The aim of the study was to determine the effect of pituitary transcription factor 1 (POU1F1, Pit1) and the polymorphism of growth hormone releasing hormone (GHRH) genes on selected pig performance traits. The animals used were the progeny of Polish Landrace × Polish Large White crossbred sows and Polish Landrace, Polish Large White, Duroc or Pietrain boars. Eighteen perfor-mance traits were re...

We describe the impact of recent life-history plasticity theory on insect studies, particularly on the interface between genetics and plasticity. We focus on the three-dimensional relationship between three key life-history traits: adult size (or mass), development time and growth rate, and the connections to life cycle regulation, host plant choice, and sexual selection in seasonal environment...

We develop a model for somatic growth in fishes that explicitly allows for the energy demand imposed by reproduction. We show that the von Bertalanffy (VB) equation provides a good description of somatic growth after maturity, but not before. We show that the parameters of the VB equation are simple functions of age at maturity and reproductive investment. We use this model to show how the ener...

Grandinson, K. 2003. Genetic aspects of maternal ability in sows. Doctoral dissertation. ISSN 1401-6249, ISBN 91-576-6440-4 The purpose of this thesis was to gain knowledge about the genetic background of different aspects of maternal ability in sows. Today’s selection for increased litter size at birth will put higher demands on the sow’s ability to take care of her litter, and may cause probl...

The introduction of nanoparticles into seed germination and seedling growth of plants might have a significant impact and thus, it can be used for agricultural applications for better growth and yield. The purpose of this study was to compare the effects of silica and silver nanoparticles on seed germination and early growth traits as well as percent and rate of germination, root length, shoot ...

Plasma insulin-like growth factor-1 (IGF-I) concentration taken post weaning from 1240 Bos Taurus beef cattle were used to estimate the heritability of the trait and to investigate its genetic relationship with various growth and carcase traits. IGF-I had a heritability estimate of 32% and was positively genetically correlated with various measures of carcase fatness, both on the live animal (s...

Despite the diversity of mammalian life histories, persistent patterns of covariation have been identified, such as the 'fast-slow' axis of life-history covariation. Smaller species generally exhibit 'faster' life histories, developing and reproducing rapidly, but dying young. Hormonal mechanisms with pleiotropic effects may mediate such broad patterns of life-history variation. Insulin-like gr...

In order  to study the effect of drought stress on some growth indices of oil sunflower cultivars, a study was conducted in Isfahan. The experiment was conducted as split plots in a randomized complete blocks design with three replications in Isfahan (51° 48' E, 32° 40' N).Main plots were drought stress in four levels (80, 100, 120, and 140 mm evaporation from evaporation pan class A and cultiv...

In order  to study the effect of drought stress on some growth indices of oil sunflower cultivars, a study was conducted in Isfahan. The experiment was conducted as split plots in a randomized complete blocks design with three replications in Isfahan (51° 48' E, 32° 40' N).Main plots were drought stress in four levels (80, 100, 120, and 140 mm evaporation from evaporation pan class A and cultiv...

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...