MICROPROPAGATION OF SALT TOLERANT EXOTIC POTATO GENOTYPES AND THEIR IN VITRO BIOASSAY

Abstract

In vitro bioassay of nine exotic potato genotypes namely CIP102, CIP106, CIP111, CIP 117, CIP 120, CIP124, CIP127, CIP 136 and CIP 139 was conducted for salinity tolerance at Tissue Culture Lab, Tuber Crops Research Center (TCRC), Bangladesh Agricultural Research Institute (BARI), Gazipur-1701. Single node and root tip segments of these genotypes were cultured in MS media supplemented with 0.0 (control), 80, 100, 120, 140 and 160 mM NaCl. In case of in vitro shoot bioassay, CIP 139 was found as the most salt tolerant with the highest plant height (9.67 cm), number of nodes (9.50), number of leaves (13.60), number of roots (8.00), length of root (6.50 cm), fresh weight of shoot (509.0 mg) and fresh weight of root (205.60 mg) at 160 mM NaCl (14.61 dSm ). On the other hand, CIP 106 was found as the most salinity sensitive at 120 mM NaCl (10.96 dSm -1 ) producing minimum plant height (7.17 cm), number of nodes (6.50), number of leaves (12.50), number of roots (9.70), length of roots (5.10 cm), fresh weight of shoot (572.3 mg) and fresh weight of root (244.4 mg) followed by CIP 136, CIP 117 and CIP 111 at same salinity level. However, CIP 127, CIP 102 and CIP 124 genotypes showed very good performance up to 140 mM NaCl (12.78 dSm -1 -1 ). In vitro root bioassay also revealed the highest salinity tolerance of CIP 139 up to 160 mM NaCl, CIP 127 and CIP 102 up to 140 mM NaCl as well as CIP 106 up to 120 mM salinity level. The root tips of experimented potato genotypes were not significantly affected up to 120 mM salinity level in comparison with control where CIP 120 was found as the lowest tolerant up to 120 mM salinity level in MS media. Among the 0.0 (control), 0.1, 0.5, 1.0 and 1.5 mg /L IBA concentrations supplemented with MS media 1.0 mg/ L was found best for rooting with early root initiation (6.57 days) and well development (10.48 days), highest root length (8.63 cm), 2 highest root number (17.25) and maximum fresh weight of root (332.22 mg). Interestingly, there was no significant differences between 0.5 and 1.0 mg/L IBA for in vitro root induction and development in the experimented CIP potato genotypes.