GENETIC SELECTION FOR AND EVALUATION OF NONDIAPAUSE LINES OF PREDATORY MIDGE, APHIDOLETES APHIDIMYZA (RONDANI) (DIPTERA: CECIDOMYIIDAE)

1986 ◽  
Vol 118 (9) ◽  
pp. 869-879 ◽  
Author(s):  
Linda A. Gilkeson ◽  
Stuart B. Hill
Keyword(s):  
Sex Ratio ◽  
Selection Pressure ◽  
Gradual Increase ◽  
Genetic Selection ◽  
Response To Selection ◽  
Aphidoletes Aphidimyza ◽  
Selected Lines ◽  
Line Selection ◽  
Selection For ◽  
Diapause Incidence

AbstractFour lines of Aphidoletes aphidimyza (Rond.) were selected for nondiapause (one for 50 generations) under L:D 8:16 and 21 ± 1°C. In three selected lines, diapause incidence dropped rapidly in the first four or five generations, with means of 3–11% thereafter. There was no clear response to selection in the fourth line. Neither morphology nor sex ratio was affected by nondiapause selection in any lines, nor was fecundity affected in the longest-reared line. Reciprocal crosses indicated that the diapause trait was dominant; the effect of relaxing selection pressure was a gradual increase in diapause incidence after eight generations. There was a correlation between increased diapause incidence and slower development in selected lines. Diapause larvae took longer to develop than nondiapause larvae from the same line. Selection for nondiapause under L:D 8:16 with fluctuating thermoperiods was unsuccessful.

Color Preferences in Quail Chicks: Generalization of the Effects of Genetic Selection

Behaviour ◽  
1978 ◽  
Vol 65 (1-2) ◽  
pp. 263-269 ◽  
Author(s):  
Kovach Joseph K.
Keyword(s):  
Japanese Quail ◽  
Genetic Selection ◽  
Coturnix Japonica ◽  
Selected Lines ◽  
Color Preferences ◽  
Selection For ◽  
Different Color ◽  
Color Combinations

Japanese quail (C. coturnix japonica) were artificially selected for early preferences of blue over red and red over blue. Subjects were drawn from the 2nd and 8th generations of the selected lines and were tested for color choices by five different color pairs, in addition to the blue-red pair used for selection. Eight generations of selection for choices between blue and red modified choice responses to all color combinations. Maximum preferences were not shown in the selected choices between blue and red, but in the choice of green over red in the subjects from the line selected for preference of blue and in the choice of yellow over blue in the subjects from the line selected for preference of red.

scholarly journals Response to selection for increased pupa weight in Tribolium castaneum as related to population structure

1977 ◽  
Vol 30 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Alan J. Katz ◽  
Franklin D. Enfield
Keyword(s):  
Random Mating ◽  
Selection Response ◽  
Response To Selection ◽  
Short Term ◽  
Selection Systems ◽  
Line Selection ◽  
Selection For ◽  
Seven Generations ◽  
Generation Period ◽  
Term Response

SUMMARYThe effectiveness of selection for increased pupa weight in Tribolium was compared for three different selection systems. In all three systems the same number of breeding individuals was used each generation. Population L was a large random mating population with 24 males and 48 females selected each generation. The C4 and C8 populations were each divided into 6 subpopulations (lines) consisting of 4 males and 8 fem ales. Each of the three populations was replicated. In C4, selection for pupa weight was within lines for three generations, followed by a generation of among-line selection when the best two out of six lines were selected. These lines were then crossed to produce 6 new subpopulations, and the cycle was repeated. The C8 population was handled in exactly the same manner except that seven generations of selection within lines were practised before each generation of among-line selection. Selection response for the 42-generation period was significantly greater in the L population than in either subdivided population. No consistent differences among the selection systems were apparent when evaluating short-term response for the first 12 generations of the experiment. The results were interpreted as indicating that the influence of multiple-peak epistasis was not of major importance for this trait in determining ultimate response to selection when starting from a base population of previously unselected lines and utilizing a within- and among-line selection regime.

Changes in resistance to powdery mildew in a barley composite cross

1990 ◽  
Vol 68 (4) ◽  
pp. 916-919 ◽  
Author(s):  
M. Reinhold ◽  
M. E. Bjarko ◽  
D. C. Sands ◽  
H. E. Bockelman
Keyword(s):  
Hordeum Vulgare ◽  
Powdery Mildew ◽  
Selection Pressure ◽  
Recurrent Selection ◽  
Erysiphe Graminis ◽  
Response To Selection ◽  
Multiple Alleles ◽  
Negative Effect ◽  
Selection For ◽  
Representative Samples

The response of barley composite cross XLII to selection for resistance to powdery mildew was evaluated. Representative samples from eight cycles of recurrent selection were inoculated with two isolates of Erysiphe graminis f.sp. hordei. Frequencies of resistant plants were determined for each cycle. The resistance in composite cross XLII increased with selection. Increased selection pressure in 1986 resulted in a more rapid increase in resistance than in previous years. Multiple alleles occurring in the Ml-a locus did not seem to have a negative effect on the accumulation of resistance in composite cross XLII. Key words: Hordeum vulgare, barley, Erysiphe graminis f.sp. hordei, powdery mildew, response to selection, recurrent selection.

