Having set up the data this way, we can then write the ASReml code to define the field for the ‘r’ variable as a numeric covariate, and then fit interactions between GCA and SCA effects with this covariate to capture the reciprocal effects (Holland et al., 2003b; Möhring et al., 2011; Piepho and Mohring, 2007). The full model should also include reciprocal by environment interactions, which are really three-way interaction between genetic effects, the reciprocal covariate, and environment:
Code example 5.3: Model for diallel with reciprocal crosses (Code05-‐3_reciprocal_effects.as)