The appropriate technique may depend on a number of factors, so a strong correlation between the measured trait and the ultimately desired trait, whether survival or yield after cold stress, is very important.
A likelihood ratio test of, comparing the full (mixed effects) and reduced (fixed effects only) model, is used to investigate the association between genotype groups and a measured trait.
This scoring system was produced using the evidence of associations between the DNA profile (genotype) and the actual measured trait (phenotype) from other breeds of cattle.
In the genetic association study setting, interest is in characterizing the association between the latent variables, U i, and the measured trait, given by y i. Formally, a test of association is given by a Wald test of the null hypothesis,.
MEMs, widely used to address correlations in repeated-measures and multi-level data (Laird and Ware, 1982), are an alternative latent variable modeling strategy that has been described for characterizing association between multiple SNPs, within and across genes, and a measured trait (Foulkes et al., 2005; Goeman et al., 2004; Foulkes and De Gruttola, 2002).
To compare differences between plant pairings (two sample t-test), for each plant pair the two values of a measured trait were subtracted from each other, and the mean difference for all replicates of a pairing is referred to as Δ, combined with subscripts that describe the measured trait (e. g. Δnicotine).
For paired t-tests we compared means of the measured trait of each of the two lines of a pairing.
The total contribution of the genetic, shared environmental and non‐shared environmental factors to the phenotypic correlation between any two measured traits can be derived by multiplying each element in a path chain from one measured trait to the other, then summing these products for the A, C and E chains.
The third measured trait was plant survival.
In terms of different populations, one QTL for five measured traits in bin 5.06, one QTL for three measured traits in bin 9.06, and one QTL for one measured trait in bin 10.04 were located across two RIL populations.
