Heritability with positive Interaction Variance

    Variety 2 consistently outperforms Variety 1 by more than 50% under poor environmental conditions (e.g., nutrient-poor soil at EQ = 50). However, Variety 1 outperforms Variety 2 only in a very good environment (e.g., added fertilizer at EQ = 80). In intermediate environments (EQ = 65~75), the two varieties on average perform equally well, with considerable variance. Although increased yield always occurs with increased environmental quality, the differential response is not predictable from experiments in either extreme environment separately. Also, Variety 1 in a better environment (EQ=70) performs equally well with Variety 2 in a poorer environment (EQ=60). Choice of which variety to plant will depend on environmental availability.

Figure 2002 by Griffiths et al.; all text material 2014 by Steven M. Carr