EFFECTS OF THREE CRUCIFEROUS WEEDS ON YIELD AND YIELD COMPONENTS OF WINTER WHEAT (TRITICUM AESTIVUM)

摘要

In order to evaluate the damage and competitive ability of three broadleaf weeds (turnip weed: Rapistrum rugosum, wild mustard: Sinapis arvensis, tansy mustard: Descurainia sophia) with winter wheat (Triticum aestivum, L.CV.: C-73-5) an experiment was conducted in 2000 in Iran. The experimental design was complete block with factorial arrangement of treatments and four replications. Treatments included above three weed species and four weed densities (0,4,8 and 16 plants per m~2). Wheat density was fixed at 450 plant per m~2. Results showed that turnip weed emerged earlier, were taller, had higher leaf area and competition ability than other two weeds. It was observed that relative growth rate (RGR) of turnip weed and wild mustard was greater than wheat. Turnip weed had the greatest leaf area index (LAI), crop growth rate (CGR) and accumulation rate compared to wild mustard and tany mustard. Turnip weed caused greatest wheat yield reduction in 16 plant per m~2 density. Among wheat yield components, number of spike per m~2 and grains per spike decreased by increasing of weed species densities. The greatest reduction was observed in turnip weed. Wheat infertile spikletS decreased by increasin weed densities, specially in competition with turnip weed, but average wheat seed weight remained unchanged.