Somatic Mutations and Their Implications to the Conservation Strategies of the East African Highland Bananas (Musa spp.)

Somatic mutations in bananas (Musa spp.) have been exploited for selection of favorable traits, both for consumption and commercial purposes, and they have been responsible for the current diversity of the East African highland bananas (EAHB). The role of mutations in the selection and subsequent conservation of banana cultivars by communities is not clearly understood. It is, however, believed that farmers play important roles in initiating and adjusting the proportions of cultivars on-farm, based on different traits. The purpose of this study was to: (a) initially determine the levels of somatic mutations in each clone set of the EAHB exsitu collections; (b) establish cultivar richness and evenness to understand the conservation potential of each clone set; (c) determine the relationship between mutant traits with richness and evenness; and (d) compare the similarity between cultivar selection criteria and the mutant traits. Correlation and distance coefficients were used to determine accessions that are closely related, but not identical, on the basis of 61 morphological traits of 192 EAHB accessions of ex-situ collections in Uganda. Cultivar richness and evenness of clone sets of the landraces were then determined in three benchmark sites in Uganda and Tanzania. These measures of diversity were correlated with overall mutant traits and comparisons were made between cultivar selection criteria and the traits. Mutations were more frequent in 'Nfuuka' and a positive strong correlation between richness and mutant traits supported this. There was, however, a highly negative correlation between mutant traits and evenness. The traits that were more associated with mutations and selection criteria of farmers were related to bunches and fruits; an indication of the possible role of mutations in the selection and subsequent conservation of banana diversity on-farm.