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  • 1
    ISSN: 1432-2242
    Keywords: Key words Potato breeding ; Family selection ; Cross prediction ; Breeders’ visual preference ; Within-family selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In 1992, 72 seedlings from each of 198 pair crosses were grown in a glasshouse, and the tubers produced by each plant were visually assessed on a 1–9 scale of increasing preference. Three groups of four progenies with high, medium and low mean scores were chosen to progress, without selection via tuber progenies and four-plant plots at a high-grade seed site, to replicated yield trials in the third clonal generation. The three groups maintained their high, medium and low scores for visual preference over the three clonal generations and also had high, medium and low scores in the second and third clonal generations for yield, size and appearance of tubers, all of which were components of visual preference. The three groups were predicted to have 13.6%, 1.8% and 0.2% of their clones exceeding the mean of 13 control cultivars for visual preference in the replicated trials, and 12.1%, 4.9% and 1.4% for yield, and 56.8%, 37.1% and 14.8% for appearance. The experiment confirmed that selection for visual preference within crosses in the seedling and first clonal generations is very ineffective, but that worthwhile progress can be made from selection in the second clonal generation, with correlated responses for faster emergence, earlier maturity, higher yield and greater regularity of shape (appearance). Combining selection of the high group of progenies with selection in the second clonal generation of the best 34 out of the 120 clones in this group, produced a response in visual preference in the third clonal generation of 1.00 compared with a maximum possible of 1.74. Ways of achieving further improvements in early-generation selection are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 68 (1984), S. 503-508 
    ISSN: 1432-2242
    Keywords: Kale breeding ; Population improvement ; Family selection ; Computer simulation ; Genetic drift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three recurrent selection schemes suitable for kale (Brassica oleracea L.), involving half-sib (HS), full-sib (FS) and selfed (S) families, were compared by computer simulation. All combinations of 6, 12 and 24 families selected, out of 120 and 240 assessed, were investigated for a range of genetical models. Selection was simulated for 20 generations from an initial allele frequency of 0.05 and for 16 generations from an initial frequency of 0.20. With an initial frequency of 0.05 there was a serious loss of desired alleles ranging from 0.31 out of 20 for the HS scheme with 24 out of 240 families selected to 9.19 for the S scheme with 6 out of 120 families selected. It was concluded that if as many as 20 cultivars were included in the initial population the selection scheme should be chosen to minimise the loss. With an initial frequency of 0.20 there were no losses with 12 and 24 families selected in the HS and FS schemes respectively, and the highest loss was 2.88 for the S scheme with 6 out of 120 families selected. It was concluded that if as few as five cultivars were included in the initial population a compromise between the initial response to selection and the loss of desired alleles should be sought. Selecting 6, 12 and 24 families for the HS, FS and S schemes respectively, resulted in average relative responses per generation of 2.28, 2.74 and 2.76, respectively for the first five generations, and losses of 0.22, 0.13 and 0.35, respectively after 16 generations. Practical considerations favour the FS scheme over the S scheme.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1871-4528
    Keywords: Phytophthora infestans ; Solanum tuberosum L. ; progeny test ; disease screening ; inheritance ; general combining ability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary TenSolanum tuberosum genotypes differing in resistance to late blight (Phytophthora infestans (Mont.) de Bary) in foliage and tubers were intercrossed to determine the inheritance of disease resistance in their progenies. Plots of 10–15 clones per progeny were established in each of 2 years and resistance assessed by field or laboratory tests. The parental genotypes were similarly tested each year. The parents differed in general combining ability (GCA) for both foliage blight (FB) and tuber blight (TB). The parental and GCA scores were significantly correlated for both aspects of the disease, but the correlations between foliage and tuber scores for parents and for GCAs were not significant. Three parental genotypes were highly resistant in both foliage and tubers, and the genotype with the highest GCA for resistance to both FB and TB (cv. stirling) is recommended as the best parent. There was no evidence of strong genetic correlation between both aspects of resistance, and it is suggested that both be selected for in a breeding programme.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Potato research 36 (1993), S. 189-193 
    ISSN: 1871-4528
    Keywords: disease screening ; progeny test ; Fusarium coeruleum ; Fusarium sulphureum ; general combining ability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Glasshouse-grown seedling tubers of 22 progenies from parents differing in resistance toFusarium coeruleum andF. sulphureum (Gibberella cyanogena) were wound-inoculated with a cornmeal + sand culture of one or other of these dry rot pathogens. WithF. coeruleum, differences between progenies were due entirely to differences in the general combining abilities (gca) of the parents. Parental and gca values were highly correlated, as were the mean resistance of a progeny and that of its parents. WithG. cyanogena the agreement between replicates was poor and differences between progenies were less clear. It is suggested that different resistance mechanisms operate against these two pathogens.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Potato research 38 (1995), S. 345-351 
    ISSN: 1871-4528
    Keywords: disease screening ; progeny test ; Fusarium coeruleum ; Fusarium sulphureum ; Gibberella pulicaris ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Field-grown tubers of 22 progenies ofSolanum tuberosum L. generated in a crossing programme involving seven parents differing in resistance toFusarium coeruleum Lib. ex Sacc. andF. sulphureum Schlect. (=F. sambucinum Fuckel, teleomorphGibberella pulicaris (Fr.) Sacc.) were wound-inoculated with a cornmeal + sand culture of each pathogen. Parental genotypes were also included. The mean lesion size of each progeny was compared in 2 years of tests, as well as with published data on glasshouse-grown tubers. ForF. coeruleum there was a high correlation between years as well as with the glasshouse data, but no such correlations were apparent withG. pulicaris. Furthermore, parental and GCA values, as well as progeny means and mid-parent scores, also correlated highly forF. coeruleum but not forG. pulicaris. Glasshouse-grown tubers of 11 wildSolanum spp. were also inoculated with both pathogens. Some resistance to one or other, or both, was apparent, particularly inS. chacoense.
    Type of Medium: Electronic Resource
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