Effects of voluntary activity and genetic selection on muscle metabolic capacities in house mice Mus domesticus

2000 ◽  
Vol 89 (4) ◽  
pp. 1608-1616 ◽  
Author(s):  
Philippe Houle-Leroy ◽  
Theodore Garland ◽  
John G. Swallow ◽  
Helga Guderley
Keyword(s):  
Lactate Dehydrogenase ◽  
Citrate Synthase ◽  
Wheel Running ◽  
Genetic Selection ◽  
House Mice ◽  
Male Mice ◽  
Selected Lines ◽  
Voluntary Wheel Running ◽  
Selection For ◽  
Voluntary Wheel

Selective breeding is an important tool in behavioral genetics and evolutionary physiology, but it has rarely been applied to the study of exercise physiology. We are using artificial selection for increased wheel-running behavior to study the correlated evolution of locomotor activity and physiological determinants of exercise capacity in house mice. We studied enzyme activities and their response to voluntary wheel running in mixed hindlimb muscles of mice from generation 14, at which time individuals from selected lines ran more than twice as many revolutions per day as those from control (unselected) lines. Beginning at weaning and for 8 wk, we housed mice from each of four replicate selected lines and four replicate control lines with access to wheels that were free to rotate (wheel-access group) or locked (sedentary group). Among sedentary animals, mice from selected lines did not exhibit a general increase in aerobic capacities: no mitochondrial [except pyruvate dehydrogenase (PDH)] or glycolytic enzyme activity was significantly ( P < 0.05) higher than in control mice. Sedentary mice from the selected lines exhibited a trend for higher muscle aerobic capacities, as indicated by higher levels of mitochondrial (cytochrome- c oxidase, carnitine palmitoyltransferase, citrate synthase, and PDH) and glycolytic (hexokinase and phosphofructokinase) enzymes, with concomitant lower anaerobic capacities, as indicated by lactate dehydrogenase (especially in male mice). Consistent with previous studies of endurance training in rats via voluntary wheel running or forced treadmill exercise, cytochrome- c oxidase, citrate synthase, and carnitine palmitoyltransferase activity increased in the wheel-access groups for both genders; hexokinase also increased in both genders. Some enzymes showed gender-specific responses: PDH and lactate dehydrogenase increased in wheel-access male but not female mice, and glycogen phosphorylase decreased in female but not in male mice. Two-way analysis of covariance revealed significant interactions between line type and activity group; for several enzymes, activities showed greater changes in mice from selected lines, presumably because such mice ran more revolutions per day and at greater velocities. Thus genetic selection for increased voluntary wheel running did not reduce the capability of muscle aerobic capacity to respond to training.

Changes in skin and fleece characteristics of Scottish cashmere goats following selection for increased annual production and decreased fibre diameter

2003 ◽  
Vol 76 (3) ◽  
pp. 517-522 ◽  
Author(s):  
M. Merchantt ◽  
D. J. Riach
Keyword(s):  
Genetic Selection ◽  
Fibre Diameter ◽  
Control Line ◽  
Selected Lines ◽  
Financial Return ◽  
Fine Line ◽  
Growing Period ◽  
Cashmere Goats ◽  
Selection For ◽  
Staple Length

AbstractThe aim of this experiment was to determine the mechanisms involved in changes in the production of cashmere as a consequence of genetic selection. Skin follicle parameters and pattern of cashmere growth were compared in two selected lines of Scottish cashmere goats and a randomly bred control line. One line, the fine line, had been selected for low fibre diameter, and this had resulted in lower fibre diameter, but the weight of cashmere produced had also been reduced. Selection for fibre quantity and quality to give maximum financial return (the value line) had increased cashmere weight without a significant increase in cashmere diameter.Skin follicle density and the ratio of secondary to primary follicles (S/P ratio) were measured at 5 months of age in 25 female kids from each line. The density of follicles in the value line was greater (P · 0.05) than that in the fine or control lines (means were 21·8, 19·8 and 20·1 follicles per mm2 respectively, s.e.d. 0.73). S/P ratio increased (P · 0.001) from control to fine to value lines (means were 6.5, 7.7 and 8.4 respectively, s.e.d. = 0.30).The rate of cashmere growth (length), peak cashmere length, the duration of the cashmere growing period and dates of initiation and cessation of growth were measured in the same 25 goats from each line between 2 and 3 years of age. These traits were estimated from the regression of measurements of staple length taken at approximately 6-weekly intervals from the start of the growing period until peak staple length was reached. Measurements were made on the shoulder, mid side and hip. There was no difference in cashmere growth rate between the selection lines (average 0·29 (s.e. 0.006) mm/day). Cashmere growth started earliest in the value line and latest in the fine line but the date of cessation of growth was not different. This affected the duration of the growing period which was 183, 163 and 214 days (s.e.d. 9.6, P · 0.001) for the control, fine and value lines respectively. Peak staple length of cashmere was longest in the value line.Increased weight of cashmere in the value line was brought about through an increase in the number of secondary follicles and by an increase in the length of cashmere due to an increase in the duration of the growing period.

