Introgressions from Oryza rufipogon Increase Photosynthetic Efficiency of KMR3 Rice Lines

doi:10.1016/j.rsci.2016.07.006

Abstract

Abstract:

To understand the wild Oryza genome effect on photosynthesis and its relation to total dry matter accumulation in an elite rice variety, a set of 40 stable introgression lines (ILs) BC₃F₈derived from a cross of Oryza sativa (KMR3) × Oryza rufipogon (WR120) were grown under well watered conditions. Leaf gas exchange measurements and leaf chlorophyll estimates were conducted at the flowering stage. The results revealed significant variations in net photosynthetic rate (Pn), transpiration rate (E), transpiration efficiency (Pn/E) and carboxylation efficiency (Pn/C_i). Pn showed significant positive correlation with E, stomatal conductance (g_s), Pn/C_i and total canopy dry matter. Specific leaf area and leaf thickness were not significantly correlated with Pn. Thirty-seven out of 40 ILs showed higher Pn than KMR3 [11.28 μmol/(m²∙s)], and 20 ILs showed higher Pn than WR120 [15.08 μmol/(m²∙s)]. The line IL194 showed the highest Pn [21.62 μmol/(m²∙s)] with increased total canopy dry matter followed by lines IL381, IL106, IL363-12, IL198, IL86-18 and IL50, which exhibited Pn above 18.0 µmol/(m²∙s). The ILs with enhanced Pn are a potential source for developing rice varieties and hybrids with higher biomass and yield.

Key words: photosynthesis, wild species, rice, yield, biomass, introgression line

Haritha G., Vishnukiran T., Yugandhar P., Sarla N., Subrahmanyam D.. Introgressions from Oryza rufipogon Increase Photosynthetic Efficiency of KMR3 Rice Lines[J]. Rice Science, 2017, 24(2): 85-96.

Figures/Tables 5

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Parameter	Sum square	Mean square	Mean square error	F-value
Chl a	22.72	0.57	0.29	1.95*
Chl b	3.86	0.10	0.04	2.56**
Chl (a+b)	42.57	1.06	0.50	2.12*
Chl a/b	7.23	0.18	0.09	2.10**
SLA	36173.0	904.3	657.6	1.37
LT	0.051	0.000	0.000	3.27***
Pn	613.5	15.3	4.7	3.28***
E	64.9	1.62	0.56	2.90***
g_s	0.368	0.010	0.005	1.67
C_i	12483.0	312.1	164.6	1.90*
ΔT	2.229	0.060	0.017	3.20***
C_i/C_a	0.076	0.000	0.001	1.84*
Pn/g_s	3948.0	98.7	52.1	1.89*
Pn/C_i	0.009	0.000	0.000	3.32***
Pn/E	13.839	0.350	0.116	2.99***
Chl a, Chlorophyll a; Chl b, Chlorophyll b; Chl (a+b), Total chlorophyll; Chl a/b, Ratio of Chl a and Chl b; SLA, Specific leaf area; LT, Leaf thickness; Pn, Photosynthetic rate; E, Transpiration rate; g_s, Stomatal conductance; ΔT, Difference between leaf temperature and air temperature; C_i, Intercellular CO₂; C_a, Ambient CO₂. Data were analyzed by one-way analysis of variance and significant differences were tested using Tukey’s honestly significant difference test (n = 3). , * and *** indicate significant differences at the 0.05, 0.01 and 0.001 levels, respectively.

Parameter	Sum square	Mean square	Mean square error	F-value
Chl a	22.72	0.57	0.29	1.95*
Chl b	3.86	0.10	0.04	2.56**
Chl (a+b)	42.57	1.06	0.50	2.12*
Chl a/b	7.23	0.18	0.09	2.10**
SLA	36173.0	904.3	657.6	1.37
LT	0.051	0.000	0.000	3.27***
Pn	613.5	15.3	4.7	3.28***
E	64.9	1.62	0.56	2.90***
g_s	0.368	0.010	0.005	1.67
C_i	12483.0	312.1	164.6	1.90*
ΔT	2.229	0.060	0.017	3.20***
C_i/C_a	0.076	0.000	0.001	1.84*
Pn/g_s	3948.0	98.7	52.1	1.89*
Pn/C_i	0.009	0.000	0.000	3.32***
Pn/E	13.839	0.350	0.116	2.99***
Chl a, Chlorophyll a; Chl b, Chlorophyll b; Chl (a+b), Total chlorophyll; Chl a/b, Ratio of Chl a and Chl b; SLA, Specific leaf area; LT, Leaf thickness; Pn, Photosynthetic rate; E, Transpiration rate; g_s, Stomatal conductance; ΔT, Difference between leaf temperature and air temperature; C_i, Intercellular CO₂; C_a, Ambient CO₂. Data were analyzed by one-way analysis of variance and significant differences were tested using Tukey’s honestly significant difference test (n = 3). , * and *** indicate significant differences at the 0.05, 0.01 and 0.001 levels, respectively.

