Effect of Plant Density on Yield and Yield Components of Three Cultivars of Forage Sorghum

In order to evaluate the effect of row and plant spacings on the yield and yield components of three cultivars of forge sorghum, a field experiment was conducted in Isfahan University of Technology, Lavark, during spring, 2001. Experimental design was a split-factorial with three replications. Main plots consisted of three row spacings (45, 60, 75 cm) and subplots were combinations of three cultivars of forage sorghum(cultivars KFS1, IS722, IS3313) and three plant spacings (4, 6 and 8 cm). The results showed that the number of young and adult tillers, the number of leaf per square meter and shoot and leaf dry weight were influenced by row and plant spacings and significantly decreased with increasing row and plant spacings. Forage yield also decreased with increasing row and plant spacing. The highest dry forage yield was produced by 45 cm row spacing and 4 cm plant spacing. The KFS1 cultivar produced more forage yield than IS722 cultivar. The number of young and adult tiller per square meter and the number of leaf per square meter were significantly (p< 0.01) influenced by the interaction between row spacing and cultivar, row spacing and plant spacing and plant spacing and cultivar in two cuts. Shoot and leaf dry weight (kg/m2) was also significant (p< 0.01) influenced by the interaction between row spacing and cultivar, and between plant spacing and cultivar in the second cut. The density of 45 cm row spacing and 4 cm plant spacing produced the maximum forage yield.