Enlarged Sink Capacity and Optimized Population Physiological Characteristics are Key to High Yield in Conventional Japonica Rice

doi:10.1016/j.rsci.2025.10.004

Abstract

Abstract:

Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security. Therefore, a two-year field trial with two conventional japonica varieties was conducted at four planting densities: 16 cm × 30 cm (D1), 14 cm × 30 cm (D2), 12 cm × 30 cm (D3), and 10 cm × 30 cm (D4). This study aimed to investigate how photosynthetic and population characteristics influence grain yield under varying planting densities. The results indicated that higher yields were primarily driven by increased grain weight and seed-setting rate (with a 9.68%‒11.40% higher single panicle weight), supported by optimized dry matter translocation and source-sink relationships. Elevated planting density (D2‒D4) enhanced panicle number and total spikelet number (by 3.91%‒15.00%) but reduced the number of spikelets per panicle, 1000-grain weight, and photosynthetic efficiency due to mutual shading. Despite these trade-offs, yield increased by 4.10%‒12.42% under higher densities. The use of planting density D4 in japonica rice cultivation contributed to maximize yield. These findings provide important theoretical insights and practical significance for increasing the yield of conventional japonica rice and ensuring food security.

Key words: conventional japonica, yield, population characteristics, photosynthetic efficiency, planting density

Zhang Haipeng, Mi Kailiang, Chen Ting, Zhang Muyan, Xu Fangfu, Zhang Hongcheng. Enlarged Sink Capacity and Optimized Population Physiological Characteristics are Key to High Yield in Conventional Japonica Rice[J]. Rice Science, 2026, 33(1): 113-128.

Figures/Tables 7

References 48

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Year	Variety	Treatment	No. of panicles per hm² (×10⁴)	Total spikelet number per m²	Seed-setting rate (%)	1000-grain weight (g)	Yield (t/hm²)
2023	Ningxiangjing 9	D1	286.11 ± 3.54 d	52 321.5 ± 864.6 c	84.87 ± 0.73 a	24.50 ± 0.20 a	10.73 ± 0.09 c
		D2	305.55 ± 2.97 c	55 633.4 ± 355.2 b	84.70 ± 1.01 a	24.44 ± 0.29 a	11.36 ± 0.13 b
		D3	322.22 ± 6.00 b	58 193.5 ± 791.1 a	84.11 ± 0.09 a	24.33 ± 0.31 a	11.68 ± 0.12 a
		D4	334.44 ± 6.85 a	59 666.2 ± 697.9 a	83.82 ± 0.93 a	24.17 ± 0.15 a	11.91 ± 0.06 a
		Mean	312.08	56 453.6	84.37	24.36	11.42
	Songxiangjing 1018	D1	281.95 ± 2.60 d	48 225.5 ± 411.3 d	88.39 ± 0.52 a	27.91 ± 0.11 a	11.72 ± 0.04 c
		D2	296.83 ± 2.97 c	50 144.7 ± 309.6 c	88.13 ± 0.24 a	27.84 ± 0.08 a	12.20 ± 0.06 b
		D3	318.52 ± 3.46 b	52 748.0 ± 238.0 b	87.67 ± 0.28 a	27.76 ± 0.17 a	12.58 ± 0.18 a
		D4	332.22 ± 5.66 a	54 099.7 ± 498.9 a	87.36 ± 0.58 a	27.63 ± 0.26 a	12.76 ± 0.09 a
		Mean	307.38	51 304.5	87.89	27.79	12.31
2024	Ningxiangjing 9	D1	301.39 ± 2.60 d	52 931.9 ± 442.5 d	84.74 ± 0.35 a	24.32 ± 0.02 a	10.62 ± 0.01 d
		D2	317.46 ± 2.97 c	55 003.9 ± 542.1 c	84.61 ± 0.20 a	24.25 ± 0.04 b	11.07 ± 0.02 c
		D3	335.19 ± 3.46 b	57 330.3 ± 586.1 b	84.23 ± 0.21 a	24.20 ± 0.03 bc	11.44 ± 0.04 b
		D4	355.56 ± 4.16 a	59 580.6 ± 1 251.1 a	83.66 ± 1.19 a	24.15 ± 0.03 c	11.70 ± 0.09 a
		Mean	327.40	56 211.7	84.31	24.23	11.21
	Songxiangjing 1018	D1	283.33 ± 1.70 d	46 997.6 ± 207.7 d	87.62 ± 0.31 a	27.71 ± 0.02 a	11.23 ± 0.09 d
		D2	300.00 ± 1.94 c	48 918.2 ± 226.6 c	87.44 ± 0.20 a	27.67 ± 0.01 ab	11.71 ± 0.06 c
		D3	321.30 ± 4.72 b	51 559.4 ± 757.8 b	87.17 ± 0.17 a	27.64 ± 0.02 b	12.21 ± 0.08 b
		D4	341.11 ± 6.85 a	54 048.7 ± 1 132.4 a	86.53 ± 0.17 b	27.59 ± 0.03 c	12.62 ± 0.04 a
		Mean	311.44	50 381.0	87.19	27.65	11.94
Year (Y)			**	NS	NS	NS	**
Variety (V)			**	**	**	**	**
Treatment (T)			**	**	**	NS	**
Y × V			**	NS	NS	NS	NS
Y × T			NS	NS	NS	NS	NS
V × T			NS	NS	NS	NS	NS
Y × V × T			NS	NS	NS	NS	NS

