Self-Fertilization of a Schlumbergera truncata Cultivar: Breakdown of Self-incompatibility

Abstract

Plants of the genus Schlumbergera are popular houseplants cultivated throughout the world. While most species in the genus, including the cultivars of Schlumbergera truncata, have been found to be self-incompatible, one cultivar, S. truncata ‘Thor Olga’, is shown here to produce fruit containing viable seeds through self pollination. Three of seven flowers (~43%) set fruit, including two fruits from which viable seeds were collected. A total of 35 seeds from these two fruits were sown, of which nine germinated (~26% viability). The phylloclade shape for all nine progeny plants appeared similar to the S. × buckleyi type for the first year, with gently scalloped rounded edges and no teeth. After the first year, the phylloclade shape began to differentiate, with some remaining similar to the S. × buckleyi shape and others developing the typical S. truncata shape. One of the progeny resulting from the self fertilization was brought to flower, and, in addition to differing in flower color from the parent plant, the progeny plant is very dissimilar to its parent in its branching architecture and its arching pendulous habit, as well as in the size and shape of the phylloclades. The breakdown in self-incompatibility is thought to be associated with delayed pollination, since fresh mature pollen was placed on over-mature stigmas. This appears to be the first time successful self-fertilization of Schlumbergera truncata has been reported in the literature. It is reasonable to predict that other Schlumbergera cultivars/hybrids may likewise exhibit some degree of self-compatibility. The fact that the self-incompatibility mechanisms can be broken down, may lead to the development of a new range of cultivars with unique traits.