Fig. 2

Venn diagram showing sets of reactions that contribute to biomass production and/or heterosis. Of the 456 reactions operating in the network, about one-third are coupled to biomass production, or their flux is correlated with heterosis in at least one F1 population, or alleles at the corresponding locus can be shown to directly contribute to heterosis. However, although the overlap between biomass coupling and flux correlation with heterosis is high, most direct genetic contributions to heterosis come from loci corresponding to uncoupled and uncorrelated reactions. The data on which the diagram is based are summarised in Table S1. The thresholds used to establish the set boundaries were |r| >0.9 (for correlations) and variance >1e − 8 for the contribution to heterosis