Tel-Zur, N., French Associates Institute for Agriculture and Biotechnology of Drylands, The JacobBlaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer, Israel
Dudai, M., Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Raveh, E., The Agricultural Research Organization, Gilat Research Center, Mobile Post, Negev 85280, Israel
Mizrahi, Y., Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Self-incompatibility (SI) is the major factor that limits the development of the exotic fruit crops belonging to Hylocereus species. The selection of self-compatible (SC) hybrids would greatly benefit growers by eliminating the need to grow complementary cultivars for cross-pollination. With this breeding objective in mind, a total of 182 plants that resulted from the first and second generations of hybrids and a first generation of back-crosses were screened for SC. Five hybrids, all of which were a cross between the triploid hybrid 'S-75' and the diploid Hylocereus undatus, were found to be fully SC; they exhibited similar fruit weights and similar total seed numbers following cross- or self-pollination. Flow cytometric analyses revealed that all the SC hybrids were tetraploids, suggesting a possible relation between SC and ploidy level. Further studies will be needed for an efficient identification of SC hybrids during their juvenile period. © 2012 Blackwell Verlag GmbH.