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

4. 3. 2. 4. Plant selection by combining DDP-days, II-% and LDNA-%
In this research, the three variables DDP-days, II-% and LDNA-
% were study to assess black Sigatoka response in the irradiated materials.
The data analyzed by linear regression permitted to categorize the plants
showing better response against to this disease. Fig. 47 shows the LDNA-%
regression versus II-% (A), LDNA-% regression versus DDP-days (B) and
DDP-days regression versus II-% (C) in ‘Williams’. The regression among
the three combined variables permitted to observe close relationships in six
plants. The code number are ‘W 16 II 74’, ‘W 128 I 67’, ‘W 1 II 148’, ‘W
8 II 13’, ‘W 1 II 19’ and ‘W 1 II 31’. This group of plants were selected as
candidates possessing better response against to black Sigatoka. In the case
of ‘Cavendish Enano’, two plants with the code numbers CE 4 II 30 and
CE 64 I 5 (Fig. 48) were found out showing high relationship when the
three variables were combined (Table 12). Those results allow to allege
that the sensitivity to the irradiation of ‘Williams’ determined by LD50
could explain the variation in the number of mutated plants that shows six
candidates, compared with the two candidates obtained in ‘Cavendish
Enano’. That means that high sensitivity cultivars to Carbon ion-beams
irradiation may produce a wide range of mutagenesis expressing
tolerant/resistant to black Sigatoka, deducing that the sensitivity is cultivar
dependent.
Romero and Sutton (1997) indicated that artificial inoculations
of 10-week-old tissue culture plants with conidia of M. fijiensis could be
used to test the susceptibility or resistance of different genotypes. In this
study, which is the first report in banana using ion beams to alter the
banana response against to black Sigatoka, from a viewpoint of complete
assessment of the candidate plants, field experiment based on the whole
plant cycle must be necessary to evaluate not only the response to black
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