investigation of plant density effects on grain yield and its components of grain sorghum (sorghum bicolor l.) in birjand

in order to investigation of morphological traits, yield and its components in three cultivars of grain sorghum (kimia, sepideh, payam) and two promising lines (m5, m2) under four density (240000, 205000, 170000 and 135000 plant/m2), experiment was conducted as factorial design based on randomized complete block design with three replications in birjand agricultural research station, during 2002 and 2003 grown season. grain yield, yield components and some of morphological traits were measured. combined analysis results from two years (2002 and 2003) showed that cultivars and lines were significantly different at 1% level for all traits except grain yield. different plant densities were significantly different for tiller number, biological yield and grain yield at 1% level and stem diameter at 5% levels. interaction between cultivar and density was significantly different for tiller number and harvest index at 1% level. according to the results, we can recommend the density of 240000 plant/ha and m5 promising line in birjand.