Micropropagation through axillary shoot proliferation is a simple technique which ensures genetic stability of the propagules. To enhance the rate of multiplication, different doses of sucrose and NaC1 were used for axillary shoot proliferation in sweetpotato. Murashige and Skoog’s basal medium supplemented with growth regulators [NA A (0.5 mg/l) + BA (1.0 mg/l) + GA, (0.5 mg/l)] and variable doses of sucrose and NaCl were used. Among the different doses tested, 4% sucrose resulted in minimum bud dormancy. However, the overall shoot multiplication rate was optimal with 3% sucrose. Although the time required to bud break was considerably stable up to 0.5 g/l of NaCl supplementation and with 3% sucrose, the mean number of shoots produced per explant improved (3.5 — 5.5 shoots/ex-plant) with increasing NaCl level up to 1.0 g/l irrespective of the genotype tested. High rate of multiplication with supplementation of 1.0 g/I is significant for in vitro multiplication and also to use axillary meristem as target tissue for genetic transformation. Delayed bud break response with 2.0 g/l NaCl supplementation can be exploited for in vitro storage of sweetpotato.
Keywords: axillary shoot proliferation. growth regulators. sodium chloride. sweetpotato.
Annals of Tropical Research 23(1):(2001)