SELECTION OF SOME IMPORTANT SPECIES IN GENUS BRASSICA AGAINST DROUGHT AND SALT TOLERANCE BY MORPHOLOGICAL OBSERVATIONS ON GERMINATION AND SEEDLING GROWTH PARAMETERS

It is very important to identify physiological responses of species against major stresses like drought and salinity to select and screen high yielding species under the available environmental conditions for better yield. This study evaluated the effects of PEG 6000 (0.0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa) and NaCl (0, 5, 10, 15, 20, 25, 30 and 35 dSm-1) on germination and early seedling growth of 4 species in genus Brassica including Brassica juncea, B. rapa, B. nigra and Sinapis alba. Results revealed that the species showed different responses to PEG and NaCl stress. Comparing the results with controls, the B. juncea and B. rapa were more tolerant against drought and salinity stress compared to B. nigra and S. alba. The germination percentage and seedling growth parameters decreased gradually by treating the species using >-0.4 MPa PEG and > 10 dSm-1 NaCl. The effects of NaCl were less pronounced on germination and seedling growth compared to these effects due to PEG. The seed germination was completely stopped using > -1.0 MPa PEG treatments in B.juncea, B. rapa, and 5. alba; and at >0.8 MPa treatment in B. nigra. Correspondingly, seed germination was completely inhibited at 35 dSm-1 NaCl induced stress treatments in B. juncea, B. rapa, and B. nigra. Whereas, S. alba was a bit sensitive and induced stopage of germination at 30 dSm-1 NaCl induced stress. This study highlighted the significance of screening B. juncea, B. rapa, B. nigra and S. alba species against NaCl and PEG stresses for better crop management.