الفهرس 
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Abstract
The present work was carried out at the Biotechnology laboratory, Crop Science Department, Faculty of Agriculture, Alexandria University, Egypt, during the period from 2019 to 2021. The ultimate goal was to improve salinity tolerance in maize. To achieve this aim five maize hybrids, have been utilized to measure their performance for salinity tolerance. The study aimed to accomplish the following objectives:
1. Describing the assessment of five maize genotypes for their capabilities of shoot formation on four medium protocols, using immature embryo explants. These studies of morphogenesis would provide useful information for subsequent investigations regarding in vitro selection.
2. To compare two in vitro selection methods for developing salinity tolerance cell lines from maize genotypes, which have the high frequency of shoot formation and to regenerate plants from selected cells.
3. SSR method was used as molecular markers for genetic differentiation among somaclones and their parent.
First Experiment: Morphogenesis from tissue culture: This experiment was conducted to screen five maize hybrids using four medium protocols and the immature embryo explants to determine the best maize hybrid thatcan grow on the best media and use this information in the selection studies. The results obtained from this experiment could be summarized as follows:
The analysis of variance indicated that callus induction was significantly influenced by differences in maize hybrids, medium protocols and the interaction between genotypes and the medium protocols.
The percentage of immature embryo explants that developed calli ranged from 27% (Syngenta hybrid) to 55% (single cross hybrid 30 N11 “pioneer) for all genotypes across the four medium protocols with an average of 39%.
The medium protocol D gave the highest a average of callus induction (56.8%) across genotypes. However, it was not significantly different from medium B (50.4%) and medium C (47.2%), while, medium protocol A did not give any response for callus induction % across all genotypes.