Gamma Rays and CarbonIon-Beams Irradiation for Mutation ...

placement among the plants (Fig. 30, C). Three leaf-fragments were placed
per plant; two at the base of the plant and one inside the canopy for
inoculation (Fig. 30, D). To ensure the inoculation of the plants, 170 leaf-
fragments were placed on the flat at the nursery. All the leaf-fragments
were sited exposing the abaxial side of the leaf to the plants.
As a preparation of the plants to be inoculated, the abaxial side
of the leaf was cleaned by using a soft cotton tissue to remove the cuticular
wax substance in order to permit a fast penetration of the fungus. The
plants were grouped and the leaf-fragments inoculums were sited. Finally,
by using a fickle cotton sheet the plants were covered to simulate an
incubation chamber to ensure the sporulation and enhance the inoculation.
The fickle cotton sheet was moistened thrice a day within 48 hours (Fig. 30,
E). After this, the cotton sheet was removed. Around 10 days interval, both
the second and the third leaf were inoculated using this method, however
this inoculation also has an effect on the inoculation of the whole plant.
After inoculation, the plants were kept in the nursery area and a week later
the experiment was established at field conditions (June, 2006). ‘Williams’
vitroplants obtained from a commercial nursery were planted surrounding
the experiment to avoid edge effects for the statistical analysis. The
available numbers of plants per doses/cultivar were distributed in two
replications (Fig. 31). To increase the pressure of inoculum in the
environment where the plants were planted, diseased leaves from a banana
collection belonging to the Estación Experimental Tropical Pichiligue were
collected and placed near to the plants in the experiment (Fig. 32).
The disease development periods (DDP-days) was recorded,
which consisted in the days between the inoculation time until the full
development of the spot with dry gray center, using the stages of symptoms
described by Fouré’s scale and the disease severity determined by the
infection index (II-%) calculated using the values obtained from the
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