Abstract

Effect of high (37°/27°), medium (29°/21°) and low (23°/20°C, day/night) temperature regimes and low light stress (40 and 60% shading) from flowering to harvest on grain yield and its components were studied using rice cv. IR 44. The control plants gave the highest yield. High temperature reduced the percentage of filled spikelets, 1000 gmin weight and consequently the grain yield. Low temperature decreased the number of filled spikelets but there was slight increase in 1000 grain weight. The medium temperature regime caused significant reduction in 1000-grain weight only. The percentage of filled spikelets and the grain yield per plant were signficantly reduced under shaded treatments.

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