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Search Results: 1 - 10 of 728 matches for " heritability "
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Heritability of Blood Pressure in an Iranian Population
M Saadat,M Sadeqi,DD Farhud,A Bahaoddini
Iranian Journal of Public Health , 2001,
Abstract: The fact that life styles and personal interests, aggregate within families suggests that shared environment in addition to shared bioligical factors could play a role in determining the phenotypic similarity of idividuals living in the same household. It is a major concern of cardiovascular epidemiologists to know how much of the familial aggregation of blood pressure is attributable to shared genes and/or shared family environment. Genetic and environmental influences on blood pressure was examined in a sample representative of the adult population of Shiraz, Fars province, south of Iran. The studied population was the 107 pairs of mother and dauther. Analysis of the data suggest that the genetic heritabilities were estimated to be 0.58,0.30, 0.60 for systolic, diastolic, and mean blood pressure, respectively.
Critical analysis of correlation and heritability phenomenon in the silkworm, Bombyx mori (Lepidoptera: Bombycidae)  [PDF]
Tribhuwan Singh, Madan Mohan Bhat, Mohammad Ashraf Khan
Advances in Bioscience and Biotechnology (ABB) , 2011, DOI: 10.4236/abb.2011.25051
Abstract: Correlation and heritability studies of quantitative traits are a pre-requisite for judicious selection for genetic improvement of complex characters of economic importance. The success of selection is governed by the degree to which the desired trait is transmitted to the succeeding generation. The nature of selection is to be given due consideration at appropriate developmental stages for pursuing selection in desired direction while improving or evolving high productive breeds or hybrids of the silkworm. Characters showing high heritability as well as high genetic advance respond better to simple phenotypic selection while those having low heritability and low genetic advance may respond better to mass selection. Characters showing high heritability and low genetic advance may yield good response to hybridization and recurrent selection. An attempt has been made in this review article to briefly discuss the magnitude of correlation and heritability in selection strategies for the improvement of quantitative traits in desired direction in the silkworm, Bombyx mori (L.).
Hybrid Vigour and Genetic Control of Some Quantitative Traits of Tomato (Solanum lycopersicum L.)  [PDF]
Chinedozi Amaefula, Christian U. Agbo, Godson Emeka Nwofia
Open Journal of Genetics (OJGen) , 2014, DOI: 10.4236/ojgen.2014.41005

Parental lines, F1 generation of domesticated tomato (Solanum lycopersicum L.) and Lycopersicon pimpinellifolium L. were evaluated at Department of Crop Science, University of Nigeria, Nsukka for improvement in their quantitative traits. The experiment was laid out in a randomized complete block design with three replications. Data were collected on the quantitative traits and fruit yield. Better Parent Heterosis (BPH), genetic variances, gene effects and heritability of the traits were estimated for the hybrids. BPH result showed that the Wild × Petomech cross had the highest positive BPH of 358.36% in fruit yield. The highest negative BPH of -95.59% was recorded for the hybrid, Wild × Grosso in average fruit weight while the hybrid, Insulata × Grosso had the lowest negative BPH of -16.27% in average fruit weight. Additive gene action and additive × additive gene action (aa) were significantly in control of three crosses, W × P, W × In and W × G in fruit yield. Additive variance was higher than dominance variance in fruit yield for all the hybrids with wild as one of its parents. Again, hybrids with wild as one of its parent as, W × G, W × In, and W × P had the highest narrow sense heritability in fruit yield (59.15%, 51.69%, 59.88%, respectively). High level of epistasis controlled some of the quantitative traits and hybridization evidenced by the result was effective in developing new tomato cultivars with positive heterotic effects in fruit yield.

Genetic Variation for Biomass and Related Morphological Traits in Cup Plant (Silphium perfoliatum L.)  [PDF]
Teshale Assefa, Jixiang Wu, Kenneth A. Albrecht, Paul J. Johnson, Arvid Boe
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.68114
Abstract: Cup plant (Silphium perfoliatum L.) has demonstrated potential for bioenergy production in North America, South America, and Europe. Our objectives were to: 1) determine genetic variation and narrow-sense heritability for biomass and related morphological traits, and 2) identify half-sib families with superior biomass yield and potential for use in cultivar development in cup plant. Thirty three half-sib families and a check were evaluated at two locations in 2011, 2012, and 2013. Annual biomass yield at Brookings ranged from 2183 kg·ha-1 in 2012 to 8053 kg·ha-1 in 2013; whereas, yields at Arlington were similar among years. Mean individual half-sib family biomass yield ranged from 3912 to 6784 kg·ha-1 at Brookings and from 5682 to 11,269 kg·ha-1 at Arlington. Heritability estimates for five biomass-related morphological traits ranged from 0.52 to 0.72. This cup plant population had potential for biomass production in the north central USA and contained sufficient additive genetic variation to expect progress from among-and-within-family selection for biomass yield and related traits.
