Density on Seed Yield and Yield Components of Corn Hybrids

In order to study the effect of plant density on seed yield and its components, a field experiment was conducted in 2007-2008 in Firouz-Abad province of Fars, Iran. The experiment was a split plot based on randomized completely block design with three replications. Main plots consisted of four corn varieties [late maturing 704 (V1), mid maturing 604 (V2), early maturing 370 (V3) and mid maturing 647 (V4)] and Sub plots four plant densities [6.5 plant/m-2 (D1), 7.5 plant/m-2 (D2), 8.5 plant/m-2 (D3) and 9.5 plant/m-2 (D4)]. The results showed that the highest grain yield, grain number per ear row, 1000-grains weight, biologic yield, plant height, stem diameter, ear length belonged to late maturing 704; and highest grain number per ear and harvest index were by mid maturing 647 and early maturing 370. Reaction of traits in hybrids to increase in density were different. For example, hybrid 704 produced highest yield so with 7.5 plant.m-2, hybrids 604 and 647 from 8.5 plant.m-2 and hybrid 370 with 9.5 plant.m-2. In all of the hybrids used increase in plant density from 6.5 to 9.5 plant.m-2. Grain number per ear row, grain number per ear, stem diameter and ear length descreased.