@ARTICLE{, author = {}, title = {تأثیر زمان سم‌پاشی بر عملکرد و برخی شاخص‌های فیزیولوژیک چهار رقم گندم آبی (Triticum aestivum L.) تحت شرایط رقابت با علف‌های هرز}, volume = {1}, number = {2}, abstract ={To investigate the competitive ability of wheat cultivars with weeds on yeild and growth indices of wheat cultivars in Kurdistan, an experiment was conducted in split plot arrangement on a randomized complete block design with four replication in Agricultural Research Station of Qamlv in 2011. Main plots consisted of four cultivars of wheat including Alvand, Zarin, Roshan back cross and Shahriar and sub​​-plots consisted of four different times of 2, 4-D application: early spring spraying (2 to 4 leaves), spraying in mid-spring (full tillering), late spring (pasty seed) and no spraying check. Results showed that the highest LAI (Leaf Area Index), CGR (Crop Growth Rate), NAR (Net Assimilation Rate) and seed yield were obtained from Roshan cultivar, while at the early stages of growth, the highest LAR was obtained in Shahriar cultivar. The highest LAI, CGR, NAR, LAR (Leaf Area Ratio) and yield were obtained when 2, 4-D was sprayed in mid-spring (full tillering). Roshan back cross cultivar had more competitive ability with weeds than others. In current experiment, with increasing yeild to the point of 1250 Kg/ha (41.6 percent) spraying in mid-spring was the most effective time of spraying to eliminate the competitive effects of weeds and Roshan back cross cultivar was found as the best cultivar which can highly compete with broad-leaved weeds. }, URL = {http://arpe.gonbad.ac.ir/article-1-136-en.html}, eprint = {http://arpe.gonbad.ac.ir/article-1-136-en.pdf}, journal = {2}, doi = {}, year = {2014} }