Creation of novel interspecific-interploid Hylocereus hybrids (Cactaceae) via embryo rescue Aroldo Cisneros • Reinerio Benega Garcia • Noemi Tel-Zur Received: 16 July 2012 / Accepted: 15 September 2012 Ó Springer Science+Business Media Dordrecht 2012 Abstract In this study we developed a technique for rescuing embryos at a very early developmental stage following interspecific-interploid crosses between Hylocereus sp. Controlled hand pollinations were performed between the tetraploid H. megalanthus (Vaup.) Bauer as the female parent and either diploid H. monacanthus (Lem.) Britton et Rose or H. undatus (Haw.) Britton et Rose as the male parent. The fertilized ovules were excised from ovaries 10 or 30 days after pollination (DAP). Pollinated ovules containing the funiculi and placental tissue and immature embryos were placed on half-strength basal Murashige and Skoog (MS) medium containing 680 lM glutamine, 0.54 lM a-naphthaleneacetic acid, and 0.45 lM thidiazuron and supplemented with 0.00, 0.09, 0.17 or 0.26 M sucrose concentrations. The best ovule response was recorded at 30 DAP, and the most prolific callus formation was observed at 10 DAP. Callus formation was observed in most of the treatments using whole ovules but not in the isolated immature embryos. The calli were mucilag- inous or compact, transparent and friable, but they did not form embryogenic structures. Embryo develop- ment was significantly affected by the sucrose con- centration, and the best results were obtained with 0.17 M sucrose. More than 70 % of the obtained hybrids were successfully hardened off and trans- planted in soil where they grew normally. Ploidy level analyses of 77 putative hybrids exposed diploid, triploid, tetraploid, and higher than tetraploid levels. Among those hybrids studied, 22 progenies were randomly chosen for amplified fragment length poly- morphism analysis, and all were identified as genuine hybrids. The technology described here is an addi- tional stage in the breeding program for Hylocereus species resulting in novel, interspecific hybrids obtained using the embryo rescue technique. Keywords Amplified fragment length polymorphism (AFLP) Á Flow cytometry Á a-Naphthaleneacetic acid Á Ovule culture Á Thidiazuron Á Vine cacti Abbreviations AFLP Amplified fragment length polymorphism BGU Ben-Gurion University of the Negev DAP Days after pollination IE Immature embryos MS Murashige and Skoog NAA a-Naphthaleneacetic acid NIB Nuclei isolation buffer TDZ Thidiazuron WO Whole ovules A. Cisneros Á R. B. Garcia Á N. Tel-Zur (&) French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev (BGU), 84990 Sede-Boqer Campus, Sede-Boqer, Israel e-mail: telzur@bgu.ac.il 123 Euphytica DOI 10.1007/s10681-012-0800-3