Epistasis Epistasis, Genetic GWAS Gene Frequency Genetic Variation Genetic variances Genome-Wide Association Study Genotype Inbreeding Linkage Disequilibrium Linkage disequilibrium Models, Genetic Phaseolus Phaseolus vulgaris Phenotype Plant Breeding Polymorphism, Single Nucleotide Seeds additive effect anatomy and histology article association mapping biological model covariance dominant gene epistasis gene frequency gene linkage disequilibrium genetic variability genetic variation