Table 1.

Models for the relationship between plant growth rate during the critical period for seed set (G_C) and initial shoot biomass per plant (S_P) in soybean, sunflower and maize crops grown at high plant population density (56·5, 10·3 and 16·9 plants m^–2)

Species	Model type	Parameters ± s. e.	R2*	n †
Soybean	GC = a*SPb	a = 0·053 ± 0·005	0·89	114
		b = 1·15 ± 0·046
Sunflower	GC = a/{1+ exp [–(SP – b)/c]}	a = 2·60 ± 0·138	0·68	111
		b = 35·12 ± 1·861
		c = 11·15 ± 1·878
Maize	GC = a + bSP	a = –0·58 ± 0·222	0·57	105
		b = 0·07 ± 0·006

* Coefficient of determination; all models and parameters were significant at P < 0·0001 except for parameter a in maize (P < 0·01).

^† Number of individuals.