Efficiency of conversion of food to wool. I. Correlated response to selection for high and low clean wool weight

1960 ◽  
Vol 11 (5) ◽  
pp. 836 ◽  
Author(s):  
CHS Dolling ◽  
RW Moore
Keyword(s):  
The Other ◽  
Correlated Response ◽  
Response To Selection ◽  
Merino Sheep ◽  
Wool Production ◽  
The Family ◽  
Selection For ◽  
The Difference ◽  
Selection Of

The offspring of two families of medium Peppin Merino sheep, one family being selected for high and the other for low clean wool weight per head at 15-16 months of age under grazing conditions, have also been shown to differ significantly in the ratio of wool production to food eaten in pens, on a ration slightly above maintenance. These ratios were in the proportion 108 : 100, and the difference between the families can be taken as reflecting closely a difference in net efficiency of conversion of food to wool. It may be concluded that selection for high clean wool weight per head under grazing conditions had also resulted in the selection of more efficient animals. Clean wool production per head in the two families was in the ratio 110 : 100 in the pens, compared with 124 : 100 under grazing. The difference under grazing probably results from both the higher efficiency of the family selected for high clean wool weight and a higher grazing intake by this family.

Corrigendum - Response to partial selection on clean fleece weight in South Australian strong-wool Merino sheep

1969 ◽  
Vol 20 (1) ◽  
pp. 151
Author(s):  
O Mayo ◽  
JC Potter ◽  
RE Brady ◽  
CW Hooper
Keyword(s):  
Fibre Diameter ◽  
Index Method ◽  
Visual Method ◽  
Merino Sheep ◽  
Index Group ◽  
Agricultural College ◽  
Selection For ◽  
The Difference ◽  
Fleece Weight ◽  
Selection Of

This paper reports the results of an experiment carried out at Roseworthy Agricultural College from 1953 to 1966 comparing two bases of selection of rams: (1) visual appraisal (the "visual" method); (2) visual culling of 70% of rams followed by selection of breeding animals from the remaining 30% on the basis of clean fleece weight (the "index" method). No selection for fleece weight was practiced on ewes. Seven rams were used in each of the two flocks, and six of the seven were replaced each year by 16-month-old animals from the succeeding drop, the seventh being a year older. Rams used for breeding in the Index flock were significantly higher in clean fleece weight than those of the Visual flock, and were higher, though not always significantly so, in greasy fleece weight. This led to a divergence between the flocks for clean fleece weight (P < 0.05), with an increase of c. 0.05 lb per year per head for the Index animals over the Visual animals. The Index rams were more wrinkly and lighter, on the whole, than the Visual rams, and the wrinkly effect carried over into their offspring with a slight divergence apparent, the Index animals becoming more wrinkled than the Visual (P < 0.05). In fibre diameter there were no differences between selected animals or between flocks. Visual rams tended to have more crimps per inch in their wool, and this was observed in the flocks also, but the divergence was not significant (P > 0.05). Index rams had longer wool than Visual rams, with the difference generally significant within years, and this tendency carried over in a lesser manner to the flocks. Fleece density was generally greater in the Index group, though not usually significantly so. This experiment did not include a randomly bred control flock, but was rather designed to compare two practical methods of selecting rams. Merits of this scheme are discussed in the light of both groups' failure to show increases in fleece weight over the course of the experiment

scholarly journals The genetic analysis of the direct and correlated response to selection for chaetae in Drosophila melanogaster

1973 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
W. R. Scowcroft
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Genetic Correlation ◽  
Statistical Approach ◽  
Correlated Response ◽  
Minor Importance ◽  
Response To Selection ◽  
Genetic Changes ◽  
Selection For ◽  
Selection Of

SUMMARYThe direct and correlated response to selection of scutellar microchaetae and scutellar bristles has been analysed by determining the contribution of the three major chromosomes, alone and in combination with each other, to the overall response. The results of the analysis confirm a previous finding, based on a formal statistical approach, that response to selection for microchaetae had highly pleiotropic effects on scutellar bristles. In lines selected, each for high and low microchaetae, genetic changes in the 2nd and 3rd chromosomes are pre-eminent and essentially equal. Inter-chromosomal interactions are of relatively minor importance in interpreting the response to selection for microchaetae but assume greater importance with respect to the correlated character. The results are discussed in terms of the genetic correlation between fitness and the character measured.

