Table 2.

Results of permutation test for evolutionary change in resource use. p-values from permutation tests are shown for each response variable for each contrast. GV = genetic variation; Comp = competition; σ² = variance; W = wheat (see §2e). ‘interaction group’ indicates the four treatment groups (table 1 and electronic supplementary material, appendix A).

response variable	effect	effect size	contrasted generations				Δ effect (4−W versus 8−4)
			4−W	8−4	8−W	0−W
Δ mean δ13C	GV	Δhigh GV—Δlow GV	0.31	0.26	0.70	0.36	0.29
	Comp	Δhigh Comp—Δlow Comp	0.55	0.03	0.63	0.50	0.06
	GV × Comp	σ2 (Δinteraction group)	0.68	0.03	0.99	0.51	0.42
Δ variance δ13C	GV	Δhigh GV—Δlow GV	0.25	0.02	0.12	0.40	0.004
	Comp	Δhigh Comp—Δlow Comp	0.15	0.35	0.65	0.32	0.17
	GV × Comp	σ2 (Δinteraction group)	0.26	0.25	0.49	0.38	0.28