Elucidating the resistance response of irradiated banana cv. Lakatan to banana bunchy top virus (BBTV) infection transmitted by the banana aphid Pentalonia nigronervosa Coquerol

Development of banana bunchy top virus (BBTV)-resistant banana variety Lakatan through gamma-irradiation had been successfully done as part of integrated management strategies against the disease. Ten irradiated Lakatan lines exhibited resistance to BBTV. Resistance of these lines was evaluated based on symptomatology and host-virus relationship. Insect colony development on Lakatan banana irradiated lines was monitored by artificially inoculating viruliferous banana aphids, Pentalonia nigronervosa, and counting the resulting number of aphids per plant at weekly intervals. Resistance to virus multiplication of Lakatan irradiated lines was characterized by quantifying the virus titer through Enzyme-Linked Immunosorbent Assay (ELISA). Results showed that not all lines were suitable as hosts in establishing aphid population. The reaction of the mutant lines to the vector and the pathogen varied to some extent. Disease incidence in some cases was correlated with aphid preference. Disease incidence was significantly higher (50%) on lines that were preferred by aphids and lower (50%) in those that were not colonized. Some mutant lines with very low aphid colony count, however showed high BBTV incidence. Variability in the results could be affected by other factors such as the developmental stage of the plant and prevailing environmental conditions during the conduct of the experiment. Virus titer was also reduced on these mutant lines, thus reduced virus multiplication. Non-irradiated (control) Lakatan banana had comparably high population of aphids, high disease incidence, and high virus titer