Effect of Different Levels of Nitrogen Fertilizer and Cultivars on Growth, Yield and Yield Components of Romaine Lettuce (Lactuca sativa L.)

In order to determine the effect of nitrogen fertilizer rates and cultivars on growth and critical yield of lettuce, an experiment was conducted at Shahid Chamran University of Ahwaz, Iran during 2005-2006. This study was arranged in a spilt plot experiment based on a randomized complete block design, in three replications. The treatments included four nitrogen rates (0, 60, 120, and 180 kg N ha -1 ) as the main plot and two lettuce cultivars...