Year	Variety	Treatment	No. of panicles per hm² (×10⁴)	Total spikelet number per m²	Seed-setting rate (%)	1000-grain weight (g)	Yield (t/hm²)
2023	Ningxiangjing 9	D1	286.11 ± 3.54 d	52 321.5 ± 864.6 c	84.87 ± 0.73 a	24.50 ± 0.20 a	10.73 ± 0.09 c
		D2	305.55 ± 2.97 c	55 633.4 ± 355.2 b	84.70 ± 1.01 a	24.44 ± 0.29 a	11.36 ± 0.13 b
		D3	322.22 ± 6.00 b	58 193.5 ± 791.1 a	84.11 ± 0.09 a	24.33 ± 0.31 a	11.68 ± 0.12 a
		D4	334.44 ± 6.85 a	59 666.2 ± 697.9 a	83.82 ± 0.93 a	24.17 ± 0.15 a	11.91 ± 0.06 a
		Mean	312.08	56 453.6	84.37	24.36	11.42
	Songxiangjing 1018	D1	281.95 ± 2.60 d	48 225.5 ± 411.3 d	88.39 ± 0.52 a	27.91 ± 0.11 a	11.72 ± 0.04 c
		D2	296.83 ± 2.97 c	50 144.7 ± 309.6 c	88.13 ± 0.24 a	27.84 ± 0.08 a	12.20 ± 0.06 b
		D3	318.52 ± 3.46 b	52 748.0 ± 238.0 b	87.67 ± 0.28 a	27.76 ± 0.17 a	12.58 ± 0.18 a
		D4	332.22 ± 5.66 a	54 099.7 ± 498.9 a	87.36 ± 0.58 a	27.63 ± 0.26 a	12.76 ± 0.09 a
		Mean	307.38	51 304.5	87.89	27.79	12.31
2024	Ningxiangjing 9	D1	301.39 ± 2.60 d	52 931.9 ± 442.5 d	84.74 ± 0.35 a	24.32 ± 0.02 a	10.62 ± 0.01 d
		D2	317.46 ± 2.97 c	55 003.9 ± 542.1 c	84.61 ± 0.20 a	24.25 ± 0.04 b	11.07 ± 0.02 c
		D3	335.19 ± 3.46 b	57 330.3 ± 586.1 b	84.23 ± 0.21 a	24.20 ± 0.03 bc	11.44 ± 0.04 b
		D4	355.56 ± 4.16 a	59 580.6 ± 1 251.1 a	83.66 ± 1.19 a	24.15 ± 0.03 c	11.70 ± 0.09 a
		Mean	327.40	56 211.7	84.31	24.23	11.21
	Songxiangjing 1018	D1	283.33 ± 1.70 d	46 997.6 ± 207.7 d	87.62 ± 0.31 a	27.71 ± 0.02 a	11.23 ± 0.09 d
		D2	300.00 ± 1.94 c	48 918.2 ± 226.6 c	87.44 ± 0.20 a	27.67 ± 0.01 ab	11.71 ± 0.06 c
		D3	321.30 ± 4.72 b	51 559.4 ± 757.8 b	87.17 ± 0.17 a	27.64 ± 0.02 b	12.21 ± 0.08 b
		D4	341.11 ± 6.85 a	54 048.7 ± 1 132.4 a	86.53 ± 0.17 b	27.59 ± 0.03 c	12.62 ± 0.04 a
		Mean	311.44	50 381.0	87.19	27.65	11.94
Year (Y)			**	NS	NS	NS	**
Variety (V)			**	**	**	**	**
Treatment (T)			**	**	**	NS	**
Y × V			**	NS	NS	NS	NS
Y × T			NS	NS	NS	NS	NS
V × T			NS	NS	NS	NS	NS
Y × V × T			NS	NS	NS	NS	NS