Heritability, correlated response, and indirect selection involving spectral reflectance indices and grain yield in wheat

2007 ◽  
Vol 58 (5) ◽  
pp. 432 ◽  
Author(s):  
M. A. Babar ◽  
M. van Ginkel ◽  
M. P. Reynolds ◽  
B. Prasad ◽  
A. R. Klatt
Keyword(s):  
Grain Yield ◽  
Spectral Reflectance ◽  
Genetic Correlations ◽  
Grain Filling ◽  
Indirect Selection ◽  
The Other ◽  
Correlated Response ◽  
Response To Selection ◽  
Selection For ◽  
Reflectance Indices

The objectives of this study were to assess the potential of using spectral reflectance indices (SRIs) as an indirect selection tool for grain yield in wheat under irrigated conditions. This paper demonstrates the genetic correlation between grain yield and SRIs, heritability and expected response to selection for grain yield and SRIs, correlated response to selection for grain yield estimated from SRIs, and efficiency of indirect selection for grain yield using SRIs in different spring wheat populations. Four field experiments, GHIST (15 CIMMYT globally adapted genotypes), RLs1 (25 random F3-derived families), RLs2 (36 random F3-derived families), and RLs3 (64 random F5-derived families) were conducted under irrigated conditions at the CIMMYT research station in north-west Mexico in 3 different years. Spectral reflectance was measured at 3 growth stages (booting, heading, and grain filling) and 7 SRIs were calculated using average values of spectral reflectance at heading and grain filling. Five previously developed SRIs (PRI, WI, RNDVI, GNDVI, SR), and 2 newly calculated SRIs (NWI-1 and NWI-2) were evaluated in the experiments. In general, the within- and between-year genetic correlations between grain yield and SRIs were significant. Three NIR-based indices (WI, NWI-1, and NWI-2) showed higher genetic correlations (0.73–0.92) with grain yield than the other indices (0.35–0.67), and these observations were consistent in all populations. Broad-sense heritability estimates for all indices were in general moderate to high (0.60–0.80), and higher than grain yield (0.45–0.70). The realised heritability for the 3 NIR-based indices was higher than for the other indices and for grain yield itself. Expected response to selection for all indices was moderate to high (0.54–0.85). The correlated response for grain yield estimated from the 3 NIR-based indices (0.59–0.64) was much higher than the correlated response for grain yield estimated from the other indices (0.31–0.46), and the efficiency of indirect selection for these 3 NIR-based indices was 90–96% of the efficiency of direct selection for grain yield. These results demonstrate the potential for using the 3 NIR-based SRI tools in breeding programs for selecting for increased genetic gains for yield.

Response to partial selection on clean fleece weight in South Australian strong-wool Merino sheep

1969 ◽  
Vol 20 (1) ◽  
pp. 151
Author(s):  
O Mayo ◽  
JC Potter ◽  
RE Brady ◽  
CW Hooper
Keyword(s):  
Fibre Diameter ◽  
Index Method ◽  
Visual Method ◽  
Merino Sheep ◽  
Index Group ◽  
Agricultural College ◽  
Selection For ◽  
The Difference ◽  
Fleece Weight ◽  
Selection Of

This paper reports the results of an experiment carried out at Roseworthy Agricultural College from 1953 to 1966 comparing two bases of selection of rams: (1) visual appraisal (the "visual" method); (2) visual culling of 70% of rams followed by selection of breeding animals from the remaining 30% on the basis of clean fleece weight (the "index" method). No selection for fleece weight was practiced on ewes. Seven rams were used in each of the two flocks, and six of the seven were replaced each year by 16-month-old animals from the succeeding drop, the seventh being a year older. Rams used for breeding in the Index flock were significantly higher in clean fleece weight than those of the Visual flock, and were higher, though not always significantly so, in greasy fleece weight. This led to a divergence between the flocks for clean fleece weight (P < 0.05), with an increase of c. 0.05 lb per year per head for the Index animals over the Visual animals. The Index rams were more wrinkly and lighter, on the whole, than the Visual rams, and the wrinkly effect carried over into their offspring with a slight divergence apparent, the Index animals becoming more wrinkled than the Visual (P < 0.05). In fibre diameter there were no differences between selected animals or between flocks. Visual rams tended to have more crimps per inch in their wool, and this was observed in the flocks also, but the divergence was not significant (P > 0.05). Index rams had longer wool than Visual rams, with the difference generally significant within years, and this tendency carried over in a lesser manner to the flocks. Fleece density was generally greater in the Index group, though not usually significantly so. This experiment did not include a randomly bred control flock, but was rather designed to compare two practical methods of selecting rams. Merits of this scheme are discussed in the light of both groups' failure to show increases in fleece weight over the course of the experiment

scholarly journals Linear heritability estimates

1961 ◽  
Vol 2 (3) ◽  
pp. 439-448 ◽  
Author(s):  
Hans Abplanalp
Keyword(s):  
Genetic Correlation ◽  
The Other ◽  
Correlated Response ◽  
Response To Selection ◽  
Population Mean ◽  
Straight Line ◽  
The Mean ◽  
Heritability Estimates ◽  
Selection Of ◽  
Prospective Parents

A method for obtaining linear estimates of heritability and genetic correlation is given. It is based, essentially, on selecting, from a pedigreed population, prospective parents for which estimates of average genotype and phenotype values are obtained; a regression of genotype on phenotype value is then determined from a straight line fitted through points representing the population mean genotype and phenotype on one hand and the mean genotype and phenotype of selected parents on the other.The method permits an evaluation of asymmetry in response for a trait selected in both directions, as well as asymmetry in correlated response to selection of two different traits, with data from a single pedigreed population.

