Table 2.

Internode length, plant height, gravity center height and grain yield under the two nitrogen fertilizer management practices.

Variety	Nitrogen management practice	Internode length(cm)						Plant height (cm)	Gravity center height (cm)
		I1	I2	I3	I1 + I2 + I3	I4	I5
YJRZ	FFP	3.4 ± 0.1a*	8.1 ± 0.2a	16.9 ± 0.4a	28.4 ± 0.6a	18.4 ± 0.5a	36.8 ± 0.1a	104.0 ± 0.9a	43.9 ± 0.9a
	OPT	2.8 ± 0.2a	6.8 ± 0.5b	13.2 ± 0.6b	22.7 ± 0.9b	19.8 ± 0.6a	39.6 ± 0.6a	110.1 ± 3.3a	46.7 ± 0.8a
	%**	−18.3	−16.6	−22.1	−20.1	7.7	7.6	5.8	6.4
YZ889	FFP	3.6 ± 0.3a	8.7 ± 0.3a	17.8 ± 0.4a	30.1 ± 0.9a	16.3 ± 0.5b	34.6 ± 0.1b	102.9 ± 1.9a	45.5 ± 1.6a
	OPT	3.4 ± 0.2a	7.1 ± 0.5b	14.2 ± 0.5b	24.6 ± 1.1b	18.0 ± 0.7a	38.9 ± 0.4a	108.8 ± 2.1a	48.4 ± 1.4a
	%	−5.9	−18.7	−20.4	−18.2	10.7	12.3	5.7	6.5

Note: I1, I2, I3, I4 and I5 denote the 1^st–5^th internodes being counted upwards from the base. *Mean ± standard error, values within a column followed by different letters are significantly different at the 0.05 probability level for a given variety. **Percent change of a certain trait under OPT is relative to that of FFP for a given variety.