Abstract

                                An experiment in NaCl solution culture was conducted to observe the mechanism of salinity tolerance in selected three wheat (Triticum aestivum L.) cultivars, [BWIR7 (Mexico), Gutha (Australian) and KRL19 (Indian)] differing in salinity tolerance. Fifteen days old seedlings of each cultivar grown in half strength Hoagland nutrient solution were subjected to incremental salt stress until the required salinity levels (0, 180-mol m-3) were obtained. Dry matter yield (DMY) at 30 days, indole acetic acid (IAA), abscisic acid (ABA) and total free amino acid (AA) contents of leaves/root at 29 days and dehydrogenase activity of roots at 34 days were determined after initiation of the salinity stress. Shoot and root weight (DMY), dehydrogenase of root and IAA contents both in leaves and root of all the cultivars decreased whereas, ABA and AA contents increased. At saline treatment, cultivar, KRL19 produced maximum shoot DMY and BWIR7 minimum. Whereas, in case of roots Gutha produced maximum and KRL 19 minimum DMY. Dehydrogenase activity of root BWIR7 was more affected followed by Gutha and KRL19. The extent of decrease of IAA content in leaves and roots of Gutha was more pronounced than the other cultivars. Increase in ABA contents of shoots and roots were more in KRL 19 followed by BWIR7 and Gutha respectively. The extent of increase of AA contents was more in the leaves of KRL 19. From this study, it was concluded that cultivar KRL 19 has the salinity inclusion and Gutha salinity exclusion mechanism. The salinity tolerance cultivars were in order of KRL 19 > Gutha> BWIR7

Key words : Salinity, dehydrogenase activity; IAA, ABA, AA