Trait	GY	TDM	HI	Chl a	Chl b	Chl (a+b)	Chl a/b	Pn	E	g_s	C_i	ΔT	C_i/C_a	Pn/g_s	Pn/C_i	Pn/E
TDM	0.14
HI	0.64**	-0.45**
Chl a	-0.12	0.05	-0.04
Chl b	-0.01	0.04	0.09	0.85**
Chl a+b	-0.09	0.05	0.00	0.99**	0.93**
Chl a/b	-0.16	-0.04	-0.13	-0.06	-0.54**	-0.20**
Pn	0.01	0.35*	-0.14	0.26	0.18	0.24	-0.02
E	-0.16	0.13	-0.12	0.21	0.16	0.21	-0.02	0.48**
g_s	-0.11	0.23	-0.23	0.29	0.24	0.28	-0.12	0.55**	0.86**
C_i	-0.09	-0.13	-0.07	0.02	0.04	0.03	-0.03	-0.60**	0.23	0.30
ΔT	0.15	-0.12	0.10	-0.18	-0.14	-0.17	0.02	-0.50**	-0.99***	-0.82**	-0.16
C_i/C_a	-0.11	-0.09	-0.11	0.04	0.06	0.05	-0.07	-0.51**	0.33*	0.42**	0.99***	-0.26
Pn/g_s	0.13	0.08	0.12	-0.05	-0.06	-0.05	0.07	0.48**	-0.38*	-0.45**	-0.98***	0.32*	-1.00***
Pn/C_i	0.03	0.33*	-0.11	0.21	0.14	0.20	-0.01	0.99***	0.38*	0.42**	-0.71**	-0.41**	-0.63**	0.61**
Pn/E	0.17	0.22	-0.03	0.06	0.02	0.05	0.01	0.62**	-0.37*	-0.19	-0.85**	0.34*	-0.84**	0.86**	0.70**
VPD_L	-0.08	-0.22	0.27	-0.17	-0.12	-0.16	0.11	-0.21	0.05	-0.45**	-0.24	-0.13	-0.29	0.25	-0.13	-0.27
GY, Grain yield; TDM, Total canopy dry matter; HI, Harvest index; Chl a, Chlorophyll a; Chl b, Chlorophyll b; Chl (a+b), Total chlorophyll; Chl a/b, Ratio of Chl a and Chl b; Pn, Photosynthetic rate; E, Transpiration rate; g_s, Stomatal conductance; C_i, Intercellular CO₂; C_a, Ambient CO₂; ΔT, Difference between leaf temperature and air temperature; VPD, Vapour pressure deficit. , * and *** indicate significant differences at the 0.05, 0.01 and 0.001 levels, respectively.

Trait	GY	TDM	HI	Chl a	Chl b	Chl (a+b)	Chl a/b	Pn	E	g_s	C_i	ΔT	C_i/C_a	Pn/g_s	Pn/C_i	Pn/E
TDM	0.14
HI	0.64**	-0.45**
Chl a	-0.12	0.05	-0.04
Chl b	-0.01	0.04	0.09	0.85**
Chl a+b	-0.09	0.05	0.00	0.99**	0.93**
Chl a/b	-0.16	-0.04	-0.13	-0.06	-0.54**	-0.20**
Pn	0.01	0.35*	-0.14	0.26	0.18	0.24	-0.02
E	-0.16	0.13	-0.12	0.21	0.16	0.21	-0.02	0.48**
g_s	-0.11	0.23	-0.23	0.29	0.24	0.28	-0.12	0.55**	0.86**
C_i	-0.09	-0.13	-0.07	0.02	0.04	0.03	-0.03	-0.60**	0.23	0.30
ΔT	0.15	-0.12	0.10	-0.18	-0.14	-0.17	0.02	-0.50**	-0.99***	-0.82**	-0.16
C_i/C_a	-0.11	-0.09	-0.11	0.04	0.06	0.05	-0.07	-0.51**	0.33*	0.42**	0.99***	-0.26
Pn/g_s	0.13	0.08	0.12	-0.05	-0.06	-0.05	0.07	0.48**	-0.38*	-0.45**	-0.98***	0.32*	-1.00***
Pn/C_i	0.03	0.33*	-0.11	0.21	0.14	0.20	-0.01	0.99***	0.38*	0.42**	-0.71**	-0.41**	-0.63**	0.61**
Pn/E	0.17	0.22	-0.03	0.06	0.02	0.05	0.01	0.62**	-0.37*	-0.19	-0.85**	0.34*	-0.84**	0.86**	0.70**
VPD_L	-0.08	-0.22	0.27	-0.17	-0.12	-0.16	0.11	-0.21	0.05	-0.45**	-0.24	-0.13	-0.29	0.25	-0.13	-0.27
GY, Grain yield; TDM, Total canopy dry matter; HI, Harvest index; Chl a, Chlorophyll a; Chl b, Chlorophyll b; Chl (a+b), Total chlorophyll; Chl a/b, Ratio of Chl a and Chl b; Pn, Photosynthetic rate; E, Transpiration rate; g_s, Stomatal conductance; C_i, Intercellular CO₂; C_a, Ambient CO₂; ΔT, Difference between leaf temperature and air temperature; VPD, Vapour pressure deficit. , * and *** indicate significant differences at the 0.05, 0.01 and 0.001 levels, respectively.

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