Year	Variety	Treatment	Dry matter (t/hm²)			Harvest index (%)
Year	Variety	Treatment	Jointing stage	Heading stage	Maturity stage	Harvest index (%)
2023	Ningxiangjing 9	D1	4.32 ± 0.03 b	13.64 ± 0.18 c	20.92 ± 0.10 d	50.94 ± 0.69 a
		D2	4.67 ± 0.07 ab	14.35 ± 0.18 b	22.20 ± 0.32 c	50.79 ± 0.20 a
		D3	4.90 ± 0.03 a	14.76 ± 0.29 ab	22.99 ± 0.32 b	50.46 ± 1.20 a
		D4	5.09 ± 0.37 a	15.15 ± 0.25 a	23.64 ± 0.04 a	49.91 ± 0.18 a
		Mean	4.74	14.48	22.44	50.53
	Songxiangjing 1018	D1	4.79 ± 0.04 d	14.30 ± 0.12 d	22.32 ± 0.26 c	52.52 ± 0.41 a
		D2	5.21 ± 0.10 c	14.80 ± 0.33 c	23.32 ± 0.30 b	52.34 ± 0.60 a
		D3	5.56 ± 0.06 b	15.29 ± 0.18 b	24.26 ± 0.23 a	51.85 ± 0.51 a
		D4	5.80 ± 0.13 a	15.87 ± 0.15 a	24.88 ± 0.29 a	51.29 ± 0.97 a
		Mean	5.34	15.07	23.69	52.00
2024	Ningxiangjing 9	D1	4.17 ± 0.05 c	13.69 ± 0.14 c	20.85 ± 0.11 d	50.94 ± 0.25 a
		D2	4.44 ± 0.06 bc	14.14 ± 0.06 b	21.86 ± 0.13 c	50.63 ± 0.23 a
		D3	4.67 ± 0.06 ab	14.46 ± 0.13 a	22.62 ± 0.28 b	50.57 ± 0.47 a
		D4	4.81 ± 0.24 a	14.69 ± 0.11 a	23.18 ± 0.14 a	50.45 ± 0.23 a
		Mean	4.52	14.24	22.13	50.65
	Songxiangjing 1018	D1	4.52 ± 0.10 d	13.90 ± 0.15 d	21.54 ± 0.16 d	52.11 ± 0.51 a
		D2	4.97 ± 0.07 c	14.49 ± 0.05 c	22.65 ± 0.19 c	51.71 ± 0.16 a
		D3	5.30 ± 0.09 b	15.00 ± 0.17 b	23.76 ± 0.23 b	51.39 ± 0.41 ab
		D4	5.61 ± 0.11 a	15.63 ± 0.12 a	24.88 ± 0.20 a	50.72 ± 0.37 b
		Mean	5.10	14.75	23.21	51.48
Year (Y)			**	**	**	NS
Variety (V)			**	**	**	**
Treatment (T)			**	**	**	**
Y × V			NS	NS	NS	NS
Y × T			NS	NS	NS	NS
V × T			NS	NS	NS	NS
Y × V × T			NS	NS	NS	NS