Genetic Variability and Direct Selection Criterion for Seed Yield in Segregating Generations of Barley (Hordeum vulgare L.)  [PDF]
Sunil K. Yadav, Ashok K. Singh, Praveen Pandey, Smita Singh
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.69153
Abstract: The aim of this study was to determine nature and extent of variability parameters and their utilization in barley breeding programme. A total of 45 F1s along with their parents and F2 populations were evaluated in a randomized block design with 3 replications during Rabi (winter season) 2014. The various traits measured were days to 50% flowering, days to maturity, plant height, flag leaf area, upper leaf area, tillers-plant, spikes-plant, spike length, grains-spike, spike weight, grain weight-spike, spike harvest index, 1000 grain weight, biological yield-plant, grain yield-plant (g), harvest index, grain size, husk content and protein content. Results showed that significant variation was observed for all the traits studied in the entire gene pool. The degree of genotypic and phenotypic coefficient of variation was high for tillers-plant, spike-plant, grain yield-plant, flag leaf area, harvest index, 1000 grain weight, grain weight-spike, upper leaf area and husk content. High heritability coupled with high genetic advance was recorded for tillers-plant, spikes-plant, grain yield-plant, flag leaf area, harvest index, grain weight-spike, upper leaf area, husk content, grain size and plant height suggesting that these traits are highly heritable and governed by additive gene action. Moderate heritability coupled with high genetic advance was observed for 1000 grain weight, biological yield-plant, spike length, protein content, grains-spike and spike weight; however, days to 50% flowering and days to maturity had moderate heritability coupled with low genetic advance suggesting preponderance on non-additive gene action in the inheritance of these traits. It could be concluded that
Genetic parameters of eventing horse competition in France
Anne Ricard, Isabelle Chanu
Genetics Selection Evolution , 2001, DOI: 10.1186/1297-9686-33-2-175
Abstract: (To access the full article, please see PDF)
Parametros genéticos e ganhos com a sele??o de progênies de Euterpe oleracea na fase juvenil
Farias Neto, Jo?o Tomé de;Oliveira, Maria do Socorro Padilha de;Resende, Marcos Deon Vilela de;Rodrigues, Juliana Chagas;
CERNE , 2012, DOI: 10.1590/S0104-77602012000300020
Abstract: genetics parameters and selection gains, obtained 36 months after planting, are presented and discussed for progenies of open pollinated population of a?ai palm for plant height (ap), plant diameter (dpc), number of live leaves ( nfv) and tiller number (np), based on the linear mixed model methodology (reml / blup). the thirty progenies were evaluated in a randomized blocks design with three replications and plots of five plants, spaced at 6m x 4m. the values obtained for individual heritability (0.55, 0.44, 0.38 and 0.43) and for progeny means (0.64, 0.54, 0.58 and 0.64) for ap, dpc, nfv and np, respectively, were expressives, which indicates the possibility of genetic progress with the selection. the accuracy among the genetics values predicted and the true were of 0.802 for height, 0.736 for diameter, 0.760 for number of live leaves and 0.797 for tiller number. with the exception of nfv character, the coefficients of individual genetic variation were high (>10%), confirming the potential of the population for selection. predicted genetic gains of 89.3% were obtained for the character ap and 2.1% for dcp, with the selection of the twenty top individuals. correlation was found between height and diameter of the plant. among ages, for the same characters, positive correlations of mean magnitudes were found.
