In 'vitro' selection and characterization of water stress tolerant lines among ethyl methanesulphonate (ems) induced variants of banana ('Musa' spp., with AAA genome)

Water stress enforces a serious threat to banana productivity. Therefore, the attempts to develop tolerant lines are of massive worth to increase cop productivity. To develop an efficient in vitro screening of banana for water stress tolerance, twelve EMS - induced variants derived from cultivars; 'Berangan Intan' and 'Berangan' involving shoot tips were subjected to a stepwise selection procedure contained three levels (10, 20 and 30 g L -1 ) of PEG induced water stress. Water stress adversely affected fresh weight increase, shoot vigour and multiplication rate. However, L2-5 on the medium fortified with 30 g L -1 PEG, had significantly the greatest fresh weight increase (1.85 ± 0.18 g) while the parental lines (L 1-1 and L 2-1) exhibited the lowest fresh weight increase (0.29 ± 0.08 and 0.28 ± 0.1 g, respectively). Higher proliferation rate was observed with L2-5 and L 1-5 followed by L 2-4, L 1-4 and L 2-6.at each stress level. Proline content was increased noticeably in L2-5 and L 1-5 followed by L 1-4, L 1-6, L 2-3, L 2-4 and L 2-6. A significant decrease in leaf water loss associated with the lessened levels of MDA and H 2O2 were recorded with the water stress tolerant lines as compared to susceptible and non - mutated parental lines exposed to PEG. It was concluded that in vitro selection of banana could provide a method for distinguishing the variants for their morphological and physiological responses to water stress whereby L 2-5, L 1- 5, L 2-6, L1-6, L 1-4 and L 2-3 demonstrated better tolerance against water deficit than the rest and control plants.