Stomatal density in plantains materials (Musa AAB, AAAB and ABB) susceptible and resistant to Black Sigatoka (Mycosphaerella fijiensis, Morelet)

A study on stomatal density and influence on the probability of fungi penetration was carried out in order to generate basic information on the possible relation between partial resistance and fungi attack causing Black Sigatoka. More than 70% of the penetration occurs through stomates. Different plantain varieties from the Maracaibo Lake's south zone were chosen: FHIA 20, fhia 21 AND Topocho Cachaco as resistant; Horn and Africa as susceptible clones. Leaf sample were taken from the fifth position in flowering plants. Stomates were observed under a microscope (40X) and counted with the help of a New Bauer camera. Stomatal density was given per mm 2 for both upper and leaf surfaces. In terms of stomatal density for the lower surface, mean values were higher for Hartón and Africa clones (337 and 342, respectively), followed by Topocho, FHIA 21 and FHIA 20 (208, 196 and 151 respectively). Hartón presented the maximum value on the upper surface (58), while Topocho showed the minimum (32). The minimum value for stomates on the lower surface was for FHIA20 (75) and the maximum (550) for Hartón.