ISHS Acta Horticulturae 663: XI Eucarpia Symposium on Fruit Breeding and Genetics
TRANSFORMATION OF DWARFING APPLE AND PEAR ROOTSTOCKS WITH THE ROLB GENE AND ITS INFLUENCE ON ROOTING AND GROWTH |
| Authors: | M. Welander, L.H. Zhu, X.Y. Li |
| Keywords: | field trial, Malus, Pyrus communis, in vitro rooting, ex vitro rooting |
| Abstract:
Regeneration and transformation protocols have been elaborated for the dwarfing apple rootstocks M26 and M9/29 and the dwarfing pear rootstock BP10030. Transformed plants have been verified by PCR and Southern blot analyses. The in vitro rooting ability of transformed shoots without auxin treatment varied between 83-100% whereas untransformed shoots did not root at all. For nodal cuttings of transformed clones the rooting ability varied between 91-95% and 20-46% for untransformed plants. Not only the rooting percentage but also the root number increased for the transgenic clones. The root number per cutting varied between 14 and 31 for the transgenic clones and between 1 and 5 for the untransformed plants. Growth analysis revealed that some transformed clones showed significantly shorter internode length and stem length compared to the untransformed controls. This means that the rolB gene not only improved the rooting ability, but also introduced some dwarf characteristics into the transformed plants. The permission for field trial on the transformed rootstocks has been obtained from the Board of Agriculture in Sweden. Plants of different transformed clones and the untransformed controls of M26 and M9/29 have been produced and grown in the field for two years. Five apple cultivars commonly used in Sweden and Europe have been budded onto the rootstocks to evaluate the influence of transgenes on growth and development of the cultivars. | |
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