Evaluation of canopy characteristic role on tolerance index of wheat cultivars in interference with feral rye (Secale cereale)

This research was carried out for evaluation of competitive ability of some wheat cultivars (Triticum aestivum L.) of recommended wheat in Dargaz region with common weed of feral rye (secale cereale). Experiment was conducted as factorial based on randomized complete blocks design with three replications in 2010-2011 growing season. Experimental factors were included four wheat cultivars of Sayson, Alvand, Chamran and Sepahan and feral rye densities were at five levels of 0, 20, 40, 60 and 80 plants m-2. The results showed that by increasing feral rye density were reduced leaf area index, accumulation dry matter, leaf area index duration and dry matter duration of wheat cultivars. Rate of height increasing of Alvand and Sepahan in competition with weed were increased than pure stand. Also mentioned two cultivars had more leaf area index duration and dry matter duration in interference condition with weed than Chamran and Sayson and percent of leaf area index of canopy upper layer increased. Contrarily, plant height and leaf area index percent of mid-upper of canopy of Chamran and Sayson reduced in interference condition. Interference tolerance index (ITI) of wheat cultivars in biologic yield were obtained more than grain yield. At all density levels of feral rye, Alvand and Sayson had maximum and minimum interference tolerance index in biologic and grain yield, respectively. By increasing plant density, leaf area index percent of feral rye canopy downer layers reduced and increased its upper layers.