Table 1.

Maturation, heading date, average temperature of T _20DAH , tolerance rank, and notes for rice cultivars under test

Cultivargroup A	Cultivar(CV)	Heading date		T 20DAH B °C		Tolerancerank C	Year ofrelease	Note
		FACE	AMB	FACE	AMB
ST	Akitakomachi	7/24	7/26	26.8 ± 0.3	26.9 ± 0.3	S	1982	Standard cultivar in this study
	Kinuhikari	7/30	7/30	26.7 ± 0.3	26.7 ± 0.3	S	1983	Big grains, Standard cultivar in this study
	Koshihikari	7/31	8/1	26.6 ± 0.3	26.5 ± 0.3	MT	1953	Standard cultivar in this study
	Nipponbare	8/5	8/6	26.6 ± 0.3	26.6 ± 0.3	MT	1961	Standard cultivar in this study
	Matsuribare	8/6	8/7	26.6 ± 0.3	26.6 ± 0.3	S	1990	Standard cultivar in this study
HT	Mineharuka	7/29	7/30	26.8 ± 0.3	26.7 ± 0.3	VT	2002	Long & thin grains (Saka et al., [2007])
	Toyama 80	7/30	7/31	26.7 ± 0.3	26.6 ± 0.3	VT	2012	Apq1 on chromosome 7 (Ebitani et al., [2013])
	Eminokizuna	7/31	7/31	26.6 ± 0.3	26.6 ± 0.3	VT	2008	Small grains, useful for sushi
	Wa2398	7/31	7/31	26.6 ± 0.3	26.6 ± 0.3	VT	not released	QTL on chromosome 2. Derived from ‘Ma Li Xian’
	Kanto 257	8/1	8/1	26.5 ± 0.3	26.5 ± 0.3	T	2011	Derived from Mineharuka × Ikuhikari
	Kanto 259	8/5	8/5	26.6 ± 0.3	26.6 ± 0.3	MT– T	2012	High-yielding cultivar
	Saikai 290	8/6	8/6	26.6 ± 0.3	26.6 ± 0.3	VT	2012	High-yielding cultivar; good quality, good eating quality
Source of variation	df	Statistical significance
Block	3
CO2	1	*
Main plot error	3
CV	11	***
GroupD	1	P = 0.055
STD	4	***
HTD	6	***
CO2 × CV	11	*
CO2 × GroupE	1	ns
CO2 × STE	4	**
CO2 × HTE	6	ns
Split plot error	66

^AST, standard cultivars; HT, heat-tolerant cultivars.

^BT_20DAH, air temperatures averaged for 20 days after heading ± standard error of mean.

^CVT, very tolerant; T, tolerant; MT, moderately tolerant; S, susceptible.

^DSub-division of variation among the cultivars.

^ESub-division of variation among the CO₂ × CV interaction.

***P < 0.001; **P < 0.01; *P < 0.05; ns, not significant.