Preliminary assessment of Crambe germplasm resources     

E. E. Leppik  George A. White 《Euphytica》1975,24(3):681-689

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Tosa Han: A study of a Fief in 17th Century Japan—     

George H. Kakiuchi 《Asia Pacific viewpoint》1967,8(1):1-16

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Inheritance of resistance to angular leaf spot in common bean and validation of the utility of resistance linked markers for marker assisted selection out side the mapping population     

Annet Namayanja  Robin Buruchara  George Mahuku  Patrick Rubaihayo  Paul Kimani  Stephen Mayanja  Hellen Eyedu 《Euphytica》2006,151(3):361-369

Inheritance of resistance to angular leaf spot (ALS) disease caused by Phaeoisariopsis griseola (Sacc.) Ferr was investigated in two common bean cultivars, Mexico 54 and BAT 332. Both Andean and Mesoamerican backgrounds were used to determine the stability of the resistance gene in each of the two cultivars. Resistance to P. griseola was phenotypically evaluated by artificial inoculation with one of the most widely distributed pathotypes, 63–39. Evaluation of the parental genotypes, F₁, F₂ and backcross populations revealed that the resistance to angular leaf spot in the cultivars Mexico 54 and BAT 332 to pathotype 63–39 is controlled by a single dominant gene, when both the Andean and Mesoamerican backgrounds were used. Allelism test showed that ALS resistance in Mexico 54 and BAT 332 to pathotype 63–39 was conditioned by the same resistance locus. Resistant and susceptible segregating populations generated using Mexico 54 resistant parent were selected for DNA extraction and amplification to check for the presence /absence of the SCAR OPN02 and RAPD OPE04 markers linked to the Phg-2 resistance gene. The results indicated that the SCAR OPN02 was not polymorphic in the study populations and therefore of limited application in selecting resistant genotypes in such populations. On the other hand, the RAPD OPE04 marker was observed in all resistant individuals and was absent in those scored susceptible based on virulence data. Use of the RAPD OPE04 marker in marker-assisted selection is underway.  相似文献   

Transmission of resistance to common scab from the diploid to the tetraploid level via 4x-2x crosses in potatoes   总被引：1，自引：0，他引：1  

Agnes M. Murphy  Hielke De Jong  George C. C. Tai 《Euphytica》1995,82(3):227-233

Summary Diploid potato clones selected for their reaction to common scab and their ability to produce 2n male gametes were used in a series of crosses to a susceptible tetraploid female parent (cv. Shepody). In addition, two tetraploid clones were also selected for their reaction to common scab and crossed with Shepody as a female parent. Results indicated that resistance to common scab can be effectively transmitted from the diploid to the tetraploid level via 4x-2x crosses. Diploid parents producing 2n pollen via either first division or second division restitution can be used to transmit scab resistance. A relatively small proportion of resistant individuals could be recovered from susceptible x susceptible crosses in both 4x-2x and 4x-4x combinations. The data support a previously developed hypothesis that scab resistance is relatively simply inherited.  相似文献   

Path analysis of genotype-environment interactions of potatoes exposed to increasing warm-climate constraints     

George C. C. Tai  David Levy  Warren K. Coleman 《Euphytica》1994,75(1-2):49-61

Summary Twenty potato cultivars were tested in replicated trials in three seasons. The weather gradually changed from relatively high humidity and cold air temperatures in February to dry and hot in July. Fresh and dry weights, sucrose, reducing sugar and starch contents were recorded on tubers sequentially harvested over four stages during the growing period of each of the three trials. The data were analyzed for genotype-environment interactions by a path regression model which is composed of a main effect and four multiplicative effects. The model fitted well to the observed data for all traits but reducing sugar. Results of dry tuber weight were used to calculate a heat susceptibility index for each of the cultivars. Four components of the index were identified based on the path model. Comparison of sizes of the components provided information on the degree of response to the environmental stress of each of the cultivars during successive stages of growth. High yielding and heat tolerant cultivars were identified based on the experimental results.  相似文献   

