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

Table 4

Yield components of the four rice varieties grown under two water management treatments and two N rates at the IRRI farm for the three consecutive seasons.

	Spikelets panicle^−1		Panicles m^2		Grain filling (%)		Grain weight (mg)
	AWD	CF	AWD	CF	AWD	CF	AWD	CF
2009 DS
IR72	80.2^c	83.4^c	412.3^a	441.2^a	87.9^a	85.5^a	23.2^d	23.0^d
PSBRc80	101.7^b	104.6^b	370.3^b	363.8^b	82.8^ab	81.6^b	23.9^c	23.6^c
IR82372H	120.0^a	117.4^a	330.2^c	344.8^b	78.3^b	77.1^c	24.4^b	24.5^b
SL-8H	119.8^a	124.8^a	228.3^d	301.1^c	81.3^b	83.0^ab	26.8^a	27.1^a
Mean	105.4	107.6	335.3	362.7	82.6	81.8	24.6	24.6
2009 WS
IR72	79.6^b	81.0^b	351.1^a	351.6^a	74.0^a	75.9^ab	21.9^c	22.1^c
PSBRc80	94.3^a	96.9^a	295.6^b	296.1^b	74.9^a	76.7^a	22.7^b	22.5^b
IR82372H	98.5^a	99.6^a	307.8^b	298.7^b	66.6^b	71.5^b	23.2^a	23.4^a
Mestizo7	100.4^a	95.2^a	291.2^b	298.2^b	72.1^a	74.7^ab	23.4^a	23.5^a
Mean	93.2	93.2	311.4	311.2	71.9	74.7	22.8	22.9
2010 DS
IR72	70.5^b	72.9^c	517.5^a	504.5^a	90.0^a	89.8^a	22.4^d	22.7^d
PSBRc80	97.4^a	98.8^b	424.0^b	420.1^b	81.9^bc	83.6^ab	23.0^c	23.1^c
IR82372H	108.9^a	106.6^ab	390.3^c	407.0^b	79.0^c	82.4^b	23.5^b	23.8^b
SL-8H	105.9^a	110.1^a	346.9^d	344.0^c	84.8^b	85.9^ab	26.2^a	26.5^a
Mean	95.7	97.1	419.7	418.9	83.9	85.4	23.8	24.0

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