Quantitative genetics of stamen fertility in Spergularia salina (Caryophyllaceae)

1994 ◽  
Vol 72 (11) ◽  
pp. 1598-1604 ◽  
Author(s):  
Linus Svensson ◽  
Helena Persson
Keyword(s):  
Analysis Of Variance ◽  
Quantitative Genetics ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Population Variation ◽  
Hierarchical Design ◽  
Fertility Variation ◽  
Four Levels ◽  
Nested Analysis ◽  
The Relationship

Heritability of stamen fertility was studied in Spergularia salina (Caryophyllaceae), a selfing annual that shows extensive phenotypic variation in stamen fertility. Variation within and among 70 maternal families, derived from plants representing two natural populations from Sweden, was used to estimate heritabilities of stamen fertility for each of the 10 stamen positions in the flower. The hierarchical design of the study allowed partitioning of variation among four levels of organization using nested analysis of variance. Heritabilities ranged from 0.27 to 0.65 for stamen positions in the antipetalous whorl of stamens and from 0.18 to 0.67 for positions in the antisepalous whorl. When stamen fertility was pooled across all stamen positions of a flower, the heritability was 0.73 in both populations. The nested ANOVA indicated that antipetalous stamen positions have comparatively higher proportions of among-family and among-population variation than the antisepalous stamen positions. Furthermore, highly significant genetic correlations exist between the two antisepalous stamen positions STA 2 and STA 8 and among the other eight positions but not so between these two groups. The relationship between tetraploidization and stamen number reductions in Caryophyllaceae is discussed. Key words: Spergularia salina, stamen fertility, stamen position, heritability, hierarchical analysis of variance, quantitative genetics.

scholarly journals A quantitative genetic study of starvation resistance at different geographic scales in natural populations of Drosophila melanogaster

2010 ◽  
Vol 92 (4) ◽  
pp. 253-259 ◽  
Author(s):  
JULIETA GOENAGA ◽  
JUAN JOSÉ FANARA ◽  
ESTEBAN HASSON
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Food Shortage ◽  
Population Variation ◽  
Phenotypic Variance ◽  
Starvation Resistance ◽  
Natural Genetic Variation ◽  
Quantitative Genetic ◽  
Variation Explained

SummaryFood shortage is a stress factor that commonly affects organisms in nature. Resistance to food shortage or starvation resistance (SR) is a complex quantitative trait with direct implications on fitness. However, surveys of natural genetic variation in SR at different geographic scales are scarce. Here, we have measured variation in SR in sets of lines derived from nine natural populations of Drosophila melanogaster collected in western Argentina. Our study shows that within population variation explained a larger proportion of overall phenotypic variance (80%) than among populations (7·2%). We also noticed that an important fraction of variation was sex-specific. Overall females were more resistant to starvation than males; however, the magnitude of the sexual dimorphism (SD) in SR varied among lines and explained a significant fraction of phenotypic variance in all populations. Estimates of cross-sex genetic correlations suggest that the genetic architecture of SR is only partially shared between sexes in the populations examined, thus, facilitating further evolution of the SD.

scholarly journals Genetic variation in phenology and growth among and within Norway spruce populations from two altitudinal transects in Mid-Norway

Silva Fennica ◽  
2019 ◽  
Vol 53 (1) ◽  
Author(s):  
Tore Skrøppa ◽  
Arne Steffenrem
Keyword(s):  
High Altitude ◽  
Norway Spruce ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Height Growth ◽  
Population Variation ◽  
Clinal Variation ◽  
Short Term ◽  
Narrow Sense Heritability

Progenies from open pollinated cones collected in natural populations of Norway spruce ( (L. Karst.)) distributed along two altitudinal transects in Mid-Norway were tested in the nursery, in short term tests and in long-term field trials. The populations showed clinal variation related to the mean annual temperatures of the populations, with the earliest bud flush and cessation of shoot elongation and lowest height at age nine years for the high altitude populations. Within population variation was considerable as the narrow sense heritability for these traits was 0.67, 0.31 and 0.09 in one transect and 0.55, 0.18 and 0.14 in the other transect, respectively. Lammas shoots occurred in the short term trials with large variation in frequency between years. There was significant family variation for this trait, but also interactions between populations and year. The variance within populations was considerably larger in the populations from low altitude compared to the high-altitude populations. Significant genetic correlations between height and phenology traits and damage scores indicate that families flushing early and ceasing growth late were taller. Taller families also had higher frequencies of damages. Selection of the top 20% families for height growth in short term tests at age nine years gave a simulated gain of 11% increased height growth at age 18 years in long term trials at altitudes similar to those of origin of the populations. The gain was negative when high altitude populations were selected based on testing in the lowland.Picea abies

scholarly journals Increased variation in sex organ positions can increase reciprocity and pollination success in heterostylous plant populations

