Abstract
This study was conducted to show the effect of foliar application with a growth mixture containing indole acetic acid (IAA) and naphthalene acetic acid (NAA) at the levels of 0 + 0, 50 + 25, 100 + 50 and 150 + 75 ppm, respectively, and/or zinc concentration of 0, 50, 100, and 150 ppm sprayed three times after 20, 40 and 60 days of sowing, on growth, yield as well as some physiological and chemical composition parameters of barley plants. A complete randomized block design experiment in factorial arrangement with four replicates was carried out at the farm of the National Research Centre, Shalakan, Kalubia, Egypt, during two successive seasons. The obtained results revealed that either foliar spraying by the growth regulators mixture or Zinc concentrations had a significant promotive effect on the studied growth and yield as well as the physiological and chemical parameters of barley when compared with the control treatment. While the highest values of the previous parameters were attained by using the concentration of 150 ppm zinc, followed by 100 and 50 ppm in decreasing order. The rate of promotion was increased by increasing the concentration of growth regulators. The highest levels of all studied parameter were detected by spraying 150 ppm IAA + 75 ppm NAA. It is worthy to note that the interaction among adapted levels of growth promoter's mixture and zinc provided significant increases in most traits examined in this investigation. The most effective treatment was spraying 150 ppm IAA+ 75 ppm NAA combined with 150 ppm zinc.
Key words: Foliar application, chemical properties, barley, growth parameters, photosynthetic pigments.
