Effect of different planting densities on yield, yield components, and protein content of two sorghum cultivars in Alborz province

To investigate the effects of plant density on yield and yield components of two cultivars of grain sorghum, an experiment was conducted in 2009 in the northwest of Karaj. In this experiment, two cultivars (‘Payam’ and ‘Kimia’) and four density levels (100, 150, 200, and 250 thousand plants per hectare) were evaluated in a factorial experiment based on a randomized complete block design with four replications. The results of the mean comparison showed that the highest biological yield, grain and protein yield per unit area, protein percentage, grain yield per plant, and a number of grains per panicle were observed in the Kimia cultivar and the highest grain weight has belonged to the Payam cultivar. Increased density led to increased grain yield, protein yield, biological yield, and a number of panicles per square meter; Thus, the highest grain and protein yields were obtained with an average of 7924.01 and 913.17 kg/ha at a planting density of 250,000 plants per hectare, respectively. Increasing the density reduced the number of grains per panicle and 1000-grain weight, but did not affect protein percentage. Based on the results of our experiment, to achieve maximum grain yield and grain protein, Kimia and Payam cultivars with a density of 250,000 plants per hectare are recommended.