Abstract

In order to study the effects of seedling age and planting date on yield and yield components of rice (Oryza sativa), a field experiment was carried out in the field of Qaemshahr Azad University. Experimental design was arranged in split split plot in basis of Randomized Completely Block design with four replications. Planting date in three levels (23 May and 12 June) were allocated in the main plots and seedling age in two levels (25,35 day) were allocated in sub-plots and two rice cultivars (Mahali Tarom, Hashemi Tarom)  were allocated in the sub-sub plots.  Some agronomical traits such as total tiller number, fertile tiller number, panicle number per m², total spikelet per panicle, total sterile spikelet per panicle, 1000 grains weight, plant height, biologic yield, grain yield and harvest index were measured. Results showed that the effect of planting date on plant height, total sterile spikelet per panicle, 1000 grains weight, total tiller number, panicle number per m2, grain yield and harvest index was significant at 0.01 probability level. Also planting date had a significant effect on fertile tiller number at 0.05 probability levels. Seedling had a significant effect on fertile tiller at 0.05 probability level. When date of planting is delayed grain yield decreases because the 1000 grains weight decreases and total strile spikelet per panicle increases. In the Mahali Tarom total spikelet per panicle and total sterile spikelet per panicle are more than Hashemi Tarom.

Key word: Oryza sativa, planting date, seedling age, grain yield and yield components.