Estima??o de parametros genéticos entre pesos pré e pós-desmama na ra?a Nelore
Garnero,A.V.; Mu?oz,M.C.C.D.; Marcondes,C.R.; L?bo,R.B.; Lira,T.; Gunski,R.J.;
Archivos de Zootecnia , 2010, DOI: 10.4321/S0004-05922010000200019
Abstract: correlations among two or more traits indicate the extent to which they are associated. the level and magnitude of this association are key factors in genetic improvement because the goal is to enhance the genetic makeup of a group of traits that act simultaneously. therefore, the aim of this study was to estimate the components of variance and heritability for standard weights at 120, 240, 365, 450 and 550 days of age (p120, p240, p365, p450 and p550, respectively), and the genetic correlation among p120 and other weights in nellore cattle using a database of 29 769 records. bivariate analysis was carried out for all the traits using p120 as an anchor, and additive covariance was fixed as an analytical strategy in order to obtain genetic correlation estimates. heritability (h2) values were 0.21 for p240; 0.37 for p365; 0.36 for p450 and 0.42 for p550. the estimation of h2 varied between 0.23 and 0.31 for w120. genetic correlation estimates were high and positive, 0.96, 0.87, 0.79 and 0.76 among p120 and p240, p365, p450 and p550, respectively. these values indicate that selection for weight at younger ages will lead to a corresponding change in later weight, in the same direction.
Parametros e tendência genética de peso de bovinos criados á pasto no Brasil
Souza,J.C.; Silva,L.O.C.; Gondo,A.; Freitas,J.A.; Malhado,C.H.M.; Filho,P.B.F.; Sereno,J.R.B.; Weaber,R.L.; Lamberson,W.R.;
Archivos de Zootecnia , 2011, DOI: 10.4321/S0004-05922011000300035
Abstract: genetic parameters and trends of weights were estimated for nellore cattle from central west and south east in brazil. abcz/embrapa provided weights (kg) at 120 (w120), 205 (w205), 365 (w365) and 540 (w540) for 86 852, 86 852, 61 637, 36 187 animals, respectively, from 1975 to 2001. parameters were obtained using mtdfreml in single trait analyses. fixed effects were contemporary group (dry or wet season), year, sex and farm and age of dam (linear and quadratic covariate). random effects were direct and maternal genetic effects, their covariance, and the uncorrelated maternal permanent environmental effect. the analysis was restarted until twice the logarithms of the likelihoods changed no more than two decimal places. estimates of direct and maternal genetic variances, direct-maternal covariance, and environmental and phenotypic variances were [51.1, 17.9, -12.0, 190.5 and 280.4] for w120; [128.6, 47.2, -25.9, 695.7 and 932.4] for w205; [435.9, 32.2, -27.4, 2934.0 and 3604.9] for w365; and [607.9, 177.7, -117.6, 5637.7 and 6602.5] for w540. direct heritabilities ranged from 0.09 to 0.18, maternal heritabilities from 0.01 to 0.06, direct-maternal genetic correlations from -0.23 to -0.36, and permanent environmental effects from 0.05 to 0.12. direct and maternal genetic and environmental trends from 1975 to 2001 were 10.4, -1.6 and 18.43 kg for w120; 16.6, -2.8; and 23.0 kg for w205; 21.7, -1.3 and 23.6 kg for w365, and, 25.5, -3.6, and -8.1 kg for w540, respectively. the direct genetic trends were positive and maternal trends were small. the importance of maternal performance for w120 and w205 suggests it should be considered in breeding programs although it has a low heritability and modestly adverse genetic correlation with direct genetic effects.
Análisis preliminar de parámetros genéticos para el carácter de prolificidad en la oveja Canaria de Pelo
Delgado,J.V.; León,J.M.; Bermejo,L.A.; López-Gallego,F.; Camacho,A.; Santolaria,J.;
Archivos de Zootecnia , 2012, DOI: 10.4321/S0004-05922012000100017
Abstract: this paper presents the values of genetic parameters for prolificacy in the canary haired sheep, obtained from the use of an animal model with repeated observations on the information generated in the nucleus of meat yield control of the breed. the genetic analysis model included as fixed effects in herd, year, season and number of parturition, and as random effects, the additive genotype of the animal and permanent environmental effect. it was used as information base a total of 7657 births registered in 2889 animals from 5 herds between 1996 and 2008, which represented an average of 2.65 births registered per animal, sufficient to obtain a good estimate of permanent environmental effect. the observed values for the heritability and repeatability were 0.05 and 0.1 respectively, values within the limits of the species. also values for additive, phenotypic and permanent environmental variances are provided. this is the first genetic parameter estimation in this breed with field data, which represents an important advance for its selection scheme.
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