EVALUATION OF WHEAT GENOTYPES TO ALLEVIATE THE ADVERSE EFFECT OF SALT STRESS

Abstract

Development of salt tolerant wheat genotypes and/or amelioration of the effect of salt stress are the possible options for utilizing salt affected coastal soil in Bangladesh. In the present investigation, five experiments were carried out during September 2013 to April 2015.To investigate the influence of salinity on germination characters and seedling growth thirty wheat genotypes were tested in petridish under control and saline (15 dS m-1) condition and found that salinity delayed germination and affected seedling growth in different scale in different wheat genotypes. Based on seedling dry weight twenty two wheat genotypes showed more than 0.8 Salt Tolerance Index (STI) and eight genotypes provided less than 0.80 STI. Thirty wheat genotypes were grown in tray containing different levels (Control, 6 and 12 dSm1) of artificially developed saline soil up to 30 days. Emergence index, shoot length, root length and seedling dry weight were found to be reduced in different scale with the increment of soil salinity levels. Eight wheat genotypes showed more than 0.5 STI and twenty two genotypes provided less than 0.50 STI at moderate salinity level. At higher salinity level only five genotypes showed more than 0.3 STI and twenty five genotypes provided less than 0.3. Three comparatively salt tolerant (Sourav, Shatabdi and BAW 1186) and one salt sensitive (BAW 1199) wheat genotypes selected from experiment 1 and 2 based on seedling dry weight were grown in pot under different artificially developed soil salinity levels (Control, 6 dS m-1, 8 dS m-1 and 10 dS m1) to observe the sensitivity of physiological traits resulting reduced grain yield under saline condition. Wheat genotype Sourav and ix Shatabdi accumulated greater quantity of proline, lesser amount of Na+, greater amount of K+ and maintained greater K+ to Na+ ratio under saline condition than BAW 1186 and BAW 1199. Grain yield per plant was reduced with the increment of soil salinity in all the wheat genotypes where Shatabdi affected lesser than others wheat genotypes. Different seed priming treatments were found to be effective to improve speed of germination and early seedling growth of different wheat genotypes (Shatabdi, Sourav and BARI Gom 26) under saline condition. Based on seedling dry weight hydropriming, osmopriming with KCl and osmopriming with NaCl were found to be effective for Sourav, hormonal priming with salicylic acid, osmopriming with CaCl2 and osmopriming with KCl were found effective for Shatabdi and all seed priming treatments except hormonal priming with salicylic acid were found effective for BARI Gom 26.These three wheat genotypes were tested in a pot experiment with four nutrient management treatments and only extra K+ management was found effective to improve grain yield per plant in Shatabdi. The overall results indicated that based on physiological tolerance and agronomic traits Shatabdi was found to be more salt tolerant than all other wheat genotypes tested in the present study and extra K+ management could improve grain yield per plant in only in Shatabdi.