Growth, Yield and Mineral Contents of Lettuce Cultivars Grown in Nutrient Film Technique (NFT) at Different Transplanting Dates.

An experiment was conducted at the Arid Land Agricultural Research and Services Center (ALARC), Faculty of Agriculture, Ain Shams University, Shoubra El-Kheima, Cairo, Egypt during winter and spring seasons of 2007/2008 and 2008/2009 to investigate the influence of different transplanting dates (mid-September, mid-November, mid-January and mid-March) on vegetative growth, head yield leaf and root tissue mineral contents of two lettuce (Lactuca sativa L.) cultivars DP-400 and New Red Fire grown in nutrient film technique (NFT). DP-400 cultivar was superior than New Red Fire cultivar since it gave significantly higher values for head fresh and dry weights as well as head yield (kg/m 2 ). However, No significant differences were detected between studied cultivars concerning their contents of mineral contents in both leaves and roots.The most suitable transplanting date was the second transplanting date (15 th Nov.) for lettuce production under nutrient film technique (NFT) while the worst transplanting date was the fourth transplanting date (15th Mar.) under the conditions of the experiment.Concerning the interaction between two lettuce cultivars and four transplanting dates a significant effect was detected on all measured parameters in both seasons of study except for Mg and Ca contents in leaves tissue. The best results were obtained by planting DP-400 lettuce cultivar in the second transplanting date (15 th Nov.) followed by the third transplanting date (15 th Jan.) in both