INDUCTION OF DROUGHT TOLERANCE CAPACITY OF MUNGBEAN THROUGH MANNITOL AND HYDROPRIMING

Abstract

A laboratory experiment was set-up at the Agronomy lab of the Central Laboratory, Sher-e-Bangla Agricultural University (SAU), Sher-e-Bangla Nagar, Dhaka-1207 during 22 April to 15 June, 2018. The experiment was undertaken to evaluate the effect of pre-sowing seed treatment with mannitol in relation to drought tolerance and to optimize the priming time of the best priming solution concentration on mungbean (Vigna radiata L.) (BARI Mung 6 and Binamoog 5). The whole experiment was alienated into three experiments. In first experiment, two mungbean varieties were primed in water and mannitol (2%, 4%, 6%, and 8%) for 9 hours and dry seed used as control. The highest germination percentage (96.66%), germination index (80.75) and energy of emergence (98.00%) was were obtained from seeds primed in 4% mannitol for Binamoog 5 and highest coefficient of velocity (22.46), shoot length (153.8 mm), root length (92.98 mm), seedling dry weight (90.49 mg), vigor index (235.3), water content (90.47%) and water retention capacity (20.70) were obtained from seeds primed in 6% mannitol for BARI Mung 6. In second experiment, BARI Mung 6 and Binamoog 5 was primed in under 6% and 4% mannitol solution and distilled water respectively for 0, 3, 6, 9, 12 and 15 hours. 9 hours priming with 6% mannitol showed the best result in BARI Mung 6 and in Binamoog 5, 6 hours priming with 4% mannitol stated the best results for inducing drought tolerance. In the final experiment, seeds were primed with distilled water and 6% mannitol with 9 hours for BARI Mung 6 and 4% mannitol with 6 hours for Binamoog 5; dry seed used as control and were exposed to 0%, 5%, 10%, 15%, and 20% Polyethylene Glycol (PEG) induced drought stress conditions in Petri dishes. Priming with mannitol followed by water were more effective than the control seed in inducing drought tolerance of mungbean cultivars owing to enhance germination and growth parameters under drought stress condition. From the results of the study, it was observed that 9 hours priming with 6% mannitol showed the best result in BARI Mung 6 and in Binamoog 5, 4% mannitol priming for 6 hours stated the best results in comparison to water primed seed and non-primed seed.