Effectiveness of biodiversity indicators varies with extent, grain, and region     

George R. Hess  Rebecca A. Bartel 《Biological conservation》2006,132(4):448-457

The use of indicator taxa for conservation planning is common, despite inconsistent evidence regarding their effectiveness. These inconsistencies may be the result of differences among species and taxonomic groups studied, geographic location, or scale of analysis. The scale of analysis can be defined by grain and extent, which are often confounded. Grain is the size of each observational unit and extent is the size of the entire study area. Using species occurrence records compiled by NatureServe from survey data, range maps, and expert opinion, we examined correlations in species richness between each of seven taxa (amphibians, birds, butterflies, freshwater fish, mammals, freshwater mussels, and reptiles) and total richness of the remaining six taxa at varying grains and extents in two regions of the US (Mid-Atlantic and Pacific Northwest). We examined four different spatial units of interest: hexagon (∼649 km²), subecoregion (3800-34,000 km²), ecoregion (8300-79,000 km²), and geographic region (315,000-426,000 km²). We analyzed the correlations with varying extent of analysis (grain held constant at the hexagon) and varying grain (extent held constant at the region). The strength of correlation among taxa was context dependent, varying widely with grain, extent, region, and taxon. This suggests that (1) taxon, grain, extent, and study location explain, in part, inconsistent results of previous studies; (2) planning based on indicator relationships developed at other grains or extents should be undertaken cautiously; and (3) planning based on indicator relationships developed in other geographic locations is risky, even if planning occurs at an equivalent grain and extent.  相似文献   

Fumonisin B-glucose reaction products are less toxic when fed to swine     

Fernández-Surumay G  Osweiler GD  Yaeger MJ  Rottinghaus GE  Hendrich S  Buckley LK  Murphy PA 《Journal of agricultural and food chemistry》2005,53(10):4264-4271

The effects of fumonisin B-glucose reaction products in swine diets was examined. Pigs were fed diets containing 528 micromol of total fumonisin B/kg (FB), 528 micromol of total FB-glucose adducts/kg (FB-G, 122 micromol of unreacted FB/kg), or 0 micromol of total FB/kg for 15 days to test the efficacy of the FB-G reaction products in detoxifying FB. Weight gain in FB pigs was lower than in FB-G or controls, which was correlated with feed intake reduction in FB pigs. Serum aspartate aminotransferase, gamma-glutamyltransferase, and total bilirubin in FB pigs were higher than in FB-G or control pigs. Serum sphinganine/shingosine ratios in FB pigs were higher than in FB-G or control pigs. Microscopic examination of tissues from FB pigs showed generalized liver necrosis and apoptosis with marked cellular pleomorphism and disorganized hepatic cords. The liver and kidneys in the FB-G group appeared to be normal. Tissues of controls were free of lesions. Results suggest that dietary FB-G products are less toxic to swine and may provide an detoxification approach in instances of widespread FB grain contamination (p < 0.05).  相似文献   

Residues of spiroxamine in grapes following field application and their fate from vine to wine     

Tsiropoulos NG  Miliadis GE  Likas DT  Liapis K 《Journal of agricultural and food chemistry》2005,53(26):10091-10096

Dissipation of the fungicide spiroxamine in grapes of two vine varieties, Roditis and Cabernet Sauvignon, exposed to field treatments was evaluated. Vines of a grape vineyard located in central Greece were sprayed once or twice with a commercial formulation of the fungicide at 30 g a.i./hL. Residues in grapes, must, and wine were determined by gas chromatography/IT-MS after extraction with cyclohexane-dichloromethane (9:1), with a limit of quantitation 0.02 mg/kg in grapes and 0.012 mg/kg in wine. Under field conditions, spiroxamine dissipation on grapes was faster during the first 2 weeks and then slower to the sixth week. About 7 days after application, half of the initial spiroxamine concentration remained on the grapes; the respective proportion at 42 days was about 10%. At 14 and 35 days, residues were lower than 0.44 and 0.22 mg/kg, respectively, values below the maximum residue levels set by the European Union (1 mg/kg). Spiroxamine residues transferred from grapes into the must and through the vinification process into the wine were also studied. Mean transfer factors of 0.26 and 0.55 were found from grapes into wine for the wines obtained without maceration and with maceration, respectively. Residues in wine, prepared from grapes with a spiroxamine content of 0.11-0.20 mg/kg, varied from <0.026 to 0.09 mg/kg. Spiroxamine diastereomer B was found to dissipate slower than diastereomer A in the field as well as during the vinification process.  相似文献   

