Response yield and yield components of wheat (Triticum aestivum L.) cv. ʼMorvaridʼ to light intensity under weed competition

This study was aimed to investigate the change of yield of wheat in different light intensities and weed competition at research farm of Sari Agricultural Sciences and Natural Resources University of in 2014. Treatments were arranged in randomized complete block design in split-split plot with three replications. Two time to shading in flowering and grain filling stages as the main plot, three light intensities (normal and 50 and 70% of normal light) in sub plots and two levels of weed competitions (weed free and weed infested) as sub-sub plots were the treatments. The results indicate that under weed competition and 70% of light intensity, shading at grain filling and flowering reduced tiller and spike numbers by 20 and 26%, respectively. Also, lowering light intensity at flowering and grain filling stage reduced nearly 21and 44% of biological yield versus 18 and 46% of grain yield, respectively. Weed competition declined up to 19 and 23% of wheat biological and grain yield, respectively. In conclusion, result represented that lowering of light intensity along with weed competition could adversely influenced wheat yield and yield components.