Genetic studies on the inheritance of early blight resistance revealed different sources for resistance, in tomato lines and their hybrids to understand their performances, genetics and resistant reaction of selected accessions of plant. The classical studies on the inheritance of EB resistance reached the conclusion that the resistance is a quantitative trait that is controlled polygeneticaly (Chaerani and Voorrips, 2007). Data revealed that early blight resistance in NCEBR2 and NCEBR4 was quantitatively controlled by more than one gene or quantitative trait locus under controlled glasshouse environment, (Çalıs and Topkaya 2011)).
The aim of the present study is to evaluate some certain genotypes of tomato for resistance to early blight caused by (Alternaria solani) under the plastic greenhouses and field conditions. The disease occurs naturally on the plants grown in the north coast of Egypt whereas, the dew, rainfall and humidity.