INDUCTION OF DROUGHT TOLERANCE IN WHEAT THROUGH OSMO AND HYDRO PRIMING

Abstract

A series of experiment were conducted under the laboratory condition of the Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka from 29 August 2013 to 13 February 2014 to evaluate the effect of pre-sowing seed treatment with Polyethylene Glycol (PEG) on germination behavior of wheat (BARI Gom 27 and BARI Gom 28) in relation to drought tolerance and to optimize priming time of PEG. In the 1st experiment, wheat seeds of BARI Gom 27 and BARI Gom 28 were pre-soaked in 0, 5, 10, 15 and 20% PEG solution and untreated seeds were served as control. Results revealed that seed priming enhanced germination percentage (GP), vigor index (VI) and germination index (GI) of wheat seed. The highest GP (95.55%), VI (201.00) and GI (43.73) were obtained from seeds of BARI Gom 27 pre-treated with 10% PEG solution compared to BARI Gom 28 (75.55%, 128.71 and 27.12 of GP, VI and GI, respectively) and then decreased gradually with increasing PEG concentration. In the 2nd experiment, BARI Gom 27 was primed in 0 to 18 hours under 10% PEG solution and distilled water. The highest GP (87.77%), VI (142.31) and GI (41.23) were obtained from seeds pre-soaked in 12 hours with 10% PEG solution compared to hydro-priming (84.44%, 133.83 and 36.62 of GP, VI and GI, respectively) and untreated control (57.77%, 84.85 and 29.75 of GP, VI and GI, respectively), and then decreased gradually with increasing priming time. In the 3rd experiment non primed and primed seeds (osmoprimed and hydroprimed) were germinated under 0, 5, 10, 15 and 20% PEG solution induced drought stress conditions. Results showed that wheat seeds primed with 10% PEG and distilled water enhanced germination behavior and seedling growth over nonprimed seeds. The drought tolerant capability of nonprimed and hydroprimed seeds decreased drastically as drought stress increased but osmoprimed seeds showed considerable tolerance capability upto stress level induced by 10% PEG then significantly decreased with increasing drought stress. Seeds pre-soaked with 10% PEG and distilled water showed better performance in terms of germination behavior and seedling growth compared to untreated control under drought stress. These results suggest that wheat seed primed with 10% PEG for 12 hours is considered as best priming concentration and time to induce drought tolerance capability of wheat for enhancing germination behavior and seedling growth under a certain level of water stress conditions.