. 2011 Sep 6;108(7):1347–1353. doi: 10.1093/aob/mcr227

Table 3.

Analysis of covariance for the fixed effects of genotype and irrigation, and the interactions between them, on shoot biomass (B_S), leaf N pool (N_L), leaf N content (N_A) and specific leaf area (SLA) assessed in 200 willow genotypes pot-grown in the glasshouse

Source of variation	d.f.	B_S (g)		N_L (mmol)		N_A (mmol m⁻²)		SLA (m² kg⁻¹)
Source of variation	d.f.	MS	P	MS	P	MS	P	MS	P
Block	1	0·49	0·019	0·37	0·019	3888	<0·001	1375	<0·001
Initial shoot height	1	70·34	<0·001	48·36	<0·001	–	–	–	–
Genotype (G)	199	0·11	0·034	0·10	<0·001	101	<0·001	45	<0·001
Irrigation (I)	1	88·76	<0·001	31·40	<0·001	9150	<0·001	7093	<0·001
G × I	199	0·12	0·049	0·07	0·185	57	0·003	24	0·150
Error	780*	0·09		0·07		42		22

Block and initial shoot height (cm) at the start of the treatments were used as covariates. B_S and N_L were log_e transformed prior to analysis.

Significant differences (P < 0·05) are highlighted in bold.

d.f., Degrees of freedom; MS, mean squares (variance).

* d.f. = 718 for the analyses of N_A and SLA, in which no covariate was used and individuals with B_S < 0·5 g were excluded.