Effect of Water Quality on Biochemical and Physiological Parameters in Different Mustard (Brassica juncea) Genotypes

The experiment was conducted in permanent microplots of 2 m × 2 m in size with five mustard genotypes and four quality of irrigation water ECiw (canal 0.3, 2.5, 5.0 and 7.5 dS m-1) to evaluate the effect of different quality of water on biochemical and physiological parameters in different mustard (Brassica juncea) genotypes. It was observed that total chlorophyll content was significantly decreased and relative stress injury percent was significantly increased in mustard genotypes with the application of saline irrigation water. Among different salinity levels, the significantly highest mean chlorophyll content (2.07 mg g-1 FW) was reported under canal water irrigation over ECiw 5.0 (1.76 mg g-1FW) and 7.5 dS m-1 (1.59 mg g-1 FW) and being statistically at par with ECiw 2.5 dS m-1 (1.97 mg g-1 FW). The minimum relative stress injury % was recorded in CS 2002-99 (10.45 %) at canal water irrigation (ECiw 0.3 dS m-1). The significant increment was reported in relative stress injury percent at ECiw 5.0 and 7.5 dS m-1 i.e., 18.17 and 20.26 %, respectively whereas statistically at par with ECiw 2.5 dS m-1 (15.67 %) as compared to canal water irrigation (ECiw 0.3 dS m-1). Total soluble sugar content and proline content in mustard genotypes significantly increased with the application of saline water irrigation. The results showed a percent reduction in mean relative water content of about 0.91, 20.21 and 25.28 % at ECiw 2.5, 5.0 and 7.5 dS m-1 over canal water irrigation (ECiw 0.3 dS m-1), respectively. When salinity susceptibility index (SSI) was less than 1, it indicated that the genotype was more tolerant under salinity stress. The lowest salinity susceptibility index (SSI) was observed under genotype CS 60 (0.61) with ECiw 2.5 dS m-1, CS 60 (0.82) with ECiw 5.0 dS m-1 and CS 2005-143 (0.82) with ECiw 7.5 dS m-1 showing the salt tolerance in mean these mustard genotypes.