Table 4. Correlation coefficients of peak hormone contents in maize grain with the maximum grain filling rate (G_max), mean grain filling rate (G_mean), maximum grain weight (W_max) and activity grain-filling period (D) of maize.

		Wmax	Gmax	Gmen	D
Upper	IAA	0.8543*	0.9071*	0.8846*	0.4473
	Z+ZR	0.9787**	0.9922**	0.982**	0.665
	ABA	0.8807*	0.9258**	0.9002*	0.4834
	ETH	-0.9826**	-0.9947**	-0.9738**	-0.6765
	GA	0.4222	0.5192	0.3441	0.4315
Middle	IAA	0.824*	0.860*	0.876*	0.131
	Z+ZR	0.882*	0.919**	0.856*	0.379
	ABA	0.8744*	0.8861*	0.8169*	0.1046
	ETH	-0.8673*	-0.8169**	-0.8646**	-0.2917
	GA	0.6123	0.7582	0.5987	0.4396
Basal	IAA	0.316	0.3517	0.0548	0.2656
	Z+ZR	0.6228	0.6705	0.5132	0.5638
	ABA	0.8515*	0.8517*	0.8365*	0.1512
	ETH	-0.8588*	-0.8263*	-0.8578*	-0.6486
	GA	0.6233	0.856*	0.5092	0.4094
Mean	IAA	0.738**	0.825**	0.835**	-0.246
	Z+ZR	0.871**	0.918**	0.924**	-0.15
	ABA	0.772**	0.871**	0.955**	-0.291
	ETH	-0.863**	-0.965**	-0.921**	0.056
	GA	-0.076	-0.088	-0.36	0.645**

*Significant at the 0.05 probability level (for the mean grains, n = 18; for the upper grain, middle grain, basal grain, n = 6).

**Significant at the 0.01 probability level (for the mean grains, n = 18; for the upper grain, middle grain, basal grain, n = 6)).

IAA, indole-3-acetic acid; ABA, abscisic acid; Z, zeatin; ZR, zeatin riboside; GAs, gibberellins 1 plus 4; ETH: ethylene; W_max: the final grain weight (mg); Gmax: maximum grain-filling rates; Gmean: mean grain-filling rates.