data on 361 lambs of mehraban (n=90), ghezel (n=92), ghezel × mehraban (n=87), and mehraban × ghezel (n=92, sire breed listed first) were used to estimate individual heterosisfor lamb growth. the obtained results demonstrated that lambs of purebreds of ghezel and mehraban showed the highest and the lowest birth weight, respectively (p

This study was conducted to evaluate maternal breed effects, direct breed effects, and individual heterosis on subsequent steer performance, carcass, and feed efficiency traits. This was a consecutive 2-yr trial using 158 steers. The same dam breeds, Angus (AN) and purebred Simmental (SM), were used both years. Also, the same AN and SM sires (n=11) were used both years. Steers were AN, SM, or A...

Data on 361 lambs of Mehraban (n=90), Ghezel (n=92), Ghezel × Mehraban (n=87), and Mehraban × Ghezel (n=92, sire breed listed first) were used to estimate individual Heterosisfor lamb growth. The obtained results demonstrated that lambs of purebreds of Ghezel and Mehraban showed the highest and the lowest birth weight, respectively (P

Heterosis Heterosis, or hybrid vigor, refers to the increased vitality or “doing ability” of the crossbreds as compared to the average of the parental breeds. The only way to get heterosis is through crossbreeding. Heterosis is expressed by the crossbred lamb (individual) and by the crossbred ewe (maternal). Crossbred lambs, on the average, are more vigorous and have a higher survivability than...

To understand the genetic basis of inbreeding depression and heterosis in rice, main-effect and epistatic QTL associated with inbreeding depression and heterosis for grain yield and biomass in five related rice mapping populations were investigated using a complete RFLP linkage map of 182 markers, replicated phenotyping experiments, and the mixed model approach. The mapping populations included...

In this article we investigate multiplicative effects between genes in relation to heterosis. The extensive literature on heterosis due to multiplicative effects between characters is reviewed, as is earlier work on the genetic description of heterosis. A two-locus diallelic model of arbitrary gene action is used to derive linear parameters for two multiplicative models. With multiplicative act...

Enhancement of performance in traits of economic importance by use of heterosis (hybrid vigor) is routine in poultry breeding. There is, however, no reliable method to predict the level of heterosis that will occur from the mating of individuals from two populations. DNA fingerprints (DFP) were used as a measure of genetic distance between mating pairs of chickens where each individual of a pai...

Despite its importance to agriculture, the genetic basis of heterosis is still not well understood. The main competing hypotheses include dominance, overdominance, and epistasis. NC design III is an experimental design that has been used for estimating the average degree of dominance of quantitative trait loci (QTL) and also for studying heterosis. In this study, we first develop a multiple-int...

Despite its importance to agriculture, the genetic basis of heterosis is still not well understood. The main competing hypotheses include dominance, overdominance and epistasis. NC Design III is an experimental design that has been used for estimating the average degree of dominance of QTL and also for studying heterosis. In this study, we first develop a multiple interval mapping model (MIM) f...

Heterosis is widely used in breeding, but the genetic basis of this biological phenomenon has not been elucidated. We postulate that additive and dominance genetic effects as well as two-locus interactions estimated in classical QTL analyses are not sufficient for quantifying the contributions of QTL to heterosis. A general theoretical framework for determining the contributions of different ty...