Evaluation of mungbean genotypes for salt tolerance at seedling stage and alleviation of saline stress by gypsum

Abstract

Mungbean is severely affected by salt stress causing significant yield loss. Therefore, cultivation of salt tolerant cultivar and alleviation of saline stress are very important for successful production of mungbean in coastal areas. Laboratory experiments were conducted for screening salt tolerance of mungbean genotypes and to alleviate salinity stress through gypsum fertilization. For screening test eleven mungbean genotype (BARI mung 2, BARI mung 3, BARI mung 4, BARI mung 5, BARI mung 6, BINA mung 1, BINA mung 2, BINA mung 5, BINA mung 6, BINA mung 7 and BINA mung 8) were tested in three salinity levels (0, 50 and 100 mM) of NaCl. The seedling growth characteristics of all mungbean genotypes were reduced with increasing level of salinity compared to control. BINA mung 8 showed better performances in terms shoot and root growth (length, fresh and dry weights) and BARI mung 2 showed lowest performances in saline environment. Results on seedling growth indicate that BINA mung 8 was more tolerant and BARI mung 2 was more sensitive. BINA mung 8 was also used for alleviation of salinity through gypsum (CaSO4.2H2O) application at five different treatments (Control, 50 mM NaCl, 100 mM NaCl, 50 mM NaCl +10 mM gypsum and 100 mM NaCl +10 mM gypsum). Most of the morphological characters viz., length of shoot and root, branches plant-1, weight of leaf, stem, root, yield and yield contributing characters (pods plant-1, seeds plant-1, 1000 seed weight) performed better at 50 mM NaCl with 10 mM gypsum level, and showed lower performance in respect of above terms at 100 mM saline condition. Therefore, BINA mung 8 should be cultivated in saline soil by the application of 10 mM gypsum at three growth stage viz., pre-flowering, flowering and pod formation stage. The study revealed that gypsum treatment could alleviate the adverse effect of salinity on mungbean.