Assessment and Attempt To Explain the High-performance of Azolla in Subdesertic Tropics Versus Humid Tropics

Two similar experiments aimed at selecting performing Azolla strains at Richard Toll, Senegal (subdesertic tropics) and Los Banos, Philippines (humid tropics) show that annual mean productivity of the tested strains is higher in the first site than in the second, the best ecotypes in Senegal producing more than twice as much as in the Philippines. Attempts to explain these differences by climatic or interaction of climatic variables (in the range explored) are unsuccessful. Further analyses are thus needed to understand the reasons, climatic or other, responsible for the different behaviour of Azolla under the two studied ecologies