Timing of final drainage in two rice cultivars under flooded conditions

Abstract

Two experiments were carried out to determine the ideal timing of drainage before harvest for rice cultivars IAC 435 and IR 841-63-5-L-9-33. The treatments were: drainage at seven, fourteen, 21, 28 and 35 days after flowering and drainage at complete maturatión. The grain yield of cultivar IAC 435 was not affected by the timing of drainage, while that of cultivar IR 841-63-5-L-9-33 increased as the drainage was delayed. Similarly, the percent whole rice of the two cultivars and the percent hulled rice of the cultivar IR 841-63-5-L-9-33 were higher as the drainage was delayed. However, the percent hulled rice of the cultivar IAC-435 was higher when the water was drained 31 days alter flowering. Considering the water economy in addition to grain yield and percent hulled rice, it is desirable that paddy drainage should be dons 30 days alter flowering.