الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Corn (Zea mays L.) is one of the most important cereals in Egypt, it is used as human food, poultry and livestock feeding, green fodder and silage for animal feeding. Furthermore, It is additionally employed in industries like making starch and cooking oils. maize as one of the most significant cereal crops, contributes significantly to reducing the gap between grain production and consumption in Egypt by expanding its cultivated area and improving its yield per unit area. According to the world’s total maize production in 2017 was 1134.75 million tonnes, grown over an area of 469.49 million feds with an average yield of 2416.97 kg grain/fed. In Egypt, 2.192 million fed of maize were used to generate 7.10 million tonnes of maize in 2017, with a yield of 3239.19 kg/fed on average. The overall production covers 80% of the necessary consumption, leaving a 20% reduction gap that must be covered by imports. Egypt’s maize breeding initiatives should focus more on creating new hybrids that are more tolerant of high plant densities than older ones if they want to boost grain production per unit area.
Most breeding initiatives ultimately aim to produce enhanced hybrids for commercial usage by assessing these hybrids high producing potential.
The evaluation of inbred lines is crucial for the production of hybrids. It is crucial to understand the type and quantity of tester parents that will be utilised to assess inbred lines. The problem of the type and quality of testers to be utilised in the line x tester model for assessing inbred lines is still open. The most popular technique for the evaluation process is the top cross (test cross) method, which employs testers with wide and narrow bases. In this regard, the choice of a suitable tester is an i