Table 2.

Effects of planting density and N application rate on grain yield (155 g kg⁻¹ water content) during the 2013–2015 growing seasons.

Density	N rate	Grain yield (Mg ha−1)
		2013		2014		2015
		DH618	DH605	DH618	DH605	DH618	DH605
LD	N0	11.6i	13.0g	10.4k	11.4i	10.0f	12.0e
	N180	13.5f	14.3f	13.7f	13.1f	13.3d	14.2c
	N360	13.6f	13.9g	13.8f	13.2ef	13.3d	14.3c
	N270	–	–	–	–	13.3d	14.4c
	N540	13.1g	13.8g	13.1h	12.7g	–	–
MD	N0	12.7h	13.4i	11.0i	12.1h	–	–
	N180	14.9d	15.8c	14.2de	14.3b
	N360	15.0d	15.6cd	14.5c	14.2b
	N540	14.5e	15.3e	14.1e	14.0c
HD	N0	13.0g	13.7h	10.8i	12.0h	10.5e	12.6d
	N180	16.0b	16.4b	15.0b	14.6a	14.8c	15.4b
	N360	16.7a	17.1a	15.8a	14.7a	16.0a	15.8a
	N270	–	–	–	–	15.4b	15.8a
	N540	15.6c	15.5d	15.1b	14.5a	–	–
extra-HD	N0	–	–	10.7j	11.3i	–	–
	N180			13.5g	13.3e
	N360			14.3d	13.7d
	N540			14.3d	13.7d
ANOVA
Density (D)		3604.2***		740.2***		1886.5***
N rate (N)		2845.4***		4295.8***		2697.1***
Variety (V)		947.9***		11.8**		944.6***
D × N		144.0***		53.4***		109.3***
D × V		53.4***		16.4**		66.1***
N × V		23.9***		279.2***		120.6***
D × N × V		13.4***		6.9***		18.9***

Different lowercase letters indicate a significant difference (p < 0.05) with the same year of the same variety among treatments. The numbers in the ANOVA section represent F values. ns, not significant. *Significant at the 0.05 probability level. **Significant at the 0.01 probability level. ***Significant at the 0.001 probability level. LD, MD, HD, and extra-HD refer to low density, medium density, high density, and extra-high density, respectively. N0, N180, N270, N360, and N540 represent nitrogen rates of 0, 180, 270, 360, and 540 kg ha⁻¹, respectively.