الفهرس 
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Abstract
This investigation was inducted to study the genetical and cytological effects of fungal infection with Fusarium verticillioides on six maize hybrids compared with those resulted from gamma irradiation. The maize grains (dry and soaked) were exposed to zero, 15 and 30 kilo rad (kr.) of gamma rays. Irradiated and non-irradiated grains (dry and soaked) were planted directly after irradiation treatment in infected and uninfected soil in factorial experiment in a completely randomized design. The growing plants at all planted treatments (M1 generations) were self–pollinated to produce seeds of M¬2 generations. In the second growing season, all genotypes (six maize hybrids and 36 genotypes groups which obtained from self–pollination) were cultivated in a randomized complete blocks design. In M1 and M2 generations, many traits were studied. These traits were: emergence percent, seedling weight, leaf chlorophyll content, earliness, morphological, cytological, yield and yield component traits. The main results from this study could be summarized as follows.
Fungal infection led to decrease of most studied traits. These effects were less than the effects of increasing doses of irradiation for all studied traits in M1 generation. Fungal infection and gamma irradiation treatments elicited similar types of meiotic chromosomal anomalies. The percentage of anomalies and total normal meiotic cells differed between fungal infection and gamma irradiation treatments. Fungal infection caused a significant increase in abnormal meiotic cells percent and significant decreased in pollen viability percent. These effects of infection treatment were lowest than those the effects of irradiation treatment. The results also indicated that highly significant and negative correlation between meiotic irregularities % and most studied traits were found. The results of M2 and inbreeding depression indicated that the fungal infection may lead to produce some distinct genotypes but, this effect was the lowest than that effect of irradiation treatment. In conclusion, the results illustrated that the genetical and cytological effects of fungal infection in most cases of this investigation were less than those effects of gamma irradiation.