Figure 2.

Reaction norms of parasite virulence (number of barley seeds normalized by controls) for four genotypes of barley (Morex, Oregon Wolfe Dominant (OWD), Oregon Wolfe Recessive (OWR) and Steptoe) infected with Rhinanthus angustifolius (RA, black lines) and Rhinanthus minor (RM, grey lines). Each line represents the mean reaction norm for a single genotype infected by two populations of a single species of Rhinanthus. Rhinanthus angustifolius originates from two Dutch populations (Doode Bemde (DB) and Wageningen (WA)) and R. minor from two UK populations (Somerset (S) and Wiltshire (W)). OWR, solid lines; Morex, long dashed lines; OWD, short dashed lines; Steptoe, dotted lines.