Ecophysiologic Indices of Wheat as Influenced by Plant Density and Application of Herbicide

To evaluate the effects of application of herbicides and different plant densities on seed yield, weed density and chlorophyll content in wheat (cv. Bahar), a split plot experiment based on randomized complete blocks design with three replications was conducted at the Agricultural Research Staion of Sarableh, Ilam, in 2014-2015 cropping season. Plant densities in (200, 250 and 300 kg of seed/ha) were considered as main factor and application of herbicides (2, 4-D, Granstar, Shovalyeh, and control, without herbicide application) as sub factor. Results indicated that plant densities affected traits under study significantly. As a result number of seed per spike, 1000-seed weight, relative water content, chlorophyll a and b contents decreased, while weed density and weed dry weight number of spike per m2 and percent lodging increased by increasing plant density. Application of herbicide increased number of spike per m2, number of seed per spike, 1000 seed weight, harvest index, relative water content, chlorophyll a and b contents, while it decreased weed dry weight and its density. Interaction effect of plant density and application of herbicide were significant on seed yield and biological yield. The highest seed yield (5500 kg.ha-1) was produced by using 250 kg seed/ha and application of Granstar herbicide and the lowest (2400 kg.ha-1) from 200 kg seed/ha and without application of herbicide. Thus, using 250 kg seed/ha and Granstar herbicide would increase wheat seed yield in this region as compared with the other treatments.