Ecological distribution and genetic diversity of Azolla in Uganda.

Background: Azolla is an important aquatic fern whose agronomic potential has not been fully exploited in Uganda. This study aimed at determining the genetic variation in the Azolla species existing in Uganda and the factors influencing their distribution in the different agro-ecological zones of Uganda. Molecular characterization was preferred in this study because of its efficiency in detecting variations among closely related species. Results: Four species of Azolla were identified in Uganda with 100, 93.36, 99.22 and 99.39% sequence identities to the reference database sequences of; Azolla mexicana, Azolla microphylla, Azolla filiculoides and Azolla cristata, respectively. These different species were distributed in four out of the ten agro-ecological zones of Uganda which are situated in close vicinity to large water masses. The principal component analysis (PCA) results revealed that maximum rainfall and altitude significantly accounted for the variations in the distribution of Azolla with factor loadings of 0.921 and 0.922, respectively. Conclusion: Massive destruction coupled with prolonged disturbance of Azolla's habitat negatively affected its growth, survival and distribution in the country. Therefore, there is a need to develop standard methods that can preserve the various species of Azolla, so as to salvage them for future use, research and reference. [ABSTRACT FROM AUTHOR]