Table 1.

Summary results of general lineal mixed models testing the effects of ploidy (P), water treament (T) and their interaction on variation of ecophysiological traits across multiple B. distachyon diploid and B. hybridum allotetraploid lines. The effect of ‘Line’ nested within ploidy was incorporated as a random factor in the models. We included the number of spikes as a covariate in gas exchange models. Significant values (P < 0.05) are in bold.

	A (µmol CO2 m−2s−1)			gs (mmol m−2s−1)			Integrated WUE (δ13C)
Source	d.f.	F	P	d.f.	F	P	d.f.	F	P
Ploidy (P)	1, 169	0.08	0.78	1, 165	8.79	0.0035	1, 93	8.15	0.0053
Water treatment (T)	1, 6.21	7.21	0.0351	1, 6.24	73.98	0.0001	1, 4.28	182.72	0.0001
P x T	1, 981	36.84	<0.0001	1, 977	2.63	0.105	1, 414	1.13	0.289
Random Effects		Z	P		Z	P		Z	P
Line(Ploidy)		5.38	<0.0001		4.89	<0.0001		4.86	<0.0001
Covariate	d.f.	F	P	d.f.	F	P	d.f.	F	P
Number of spikes	1, 1006	78.93	<0.0001	1, 876	125.77	<0.0001	NA	NA	NA