采用上育397和绥粳3号水稻品种，于分蘖期、长穗期、抽穗后1～10 d、11～20 d、21～30 d及1～30 d，用负压式土壤湿度计监测，分别进行土壤水势为－30～－35 kPa、－60～－65 kPa的控水处理。结果表明，抽穗前土壤水势控制在－30～－35 kPa时，两品种的产量均显著降低，以长穗期产量最低，进一步降低土壤水势产量不再明显下降；分蘖期控水的减产幅度以上育397＞绥粳3号，长穗期以上育397＜绥粳3号；2个品种穗分化期控水对籽粒品质影响最大，质量质数最低，其他时期相差不大，因此，穗分化期不仅是水稻产量的水分敏感期，也是品质的水分敏感期；比较两品种相同处理的抗旱系数和质量质数，抽穗前控水处理对产量的影响大于对品质的影响，尤其是劣势粒中表现的更为突出，抽穗后多数处理对品质的影响大于对产量的影响。
A pot experiment with controlling water treatments (CWT) for the two cultivars, Shangyu 397 and Suijing 3 at －30 kPa to －35 kPa and －60 kPa to －65 kPa of soil water potential（SWP） monitored by soil negative pressure water potential tester was carried out during tillering period, panicle formation period, 1–10 days after heading, 11–20 days after heading, 21–30 days after heading, 1-30 days after heading, respectively. The results showed that the yield of two cultivars was decreased significantly before heading stages, especially at panicle formation stage by lower SWP, but no longer obvious decrease was observed when SWP continued to be decreased .The yield lower of Shangyu 397 was greater than that of Suijing 3 at tillering stage, however that was in reverse at panicle formation stage. The effect of CWT on grain quality of the two cultivars was greater at panicle formation stage than at other stages, with the lowest comprehensive index embodied quality. Water sensitive stage of yield and quality was panicle differentiation stage. Comparing drought resistance coefficient and comprehensive index of the two cultivars, the effect of CWT after heading stages on quality was greater than that on yield.
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