Optimum water requirement of some boro rice mutant lines

The study was conducted to find out the effect of irrigation on yield and optimum water requirement of some Boro rice mutant lines developed by Bangladesh Institute of Nuclear Agriculture (BINA) and the check variety BRRIdhan 28. The rice mutant lines (RM-200©-1-17, RM-200©-1-1, RM-200©-1-13) and BRRIdhan 28 were grown maintaining five irrigation treatments. The treatments were arranged in a Randomized Complete Block Design (RCBD) with three replications. Irrigation showed significant effect on the yield and yield contributing characters of different rice mutant lines and the check variety. The highest grain yield of 6.9 t ha-1 was obtained in treatment T4 where irrigation applied to make 7 days after disappearance of previous water was imposed to the crop. It was also found that the crop grown under continuous ponding and continuous saturation of T0 and T1 treatments respectively did not increase the yield, rather caused the wastage of irrigation water. Among the three rice mutant lines and the check variety, the yield of the mutant lines were 6.08 t ha-1 in RM-200©-1-17, 6.79 t ha-1 in RM-200©-1-1, 6.20 t ha-1 in RM-200©-1-13 and 6.02 t ha-1 in BRRIdhan 28. The highest yield was 6.79 t ha-1 in treatment RM-200©-1-1.The mutant line RM-200©-1-1 was found to be superior over the other two mutant lines, and The treatment T4 was the optimum water stress condition for the check variety which produced the highest yield. The water use efficiency was 0.033 t ha-1cm-1 in T0, 0.045 t ha-1cm-1 in T1, 0.125 t ha-1cm-1 in T2, 0.168 t ha-1cm-1 in T3 and 0.216 t ha-1cm-1 in T4. The water use efficiency (WUE) was the highest (0.216 t ha-1cm-1) in treatment T4, obviously due to minimum water use. Therefore, from the experimental findings, it was revealed that irrigation treatment of T4 gave the highest yield which would help to lessen extra cost.