2009 Volume 78 Issue 4 Pages 410-416
We transformed the European pear (Pyrus communis L.) ‘La France’ and ‘Ballade’ with the Citrus FLOWERING LOCUS T (CiFT) gene, which induces early flowering. Subsequent DNA blot analysis of the transformed and wild-type plants indicated that the transformed plants carried 1–4 copies of CiFT. Of the 8 transformed ‘La France’ and 7 transgenic ‘Ballade’ plant lines obtained, 7 and 5 lines respectively, flowered early when cultivated in vitro in a micropropagation medium. No correlation was found between the CiFT copy number and early flowering in vitro, however, the results of RNA gel blot analysis indicated a strong correlation between the expression of the CiFT gene and floral bud differentiation in vitro. Flowers that developed in vitro differed from wild-type flowers in terms of phenotypic traits, such as the number of pistils, petals, sepals, and stamens. To investigate the inheritance pattern of the CiFT gene, we obtained 15 seeds from the fruits of P. communis L. ‘Bartlett’ plants that were cross-pollinated with transgenic line No. 6, which had the second highest expression of the transgene. Of 7 seedlings that expressed the CiFT gene, 5 flowered within 10 months after they were transferred to a greenhouse. This result indicated that the CiFT gene induced early flowering in the transformed pear plants and that their progeny inherited the early flowering phenotype.