Year	Variety	Treatment	Dry matter (t/hm²)			Harvest index (%)
Year	Variety	Treatment	Jointing stage	Heading stage	Maturity stage	Harvest index (%)
2023	Ningxiangjing 9	D1	4.32 ± 0.03 b	13.64 ± 0.18 c	20.92 ± 0.10 d	50.94 ± 0.69 a
		D2	4.67 ± 0.07 ab	14.35 ± 0.18 b	22.20 ± 0.32 c	50.79 ± 0.20 a
		D3	4.90 ± 0.03 a	14.76 ± 0.29 ab	22.99 ± 0.32 b	50.46 ± 1.20 a
		D4	5.09 ± 0.37 a	15.15 ± 0.25 a	23.64 ± 0.04 a	49.91 ± 0.18 a
		Mean	4.74	14.48	22.44	50.53
	Songxiangjing 1018	D1	4.79 ± 0.04 d	14.30 ± 0.12 d	22.32 ± 0.26 c	52.52 ± 0.41 a
		D2	5.21 ± 0.10 c	14.80 ± 0.33 c	23.32 ± 0.30 b	52.34 ± 0.60 a
		D3	5.56 ± 0.06 b	15.29 ± 0.18 b	24.26 ± 0.23 a	51.85 ± 0.51 a
		D4	5.80 ± 0.13 a	15.87 ± 0.15 a	24.88 ± 0.29 a	51.29 ± 0.97 a
		Mean	5.34	15.07	23.69	52.00
2024	Ningxiangjing 9	D1	4.17 ± 0.05 c	13.69 ± 0.14 c	20.85 ± 0.11 d	50.94 ± 0.25 a
		D2	4.44 ± 0.06 bc	14.14 ± 0.06 b	21.86 ± 0.13 c	50.63 ± 0.23 a
		D3	4.67 ± 0.06 ab	14.46 ± 0.13 a	22.62 ± 0.28 b	50.57 ± 0.47 a
		D4	4.81 ± 0.24 a	14.69 ± 0.11 a	23.18 ± 0.14 a	50.45 ± 0.23 a
		Mean	4.52	14.24	22.13	50.65
	Songxiangjing 1018	D1	4.52 ± 0.10 d	13.90 ± 0.15 d	21.54 ± 0.16 d	52.11 ± 0.51 a
		D2	4.97 ± 0.07 c	14.49 ± 0.05 c	22.65 ± 0.19 c	51.71 ± 0.16 a
		D3	5.30 ± 0.09 b	15.00 ± 0.17 b	23.76 ± 0.23 b	51.39 ± 0.41 ab
		D4	5.61 ± 0.11 a	15.63 ± 0.12 a	24.88 ± 0.20 a	50.72 ± 0.37 b
		Mean	5.10	14.75	23.21	51.48
Year (Y)			**	**	**	NS
Variety (V)			**	**	**	**
Treatment (T)			**	**	**	**
Y × V			NS	NS	NS	NS
Y × T			NS	NS	NS	NS
V × T			NS	NS	NS	NS
Y × V × T			NS	NS	NS	NS

