Introduction
Tomato (Solanum lycopersicum Mill) is one the most important vegetable crops at all over the world as well as in Egypt. Early blight disease caused by (Alternaria solani) is one of the most destructive common fungal diseases affecting primarily the leaves, stems, flowers and fruits of tomato. (Çalıs and Topkaya 2011). The leaf spots are generally from dark brown to black, often numerous and enlarging with concentric rings. Lower leaves are attacked first, and then disease progresses upward and affected leaves turn yellow and dry up. Stems lesions can develop on seedling, and may form canker and kill the plant. The disease can attack can attack fruits when they approach maturity at the stem end where the symptoms may be small or may enlarge to cover most of the fruit Rotem, 1994, Agrios, 1997 ; Chaerani and Voorrips, and 2007;). Pathogen Alternaria solani produces several toxic to infect tomato plants. Among these toxins altrnatic acid and solan apyrone that induce necrotic symptoms with encircled chlorosis and enhance the pathogen infection and the development of necrotic symptoms. (Langsdorf et.al., 1990) .The early blight disease is controlled mainly by the application of agrochemical against the worldwide trends towards environmentally safe methods. So, breeding program is the best suitable way to achieve this aim, to improve the commercial varieties and found new resistance lines. In North Carolina Gardner (1988) long-term breeding program developed two sister lines NC1CELBR and NC 2CELBR to combine early blight and late blight resistance into adapted fresh-market tomato backgrounds. The pedigree of the two breeding lines traces back to NC 215E-1(93), has a D.M. Spooner source PI 126445 and NC complex pedigree extending back to NCEBR-1, which has moderate foliage resistance to early blight derived from the Lycopersicon hirsutum L. (currently Solanum habrochaites S. Knapp & S. Knapp &D.M. Spooner) source PI 126445 NC EBR-2, which has moderate foliage resistance and a high level of stem lesion resistance to early blight derived from Campbell 1943. Also, Nash and Gardner (1988) evaluated the most utilized method of screening tomato for early blight resistance. Evaluating plants under natural conditions and recording disease progress throughout the entire life of the plant were recorded by Kumar and Srivastava (2013).