ISHS Acta Horticulturae 528: VII International Symposium on Grapevine Genetics and Breeding
TOWARDS MARKER-ASSISTED SELECTION FOR SEEDLESSNESS IN GRAPEVINE |
| Authors: | P. This, F. Lahogue, A.F. Adam-Blondon, A. Doligez, A. Bouquet |
| Keywords: | Vitis vinifera, table grape, seedlessness, RAPD, SCAR, selection |
| Abstract:
For the development of new seedless varieties, traditional breeding methods are based on crosses between seeded and seedless varieties, Sultanina being the main source of seedlessness. The proportion of seedless genotypes obtained in these progenies is low (10 to 30%) and depends on the parentage. New technologies such as in vitro culture, have allowed the recovery of a higher proportion of seedless indivuduals but this technique is labor intensive and time consuming. As grapevine does not produce bunches before the age of three or four years, the selection cannot be performed at an early stage. The identification of molecular markers linked to the seedless character would therefore be of great interest, creating the possibility to exclude seeded offspring at the seedling stage and to select the parents of future crosses. There would be a considerable saving of time and space, as well as a reduction in overall costs. According to Bouquet and Danglot (1996), this trait might be controlled by three complementary recessive genes regulated by a dominant gene I. Using the Bulked Segregant Analysis method, we identified two RAPD markers which appeared tightly linked to the gene I (0.7 and 3.5 cM respectively). The closest marker was used to develop a codominant SCAR named SCC8. This latter marker appeared of great value to exclude from the progeny undoubtedly seeded individuals (scc8-scc8-) or to select undoubtedly seedless individuals (SCC8+SCC8+). Moreover, SCC8 was also interesting to dissect the genetic of seedlessness. ANOVA analysis indicated that this marker accounted for at least 65% of the phenotypic variation of the seed fresh weight and for at least 79% of the phenotypic variation of the seed dry matter. The extent of usefulness of this marker was then tested on several naturally occuring seedless plants, revealing the presence of the SCC8+ allele in all Sultanina derived varieties tested. Unfortunatly, a null allele was discovered among seeded cultivars, thus transforming SCC8 into a dominant marker. | |
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