Variety	Treatment	Jointing stage	Heading stage					Maturity stage	Leaf area reduction rate per day
Variety	Treatment	Jointing stage	High-effective LAI	High-effective LAI ratio (%)	Effective LAI	Effective LAI ratio (%)	Total LAI	Maturity stage	Leaf area reduction rate per day
2023
NXJ	D1	3.08 ± 0.08 b	5.65 ± 0.04 a	81.32 ± 0.36 a	6.34 ± 0.03 a	91.40 ± 0.12 a	6.94 ± 0.04 b	3.04 ± 0.05 a	0.0814 ± 0.0017 a
	D2	3.18 ± 0.05 ab	5.71 ± 0.07 a	81.12 ± 0.30 a	6.42 ± 0.10 a	91.12 ± 0.48 a	7.04 ± 0.07 ab	3.12 ± 0.09 a	0.0816 ± 0.0010 a
	D3	3.23 ± 0.11 ab	5.75 ± 0.17 a	80.74 ± 0.96 a	6.47 ± 0.17 a	90.89 ± 0.69 a	7.12 ± 0.13 ab	3.19 ± 0.11 a	0.0819 ± 0.0010 a
	D4	3.28 ± 0.06 a	5.75 ± 0.07 a	80.02 ± 0.19 a	6.49 ± 0.11 a	90.30 ± 0.60 a	7.19 ± 0.08 a	3.23 ± 0.15 a	0.0825 ± 0.0018 a
	Mean	3.20	5.72	80.80	6.43	90.93	7.07	3.14	0.0818
SXJ	D1	3.13 ± 0.09 b	5.93 ± 0.07 a	83.42 ± 0.41 a	6.56 ± 0.09 a	92.24 ± 0.82 a	7.11 ± 0.05 c	3.10 ± 0.05 c	0.0802 ± 0.0008 a
	D2	3.22 ± 0.04 ab	6.01 ± 0.10 a	83.24 ± 0.57 ab	6.66 ± 0.12 a	92.20 ± 0.84 a	7.22 ± 0.07 bc	3.20 ± 0.07 bc	0.0803 ± 0.0030 a
	D3	3.30 ± 0.04 ab	6.05 ± 0.02 a	82.68 ± 0.43 ab	6.73 ± 0.05 a	92.03 ± 0.69 a	7.32 ± 0.03 ab	3.28 ± 0.04 ab	0.0806 ± 0.0008 a
	D4	3.37 ± 0.09 a	6.07 ± 0.05 a	82.11 ± 0.50 b	6.77 ± 0.09 a	91.58 ± 0.45 a	7.39 ± 0.06 a	3.34 ± 0.03 a	0.0810 ± 0.0018 a
	Mean	3.25	6.01	82.86	6.68	92.01	7.26	3.23	0.0805
2024
NXJ	D1	2.97 ± 0.02 c	5.58 ± 0.04 a	80.88 ± 0.38 a	6.26 ± 0.02 b	90.83 ± 0.09 a	6.89 ± 0.02 c	2.96 ± 0.03 c	0.0820 ± 0.0010 a
	D2	3.03 ± 0.02 bc	5.59 ± 0.06 a	80.44 ± 0.23 ab	6.30 ± 0.06 ab	90.58 ± 0.07 ab	6.95 ± 0.06 bc	3.01 ± 0.02 bc	0.0821 ± 0.0014 a
	D3	3.08 ± 0.04 ab	5.64 ± 0.04 a	80.15 ± 0.30 b	6.35 ± 0.04 ab	90.37 ± 0.17 ab	7.03 ± 0.04 ab	3.07 ± 0.02 ab	0.0826 ± 0.0012 a
	D4	3.15 ± 0.04 a	5.66 ± 0.06 a	79.88 ± 0.05 b	6.39 ± 0.07 a	90.21 ± 0.43 b	7.09 ± 0.07 a	3.10 ± 0.03 a	0.0831 ± 0.0008 a
	Mean	3.06	5.62	80.34	6.33	90.50	6.99	3.03	0.0825
SXJ	D1	3.06 ± 0.10 b	5.84 ± 0.06 a	83.28 ± 0.34 a	6.55 ± 0.04 b	93.41 ± 0.17 a	7.01 ± 0.04 c	2.91 ± 0.14 b	0.0805 ± 0.0033 a
	D2	3.18 ± 0.09 ab	5.88 ± 0.11 a	82.41 ± 0.90 a	6.65 ± 0.11 ab	93.12 ± 1.08 a	7.14 ± 0.06 b	3.02 ± 0.08 ab	0.0807 ± 0.0006 a
	D3	3.25 ± 0.10 ab	5.94 ± 0.06 a	82.06 ± 0.86 a	6.72 ± 0.08 ab	92.82 ± 0.74 a	7.24 ± 0.03 a	3.10 ± 0.05 ab	0.0813 ± 0.0013 a
	D4	3.31 ± 0.08 a	6.00 ± 0.08 a	81.95 ± 0.88 a	6.78 ± 0.10 a	92.56 ± 0.91 a	7.32 ± 0.05 a	3.16 ± 0.02 a	0.0816 ± 0.0007 a
	Mean	3.20	5.92	82.43	6.67	92.98	7.18	3.05	0.0810
Year (Y)		**	**	NS	*	NS	**	**	NS
Variety (V)		**	**	**	**	**	**	NS	*
Treatment (T)		**	*	**	**	NS	**	**	NS
Y × V		*	NS	NS	*	**	NS	NS	NS
Y × T		NS	NS	NS	NS	NS	NS	NS	NS
V × T		NS	NS	NS	NS	NS	NS	NS	NS
Y × V ×T		NS	NS	NS	NS	NS	NS	NS	NS