Academic literature on the topic 'Phenotypic variance (σ2ph)'

A field experiment was carried out at Nigeria institute for Oil Palm Research date palm Research substation Dutse, Jigawa state during 2004-2005 flowering season. Biparental progenies derived from 60 crosses replicated twice were subjected to analysis of variance using nested design for the purpose of estimating additives, genetic and dominance components of variances of the seven bunch traits. Significant variation was observed for the traits studied. The male components of variances (σ2m) for all the traits were negative, indicating that the estimates were not different from zero or were very small. Positive estimates were recorded for females within male variance (σ2f/m), while Non-significant negative additive variances (σ2A) were obtained for all the traits. Dominance variance (σ2D) showed significant positive values for number of fruits, spikelets, aborted fruits and unfertilized florets. Positive estimates were recorded for environmental variance (σ2e), genotypic variance (σ2g) and phenotypic variance (σ2ph). In allcases phenotypic variance was much larger than the genotypic variance. Low environmental variance were obtained for the traits indicating that the environmental condition where the experiment was carried out is homogenous and the material could perform considerably well under similar environmental conditions. The means performance of the males indicates that variability exists between the males; Males 6R3 and 1R7 are good combiners with female 12R3 for number of fruits while males 1R12 and 5R2 are good combiners with female 12R3 for number of fruits. Female 2R8 is poor general combiners for number of fruits. Males 1R12 and 5R2 are good combiners with female 1R27 for weight of fruit while male 6R3 and 1R7 are good combiners with female 12R3 for fruit weight. Recurrent and backcross selection are recommended for further date palm improvement programs.

Abstrak. Penelitian bertujuan untuk mendapatkan informasi tingkat heritabilitas tanaman padi generasi F2 hasil persilangan varietas Batutegi dangan IRBB-27. Penelitian ini dilaksanakan di rumah kaca Fakultas Pertanian, Universitas Syiah Kuala, Darussalam Banda Aceh. Pelaksanaan penelitian dimulai dari April sampai September 2017. Pendugaan nilai heritabilitas pada penelitian ini menggunakan pendugaan ragam lingkungan tidak langsung metode Mahmud-Kramer (Broad sense-per tanaman). Pendugaan nilai heritabilitas ini menggunakan data populasi P1, P2, dan F2. P1 dan P2 merupakan galur murni, sedangkan F2 merupakan turunan kedua dari persilangan P1 dan P2. Ragam fenotipe (σ2P) diduga dari σ2F2. Ragam lingkungan (σ2E) diduga dari √(σ2P1)(σ2P2). Pada karakter tinggi tanaman, jumlah malai, berat malai, berat 1000 butir, umur paner, dan potensi hasil memiliki nilai heritabilitas 92%, 55%, 51%, 89%, 64% dan 60% dengan kriteria tinggi. Sedangkan karakter panjang malai, dan persentase gabah bernas, memiliki nilai heritabilitas 29% dan 33% dengan kriteria sedang.Estimating the Heritability Value of Agronimic Character of Rice (Oryza sativa L) Generation F2Abstract. The aim of this research was to obtain information on the level of heritability of generation F2 rice produced by crossing of the Batutegi variety with IRBB-27. This research was carried out in the greenhouse of the Faculty of Agriculture, Syiah Kuala University, Darussalam Banda Aceh. The research starts from April to September 2017. Estimating the heritability value in this study uses indirect environmental estimation of the Mahmud-Kramer method (Broad sense- plant). Estimating this heritability value uses population data P1, P2 and F2. P1 and P2 are pure strains, while F2 is the second derivative of P1 and P2 crosses. Phenotype variance (σ2P) is assumed to be from σ2F2. Environmental variance (σ2E) is assumed to be from √(σ2P1) (σ2P2). In the character of plant height, panicle number, panicle weight, 1000 grain weight, paner age, and yield potential has a heritability value of 92%, 55%, 51%, 89%, 64% and 60% with high criteria. While the panicle length character, and the percentage of pithy grain, has a heritability value of 29% and 33% with medium criteria.

AbstractThe effects of heterogeneity among herds in phenotypic variance (σ2p) and in heritability (h2) on the accuracy of evaluation of dairy sires and cows are discussed with reference to estimates from field data. It is argued that heterogeneity of σ2P can be accounted for by using a (Bayesian) regression procedure. While the same procedure could be used to correct for heterogeneity of h2, in most practical situations the sampling errors of the h2 estimates for individual herds are likely to be so large that regressed estimates of h2 will differ little from each other, so constant values can be assumed.

Identification of genotypes better suited for particular region and their improvement is of immediate task to exploit their full potential. The improvement can be brought out after confirming the association among the most important growth with quality attributes. Hence, varietal evaluation becomes necessary to find out suitable variety for a particular region. Experiment was conducted with 20 different decorative types of dahlia varieties at Jambuvadi Farm, College of Horticulture, Junagadh Agricultural University, Junagadh which falls under South Saurashtra Agro-climatic Zone during 2021-22. The analysis of variance revealed significant differences among the genotypes for eleven characters in dahlia viz., plant height, number of leaves per plant, number of branches per plant, stem girth, days taken to first bud initiation, diameter of flower, stalk length, vase life, anthocyanin content, chlorophyll content and flower yield which indicated the existence of variability in the experimental material. The estimates of genotypic (σ2g) and phenotypic variances (σ2p) of each character were carried out.

