a. almodares

In order to evaluate the effect of increase plant density on stalk yield and sucrose content in two sweet sorghum cultivars, an experiment was conducted at Research Farm of Isfahan University located at Zaghmar village. A split plot layout within a randomized complete block design with tree replication was used. Main plots were plant densities (100, 200, 300, 400, 500 and 600 thousand plant/ha) and subplots were cultivars (Rio and Keller). The effect of plant density at hard dough harvest stage on plant height, stem diameter, number of tillers, stem fresh weight and juice yield were significant but had no significant effect on brix, sucrose percentage and purity. The highest juice yield and purity were produced by 400 thousand plants/ha. Keller was significantly superior for plant height, stem diameter, stem fresh weight, juice yield and brix at hard dough harvest stage as compared to Rio. Number of tiller per plant of Rio was significantly more than Keller. There were no significant difference between two cultivars for sucrose percentage and purity but sucrose percentage in Keller had highest as compared to Rio. Maximum stem fresh weight, juice yield, sucrose percentage and purity were obtained at hard dough harvest stag. On the basis of the results obtained, 400 thousand plant/ha plant density, Keller cultivar and hard dough harvest stage might be suitable for sweet sorghum production under the condition similar to the present study.