A statistical approach to study the dynamics of micropropagation rates, using banana (Musa spp.) as an example

The use of micropropagation to obtain large numbers of high-quality plantin g material has increased in recent years. Behavior in culture, mainly in te rms of multiplication rate, varies among genotypes, directly affecting plan t production planning. To study multiplication rates over time, suckers of banana, Musa spp., cv. Maca, were collected in the field and the shoot apex introduced in vitro for micropropagation. The number of new shoots produce d in each of the six multiplication cycles was recorded and the data analyz ed statistically. Variability in total shoot production and differences in multiplication rates was considerable among families, which consisted of th e initial explant and its progeny. Moreover, the adjusted Poisson regressio n models for the number of shoots showed that the multiplication rate in th is cultivar tends to decrease with time: after the seventh subculture, new shoots may form at a very low rate. Interpretation of the first and second derivatives of the regression model allowed determination of the maximum sp eed of multiplication and the time at which the multiplication rate begins to decline.