Fig. 2.

From the greenhouse experiment (2011–2012), plant defense protein activity in susceptible (−,−; Vernal), nematode resistant (+,−; PGI-437), aphid resistant (−,+; Rugged), and combined aphid and nematode resistant (+,+; Sutter) varieties. Bar color indicates treatment type (C = control, N = nematode application, A = aphids present, AN = aphids and nematode application). Values are means ±1SE. Capital letters that are different from each other represent significant (P < 0.05) main effects of variety (one letter per variety); an asterisk indicates significant differences among treatments within a variety; minus (−) and plus (+) symbols indicate varieties that are different from the variety resistant to nematodes and aphids (Sutter) when nematodes were not applied and when nematodes were applied, respectively. Main effects of aphids (for PPO, CHI, and POD) are not shown