Growth and Yield Response of Some Rice Genotype under Different Duration of Complete Submergence

Aims: An experiment was conducted to observe the effect of complete submergence at vegetative stage of plants for different duration on the growth and yield of some rice varieties.

Study Design: The experiment was laid out in randomized complete block design having split plot arrangement with three replications.

Place and Duration of Study: This experiment was conducted at the department of Agricultural Botany, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh between June 2016 and July 2017.

Methodology: For this experiment, different submergence duration (D0 = no submergence, D1 = six days submergence, D2 =ten days submergence and D3 = fourteen days submergence) and six rice varieties (V1 = BRRI dhan51, V2 = BRRI dhan46, V3 = BRRI dhan34, V4= BRRI hybrid dhan1, V5 = BRRI hybrid dhan2 and V6 = ACI hybrid1) were used. The experiment was laid out in a split plot design with three replications. The whole field was divided into three equal blocks each containing 24 plots. Each block was subdivided into four sub blocks. As such there were 12 sub blocks. Each sub blocks was encircled by the 50 cm high soil wall ridge, which was hundred percent water leakages proof. In total, there were 72 plots. The treatment was randomly assigned to each unit plot. The size of each unit plot was 3 m × 2 m. The distance between two blocks and two plots were kept 1m and 0.80 m respectively. The plant was submerged completely in unit plot to a depth of 40 cm above the soil level. The water level was higher than the plant height. The field conditions were made as similar as possible to the conditions which occur during actual flooding in nature.

Results: All parameters were significantly affected by the submergence duration. The cultivars also significantly varied for the studied traits. The highest number of leaves was achieved in BRRI dhan51. The highest grain yield m-2 was found from D0 (0.62 kg) whereas the lowest yield was recorded from D3 (0.38 kg) treatment. The V4 (BRRI hybrid dhan1) produced the highest (0.78 kg) grain yield m-2 and the lowest grain weight m-2 (0.23 kg) was found from V3 (BRRI dhan34). The highest (0.85 kg) grain yield m-2 was found from the combination of D0V4 and the lowest (0.12 kg) from D3V3 treatment. The test genotypes showed wide variation in percent of yield reduction at different submergence duration. The highest percent reduction of yield (65.71) was found from the combination of D3V3 and the lowest (2.22) from D1V1 treatment.

Conclusion: BRRI dhan51 followed by BRRI hybrid dhan1 showed lower grain yield reduction % in submerged conditions compare to control by attaining good yield contributing characters and thus proved as tolerant varieties. On the other hand, BRRI dhan34 and ACI hybrid1 were susceptible to submergence.