Silicon nutrition of tomato and bitter gourd with special emphasis on silicon distribution in root fractions     

Gregor Heine  George Tikum  Walter J. Horst 《植物养料与土壤学杂志》2005,168(4):600-606

Two plant species, tomato (Lycopersicon esculentum Mill.) and bitter gourd (Momordica charantia), were used for in‐depth studies on the dynamics of silicon (Si) uptake and translocation to the shoots and compartmentation of Si in the roots. The experiments were conducted under controlled environmental conditions in nutrient solutions, which were partly amended with 1 mM Si in the form of silicic acid. At harvest, xylem exudates were collected, and Si concentrations and biomass of roots and shoots were determined. Mass flow of Si was calculated based on the Si concentration of the nutrient solution and transpiration determined in a parallel experiment. Plant roots were subjected to a fractionated Si analysis, allowing attributing Si to different root compartments. Silicon concentrations in the roots compared to the shoots were higher in tomato but lower in bitter gourd. A more ready translocation from the roots to the shoots in bitter gourd was in agreement with Si concentrations in the xylem exudates which were higher than in the external solution. In tomato, the xylem‐sap Si concentration was lower than in the nutrient solution. Calculated Si mass flow to the root exceeded Si uptake in tomato, which was consistent with the measured accumulation of Si in the root water‐free space (WFS). In contrast, Si concentration in the root WFS was lower than in the nutrient solution in bitter gourd, reflecting the calculated Si depletion at the root surface based on the comparison of Si mass flow and Si uptake. Within the roots, more than 80% of the total Si was located in the cell wall and less than 10% in the cytoplasmic fractions in tomato. In bitter gourd, between 60% and 70% of the total root Si was attributed to the cell‐wall fraction whereas the proportion of the cytoplasmic fraction reached more than 30%. Our results clearly confirm that tomato belongs to the Si excluders and bitter gourd to the Si‐accumulator plant species for which high Si concentrations in the cytoplasmic root fraction appear to be characteristic.  相似文献   

Ionic composition of acid lakes in relation to airborne inputs and watershed characteristics     

Gary E. Glass  John A. Sorensen  Barbara W. Liukkonen  George R. Rapp Jr.  Orie L. Loucks 《Water, air, and soil pollution》1986,31(1-2):1-15

Present acid forming emissions to the atmosphere have the potential to alter significantly the chemistry of rain, snow, and surface water of weakly buffered lakes in the Upper Midwest. Average precipitation pH from field measurements during 1979–1983 declined from west to east from 4.8, 4.6, and 4.3 along a cross-section of sites in Minnesota, Wisconsin, and Michigan respectively where 990 lake and stream sampling sites were studied. Measurements of weakly buffered lakes show a parallel decline in lake water pH with the lowest values measured, 5.1, 4.6 and 4.4, respectively in the same regions. Correspondingly, the percentage of lakes sampled with little or no acid neutralizing capacity (ANC) was found to increase from 0 to 4 and 13%, respectively. The geographic patterns in ionic composition of airborne acids and bases, and the resultant surface water concentrations are compared. The acid forming capacity (AFC) from airborne inputs is calculated using mass balance and in-lake processes. Stoichiometric acid-base reactions are used to balance the observed chemical differences between airborne inputs and surface water composition considering nitrification, denitrification, other oxidation-reduction reactions, and the evaporation concentration process. Microbial activity in surface water can result in a net decrease in ionic strength from the conversion of most of the ammonium and nitrate to neutral compounds and biomass, but only a partial reduction of about 20% of the sulfate inputs to weakly buffered lakes. The resulting AFC of airborne inputs are calculated to range from 30 to 60, 50 to 90, and 80 to 130 μeq H+L-l, respectively, in northeastern Minnesota-Ontario, northcentral Wisconsin and northern Michigan-Ontario. The differences in AFC of airborne inputs from west to east, and differences in in-lake processes explain the observed acidity of weakly buffered lakes across the region.  相似文献