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  • 1
    Electronic Resource
    Electronic Resource
    Estimates of marker-associated QTL effects in Monte Carlo backcross generations using multiple regression (1992)
    Springer
    Theoretical and applied genetics 85 (1992), S. 423-434 
    Details
    ISSN: 1432-2242
    Keywords: Genetic models ; RFLP ; Additive and dominance effects ; Genetic linkage ; Genetic simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The decision of whether or not to use QTLassociated markers in breeding programs needs further information about the magnitude of the additive and dominance effects that can be estimated. The objectives of this paper are (1) to apply some of the Moreno-Gonzalez (1993) genetic models to backcross simulation data generated by the Monte Carlo method, and (2) to get simulation information about the number of testing progenies and mapping density in relation to the magnitude of gene effect estimates. Results of the Monte Carlo study show that the stepwise regression analysis was able to detect relatively small additive and dominance effects when the QTL are independently segregating. When testing selfed families derived from backcross individuals, dominance effects had a larger error standard deviation and were estimated at a lower frequency. Linked QTL require a higher marker mapping density on the genome and a larger number of progenies to detect small genetic effects. Reduction of the environmental error variance by evaluating selfed backcross families in replicate experiments increased the power of the test. Expressions of the number of progenies for detecting significant additive effects were developed for some genetic situations. The ratio of the within-backcross genetic variance to the square of a gene effect estimate is a function of the number of progenies, the heritability of the trait, the marker map density and the portion of the genetic variance explained by the model. Different values (from 0 to 1) assigned to ρ (relative position of the QTL in the marker segment) did not cause a large shift in the residual mean square of the model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222324
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Genetic models to estimate additive and non-additive effects of marker-associated QTL using multiple regression techniques (1992)
    Springer
    Theoretical and applied genetics 85 (1992), S. 435-444 
    Details
    ISSN: 1432-2242
    Keywords: Molecular markers ; Epistatic effects ; RFLP ; Linkage ; QTL
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of molecular markers has recently raised expectations for their application in selection programs. However, some questions related to quantitative trait loci (QTL) identification are still unanswered. The objectives of this paper are (1) to develop statistical genetic models for detecting and locating on the genome multi-QTL with additive, dominance and epistatic effects using multiple linear regression analysis in the backcross and Fn generations from the cross of two inbred lines; and (2) to discuss the bias caused by linked and unlinked QTL on the genetic estimates. Non-linear models were developed for different backcross and Fn generations when both epistasis and no epistasis were assumed. Generation analysis of marked progenies is suggested as a way of increasing the number of observations for the estimates without additional cost for molecular scoring. Some groups of progenies can be created in different generations from the same scored individuals. The non-linear models were transformed into approximate multivariate linear models to which combined stepwise and standard regression analysis could be applied. Expressions for the biases of the marker classes from linked QTL were obtained when no epistasis was assumed. When epistasis was assumed, these expressions increased in complexity, and the biases were caused by both linked and unlinked QTL.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222325
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ecological effects of seaweed harvesting in the Gulf of California and Pacific Ocean off Baja California and California (1990)
    Springer
    Hydrobiologia 204-205 (1990), S. 35-40 
    Details
    ISSN: 1573-5117
    Keywords: Eucheuma uncinatum ; harvesting ; Macrocystis pyrifera ; recruitment ; seaweed ; survivorship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ecological effects of harvesting were investigated for two species, the giant kelp Macrocystis pyrifera and Eucheuma uncinatum, by using harvest records and aerial surveys that show yield changes and by using studies of recruitment, survivorship and community interactions. There were no ecological effects found for M. pyrifera harvested with contemporary methods, and there are no recommendations for changing current management practices for this species. It is recommended that E. uncinatum, which on occasion produces commercially significant standing crops, not be harvested unless special precautions are taken to leave some plants for regeneration of the harvested populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040212
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Carrageenan yield and properties of Eucheuma uncinatum (Seth. & Gard.) Daw. cultured under natural conditions (1993)
    Springer
    Hydrobiologia 260-261 (1993), S. 601-605 
    Details
    ISSN: 1573-5117
    Keywords: Eucheuma uncinatum ; carrageenan ; seaweed culture ; Gulf of California
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eucheuma uncinatum (Setch. & Gard.) Daw. from the Gulf of California was cultured in 1001 tanks in outdoor conditions. The cultures consisted of a 3 × 3 factorial design of 10, 19 and 33 % incident light and three different conditions of nutrients during winter (0; 20 µM N03; and 20:2 µM NO3:PO4) and summer (0; 40:4; and 80:8 µM of NO3:PO4). Best growth and carrageenan yield conditions were determined under each experiment. Carrageenan extracts were analyzed for total carbohydrates, 3,6-anhydrogalactose anhydrogalactose and sulphates. Higher carrageenan yields were obtained from cultures with fertilized plants under higher light conditions from winter and summer experiments although summer cultures provided the highest yields (48%). During summer a direct relationship between nutrients and sulfate content was observed. This effect was not observed in the winter experiment. An inverse carbohydrate: light relationship was observed in winter but not in summer. Maximum values of 3,6-anhydrogalactose in winter and summer were 23.9% and 18%, respectively. Results indicate that there is the potential to increase yield and quality of Eucheuma uncinatum carrageenan cultured under natural conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00049077
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    Paper (German National Licenses)
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