H2                      Calculate heritability from mixed model object
H2_Cullis               Calculate Cullis' heritability from model
                        object
H2_Cullis_parameters    Calculate Cullis heritability using variance
                        parameters
H2_Delta                Calculate average heritability of differences
                        between genotypes from model object
H2_Delta_by_genotype    Calculate heritability of differences for a
                        given genotype from model object
H2_Delta_pairwise       Calculate pairwise heritability of differences
                        between genotypes from model object
H2_Delta_parameters     Calculate heritability of pairwise differences
                        using variance parameters
H2_Oakey                Calculate Oakey's heritability from model
                        object
H2_Oakey_parameters     Calculate Oakey's heritability using variance
                        parameters
H2_Piepho               Calculate Piepho's heritability from model
                        object Compute Piepho's heritability using
                        variance differences between genotype BLUEs
H2_Piepho_parameters    Calculate Piepho's heritability using variance
                        parameters
H2_Standard             Calculate standard heritability from model
                        object
H2_Standard_parameters
                        Calculate Standard heritability using variance
                        parameters
lettuce_markers         Molecular marker data and genomic relatedness
                        matrix of 89 lettuce varieties
lettuce_phenotypes      Phenotypic of 89 lettuce varieties
