Abstract

A field experiment was conducted at the experiment of farm, College of Agriculture. Baghdad University, during 2010 to study the effects of GA3 concentrations (0, 50, 150, 250 mg. l-1) on some growth traits of soybean seed. Randomized complete block design (RCBD) was used in split plot arrangement with three replicates. A laboratory experiments were conducted to study the effect of treating the seed produced with GA3 (0, 50, 150, 250 mg. l-1) on the seed vigour and viability. The measured characters were standard germination test , accelerated aging test, and field emergence percentage. Gibberellic acid affected all studied traits. The concentration 150 mg-1 GA3 gave significant increase in the plant height, leaf area, number of pods, and total seed yield. The cultivars Differed in all studied traits. Lee74 cultivar gave a significant increase in the number of branch , number of pods, 100 seed weight, and total seed yield. The Interaction 150 mg-1 GA3 with cultivar Lee74 were superior in increasing in the number of pods, 100 seed weight, and total seed yield. Seeds treated with 150 mg-1 GA3 was superior in standard germination test , accelerated aging test and field emergence ( 90% , 85% and 56.67%) , respectively. Cultivar IPA comparison to other cultivars, was superior in giving higher percentage of standard germination test , accelerated aging test and field emergence , (88.75% , 81.25% and 52.42), respectively. Interaction of 150 mg-1 GA3 with cultivar IPA showed significant superiority in standard germination test , accelerated aging test and field emergence percentage.