Influence of Gibberellic Acid Growth Regulator on Sunflower Seed Emergence Indices and Seedling Characters under Salinity Stress

Abstract

Salinity stress is one of factors limiting seed germination and seedling development in sunflower at New halfa scheme in East of Sudan. The objective of this study was evaluation germination indices and seedling parameters of sunflower seed under salinity stress with varying concentrations of synthetic growth regulator namely GA3. From 16-30 November 2019 a laboratory experiment (in Petri dishes) of randomized complete blocks design (RCBD) with three replicates was carried out. Treatments were consisted of (four levels of GA3 were 0, 50,75 and 100 p.pm) designated as G0,G50,G75 and G100,respectively, under five levels of salinity (0, 0.5, 1.0, 1.5 and 2%) designated as Na0, Na1.0 ,Na1.5 and Na2.0. This study examined Emergence indices: Seed Emergence percentage EP%, Mean emergence time (MET), Mean daily germination (MDG), Energy of germination was( EE), Emergence index(EI), Daily germination speed (DGS), Emergence coefficient of uniformity (ECU), vigour index of seed(VIS) and seedling characters also were determined. The results indicated that application of GA3 at 50 p.pm resulted in high EP, MDG, MET and SVI as compared with other related treatments. Also application of (G75 and G100) resulted in higher values of DGS, ECU and EI. Application of high levels of salinity treatments resulted in decreasing of all germination indices in this study. The interaction treatment ( G50xNa0) on MDG had significant differences in this study. In condition, GA3 increasing up germination indices and promoting growth and compromised seedling vigor while salinity hindered seed emergence and seedling characters of sunflower.