2020 ◽  
Author(s):  
Shatarupa Ganguly ◽  
P.M. Shreenidhi ◽  
Deepak Barua
Keyword(s):  
Reproductive Success ◽  
Natural Populations ◽  
Population Variation ◽  
Success For All ◽  
Pollen Transfer ◽  
Plant Populations ◽  
Pollination Success ◽  
Naturally Occurring ◽  
Transfer Success ◽  
The Relationship

AbstractAimsThe reciprocal position of sexual organs in complementary floral morphs is central to our understanding of heterostyly. Reciprocity indices are used to quantify the spatial match between complementary sex organs, but previous indices fail to appropriately account for variation in sex organ positions among individuals in a population. The objective of this study was to examine how reciprocity and consequently reproductive success change with an increase in intra-population variation in sex organ heights. To this end, we formulated a reciprocity index that incorporates variation in sex organ positions among individuals in a population and asked if estimates of reciprocity can predict reproductive success in naturally occurring heterostylous populations.MethodsWe developed a reciprocity index that assumed pollen transfer success equalled one for a perfectly matched stigma-anther pair, and decreased to zero with increasing mismatch. Reciprocity was quantified as the average pollen transfer success for all pair-wise combinations of complementary sex organs in the population. We examined the relationship between intra-population variation and reciprocity using simulated populations that varied in the distribution of sex organ positions, and with empirical data from natural populations. We compared previously proposed indices using the simulated and natural populations, and for a subset of natural populations we tested the ability of the indices to predict reproductive success.Important FindingsIn both simulated and natural populations we observed that when differences between mean anther and stigma heights of complementary morphs are small, increasing intra-population variation in heights resulted in a monotonous decrease in reciprocity. However, when differences between mean complementary anther and stigma heights are larger, reciprocity increased, reached a peak, and then decreased with increasing variation. Previous indices failed to capture this behaviour and were largely insensitive to variation or differences in mean complementary sex organ heights. Seed set was consistently positively related to reciprocity for our index, and for two of the four previous indices. These results highlight the importance of incorporating intra-population variation in sex organ dimensions in quantifying reciprocity, and challenge the current understanding that increasing variation will always decrease reciprocity in heterostylous populations. These results may help explain why heterostylous systems exhibit, and tolerate high amounts of intra-population variation in sex organ heights.

Variation in cedar leaf blight (Didymascella thujina) resistance of western redcedar (Thuja plicata)

2007 ◽  
Vol 37 (10) ◽  
pp. 1978-1986 ◽  
Author(s):  
John H. Russell ◽  
Harry H. Kope ◽  
Peter Ades ◽  
Heidi Collinson
Keyword(s):  
British Columbia ◽  
Genetic Correlations ◽  
Natural Populations ◽  
High Elevation ◽  
Leaf Blight ◽  
Population Variation ◽  
Thuja Plicata ◽  
Western Redcedar ◽  
Queen Charlotte Islands ◽  
River Site

Western redcedar ( Thuja plicata Donn ex D. Don) seedlings from a population study with family structure were planted at four sites across coastal British Columbia. All seedlings at the time of planting were infected with cedar leaf blight (CLB) ( Didymascella thujina (E.J. Durand) Maire). CLB severity and tree heights were measured at various ages from 2 to 12 years. There were significant site differences in CLB severity with the coastal hypermaritime site showing the most and with the submaritime site showing the least. Population differences in disease severity were evident with British Columbia coastal, low-elevation populations exhibiting the most resistance and with British Columbia high-elevation and California sources showing the least. Population resistance was consistent across all four sites (all r > 0.90, p < 0.001). Coefficients of additive genetic variation in CLB severity at all four sites varied from 13.2% to 20.1% with narrow-sense heritabilities from 0.21 to 0.66. Type B genetic correlations in CLB severity across sites averaged 0.59. Type A genetic correlations between 6 year CLB severity and height at the Jordan River site on western Vanvouver Island and at the site on the Queen Charlotte Islands were –0.96 and –0.86 (p < 0.001), respectively. Results are discussed with respect to climatic influences and prior exposure to CLB on among- and within-population variation in western redcedar natural populations and impact on gene resource management.

