Investigation of light use efficiency and light extinction coefficient of wheat (Triticum aestivum L.) cultivars in competition with wild mustard (Sinapis arvensis L.) at Gorgan

In order to evaluate light extinction coefficient and light use efficiency of wheat cultivars in densities of wild mustard, an experiment was conducted in Agricultural Research Station Gorgan during 2010-2012. The experiment design consisted of four randomized complete blocks in a factorial arrangement. The design consisted of two factors, four wheat cultivars and 5 levels of wild mustard densities. The results of means comparison of cultivar×wild mustard density interaction effect showed by increasing wild mustard density, light extinction coefficient increased in wheat different cultivars. In this research, the means of light extinction coefficient in the maximum of wild mustard density in Morvarid, Moghan, Arta and Tajan was 0.23, 0.51, 0.63 and 0.65, respectively. The highest and lowest of light extinction coefficient observed in Tajan and Morvarid, respectively. By comparing the vertical distribution of leaf area in wheat cultivars was distinguished that the highest of gathering amount of leaf area in all of investigated layers observed in Morvarid in competition and pure conditions. The highest of light use efficiency in the maximum of wild mustard density (32 plant/m2) observed in Morvarid (1.85 g/Mj) in the both of years, meanwhile, Tajan (1.21 g/Mj) had the lowest of light use efficiency. Totally, the results of this experiment in two years showed Morvarid had the highest of seed yield for the reason that the most of vertical distribution of leaf area and light use efficiency and too, the lowest of light extinction coefficient in compared to other cultivars, and was the more of succeed in competition with wild mustard.