Abstract
The exploitation of genetic variability to develop new sources resistant to Aspergillus ear rot is a prime concern for corn breeders. The present study was designed to estimate gene action and inheritance for flowering traits, ear rot percent and antioxidants activities of five maize inbred lines and their 10 diallel single crosses under control and water stress conditions. Two irrigation regimes; control and water stress and the 15 genotypes were allocated to main and sub plots respectively. General (GCA) and specific (SCA) combining abilities were significant sources of variation, although GCA recorded greater contribution of the variation. The crosses INB45xINB39, INB76xINB39, INB31xINB76 and INB31xINB39 with negative and significant SCA effects for low ear rot infection were considered useful in future breeding programs targeting both reduced levels of fungal infection and early Bilking. Using ISSR marker, a total of eight bands were found to be useful positive or negative markers of drought stress.
The cluster analysis based on ISSR analysis clearly distinguished maize genotypes from each other while cluster A, B and C included tolerance parental genotypes, while sensitive genotypes were included in cluster E with most of their hybrids, that reflect its different genetic structure from other tested maize genotypes.