Resistance of potato clones to the green peach aphid and potato leafroll virus     

David Mndolwa  Guy Bishop  Dennis Corsini  Joseph Pavek 《American Journal of Potato Research》1984,61(12):713-722

During 1980 and 1981 potato cultivars and breeding selections, including cultivated species and their hybrid derivatives, were evaluated for resistance to the green peach aphid (GPA),Myzus persicae (Sulzer), and to potato leafroll virus (PLRV). Criteria used were the number of aphids which colonized the clones in free choice field experiments and the number of plants derived from these experiments which showed symptoms of PLRV infection. Generally, greater resistance to GPA was found inSolarium tuberosum gp.andigena selections and hybrids than in gp.tuberosum cultivars. There were approximately fourfold differences in season-mean GPA levels among the clones tested each year. Forty-two families, representing a cross-section of the USDA breeding populations at the University of Idaho Research and Extension Center, Aberdeen, showed a similar range in colonization levels. Resistance to GPA colonization appeared to be more prevalent in gp.andigena, gp.phureja, and gp.stenotonum derivatives. There was a weak positive correlation (r² = .34, P = .01) between foliar total glycoalkaloids and season-mean GPA colonization levels for six clones representing the range of observed resistance to GPA. Resistance to GPA colonization was apparently not directly related to resistance to PLRV infection. Katahdin, for example, was relatively susceptible to GPA colonization but very resistant to PLRV infection whereas selection A69657-4 (gp.andigena) was among the most resistant to GPA colonization but among the more susceptible to PLRV infection. Breeding for resistance to GPA colonization therefore may not be as promising for PLRV control as developing PLRV resistant cultivars.  相似文献   

Enset (Ensete ventricosum) clone selection by farmers and their cultural practices in southern Ethiopia     

Zerihun Yemataw  Hussein Mohamed  Mulugeta Diro  Temesgen Addis  Guy Blomme 《Genetic Resources and Crop Evolution》2014,61(6):1091-1104

Enset, Ensete ventricosum, is a crop that contributes to food security for more than 20 % of Ethiopia’s population. One clone never fulfills all the ecological and social requirements and hence farmers maintain a diverse range of enset cultivars on their farm. The objective of this work was to assess morphological and use value related characterization and document the indigenous knowledge of farmers on classification, cultivation and utilization of enset. A total of 280 farm households in seven zones were surveyed using individual household interviews. The observed traits showed low to high levels of variability among enset clones with a Shannon–Weaver diversity index (H′) value of 0.154–0.827 for bulla (extracted starch) quality and midrib color, respectively. Moreover, the overall H′ mean of 0.399 confirmed the existence of low to medium levels of phenotypic variation. The mean squares due to genotypes were highly significant (P ≤ 0.01) for all the quantitative traits studied, suggesting the presence of substantial genetic variability among the 165 enset clones. Kocho (fermented starch) yield had significant positive correlation with bulla quality and plant vigor. Knowledge of farmers’ practices is currently used to validate agronomic innovations and inform the setting up of a network of phenotype collections managed by farmers.  相似文献   

Characterization of volatiles in unhopped wort     

De Schutter DP  Saison D  Delvaux F  Derdelinckx G  Rock JM  Neven H  Delvaux FR 《Journal of agricultural and food chemistry》2008,56(1):246-254

The volatile fraction of wort components was studied during boiling. Not less than 118 volatile compounds were identified when unhopped pilsner wort was boiled and samples of wort and condensed vapors were analyzed with headspace SPME-GC/MS, of which 54 were confirmed with reference compounds. The wort samples contained 61 identifiable compounds, while the vapor condensate yielded 108 different compounds. Almost 30 known compounds were found that have not been described before in unhopped pilsner wort. One previously unknown aldol reaction product was tentatively identified as 2-phenyl-2-octenal. The detection of branched 2-alkenals underlines the importance of the aldol condensation in Maillard-type reactions, while the tentative identification of alkyloxazoles and alkylthiazoles could once more accentuate the central role of alpha-dicarbonyl compounds, aldehydes, and amino acids in flavor generation. The condensation of wort vapors joined with the SPME-GC/MS technique has proven to be a useful tool in volatile analysis.  相似文献   

Levels of bisphenol A in canned liquid infant formula products in Canada and dietary intake estimates     

Cao XL  Dufresne G  Belisle S  Clement G  Falicki M  Beraldin F  Rulibikiye A 《Journal of agricultural and food chemistry》2008,56(17):7919-7924

