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  • Solanum tuberosum  (6)
  • Cell & Developmental Biology  (5)
  • Motor skill  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1986), S. 218-222 
    ISSN: 1432-2242
    Keywords: Solanum tuberosum ; Selection efficiency ; Potato breeding ; Yield ; Yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A number of unselected potato (Solanum tuberosum L.) clones were grown at two locations (a seed site and a ware site) in three consecutive years. The repeatability of total yield and yield components in the first two clonal years was compared with the same characters recorded in the third clonal year. Selection for yield in the first clonal year was only marginally more effective than a random reduction in number of genotypes, while selection in the second clonal year appeared to be somewhat more effective as judged by performance in the third clonal year. The inefficiency of selection in the first clonal year was ascribed, at least in part, to the inaccuracy of yield assessment as well as the “carry-over” effect of the mother tubers. Correlations of total yield were higher between different years in the same location than between different locations. Selection under growing conditions suitable for production of seed tubers tended to result in selection of early maturing clones which would not necessarily be optimal for ware growing conditions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 77 (1989), S. 246-252 
    ISSN: 1432-2242
    Keywords: Solanum tuberosum ; Parental value ; Univariate cross prediction ; Mid-parent ; Mid-self value
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It is shown that it is possible to obtain an indication of the parental value of heterozygous cultivars of potatoes for the characters breeders' preference, total tuber weight, mean tuber weight and number of tubers. Three methods of predicting the characteristics of progeny produced from particular parental cultivars were examined, namely: univariate cross prediction (based on mean and variance), mid-parent values and mid-self values. All provided some indication of which crosses would give superior progeny, but univariate cross prediction gave rankings which correlated most highly with observed performance in the second clonal year for the characters breeders' preference and total tuber weight. Interestingly, mid-self values gave the best predictions in the case of mean tuber weight and number of tubers. It is suggested that such predictions of ‘parental value’, especially when based on univariate cross prediction at the seedling stage, are worth carrying out in practical breeding programmes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 76 (1988), S. 33-38 
    ISSN: 1432-2242
    Keywords: Potatoes ; Solanum tuberosum ; Cross prediction ; Breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Most previous studies on cross prediction methods have examined relatively few crosses, particularly in relation to the numbers involved in most breeding programmes. In this paper the feasibility of using cross prediction methods was examined in a practical potato (Solanum tuberosum) breeding scheme by the analyses of progeny from 52 crosses. The variate considered was breeder's preference, a visual assessment made of the harvested tubers to estimate their commercial potential. The results showed that it was possible to identify the superior crosses. Cross prediction based simply on the mean preference scores, averaged over scorers and clones within progenies, estimated on seedlings or first clonal year plants, provided the best estimate of a progeny's performance in the third clonal generation. Predictions based on the expected proportion of clones that would transgress a given target value also provided a good indication of a progeny's potential. The poorest prediction was obtained by using the observed frequency of desirable clones in a progeny sample. The implications for potato breeding are discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 63 (1991), S. 381-386 
    ISSN: 1439-6327
    Keywords: Motor control ; Electromyography ; Motor skill ; Triphasic electromyogram ; Muscle contraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of this investigation was to determine how the triphasic electromyogram (EMG) pattern of muscle activation developed from the agonist muscle only pattern as movement time (t mov) decreased. Six adult women produced a series of 30° elbow extension movements in the horizontal plane at speeds ranging from ballistic (〈 400-ms t mov) to very slow (〉 800-ms t mov). Surface EMG from triceps brachii (agonist) and biceps brachii (antagonist) muscles were recorded, together with elbow angle, on a microcomputer. The results showed that triphasic EMG patterns developed systematically as t mov decreased from 1000 ms to 〈 200 ms. In trials with very long t mov, many elbow extension movements were produced by a single continuous activation of the agonist triceps brachii muscle. As t mov decreased however, agonist activation became predominantly burst-like and other components of the triphasic EMG pattern [activation of the antagonist (Ant) and second agonist activation (Ag2)] began to appear. At the fastest movement speeds, triphasic EMG patterns (Ag1-Ant-Ag2, Ag1 being first activation of agonist muscle) were always present. This data indicated that the triphasic pattern of muscle activation was not switched on when a particular t mov was achieved. Rather, each component systematically developed until all were present, as distinctive bursts of activity, in most trials with t mov less than 400 ms.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 58 (1988), S. 132-140 
    ISSN: 1439-6327
    Keywords: Motor control ; Motor skill ; Electromyography ; Inaccuracy ; Isometric
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to investigate the electromyographical basis of inaccurate movement by identifying the variate and invariate characteristics of a ballistic, isometric precision-grip skill. Our results have shown that in most subjects investigated, IEMG, discharge rate and the paterns of muscle synergy were variate movement parameters while the sequence of muscle activation, the relative duration of muscle activity and the time to peak force (rise-time) remained essentially invariante. Based on these results, we can conclude that inaccurate performance of this skill, in most of the subjects investigated, was more dependant upon changes in muscle IEMG than in alterations in the temporal sequencing of muscle activity. It was apparent that from trial to trial, subjects had more difficulty in reproducing the appropriate levels of muscle contraction and synergy than in reproducing the required periods of action.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 62 (1991), S. 162-170 
