Effects of Priming Treatments on Germination Indices of Soybean Cultivars Under Osmotic Stress

Abstract

This study aimed to investigate the effects of priming treatments on germination indices of soybean cultivars under osmotic stress in a completely randomized design with a factorial arrangement of treatments in a botany laboratory located in Kordestan Province, Sanandaj, Iran. Experimental treatments included three treatments of priming (control and gibberellin at a concentration of 0.04%), cultivar (Clark and Hobbit), and osmotic stress (control and -1.5MPa) in three replications. The standard germination test was performed according to the guidelines presented by the International Seed Testing Association (ISTA) and some germination indices, including germination percentage, germination rate, germination uniformity, and mean germination time up to 10% germination (D10), were calculated at the end of the experiment using German program. In addition, some growth indices and enzymatic activities were also evaluated in this study. Results of the analysis of variance indicated that the triple interaction of A×B×C had significant effects on all germination indices and the lowest coefficient of variation (equal to 7.55) was obtained for germination rate while its highest value (equal to 17.22) was calculated for germination uniformity index. Concerning the effects of priming treatment, it was observed that the highest values for indices of germination percentage and germination rate (with averages of 48% and 0.12, respectively) were obtained under the application of gibberellin. In other words, gibberellin treatment led to increases equal to 15.58 and 90.44% for germination percentage and germination rate indices compared to the control treatment, respectively. In addition, increasing osmotic stress levels had a significant inverse relationship with germination indices so that the application of -1.5 MPa osmotic stress significantly Decreased the germination percentage and germination rate of both Clark and Hobbit cultivars. In general, it was concluded that the application of gibberellin mitigated adverse effects of osmotic stress of -1.5 MPa and resulted in an increasing percentage and rate of germination under stressful conditions.