A sensitive, efficient, and reproducible method, based on solid phase extraction and derivatization with acetic anhydride followed by gas chromatography-mass spectrometry in selected-ion monitoring mode, was developed for the determination of bisphenol A (BPA) in liquid infant formula. The method quantification limit was 0.5 ng g(-1). Extraction recoveries were 85-94% over the concentration range of 2.5-20 ng g(-1). Good reproducibility of the method was observed at levels of 0.54 and 10.4 ng g(-1) with relative standard deviations of 5.0 and 2.8%, respectively. The method was used to analyze samples of 21 canned liquid infant formula products for BPA. BPA was detected in all samples at levels ranging from as low as 2.27 ng g(-1) to as high as 10.2 ng g(-1). The probable daily intakes of BPA due to consumption of canned liquid infant formula were estimated for infants from premature to 12-18 months of age. The maximum probable daily intake of BPA was 1.35 microg kg(-1) of body weight day(-1) for 0-1-month-old infants with the maximum formula intake, which is below the provisional tolerable daily intake for BPA established by Health Canada, 25 microg kg(-1) of body weight day(-1).  相似文献   

Does living in an urban environment confer advantages for childhood nutritional status? Analysis of disparities in nutritional status by wealth and residence in Angola, Central African Republic and Senegal     

Kennedy G  Nantel G  Brouwer ID  Kok FJ 《Public health nutrition》2006,9(2):187-193

OBJECTIVE: The purpose of this paper is to examine the relationship between childhood undernutrition and poverty in urban and rural areas. DESIGN: Anthropometric and socio-economic data from Multiple Indicator Cluster Surveys in Angola-Secured Territory (Angola ST), Central African Republic and Senegal were used in this analysis. The population considered in this study is children 0-59 months, whose records include complete anthropometric data on height, weight, age, gender, socio-economic level and urban or rural area of residence. In addition to simple urban/rural comparisons, the population was stratified using a wealth index based on living conditions and asset ownership to compare the prevalence, mean Z-score and odds ratios for stunting and wasting. RESULTS: In all cases, when using a simple urban/rural comparison, the prevalence of stunting was significantly higher in rural areas. However, when the urban and rural populations were stratified using a measure of wealth, the differences in prevalence of stunting and underweight in urban and rural areas of Angola ST, Central African Republic and Senegal disappeared. Poor children in these urban areas were just as likely to be stunted or underweight as poor children living in rural areas. The odds ratio of stunting in the poorest compared with the richest quintile was 3.4, 3.2 and 1.5 in Angola ST, Senegal and Central African Republic, respectively. CONCLUSIONS: This paper demonstrates that simple urban/rural comparisons mask wide disparities in subgroups according to wealth. There is a strong relationship between poverty and chronic undernutrition in both urban and rural areas; this relationship does not change simply by living in an urban environment. However, urban and rural living conditions and lifestyles differ, and it is important to consider these differences when designing programmes and policies to address undernutrition.  相似文献   

Transcription. Gene expression needs a break to unwind before carrying on     

Haince JF  Rouleau M  Poirier GG 《Science (New York, N.Y.)》2006,312(5781):1752-1753

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Emergent properties of reduced-genome Escherichia coli     

Pósfai G  Plunkett G  Fehér T  Frisch D  Keil GM  Umenhoffer K  Kolisnychenko V  Stahl B  Sharma SS  de Arruda M  Burland V  Harcum SW  Blattner FR 《Science (New York, N.Y.)》2006,312(5776):1044-1046

With the use of synthetic biology, we reduced the Escherichia coli K-12 genome by making planned, precise deletions. The multiple-deletion series (MDS) strains, with genome reductions up to 15%, were designed by identifying nonessential genes and sequences for elimination, including recombinogenic or mobile DNA and cryptic virulence genes, while preserving good growth profiles and protein production. Genome reduction also led to unanticipated beneficial properties: high electroporation efficiency and accurate propagation of recombinant genes and plasmids that were unstable in other strains. Eradication of stress-induced transposition evidently stabilized the MDS genomes and provided some of the new properties.  相似文献   

Contemporary group estimates adjusted for climatic effects provide a finer definition of the unknown environmental challenges experienced by growing pigs          下载免费PDF全文

S.Z.Y. Guy  L. Li  P.C. Thomson  S. Hermesch 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2017,134(6):520-530

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Obituary: Professor Toshio Fujita          下载免费PDF全文

Yoshiaki Nakagawa  Guy Smagghe 《Pest management science》2018,74(2):263-263

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