Water Use Efficiency and Physiological Response of Rice Cultivars under Alternate Wetting and Drying Conditions

Table 5

Growth duration, leaf area index (LAI) at flowering, harvest index, and total dry weight of the four rice varieties grown under two water management treatments and two N rates at the IRRI farm for the three consecutive seasons.

	Growth duration (days)		LAI at flowering		Total dry weight; (g m^−2)		Harvest index; (%)
	AWD	CF	AWD	CF	AWD	CF	AWD	CF
2009 DS
IR72	104	104	5.49^b	5.35^c	1481^a	1557^a	45.5^b	46.4^c
PSBRc80	106	104	5.56^b	5.58^bc	1481^a	1459^b	50.1^a	50.1^b
IR82372H	100	100	6.63^a	6.26^ab	1441^b	1464^b	50.6^a	52.2^a
SL-8H	106	106	6.82^a	6.71^a	1478^a	1609^a	52.1^a	52.4^a
Mean	104	104	6.13	5.98	1470	1522	49.6	50.3
2009 WS
IR72	101	102	3.16^b	3.31^a	1089^a	1117^a	41.7^b	42.7^c
PSBRc80	103	103	3.30^ab	3.53^a	1078^a	1119^a	43.8^b	44.3^bc
IR82372H	102	102	3.56^a	3.50^a	1078^a	1105^a	43.5^b	44.9^b
Mestizo7	100	100	3.55^a	3.71^a	1045^b	1055^a	47.2^a	47.1^a
Mean	102	102	3.39	3.51	1073	1099	44.1	44.8
2010 DS
IR72	105	106	4.70^a	5.15^a	1545^b	1560^a	47.7^b	48.1^b
PSBRc80	107	107	4.63^a	5.40^a	1594^b	1578^a	48.6^ab	50.7^ab
IR82372H	100	100	4.72^a	5.05^a	1554^b	1631^a	50.4^a	50.0^a
SL-8H	111	111	5.04^a	5.01^a	1658^a	1667^a	49.1^ab	51.7^ab
Mean	106	106	4.77	5.15	1588	1609	49.0	50.1

Data are the means across two N rates. Within a column for each season, means followed by the same letters are not significantly different according to LSD (0.05).