Effect of Planting Dates and Spraying with Gibberelic acid on Some Yield and the Quality Traits of Corn (Zea mays L.)

The present study attempts to determine the best planting date and concentration of spraying with gibberellin to improve the performance and quality of maize's growth and yield traits. This investigation was carried out in the district of Tarmiyah - Baghdad governorate to study the effect of planting dates and spraying with gibberellin on the growth and yield of corn (Zea mays L.) of the variety (Buhooth 106) for the summer farming season in 2020. The experiment was applied according to the Randomized Complete Block Design (R.C.B.D) with the split plot system, using four planting dates (1/7, 10/7, 21/7, and 28/7/2020) and four concentrations of gibberellin (0, 150, 250, and 350 mg. Liter-1). The best significant superior value was recorded on 21/7/2020 by interference with a concentration of 350 mg. L-1 in most of the traits, as it was recorded (221.14 cm) for the height of the plant, (45.39%) for chlorophyll, (300.33 g) for the weight of 1000 kernel, (13.54 tons. h-1) for the grain yield, (18.84 rows. ear -1) for the number of rows in ear, (14.27%) for protein, and (5.22%) for oil. Whereas it significantly exceeded the date 28/7/2020 by an interference with the concentration of 350 mg. L-1 in the two traits of the number of grains in the row and the gibberellin content in leaves, its values were (44.62 grain. row-1 and 46.09 μmol) respectively. Accordingly, it is concluded that the optimal intervention mixture is determined to be an intrusion with a concentration of 350 mg. L-1 at the date of 21/7/2020 was included in the majority of the traits tested.