Assessment of herbicide efficacy on growth and yield of three maize hybrids and associated weeds

A field experiment was conducted in during spring Farm and Karbala Governorate, Al-Hindiyah District, Al-Khairat Sub-district. The experiment was implemented with two factors and using the Randomized Complete Block Design (R.C.B.D.) arrangement of the split plots design with three replicates, the first factor represented three hybrids of maize and occupied the main plots (Torro, Top and Tawer), the second factor applied six treatments to weed control, four herbicides according to the approved recommendations (2.4-D, Reef Sulfuran, Trinity and Proponit.) and the two comparison treatments (weedy) and weed free. The results showed significant differences between the hybrids under study, as the Tawer hybrid was superior in the trait of weed density, percentage of weed control after 60 days, dry weight of weeds and percentage of weed inhibition. Torro hybrid was superior in the trait of leaf area, plant height, number of grains per ear and number of grains per row in weed free treatments, followed by the 2,4-D herbicide treatments. As for the percentage of weed control, it was superior in the traits of leaf area index, chlorophyll index, number of grains per row and number of grains per ear in the weed free treatments. Followed by 2,4-D herbicide treatments, and there was a significant interaction between the study factors, as weed free treatment outperformed the Torro can be used as the high yielding hybrid under stresses of herbicide applications since it had significantly greater growth Traits and largest grain number than Top and Tower. However, Tower can be considered as the most suppressive hybrid due to the significant reduction of weed dry Wight with a greater weed suppression. 2,4-D can be used in maize cropping systems due to its efficacy in comparison with the other herbicides.