الفهرس 
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Abstract
Maize, )Zea mays (L.) and Sorghum (Sorghum bicolor (L.) Moench) are facing lots of problems caused from different weeds in most cultivated areas in Assiut Governorate, Egypt. Weeds are one of the serious pests that remarkably decrease the grain yield and affect the yield attributes of grain in maize and sorghum.
This study was carried out in three parts follows:
1. Study the effect of some single and combined herbicide for controlling broad and narrow leaved weeds associated with maize and sorghum
This investigation was carried out in two successive seasons 2020/2021 and 2021/2022 as follows: (carfentrazon 1.5% + florasulam 0.5% + flurxypyr-methyl 14%), (carfentrazon 1.5% + florasulam 0.5% + flurxypyr-meptyl 14% + halosulfuron-methyl 75%), (tribenuron-methyl 16% + carfentrazon ethyl 12%), (tribenuron methyl 16% + carfentrazon ethyl 12% + halosulfuron-methyl 75%), (bromoxynil 20% + MCPA sodium 20%), (bromoxynil 20% + MCPA sodium 20% + halosulfuron-methyl 75%), (halosulfuron-methyl 75%), (nicosulfuron 6%), nicosulfuron 6% + halosulfuron-methyl 75%), (foramsulfuron 2.25%), foramsulfuron 2.25% + halosulfuron-methyl 75%) and hand hoeing comparing with control (untreated). Halosulfuron-methel 75% (Inpul) was sprayed after on hour the spraying herbicide was added to all combinations with the purpose of improvement the effectiveness of the tested herbicides in maize and sorghum.
In maiz plots, results indicated that (nicosulfuron 6%) , halosulfuron-methyl 75%), treatment, gave the best yield attributes per feddan and reduced weed density. While (bromoxynil 20% + MCPA sodium 20% , halosulfuron-methyl 75%) treatment was the lowest in yield attributes, also in controlling associated weeds with maize plants compared with control.
In sorghum plots, results indicated that (carfentrazon 1.5% + florasulam 0.5% + flurxypyr-meptyl 14% , halosulfuron-methyl 75%) treatment, gave the best yield attributes per feddan and reduced weed density in the crop. While (bromoxynil 20% + MCPA sodium 20% , halosulfuron-methyl 75%) treatment was the lowest in yield attributes, also in controlling associated weeds. As no official recommendations for weed control in Egypt until now, field experiments had been conducted to evaluate the efficacy of some single herbicides and their combinations in controling weeds associated with sorghum plants.
2. Effect of some herbicides on the total seed proteins patterns of maize and sorghum using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE)
This investigation was carried out with maize and sorghum in summer season of 2021 to study the effect of the recommended rate of the following herbicides: (carfentrazon 1.5% + florasulam 0.5% + flurxypyr-methyl 14%), (carfentrazon 1.5% + florasulam 0.5% + flurxypyr-meptyl 14%, halosulfuron-methyl 75%), (tribenuron-methyl 16% + carfentrazon ethyl 12%), (tribenuron methyl 16% + carfentrazon ethyl 12% , halosulfuron-methyl 75%), (bromoxynil 20% + MCPA sodium 20%), (bromoxynil 20% + MCPA sodium 20% , halosulfuron-methyl 75%), (halosulfuron-methyl 75%), (nicosulfuron 6%), nicosulfuron 6% , halosulfuron-methyl 75%), (foramsulfuron 2.25%), foramsulfuron 2.25% , halosulfuron-methyl 75%), comparing with the hand hoeing and the control on the seed proteins of commercial cultivars under Assiut area conditions. Results showed that all tested treatments gave different significant increases or decreases in seed protein profiles using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE). Data obtained showed that the bands with different molecular weights (Kilo Dalton) of maize and sorghum seeds might be related to the mode of action of herbicides used to control associated weeds in these crops. The present results suggested the possibility of applying (SDS-PAGE) as supportive method to determine the sub-lethal effects of herbicides on total protein in sorghum and maize seeds.
3. Cytogenetical impact of some herbicides and their combinations on root tip cells of maize seedling
The effects of single herbicides and their combinations with recommended field rate on germination, growth, mitotic activity and mitotic aberrations were studied. The results indicated that the mitotic division rate was decreased in all treatments compared to the control. The highest decrease was in (bromoxynil 20% + MCPA sodium 20%) and (bromoxynil 20% + MCPA sodium 20% + halosulfuron-methyl 75%). On the other hand, the most frequently occurred chromosomal aberrations were sticky metaphase and the observed aberrations were bridge, laggard and disturbed anaphase, and vacuolated nucleus. In general, treatment with these pesticides caused progressive changes in germination percentage and chromosomal aberrations in mitosis division for root tip cells in maize seedlings.