Influence of Plant Population Density on Grain Yield and Yield Components of Three Different Maize Varieties (Zea mays L.) Under the Libyan West Coast Conditions.

A field experiment was conducted during 2007-2008 season at the experimental station of the Faculty of Agriculture, University of Tripoli to investigate the influence of different plant population densities namely: 30000, 40000, 50000, 60000 and 70000 plant ha-1 on two hybrids of maize namely: Geza-3060 and Geza-3084 introduced from the Arab Republic of Egypt and a local variety. Split plot design in Latin square with three replications was implemented. Main plots were assigned to the genotypes, subplots to plant population treatments. In general, results showed that maximum grain yield was obtained at 70000 plant ha-1 (8.28 ton ha-1 ) on average of the three varieties which was not significantly different when planting at the rate of 50000 plant ha-1 ,this could result in reducing seed cost. Giza-3062 out yielded Giza-3084 and the local variety on average of different population densities by 3.82 and 4.49 ton ha-1 which corresponded to 71.4% and 96.0% respectively. Number of grains per ear and the average 100 grain weight were not contribute to high grain yield, but the number of ears was responsible to high grain yield across different plant population densities. To achieve high grain yield with low cost farmers should use hybrid maize varieties at a 50000 plant ha-1