Strategy and structure of the hotel industry in Malaysia

2007 ◽  
Vol 4 (1) ◽  
pp. 97
Author(s):  
Salleh Mohd Radzi ◽  
Mohamed Amran ◽  
Abdul Razak Aziz ◽  
Azlan Supardi
Keyword(s):  
Structural Equation Modeling ◽  
Analysis Of Variance ◽  
Structural Equation ◽  
Hotel Industry ◽  
Strategic Orientation ◽  
Equation Modeling ◽  
Major Purpose ◽  
Strategy And Structure ◽  
Relationship Of ◽  
The Relationship

The major purpose ofthis study was to examine the relationship of strategy and structure. Porter s(/980) strategic typology was utilized to classify hotel firms by strategic orientation; and, an analysis of variance was performed to determine the differences in their performance. Structural Equation Modeling was used to confirm the factors underlying the strategy and structure constructs.

scholarly journals CAD-Based 3D-FE Modelling of AISI-D3 Turning with Ceramic Tooling

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Panagiotis Kyratsis ◽  
Anastasios Tzotzis ◽  
Angelos Markopoulos ◽  
Nikolaos Tapoglou
Keyword(s):  
Statistical Model ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Fe Model ◽  
Fe Modelling ◽  
3D Finite Element ◽  
Force Components ◽  
Four Levels ◽  
The Relationship ◽  
Strong Agreement

In this study, the development of a 3D Finite Element (FE) model for the turning of AISI-D3 with ceramic tooling is presented, with respect to four levels of cutting speed, feed, and depth of cut. The Taguchi method was employed in order to create the orthogonal array according to the variables involved in the study, reducing this way the number of the required simulation runs. Moreover, the possibility of developing a prediction model based on well-established statistical tools such as the Response Surface Methodology (RSM) and the Analysis of Variance (ANOVA) was examined, in order to further investigate the relationship between the cutting speed, feed, and depth of cut, as well as their influence on the produced force components. The findings of this study point out an increased correlation between the experimental results and the simulated ones, with a relative error below 10% for most tests. Similarly, the values derived from the developed statistical model indicate a strong agreement with the equivalent numerical values due to the verified adequacy of the statistical model.

Personal Adjustment and Authoritarian Attitudes toward the Mentally ILL

1972 ◽  
Vol 31 (2) ◽  
pp. 483-486 ◽  
Author(s):  
John Fracchia ◽  
Charles Sheppard ◽  
Joseph Pintyr ◽  
James Crovello ◽  
Sidney Merlis
Keyword(s):  
Analysis Of Variance ◽  
Mentally Ill ◽  
Mental Hospital ◽  
State Mental Hospital ◽  
Mentally Ill Persons ◽  
Personal Adjustment ◽  
Large State ◽  
The Relationship ◽  
State Mental ◽  
Inferior Class

The relationship between authoritarian attitudes, which reflect the belief that mentally ill persons comprise an inferior class requiring coercive handling, and personal adjustment was examined for 77 female psychiatric aides at a large state mental hospital. Correlations and analysis of variance suggested the lack of a systematic association between the two variables.

Attitudes of Parents and Guardians towards Education, School and Teachers, and Children's Academic Achievement

1996 ◽  
Vol 79 (3_suppl) ◽  
pp. 1387-1390 ◽  
Author(s):  
Varghese I. Cherian ◽  
Lily Cherian
Keyword(s):  
Academic Achievement ◽  
Analysis Of Variance ◽  
Positive Relationship ◽  
Education School ◽  
Relationship Of ◽  
The Relationship

To study the relationship of parents' attitudes towards teachers, school, and education with the academic achievement of their children, a questionnaire was given to the parents of 1021 Standard 7 pupils (369 boys and 652 girls) randomly chosen from the Standard 7/Year 9 population of 14,765 boys and 26,109 girls. Analysis of variance indicated a positive relationship between parents' attitudes and the academic achievement of their children regardless of whether the children's parents were deceased or alive.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

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