Table 1.

Effect of treatment (nematode presence or absence), plant genotype, and the treatment × genotype interaction on nodule traits

	Nodule number		Mean nodule mass		Total nodule mass
	χ2df=1	P	χ2df=1	P	χ2df=1	P
Treatment	13.85	<0.001	2.65	0.103	19.48	<0.001
Genotype	–	<0.001	24.67	<0.001	13.39	<0.001
Trt × Geno	–	0.022	0	1.000	3.51	0.060

We do not report χ ² values for the genotype and the treatment × genotype interaction for nodule number because glmmADMB models do not return χ ² values for random effects. We used glmmADMB for the nodule number analysis to accommodate zero‐inflation and overdispersion (see Methods). The values reported for nodule number are from an analysis excluding four plants with >200 nodules; the model fit poorly when these four observations were included. We obtained qualitatively similar results in both cases.