تعيين قدرت رقابتي بين گندم و چاودار )secale cereale L.( و تاثير رقابت بر عملكرد و اجزي

Investigation of competitive ability between wheat and volunteer rye (Secale cereale L.) and effect of competition on yield and yield components

Volunteer rye is one of the important weeds in wheat fields in Iran. The competitive ability of wheat against volunteer rye was evaluated at the research center of Karaj during 2002. The experimental design was randomized complete block with 24 treatments and 4 replications. The competition design was bivariate factorial. The treatments included the pure stands of wheat at four densities 350, 450, 550 and 650 plant/m2 and volunteer rye at 10, 30, 50 and 70 plant/m2 and mixed stands of two plants at complete factorial densities. In this experiment, the competitive ability of wheat (cv. Mahdavi) was investigated against volunteer rye, using reciprocal yield model.The effects of rye densities on yield and yield components of ovinter wheat were evaluated. Results indicated that, rye was a stronger competitor compared to wheat. Biologic and economic yields of wheat were mainly affected by inter-specific competition. Economic yield was more affected compared to biologic yield by rye densities. Evaluation of competitive ability, using regression coefficient showed that the effect of each rye plant on reciprocal grain yield of wheat one-plant was equivalent to 2 plants of wheat. In other words, each 0.5 plants of rye had an equivalent effect of one wheat on reciprocal economic yield of wheat one-plant. Rye densities reduced the seed per spike, spike weight, grain yield and biomass of wheat, and didnnot have significant effect on thousand kernel weight. The density 550 plant/m2 of wheat had most dry matter accumulation and grain yield in contrast with other densities.