Dominance may be an important source of non-additive genetic variance for many traits of dairy cattle. However, nearly all prediction models for dairy cattle have included only additive effects because of the limited number of cows with both genotypes and phenotypes. The role of dominance in the Holstein and Jersey breeds was investigated for eight traits: milk, fat, and protein yields; product...

Estimates of variances due to additive and dominance genetic effects and permanent and temporary environmental effects were obtained for ovulation and twinning rates from a composite population selected for twinning rate. Measures of ovulation rate after 11 mo of age on 2,317 heifers with a total of 19,209 measures were used. Twinning measures were on 1,522 first-parity cows, 1,311 later-parity...

Primary causes of heterosis are still unknown. Our goal was to investigate the extent and underlying genetic causes of heterosis for five biomass-related traits in Arabidopsis thaliana. We (i) investigated the relative contribution of dominance and epistatic effects to heterosis in the hybrid C24 x Col-0 by generation means analysis and estimates of variance components based on a triple testcro...

Using Cockerham’s approach of orthogonal scales, we develop genetic models for the effect of an arbitrary number of multiallelic quantitative trait loci (QTLs) or neutral marker loci (NMLs) upon any number of quantitative traits. These models allow the unbiased estimation of the contributions of a set of marker loci to the additive and dominance variances and covariances among traits in a rando...

We used 179,485 Yorkshire reproductive and 239,354 Yorkshire growth records to estimate additive and dominance variances by Method Fraktur R. Estimates were obtained for number born alive (NBA), 21-d litter weight (LWT), days to 104.5 kg (DAYS), and backfat at 104.5 kg (BF). The single-trait models for NBA and LWT included the fixed effects of contemporary group and regression on inbreeding per...

diallel crosses of eight genotypes of safflower were conducted and f1 and f2 generations were evaluated to estimate genetic parameters for seed-quality related traits including protein contents (%), fiber, ash and oil yeild. griffing’s methods 1 and 2 for f1 and f2 generations was used, respectively. sixty four genotypes including 8 parents and 56 f1 progenies, and half diallel crosses of f2 ge...

ISHER (1918) provided a framework for the characterization of genotypic variance whereby he partitioned it into three components: ( 1 ) a portion associated with the average effects of genes, (2) a portion associated with dominance effects (allelic interactions) of genes, and (3) a portion associated with epistatic effects (nonallelic interactions) of genes. A logical method for the further sub...

The mode of agronomic traits inheritance was investigated in safflower (Carthamus tinctorius L.) in drought stress as a new report. Five generation including P1, P2, F1, F2 and F3 that derived from the cross of IL.111 (drought sensitive) ×Mex.22-191 (drought tolerance) were used in a randomized complete block design with two replic...

Additive and dominance genetic variances were estimated for milk and fat yield in Canadian Holsteins using deriva-tivefree REML procedures. Traits were analyzed under two sire and dam models differing in assumptions on the data structure. Within herd, dam relationships were first defined to be hierarchical within sire to estimate the two genetic variances, assuming no maternal, epistatic geneti...