Table 2.

Grain yield and yield parameters in rice cultivars NL-44 and Pusa 1121 exposed to ambient and elevated [CO₂] during 2013 and elevated [CO₂] and elevated [CO₂] + HT interaction during 2014. All the parameters were obtained at physiological maturity.

Year	Cultivars (C)	Treatments (T)	Number of tillers hill−1	Number of panicles hill−1	Panicle weight (g hill−1)	Grain yield† (g hill−1)	Total number of spikelets panicle−1	Seed-set (%)	1000 Grain weight (g)	Total biomass (g hill−1)
2013	NL-44	a[CO2]	8.7 ± 0.4	8.3 ± 0.4	38.5 ± 1.6	29.9 ± 2.4	233.6 ± 6.8	82.8 ± 1.5	23.2 ± 0.2	66.4 ± 2.1
		e[CO2]	9.4 ± 0.5	9.2 ± 0.5	43.1 ± 2.8	34.5 ± 2.5	236.4 ± 6.1	87.3 ± 1.6	24.1 ± 0.5	75.2 ± 3.5
	Pusa 1121	a[CO2]	12.9 ± 0.8	12.1 ± 0.7	26.3 ± 1.4	20.3 ± 1.4	126.8 ± 2.5	71.7 ± 2.6	24.2 ± 0.0	58.8 ± 3.4
		e[CO2]	13.4 ± 0.6	12.3 ± 0.6	31.0 ± 1.5	25.1 ± 1.7	124.2 ± 5.7	79.1 ± 1.2	25.8 ± 0.1	67.3 ± 2.8
	LSD at 5%	C	1.2***	1.1***	3.8***	4.1***	11.7***	3.9***	0.6***	6.0**
		T	ns	ns	3.8*	4.1*	ns	3.9**	0.6***	6.0***
		C x T	ns	ns	ns	ns	ns	ns	ns	ns
2014	NL-44	e[CO2]	10.1 ± 0.5	9.5 ± 0.4	41.1 ± 1.4	35.9 ± 2.0	239.6 ± 2.1	83.5 ± 0.8	23.9 ± 0.2	69.8 ± 2.4
		e[CO2] + HT	9.3 ± 0.6	8.9 ± 0.5	36.5 ± 1.3	29.5 ± 1.4	235.0 ± 3.3	77.1 ± 0.9	23.1 ± 0.2	62.0 ± 1.6
	Pusa 1121	e[CO2]	13.5 ± 0.9	12.8 ± 0.8	30.4 ± 0.8	22.2 ± 0.5	124.0 ± 1.7	74.4 ± 1.4	25.7 ± 0.2	65.6 ± 2.3
		e[CO2] + HT	14.4 ± 0.5	13.5 ± 0.5	22.5 ± 0.6	15.9 ± 0.3	120.2 ± 3.4	61.7 ± 1.5	21.4 ± 0.3	48.8 ± 1.3
	LSD at 5%	C	1.3***	1.1***	2.2***	2.5***	5.8***	2.6***	ns	3.9***
		T	ns	ns	2.2***	2.5***	ns	2.6***	0.5***	3.9***
		C x T	ns	ns	ns	ns	ns	3.6*	0.7***	5.6*

Significance level: *P < 0.05, **P < 0.01, ***P < 0.001, ns = non significant [LSD = least significant difference; HT = heat stress; a[CO₂] = ambient CO₂; e[CO₂] = elevated CO₂].

^†Chaturvedi et al. 2017-Published grain yield data is used for associating the response mechanisms to the agronomic performance.