Effect of Soil Moisture Stress Duration on the Growth Characteristics and Yield of Rice Cultivars

Soil moisture stress is a major constraint to the productivity of rice under rain-fed conditions. A study was conducted to establish the effect of moisture stress duration on the growth characteristics and grain yields of rice cultivars, namely Namche-1, Namche-3 and Agoro. Rice plants were subjected to moisture stress at tillering and a thesis in the screen house. Moisture stress at tillering stage caused significant leaf rolling in Agoro than in Namche-3, but at a thesis Agoro was the least (P≤0.05) affected. Moisture stress at tillering and a thesis significantly reduced the number of tillers in Agoro, but not in Namche cultivars. The growth period of Agoro was significantly longer than that of the control when it was stressed at tillering for 15 days, but stressing Agoro at a thesis didn’t affect its maturity period. Stressing Namche cultivars at tillering and a thesis increased (P≤0.05) their maturity periods, though these periods were shorter (P≤0.05) than that of Agoro. Grain yields for all the cultivars at tillering and a thesis decreased as the stress period was prolonged. Grain yields of Namche cultivars were higher (P≤0.05) than that of Agoro. Therefore, the growing of Namche cultivars in areas with insufficient moisture for rice production would be appropriate.