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Effects of seedling age as well as density on yield and yield components in three rice cultivars were evaluated using a split factorial in randomized complete block design with three replications in 1997 at Shawer Agricultural Research Station. In this study, the main plot was represented by seedling age (25, 35 and 45 days), with subplots being
3 plant densities (15*15, 30*30, 45*45 cm) (44, 11 and 5 plants/m2 respectively) along with three rice cultivars (Anboori, Champa and LD 183). Statistical analysis indicated that grain yield decreased about 12-16% as seedling age increased and the highest yield was obtained in 15*15 cm density treatment. The highest grain yield was obtained with
LD183 (7.741 t/ha). Maximum and minimum biomass were obtained in 25 day seedling (12.219 t/ha) and 45 day seedling (10.736 t/ha) respectively. The amount of biomass in 15*15 density was 14.977 t/ha and in 45*45 it was 10.799 t/ha. Among cultivars, Champa (13.533 t/ha) and Anboori (11.562 t/ha) had higher and the lower dry matter
respectively. Grain number per panicle was not significantly different among seedling age, densities and cultivar treatments. Maximum grain number was obtained in 25 day seedlings, and with increase in plant density, grain number per panicle was reduced
rapidly. Anboori possessed higher grain number per panicle. Grain fertility percentages were not significantly different among seedling age and density tratments, but were different among cultivars. One thousand grain weight was different among seedling age, density and cultivar treatments. With increase seedling age 1000 – grain weight was
increaed however at high plant densities 1000 – grain weight reduced. Among cultivars, LD183 had the highest grain weight.