population. Similarly, 44 highest yielding F5:7 lines were selected in AM 11833 and 39 F5:7 lines in AA 11834. Thus, single plant selections were made in the F2 and F5, and plants within each plot were harvested in bulk in F3, F4, F6, and F7. Thirty nine F5:8 lines from AA 11834 and 44 lines from AM 11833, parents, and checks were evaluated at Popayán and Quilichao, Colombia in 1998 and 1999. Selected lines in both populations, on average, out-yielded the mean of their large-seeded Andean parents. Mean yield of the lines selected from AM 11833 was 50% higher than AA 11834 lines. Twelve F5:8 lines out-yielded the highest yielding Andean parents G 19833 and A 483 in AM 11833, whereas only one line yielded significantly higher (p < 0.05) than the highest yielding parent A 483 in AA 11834. However, none of selected lines out-yielded small-seeded Middle American parents used in AM 11833 (A 686 and ‘Carioca’). The mean 100 seed-weight of AA 11834 was 36 g compared to 28 G for AM 11833 F5:8 lines. Selected lines had similar days to maturity as parents in AM 11833, and matured 3 d later in AA11834. Correlation coefficients between yield and 100 seed-weight were negative in both populations. Yield and days to maturity were positively correlated in AA 11834. 相似文献
139.
Summary Five parents from each of four race groups of common bean (Phaseolus vulgaris L.) were hybridized to produce five crosses within each group. Also, five crosses were made for each of the six possible combinations among four groups. Parents, F1 and F2, and parents, F2 and F3 were evaluated for seed yield in 1990 and 1991, respecitively, at two locations in Colombia.Yield of parents belonging to Middle American races and crosses among them was higher than that of races of Andean origin. Positive correlations were found among the mid-parent value, F1, F2 and F3. Also, the mid-parent value predicted the mean seed yield of all possible lines that could be derived from the F-generation in 42 out of 47 crosses. Four crosses, all between common bean races of Andean and Middle American origin, indicated a possible loss of favorable epistatic parental alleles. On average, mean yield of interracial F1 hybrids was higher than that of intraracial ones.Positive heteroris (26.4%–123.8%) over the mid-parent in 31 crosses, and F1s yielding higher (23.7%–91.8%) than the high parent in 20 crosses and yielding higher (22.1%–53.2%) than the highest control among all parents (MAM 13) in 12 crosses, were found. Heritability, estimated by the parent-offspring regression, ranged from 0.42± 0.07 to 0.49±0.04. Expected and realized gains from selection (at 20% selection pressure) ranged from 10.3% to 21.0% over the mean of F1 hybrids and F2 and F3 population bulks. 相似文献
140.
Summary Two common bean (Phaseolus vulgaris L.) cultivars were used for recurrent backcrossing (i.e., repeated backcrossing to one of the parents) to both parents independently and for congruity backcrossing (i.e., backcrossing alternately to both parents). One cultivar, ICA Pijao of race Mesoamerica, was late maturing, with erect type II growth habit and small seeds. The other was Pinto UI 114 of race Durango, an early maturing cultivar with prostrate type III growth habit and medium seeds. One to three recurrent backcrosses (RBC) to both parents, and two rounds of congruity backcrosses (CBC), were made. Thirty-two random lines from each method along with two parents were compared in a reps-in-set design at two locations (Popayán and Quilichao) in Colombia in 1992–1993.Differences between lines derived through different methods were found for seed yield, 100-seed weight, days to maturity, growth habit, and seed color pattern. The RBC to ICA Pijao produced lines with relatively higher seed yield, smaller seed size, and delayed maturity. Similarly, the RBC to Pinto UI 114 produced lines with reduced yield, medium seed size, and earlier maturity. All lines from one, two, and three RBC to Pinto UI 114 had type III growth habit. While most lines from the RBC to ICA Pijao had erect type II Growth habit, a few type III lines were also found in all the RBC. The lines derived from the CBC mostly possessed yield, maturity, and seed characteristics between those of the two parents and lines derived from RBC to both parents independently. They also had more variation for growth habit. To maximize recombination between and retention of desirable traits from distantly related parents used in interracial crosses, use of the CBC is suggested. 相似文献