Growth-stage-sensitivity of four HYV rice cultivars to irrigation water salinity

Application of fresh water at the salinity-sensitive growth stage(s) and saline water of tolerable salinity level at the less sensitive stage(s) may be an effective irrigation technique for rice (Oryza sativa L.) cultivation in fresh water-scarce salt-affected areas. However, implementation of this technique requires adequate prior information on the sensitivity of growth stages of the rice cultivars to salinity of irrigation water. The objective of this study was therefore to identify the sensitivity of growth stages of Binadhan-8, Binadhan-10, BRRI dhan28 and BRRI dhan47 to salt stress by irrigating the crops with fresh water (control), and saline water of 6, 9 and 12 dS m1 at establishment, tillering, panicle formation, flowering, maturity and all growth stages of the crops. The experiment was laid out in a split-split pot arrangement following a completely randomized design (CRD) with three replications. The establishment and flowering stages of the rice cultivars were found to be the most sensitive to salt stress. Therefore, irrigation at these growth stages with fresh water and at the other growth stages with saline water would be an appropriate strategy for cultivation of the tested rice cultivars in fresh water-scarce saline areas like the coastal saline region of Bangladesh.