    ISSN: 1439-6327
    Keywords: Motor control ; Electromyography ; Muscle contraction ; Inaccurate movement ; Motor skill
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electromyographic basis of inaccurate performance was investigated in two rapid precision-grip skills controlled by concentric and eccentric muscle contractions respectively. Surface electromyograms, recorded from the first dorsal interosseous (DI), adductor pollicis (AP) and abductor pollicis brevis, were utilised to identify changes in the timing and intensity of muscle activation which may be responsible for inaccurate performance. The results showed that when fast precision-grip skills were controlled by concentric DI and AP muscle contractions, variations in the intensity of muscle contraction were responsible for inaccurate performance. However, when these skills were controlled by eccentric DI and AP muscle contractions, inaccurate performance resulted from variations in the timing of muscle activation. It was concluded that the nature of the deficiency in the patterns of muscle activation resulting in inaccurate performance was dependent upon the type of muscle contraction used in the skill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 104 (1998), S. 143-149 
    ISSN: 1573-5060
    Keywords: potatoes ; Solanum tuberosum ; parent selection ; cross prediction ; breeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cross prediction techniques were applied to data collected from over 600 hybrid combinations of potato (Solanum tuberosum) and analyzed to determine the potential of using early generation cross prediction techniques to identify superior parental clones. Performance of parental lines based on parameters collected in early generations were compared with the observed frequencies of desirable recombinants with a common parent in the latter stages of a breeding program. Results showed that value of parents, in their ability to produce desirable recombinants in breeding programs, can be predicted using univariate cross prediction techniques. This type of information can be available from early generation progeny trials and could easily be incorporated into a practical potato breeding scheme.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; potato yield trials ; replication ; trial efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect on yield trials of altering plot size was examined by investigating plots with varying numbers of drills (each with six tubers) planted. No evidence was found of the ware yield per drill being affected by different plot sizes nor any effect attributable to neighbouring drills, whether these were planted with another clone or left unplanted. Increasing the number of drills per plot did increase the precision of the estimated clone means as did, of course, increasing the number of replicates. It appeared, however, that increasing the number of replicates was a more efficient way to increase precision. Thus it was concluded that the most efficient utilization of limited planting space was to grow single drill plots with maximum replication.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-5060
    Keywords: Solanum tuberosum ; potato ; single plant selection ; potato breeding ; selection efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The efficiency of single plant selection in the initial selection stage of a potato breeding programme was examined. A random sample of potato clones was grown in single plant plots and also in tworeplicates of five plant plots. After harvest, each plot was visually assessed by three potato breeders; total tuber weight and number of tubers per plant were also recorded, from which mean tuber weight was calculated. The error variances of the single plant plots were found to be significantly greater than from the five plant plots for total tuber weight, mean tuber weight and number of tubers per plant, but not significantly different for breeders' preference. Coefficients of correlation between single and five plants plots were significantly greater than zero for all traits examined, but they were lower than the corresponding correlations between the two replicates of five plant plots. Although a random sample of clones was examined, each clone had been assessed for breeders' preference the previous year. When the clones were grouped according to the previous years preference scores, it was found that the correlation coefficients between single and five plant plots for breeders' preference were inversely related, in magnitude, to the mean preference score of each group. It was concluded that single plant selection was generally ineffective, particularly when only the ‘better’ clones, from the previous years assessment, are examined.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 168 (1981), S. 281-288 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microscopic examination of adipocytes isolated from adult rat epididymal adipose tissue revealed numerous small cells (〈 10 μm) morphologically similar to larger adipocytes. These small adipocytes appear identical to a new classification of adipose cells termed preadipocytes. Electron micrographs of these preadipocytes revealed examples of cells 〈 10 μm in diameter in various stages of maturation and lipid accumulation. The percent distribution pattern of these small adipocytes was not significantly altered by exercise although exercise shifted the distribution patterns of the larger cells (〉 30 μm) toward a smaller mean cell size. The quantitative significance of preadipocytes is not established but these preliminary observations indicate that adipocytes 〈 10 μm in diameter may account for a numerically greater proportion of the total adipocytes observed in collagenase isolated preparations than heretofore recognized, although their contribution to total adipose mass is probably negligible.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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