Although reproductive performance is one of the most critical components in swine production, it has been one of the most difficult areas for geneticists and animal breeders to improve. Traditional quantitative methods such as selection, inbreeding and cross-breeding have had limited success in this area (Rothschild, 1996). This is primarily due to the low heritabilities, sex-limited nature and...

Alternative reproductive tactics are ubiquitous in many species. Tactic expression often depends on whether an individual's condition surpasses thresholds that are responsible for activating particular developmental pathways. Two central goals in understanding the evolution of reproductive tactics are quantifying the extent to which thresholds are explained by additive genetic effects, and desc...

a genetic marker is a gene or dna sequence with known localization on a chromosome. it can be de-scribed as a variation that can be measured or detected by a suitable method, and can be used subsequently to detect the presence of a specific genotype. such variations occurring at chromosomal or dna level can serve as genetic markers. the progress in development of molecular markers suggests thei...

Plant species with separate genders often exhibit gender differences in traits related to reproductive allocation. In gynodioecious species, females often produce more seeds than do hermaphrodites, leading to a higher reproductive cost. The mechanisms that allow females to meet the high costs of reproduction are currently under debate. In this study, we test the hypothesis that there are geneti...

the main aim of this research was to estimate the genetic and phenotypic parameters for productive and reproductive traits of esfahan native chickens. traits included body weights at hatch (bw1), 8 weeks of age (bw8), 12 weeks of age (bw12), and at sexual maturity (wsm)], age at sex maturity (asm), egg number (en), average egg weight (aew) in the first 12 weeks of production, and egg production...

quantitative valuations of observed heterosis for 11 traits of 15 f1 hybrids generated by half diallel crosses of six diverse rice cultivars (domsefid, hashemi and binam, three iranian local cultivars; dorfak, kadous and ir30, three improved cultivars), were made in this study. fifteen f1 hybrids and their parents were evaluated in a randomized complete block design with three replications at t...