Effect of irrigation periods and brassinolide growth regulator on the growth of maize (Zea mays L.)

A field experiment was conducted during the season 2021 in Babil Governorate-Nile Experiment Station located 10 km east of Hilla city. In a sandy clay soil mixture to study the effect of irrigation periods and spraying concentrations of the growth regulator pracinolide to improve the growth efficiency of maize, variety Baghdad 3. The experiment was carried out according to the design of randomized complete blook design (RCBD) and in the order of split-plots and with three replications. The experiment included studying the effect of three periods of irrigation 6, 8 and 10 days and spraying the growth regulator pracinolide at a concentration of 0, 2, 4, 6 and 8 mg. L-1 and their interaction in the growth characteristics of maize. The results showed that the irrigation period 6 days was significant in the characteristics: plant height, leaf area, leaf area index, and stem diameter, which reached 224.40 cm, 5958 cm 2, 3.17 and 25.14 mm, while 8-day irrigation period achieved a significant superiority in the content of chlorophyll and dry weight of the plant was 55.57 Spad and 468 g, respectively. The spray concentration exceeded 8 mg. L-1 of brassinolide was significant in leaf area and its index, dry weight, content of chlorophyll and stem diameter, 6378 cm2, 3.39 and 509.06 gm plant-1, 57.15 Spad and 25.80 mm. The interactions showed a significant effect on the studied vegetative growth characteristics and gave Treatment of the interaction between 6-day irrigation period and spraying a concentration of 8 mg L-1, the highest for vegetative growth.