At this stage it may cause by terminal drought, the mainly effective develops toward at the end of growing season, but sometime being well before flowering time these is the common problem occurs in Northeastern of Thailand and Southeastern India in many years when the rains cease before maturity (Kamoshita et al., 2008). At flowering time is most critical character that plays a major role determination the grain yield in rainfed lowland rice. Flowering time is often using to characterize the phenology of a phenotype, as generally flowering to maturity time is constraint in the rainfed lowlands, development of the panicle was very sensitive to soil water availability and the rate of development was reduce with a small soil water deficit and completely ceased with development of severe drought (Fukai, 1999). Flowering was delay when drought developed, longer delay in flowering may be illustration that the genotype's susceptible to drought prone, is mainly caused reduction number of fertile spikelets per panicle via yield reduction (Selote and Chopra, 2004).