Twenty-two open-pollinated varieties (OPVs) of pearl millet (Pennisetum glaucum) genotypes were tested in two locations for three seasons in Ghana to estimate the magnitude of genetic variability, heritability, and stability for grain yield and related traits and grain micronutrients among the varieties. General analysis of variance within and across locations and years revealed very highly significant variability ( p < 0.01 ) among the genotypes. The additive main effects and multiplicative interaction (AMMI) analyses revealed significant genotype × environment interaction (GEI) that influenced the relative ranking of genotypes across the environments. Genotypic variance ( σ 2 g ) contributed a greater proportion of the phenotypic variance (σ2p) for plant height (530.31) and grain Fe content (34.72). Broad-sense heritability ( h b s 2 ) varied widely from 24.82% for grain yield to 77.53% in days to flower. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all traits, indicating strong play of environment on trait expressions. 11 out of the 22 OPVs were stable for grain yield and micronutrients across environments for the three-year period and included GB 8735 and ICMV 221 Wbr and SOSAT-C88.

Twenty eight local rice landraces were assessed for eleven morphological traits for the improvement of salt tolerance ability of rice genotypes. Genotypic variance (σ2g), phenotypic variance (σ2p), phenotypic co-variance (PCV), genotypic co-variance (GCV), heritability, genetic advance, genetic advance as a percentage of mean, correlation coefficient and path coefficient were estimated. For all the traits, PCV was higher than the GCV indicating that they were controlled by non-additive gene action and selection for the improvement of these traits would be promising. Among the traits, survival rate of plant exhibited high estimates of PCV (460.72) and GCV (324.73) indicated wide range of variability for these traits where lowest phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) where low PCV and GCV were observed for root dry weight (0.17 & 0.12) followed by shoot dry weight (0.31 & 0.16) and total number of roots (0.61 & 0.34) indicating lack of inherent variability and limited scope for improvement through selection for these traits among the genotypes. Highest heritability had observed in all traits except chlorophyll content and root length and maximum value of heritability was noticed for shoot length (75.96%). High heritability along with high genetic advance was noticed for survival rate of plant (31.14%) followed by live leaves percentage (11.98) and the lowest genetic advance was found in root dry weight (0.58) and shoot dry weight (0.58). Correlation study revealed that significant negative correlations at both phenotypic and genotypic level exist between standard evaluation score (SES) and survival rate (%), root length, shoot length, root fresh weight, root dry weight and shoot dry weight at the seedling stage further confirmed the importance of these parameters as useful selection criteria for screening for salt tolerance rice genotypes. Path analysis revealed that the root length (0.487), root dry weight (0.394) and shoot dry weight (0.047) had direct positive effect on standard evaluation score at genotypic level where live leaves (%) per plant (0.168), total number of roots (0.006), chlorophyll content (0.243) and shoot fresh weight (0.102) had direct positive effect on standard evaluation score at phenotypic level. From the correlation and path analysis it can be concluded that root length, root dry weight and shoot dry weight would be more promising for the improvement of salt tolerance in rice genotypesJ. Bangladesh Agril. Univ. 16(1): 41-46, April 2018

Abstract Background Quantitative autistic traits are common, heritable, and continuously distributed across the general human population. Patterns of autistic traits within families suggest that more complex mechanisms than simple Mendelian inheritance—in particular, parent of origin effects—may be involved. The ideal strategy for ascertaining parent of origin effects is by half-sibling analysis, where half-siblings share one, but not both, parents and each individual belongs to a unique combination of paternal and maternal half-siblings. While this family structure is rare in humans, many of our primate relatives, including rhesus macaques, have promiscuous breeding systems that consistently produce paternal and maternal half-siblings for a given index animal. Rhesus macaques, like humans, also exhibit pronounced variation in social functioning. Methods Here we assessed differential paternal versus maternal inheritance of social functioning in male rhesus macaque offspring (N = 407) using ethological observations and ratings on a reverse-translated quantitative autistic trait measurement scale. Restricted Maximum Likelihood mixed models with unbounded variance estimates were used to estimate the variance components needed to calculate the genetic contribution of parents as the proportion of phenotypic variance (σ2P) between sons that could uniquely be attributed to their shared genetics (σ2g), expressed as σ2g/σ2P (or the proportion of phenotypic variance attributable to genetic variance), as well as narrow sense heritability (h2). Results Genetic contributions and heritability estimates were strong and highly significant for sons who shared a father but weak and non-significant for sons who shared a mother. Importantly, these findings were detected using the same scores from the same sons in the same analysis, confirmed when paternal and maternal half-siblings were analyzed separately, and observed with two methodologically distinct behavioral measures. Finally, genetic contributions were similar for full-siblings versus half-siblings that shared only a father, further supporting a selective paternal inheritance effect. Limitations These data are correlational by nature. A larger sample that includes female subjects, enables deeper pedigree assessments, and supports molecular genetic analyses is warranted. Conclusions Rhesus macaque social functioning may be paternally, but not maternally, inherited by sons. With continued investigation, this approach may yield important insights into sex differences in autism’s genetic liability.