MANNITOL INDUCED SALT TOLERANT CAPACITY OF WHEAT UNDER SALT STRESS CONDITION

Abstract

The experiment was conducted at The Central Laboratory of Sher-e-Bangla Agricultural University (SAU), Sher-e-Bangla Nagar, Dhaka-1207 during the period from August to November 2016. Two experiments were conducted to study the mannitol induced salt tolerant capacity of wheat under salt stress condition. The experiment was laid out in a Completely Randomized Design (CRD) with five replications. Three wheat genotypes viz. V 1 (BARI Gom-28), V 2 (ESWYT-5) and V

(ESWYT-6) were used as test crop. Mannitol was used as priming chemicals and salt (NaCl) were used for salinity stress. Alcohol was used as surface sterilizer of wheat seeds. The data were recorded on germination percentage, root length, shoot length, root dry weight and shoot dry weight, fresh weight, turgid weight, relative water content, water retention capacity and vigour index. Data were analyzed using a computer software MSTAT-C. For the first experiment four levels of mannitol such as 2%, 4%, 6% and 8% were used for osmopriming and water was used for hydropriming. Among the genotypes, V (ESWYT-5) gave the best results on studied parameters. Results revealed that the V 2 showed the highest germination rate (96.67%), shoot length (148.40 mm), root length (109.95 mm), shoot dry weight (9.65 mg), root dry weight (6.42 mg), fresh weight (264.55 mg), turgid weight (282.65 mg), relative water content (93.21%) and vigour index (43.04) primed with 2% mannitol solution for 9 hours where seeds without priming showed lowest results in respected parameters with the genotype V 2 (BARI Gom-28). In the second experiment, 2% mannitol primed (9 hours) seeds of wheat genotypes above mentioned with and without salt (NaCl) stress condition was evaluated. The salt stress levels (0 dS/m), 5dS/m, 10 dS/m, 15 dS/m and 20 dS/m were used during experimentation. It was observed that the genotype V 1 (ESWYT-5) with primed seeds placed without salt; (control) gave the best performance on respected parameters but under salinity stress, the highest germination rate (93.33%), shoot length (142.85 mm), root length (115.20 mm), shoot dry weight (11.66 mg) and root dry weight (8.01 mg), fresh weight (215.65 mg), turgid weight (268.55 mg), relative water content (88.03%) and vigour index (238.9) were achieved from V 2 primed seeds placed with 5 dS/m NaCl where V primed seeds placed with 20 dS/m NaCl showed lowest results in respected parameters. Priming with water was more effective than control with regard to enhanced germination and growth parameters. From the result of the study, it was observed that seeds primed 2% mannitol for 9 hours showed the best result to compare with water primed and non-primed seed under salt stress condition.