Effects of Plant Density and Sowing Date on Economic Yield and Sugar Content of Sweet Corn

In order to study the effect of plant density and sowing date on ear economic yield and sugar content in sweet corn (Zea mays L. cv. Saccarata), a field experiment was conducted at Tarbiat Modarres University (Tehran West) in 2004. The experiment was carried out using split plots based on randomized complete block design of 4 replications. Four levels of sowing date (May 22th, June 10th, July 1th and July 21th) as the main factor and four levels of plant density (45000, 55000, 65000 and 75000 plants/ha) as sub-plots were investigated. Yield and yield components as well as ear formative characteritics, including ear number per plant, ear length and diameter, grain row number per ear and grain number per row were assessed. Results showed that ear fresh yield in different sowing dates was varied and S2D4 treatment (sowing in June 10th with 75000 plant/ha) with 3250 g/m2 being the superior treatment. Also ear yield was affected by plant density. This treatment carries the highest rate of total sugar and sucrose (6.96 and 4.97 percent respectively). Therefore sweet corn sowed on June 10th produced about 28 tons/ha of fresh ear (22.6 percent increment due to early sowing, May 22th). A large number of ears per unit area in the high density treatment compensated for the yield loss per each plant.