ABSENCE OF RESPONSE TO SELECTION FOR RESISTANCE TO NUCLEOPOLYHEDROSIS VIRUS IN HELIOTHIS VIRESCENS (F.) (LEPIDOPTERA: NOCTUIDAE)1

1988 ◽  
Vol 23 (4) ◽  
pp. 379-382 ◽  
Author(s):  
Mien Kaomini ◽  
R. T. Roush
Keyword(s):  
Heliothis Virescens ◽  
Selection Pressure ◽  
Laboratory Culture ◽  
Control Culture ◽  
Response To Selection ◽  
Nucleopolyhedrosis Virus ◽  
Selection For ◽  
Lepidoptera Noctuidae

A laboratory culture of Heliothis virescens was exposed to infection by a single embedded nucleopolyhedrosis virus (Baculovirus heliothis) at a selection pressure of about 80 to 90% mortality for 15 generations. There was no evidence of decreased susceptibility to the virus in this culture compared with a nonselected control culture.

scholarly journals The number of loci affecting a quantitative trait in Drosophila melanogaster revealed by artificial selection

1983 ◽  
Vol 42 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Araceli Gallego ◽  
Carlos López-Fanjul
Keyword(s):  
Initial Response ◽  
Selection Method ◽  
Base Population ◽  
Response To Selection ◽  
Family Selection ◽  
Selected Lines ◽  
Additive Variance ◽  
Bristle Number ◽  
Selection Limit ◽  
Selection For

SUMMARYIndividual and within-full-sib family selection for low sternopleural bristle number was carried out for 17 generations, with six replicate lines for each selection method. Our results can be summarized as follows: (1) the response to selection was exhausted very quickly, (2) the additive variance of the selected lines declined rapidly, (3) the variation in response to selection decreased as selection progressed, (4) genetic differences among replicates at the selection limit were small, (5) individual selection resulted in a higher initial response than within-family selection, but similar limits were achieved with both procedures. These observations are consistent with the hypothesis that the pattern of response to selection is due to the segregation in the base population of only a few loci with large effects, at intermediate frequencies.

scholarly journals Artificial selection for food colour preferences

2015 ◽  
Vol 282 (1804) ◽  
pp. 20143108 ◽  
Author(s):  
Gemma L. Cole ◽  
John A. Endler
Keyword(s):  
Poecilia Reticulata ◽  
Behavioural Response ◽  
Response To Selection ◽  
Selected Lines ◽  
Detection Mechanism ◽  
Food Detection ◽  
Food Colour ◽  
Selection For ◽  
Colour Preferences ◽  
Visually Based

Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata , we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection.

scholarly journals The limits to artificial selection for body weight in the mouse: III. Selection from crosses between previously selected lines

1967 ◽  
Vol 9 (1) ◽  
pp. 73-85 ◽  
Author(s):  
R. C. Roberts
Keyword(s):  
Body Weight ◽  
Artificial Selection ◽  
General Feature ◽  
Base Population ◽  
Response To Selection ◽  
Selected Lines ◽  
Large Size ◽  
Selection For ◽  
Linkage Of Genes

1. Four lines selected for large size were crossed to form a base population for further selection for high 6-week weight; three small lines were crossed similarly, and the crossbred population was selected for low 6-week weight.2. In every case, a cross between two selected lines resulted in heterosis increasing body weight. This shows that all of the selected lines were differentiated with respect to genes affecting body weight.3. Further selection for large size produced a stock whose mean weight was 25% higher than the largest of the original lines at its limit. But the response to selection for small size was slow, and after twenty-four generations of selection, the low weights of two of the original lines had not been recovered.4. The evidence points to linkage of genes affecting body weight in the mouse. It is suggested that this is a particular feature of crosses between previously selected lines, rather than a general feature of mouse populations.

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