Flash Flooding Effects on Post-Harvest Physiological and Phytochemical Responses of the Phourel-Amubi Rice Cultivar of Manipur

Abstract

Flooding due to heavy rainfall is a major abiotic stress that significantly affects rice (Oryza sativa L.) production during the monsoon (Kharif) season, particularly in rain-fed lowland areas. This study evaluates the impact of flash flooding on the traditional rice cultivar Phourel-Amubi. The experiment was conducted by growing 15-day-ol d seedlings in plastic pots, followed by submergence stress treatments in a concrete tank for 5, 10, and 15 days at 30, 60, and 90 days after transplanting. Morpho-physiological, biochemical, and yield-related parameters were analyzed. Results indicated a gradual increase in total free amino acid content, total phenol content, and total proline content as flooding duration increased, indicating a biochemical stress response. However, key growth and metabolic indicators, such as plant height, total chlorophyll content, soluble protein, and total soluble sugars, declined significantly. Yield and its components at 120 days after transplant were also adversely affected, with a substantial decrease in panicle number (8 to 4.17 ± 0.14), grain number per panicle (135.83 to 95.17 ± 1.52), grain weight (20.69g to 16.19g ± 0.62), and overall grain yield per hill (25.08g to 11.67g ± 0.64). These findings suggest that Phourel-Amubi is highly susceptible to submergence stress, emphasizing the need for breeding flood-tolerant rice varieties or adopting effective water management strategies to mitigate yield losses in flood-prone regions.