Tensor product smooths provide the natural way of representing smooth interaction terms in regression models because they are invariant to the units in which the covariates are measured, hence avoiding the need for arbitrary decisions about relative scaling of variables. They would also be the natural way to represent smooth interactions in mixed regression models, but for the fact that the ten...

One of the major field constraints to seed production in safflower has proven tobe soil born pathogens, Phytophthora drechsleri and Pythium ultimum. In order toevaluate the efficiency of a field-laboratory selection method to improve resistanceof safflower against soil born pathogens, Ph. drechsleri and P. ultimum, a two-yearinvestigation was conducted. The results showed that selection is an e...

In experiments where failure times are sparse, degradation analysis is useful for the analysis of failure time distributions in reliability studies. This research investigates the link between a practitioner’s selected degradation model and the resulting lifetime model. Simple additive and multiplicative models with single random effects are featured. Results show that seemingly innocuous assum...

in this research, 6517 records, collected by khojir sheep breeding station (tehran, iran), during 1991 to 2011 were used to estimate genetic parameters of lamb survival in zandi sheep. genetic parameters were estimated using 16 different models of animal model, sire and threshold models using reml procedures. the aic criterion was used to evaluate the models. the effects in the most suitable an...

in this study, the effect of maternal additive genetic and environment on body weight at 6 weeks (bwt6w), breast width (hbrs), carcass weight (carcwt), breast weight (brswt), blood hematocrit value (hem), residual feed intake (rfi), daily feed intake (dfi) and average daily gain (adg) were investigated in a commercial broiler dam line. with and without maternal effects, six different animal mod...

Quality Protein Maize (QPM) has about twice the amount of lysine and tryptophan of normal maize and hence represents an important tool of correcting its deficiency in protein quality. However, the effects of low nitrogen and drought on genetic parameters such as gene action and combining abilities of protein quantity and quality of QPM are not known. To study how these genetic parameters are af...

influence of maternal and sire-generation interaction effects on day-old chick' weight was investigated in two commercial broiler sire and dam lines, and in mazandaran native fowls. the data were analysed through restricted maximum likelihood (reml) procedures, using asreml software. ten different animal models were implemented and compared with likelihood ratio test. all models consisted ...

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...

ABSTARCT The objective of this study was to analyze the effects of factors affecting reproductive traits in the Holstein population of the Isfahan dairy farms for subsequent compilation of the model for genetic evaluation as well as for herd management practice. A data set containing 99012 records were analyzed by a linear model with fixed effects of year , herd ,season, parity of dam, calving ...