Lodging Resistance of Japonica Rice (Oryza Sativa L.): Morphological and Anatomical Traits due to top-Dressing Nitrogen Application Rates

Rice

Table 1 Culm morphology traits of the N₄ internode culm and plant height in two japonica rice cultivars under different nitrogen rates

Treatments	CD (mm)	CWT (mm)	b₁ (mm)	a₁ (mm)	b₂ (mm)	a₂ (mm)	PH (cm)	GCH (cm)
2013
Wuyunjing23
LN	4.96a	0.76a	5.26a	4.68b	3.63b	3.25b	81.6b	39.5a
MN	5.01a	0.82a	5.30a	4.78a	4.04a	3.46a	87.5a	39.7a
HN	4.96a	0.73a	5.22a	4.71ab	4.00a	3.50a	88.6a	39.8a
W3668
LN	4.24a	0.64a	4.50a	4.00b	3.56a	2.96b	94.7b	43.9b
MN	4.25a	0.64a	4.50a	4.11a	3.69a	3.06ab	99.2a	45.9a
HN	4.30a	0.65a	4.46a	4.16a	3.73a	3.16a	101.4a	47.2a
2014
Wuyunjing23
LN	4.74a	0.77a	5.02a	4.46a	3.59b	2.97b	101.5b	46.8a
MN	4.84a	0.82a	5.13a	4.55a	3.82a	3.42a	105.5a	47.8a
HN	4.93a	0.81a	5.16a	4.60a	3.88a	3.19ab	103.5ab	48.2a
W3668
LN	4.02a	0.65a	4.14b	3.78b	3.25b	2.80a	110.9a	49.5a
MN	4.03a	0.65a	4.19b	3.87b	3.26b	2.88a	112.2a	50.6a
HN	4.19a	0.64a	4.34a	4.04a	3.39a	2.89a	111.2a	51.3a
Analysis of variance
Year (Y)	24.5^b	1.3	39.4^b	45.3^b	61.9^b	44.9^b	814.7^b	325.8^b
Variety (V)	513.5^b	113.3^b	631.0^b	526.4^b	128.3^b	117.5^b	365.9^b	156.2^b
Nitrogen(N)	3.5^a	1.3	1.5	9.5^b	24.4^b	18.2^b	24.3^b	7.9^b
Y × V	0.4	0.8	2.5	0.1	14.9^b	0.1	18.8^b	19.9^b
Y × N	2.3	0.6	3.5^a	2.0	2.0	2.9	9.7^b	0.1
V × N	0.8	1.7	0.6	2.1	6.1^b	5.2^a	1.3	1.7
Y × V × N	0.2	1.2	0.2	0.1	0.1	1.7	0.2	1.2

Different lowercase letters represent a significant difference at the 0.05 level
Abbreviations: CD culm diameter, CWT culm wall thickness, GCH gravity centre height, a ₁ and a ₂ the outer and inner diameters of the minor axis in an oval cross-section, respectively, b ₁ and b ₂ the outer and inner diameters of the major axis in an oval cross-section, respectively, PH plant height
^{a, b} Means significant at the 0.05 and 0.01 probability levels, respectively