ISHS Acta Horticulturae 484: Eucarpia Symposium on Fruit Breeding and Genetics
MOLECULAR ANALYSIS OF MUTANT CLONES IN APPLE |
| Authors: | M. Pancaldi, N.F. Weeden, S. Sansavini, D.L. Mulcahy |
| Keywords: | M. pumila, molecular markers, RAPD, template mixing |
| Abstract:
The present study attempted clonal discrimination within ‘Gala’ and ‘Red Delicious’ polyclonal varieties using a new RAPD strategy, called template mixing. Within each polyclonal variety tested, DNAs of the original clone and of the bulk of the various clones (TM) were compared. According to previous template mixing research, if one of the primers is able to amplify the mutated DNA region, then an additional band (heteroduplex) should appear in the amplification profile of the DNA bulk. In our experiments, none of the amplifications showed the presence of heteroduplex bands, although amplification of DNA mixtures instead of single DNA samples enabled fast screening of a large number of primers. ‘Gala’ clones, ‘Gala’, ‘Mondial Gala’, ‘Royal Gala’ and ‘Gala Must’ gave no difference in the RAPD products generated by 560 primers. In contrast, among clones of ‘Red Delicious’, ‘Starking VF’ displayed three RAPD fragments, all generated by the primer OPK20, that were not present in either ‘Starkrimson’ or ‘Red Chief’. This difference was the only one identified in a survey of 260 primers, and it did not correspond precisely to the type of change expected for template mixing. We conclude that template mixing is not particularly efficient at locating genetic differences among mutants, the changes apparently involving too small a segment of the genome to affect the size of DNA fragments being amplified. However, the approach can lead to the identification of markers in certain instances. | |
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