Source and hybridity indicies and coefficients of directional genetic effects.

Source and hybridity indices and the resulting coefficients for the genetic effects in line cross equations, including all two-way epistatic interactions, after (Lynch and Walsh 1998, Chapter 9). Lines are created by crossing inbred parent 1 (P1) with inbred parent 2 (P2) to produce the F1 and F2 generations as well as reciprocal backcrosses to P1 (B1) and P2 (B2). Recombinant inbred lines (RIL) are formed by repeatedly selfing the F2s. The meaning of the columns: S = proportion of genome from P1; H = proportion of heterozygous loci; θS = source index, indicating the relative contributions of P1 and P2 to the generation genome; θH = hybridity index, indicating expected heterozygosity of the generation's genome on a scale of 1 to −1. μ = the mean phenotype of the F2 generation. The values in the remaining columns indicate expected contribution of the column's genetic effect to the phenotype of the row's generation. The effect types: A = additive; D = dominance; AA = dominance by dominance interaction; AD = additive by dominance interaction; DD = dominance by dominance interaction.