Table 2.

Effects of N rate and planting density on regrowth rate (%), panicles per m², spikelets per panicle, grain filling (%), grain weight (mg), and grain yield (kg ha⁻¹) in the perennial rice system from 2017 to 2019.

Treatment	Regrowth Rate (X1, %)	Panicles per m2 (X2)	Spikelets per Panicle (X3)	Grain Filling (X4, %)	Grain Weight (X5, mg)	Grain Yield (kg ha−1)
Year (Y)
2017F	100.00 c	281.65 a	158.69 c	84.19 a	23.50 b	8394.49 a
2018F	81.98 b	186.86 b	170.75 a	83.65 a	23.83 a	6029.04 b
2019F	54.12 a	111.18 c	163.73 b	83.84 a	23.38 b	3289.40 c
N rate (kg ha−1)
90	78.63 a	182.65 c	168.72 a	84.47 a	23.65 a	5808.01 b
150	78.62 a	194.28 b	165.42 b	83.32 a	23.48 a	5893.84 ab
210	78.85 a	202.76 a	159.03 c	83.89 a	23.57 a	6011.08 a
Planting density (hills per m2)
9.0	77.98 a	159.87 d	177.06 a	83.96 a	23.54 a	5319.65 c
13.5	78.32 a	185.78 c	167.52 b	83.58 a	23.44 a	5713.27 b
18.0	79.00 a	206.18 b	160.28 c	84.45 a	23.69 a	6284.55 a
22.5	78.62 a	221.08 a	152.70 d	83.58 a	23.61 a	6299.77 a
Analysis of variance
Year (Y)	**	**	**	ns	**	**
N rate (N)	ns	**	**	ns	ns	*
Planting density (PD)	ns	**	**	ns	ns	**
Y × N	ns	ns	*	ns	ns	ns
Y × PD	**	**	**	ns	ns	*
N × PD	ns	ns	ns	ns	ns	ns
Y × N × PD	ns	ns	ns	ns	ns	ns

Note: Different lowercase letters in the same column indicate significant differences at the 0.05 level. * and ** denote significant differences at the 0.05 and 0.01 probability levels, respectively, as determined using ANOVA. ns denotes non-significance based on ANOVA.