Nitrogen rate and plant density effect on dry matter accumulation and fresh ear yield of sweet corn

In order to study the effect of plant density and nitrogen rate on dry matter accumulation and fresh ear yield of sweet corn (Zea mays. var. saccarata)، cultivar KSC. 403، a field experiment was carried out in research field of Tarbiat Modares University on summer 2005. The experiment was carried out in a split plot design based on randomized complete blocks with four replications. In this research three levels of plant density (60000، 80000 and 100000 plant /ha) as main plot and four levels of nitrogen rate (120،180،240 and 300 kg N/ha) as sub plots were investigated. Yield and yield components including grain row number per ear، grain number per row، grain weight and formative characters of ear including ear number per plant، ear length، ear diameter and sucker number were measured. Results showed that sweet corn biomass at the soft dough stage were not influenced by plant density and nitrogen rate. With the increase of plant density، the number of main ear was increased but their weight was decreased. The higher ear length and ear number was obtained by using the lowest plant density and nitrogen rate. In this research with increment of plant density and nitrogen rate، the row number per ear and kernel number per row were decreased. In this respect sweet corn sowned with 60000 plant /ha and 120kg N/ha which produced the longest ear (17. 9 cm)، the most row number (16. 6)، the most kernel number per row (34. 4) and the highest grain yield 9. 33 t/ha) is recommended for the sandy soil in studied Area.