Evaluation of Competitive Ability of Wheat (Triticum aestivum L) against Rye (Secale cereal L) Using Reciprocal Yield Model in Miandoab

Rye has been known as an important weed in Iran’s wheat farms. The experiment was carried out at the Agriculture and Natural Research Station، Miandoab during 2009-10 (for 2 years). This experiment was carried out by complete randomized block design in factorial pattern. The treatments included wheat pure sowing in the 350،450،550 and 650 densities (factor A) and rye in 15، 30. 45 and 60 densities (factor B) per square meter، and also all the combination between wheat and rye. The result illustrated that rye had better competitive ability compared to wheat. The wheat yield was affected mostly by inter-specific competition. The calculation of regression coefficient indicated that the effect of each rye bush was equivalent of 3. 1 wheat bush for reciprocal wheat economic yield. The calculation of regression coefficient indicated that the effect of each rye bush was equivalent of 2. 73 wheat bush for reciprocal wheat biologic yield. Rye reduced the seed per spike، economical and biological wheat yield. The density 550 plant/m2 of wheat had most yields in contrast with other densities.