COMPARISON OF FOUR METHODS OF SELECTION FOR RESISTANCE TO LEPTOSPHAERULINA BRIOSIANA IN ALFALFA

1979 ◽  
Vol 21 (2) ◽  
pp. 179-186 ◽  
Author(s):  
R. R. Hill Jr. ◽  
K. T. Leath
Keyword(s):  
Selection Method ◽  
The Other ◽  
Correlated Response ◽  
Response To Selection ◽  
Selection Methods ◽  
Family Selection ◽  
Colletotrichum Trifolii ◽  
Family Types ◽  
Medicago Sativa L ◽  
Selection For

Three cycles of selection for resistance to Leptosphaerulina briosiana (Poll.) Graham &Luttrell were conducted in two alfalfa (Medicago sativa, L.) germplasm pools, MSA and MSB. Each germplasm pool was used to compare four methods of selection: phenotypic recurrent, half-sib family, full-sib family, and alternating generations of selfed family and half-sib family. Response to selection for resistance to L. briosiana was greater in MSA than in MSB. Differences between selection methods were not significant. Selection for resistance to L. briosiana generally increased resistance to Stemphylium botryosum Wallr., but the magnitude of the correlated response varied with germplasm pool and selection method. The initial selfed families in both germplasm pools were significantly less resistant to Colletotrichum trifolii Bain than the other family types. Resistance to C. trifolii increased with selfed family selection for resistance to L. briosiana in MSA but not in MSB.

Correlated response to selection for litter size in pigs: II. Carcass, meat, and fat quality traits

2002 ◽  
Vol 80 (10) ◽  
pp. 2566 ◽  
Author(s):  
J. Estany ◽  
D. Villalba ◽  
M. Tor ◽  
D. Cubiló ◽  
J. L. Noguera
Keyword(s):  
Litter Size ◽  
Correlated Response ◽  
Quality Traits ◽  
Response To Selection ◽  
Fat Quality ◽  
Selection For

The effect of exposure to conspecifics on restlessness in the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King
Keyword(s):  
Habitat Quality ◽  
Parasitoid Wasp ◽  
Poor Quality ◽  
The Other ◽  
Dispersal Ability ◽  
Nasonia Vitripennis ◽  
Adult Females ◽  
Selection For ◽  
The Difference ◽  
Abundance And Distribution

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.

scholarly journals Małe dzieci w chrześcijańskiej epigrafice miasta Rzymu i w nauczaniu Jana Chryzostoma

Vox Patrum ◽  
2009 ◽  
Vol 53 ◽  
pp. 233-243
Author(s):  
Bożena Stawoska-Jundziłł
Keyword(s):  
The Other ◽  
High Status ◽  
Small Children ◽  
Person Following ◽  
John Chrysostom ◽  
The Family ◽  
The Difference ◽  
Christian Families ◽  
The City ◽  
Full Maturity

The paper presents the results of studies of epitaphs for children up to almost eight years of age from the city of Rome (3rd-4th c. – B. Stawoska-Jundziłł, Vixit cum parentibus. Children aged under seven in Christian families from Rome of 3rd-4th c., Bydgoszcz 2008) in comparison with the views of John Chrysostom on the upbringing of small children. The content of over 2000 children from Rome demonstrates a high status of even the youngest offspring in the Christian families from this city. The founders cared for their religious „endowment”, bestowed their love on them and tried to remember them as members of the family even if they had died after a few days or months. It was unquestionably believed that small children are immediately saved, go to God and commune with the saints. Thanks to this the family could hope for their support and prayers. Whereas, John Chrysostom only casually mentions small children and, what is more, ambivalently: on one hand presenting them on the basis of thorough observations of their behavior and looking after them and on the other hand as mindless creatures, a harbinger of va­luable person following the Stoics e.g. Seneca. As far as the most important for me question of the death of small children is concerned he takes a stand similar to that of the Romans. The children are really without sins (they did not commit them consciously) so God shall accept them only through the hardships of illness and death. Now they are asleep (unlike in the studied epitaphs) but they will rise from the dead and join their parents. Thus, the despair after their death is pointless; God decided the best for them. The difference lies in the fact that the founders of epitaphs more decidedly see the perfection of posthumous existence of even the smallest children who there reach their full maturity whereas John does not seem to be interested in this issue since he directs his teaching mostly to maturing and mature Christians in the earthly life and not in the beyond.

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