INDUCTION OF DROUGHT TOLERANCE CAPABILITY OF SOYBEAN THROUGH POLYETHYLENE GLYCOL AND HYDROPRIMING

Abstract

The study was conducted under the laboratory condition of the Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka from March to April, 2018 to evaluate the effect of pre-sowing seed treatment with Polyethylene Glycol (PEG) on germination behavior and water relation behavior of soybean in relation to drought tolerance and to optimize priming time. In the 1 st experiment, seeds of BARI soybean 5 and BARI soybean 6 were primed with distilled water, 5%, 10%, 15% and 20% PEG solution. Results revealed that BARI soybean 6 showed better performance than BARI soybean 5 in case of germination, seedling growth and water relation behavior of soybean except water saturation deficit (WSD) at 10% PEG. BARI soybean 6 showed GP (85.56%), root and shoot length (67.55 mm and 40.12 mm respectively), root and shoot dry weight (83.28 mg and 7.78 mg respectively), Relative Water Content (82%), Water Retention Capacity (7.61), Coefficient of Germination (19.79%) and Vigor index (84.81). In the 2 nd experiment, BARI soybean seeds were soaked with 10% PEG and distill water for different priming time viz. 3,6.9.12,15 and 18hr. Osmopriming (10% PEG) showed better performance than hydropriming when seeds were soaked for 6 hrs in case of all parameters except WSD. In the 3 rd experiment, osmoprimed and hydroprimed seeds were placed under drought stress condition induced by 0%, 5%, 10%, 15% and 20% PEG. Osmopriming showed better result over hydropriming under low to moderate stress condition and this value decreased with increasing stress condition in relation to all parameters except WSD. Drought tolerance capability increased in osmopriming over hydropriming in case of GP (7.41%), RWC (8.96%), CG (26.05%) and VI (26.32%) under 10% PEG stress. From this study it can be concluded that when BARI soybean 6 primed with 10% PEG for 6 hr showed better performance and stress tolerance than hydroprimed with distill water. These results suggest that seed priming had significant effect to boost up the germination, seedling growth and water relation behavior of soybean.