PHYSIOLOGICAL EFFECT OF GIBBERELLIN (GA3) ON GROWTH AND YIELD OF SOME WHEAT VARIETIESRazaq L. Attiy, Rafid N. Aljubori, Riyadh K.Kadhium and Noor Ali AlghazaliAbstract A field experiment was conducted in the field affiliated to the Department of the field crops- College of Agriculture- University of Karbala during the winter season 2016-2017 to study the effect of spraying gibberellic acid on the growth and yield of three wheat varieties. The Randomized Complete Block Design (RCBD) included factorial experiments of two factors within three replicates was used. The first factor included three wheat varieties: Ipa99, Rasheed, and Latifya, while the second factor included four concentrations of gibberellic acids: 0, 30, 60, and 90 mg.L-1. Results showed the superiority of Rasheed variety giving the highest values of plant height (cm), 1000- grains weight (g), grain yield (t.ha-1), biological yield, and harvest index. The concentration 60mg.L-1 was superior to the other gibberellic acid concentrations in the traits: 1000-grains weight, harvest index, and grain yield, while the concentration 90mg.L-1 was superior in the two traits flag leaf area and the number of grains. Results also showed a significant effect of the interaction between the wheat varieties and gibberellic acid concentrations in the number of grains. spikes- 1. We concluded that spraying gibberellic acid at the concertation 60mg.L-1 increases the grain yield significantly. |