Genetic fidelity in tissue-cultured ‘Williams’ bananas – The effect of high concentration of topolins and benzyladenine

• Globally, the importance of bananas for food security is well known and documented.
• Use of the micropropagation technique helps to meet increasing demand for bananas.
• High rate of somaclonal variants remain a major bottleneck during micropropagation.
• The role of BA and topolins on genetic fidelity was compared at same concentration.
• Some topolins could reduce genetic variability among micropropagated plantlets.

The effects of five topolins on genetic fidelity of micropropagated ‘Williams’ bananas were compared to that of 6-benzyladenine (BA). Sterile shoot-tip explants were cultured on modified Murashige and Skoog (MS) media supplemented with 30 μM cytokinins (CKs) for 42 days. After the seventh subculture cycle, the degree of variability in regenerants was assessed using 10 inter simple sequence repeat (ISSR) markers. When compared to BA, the use of mTR and MemTTHP proved superior as they had a lower deleterious effect on the regenerants. However, the other topolins either produced a similar effect (MemTR) as BA or were even worse (mT). In as much as the CK contribute to the degree of variation, the effect of subculture cycle remain prominent. Perhaps, the establishment of new culture lines after a few subculture cycles may mitigate the rate of variability. The current findings highlight the beneficial effect as well as the increasing importance of some of the topolins in alleviation of commonly observed physiological disorders during micropropagation.