Embryo rescue of cucumber (<em>Cucumis sativus</em>), muskmelon (<em>C. melo</em>) and some wild <em>Cucumis</em> species (<em>C. anguria, C. zeyheri</em>, and <em>C. metuliferus</em>)

Abstract

Cucumis sativus is one of the most economically important crops of the Cucurbitaceae. Recent cucumber cultivars are susceptible to some serious diseases and pests, including downy mildew, powdery mildew, nematodes, and spider mites. Sources of resistance to these pathogens and pests were identified in some accessions of wild Cucumis species. One possible way of introducing these resistances into cucumber germplasm is interspecific hybridization. However, C. sativus is sexually incompatible with nearly all other Cucumis species, because of substantially different chromosome numbers, n = 7 in C. sativus versus n = 12 in C. melo and most wild Cucumis species. Overcoming this obstacle can be accomplished through the use of embryo rescue and/or ovule culture. Results of experiments using these methods, especially of embryo rescue of cucumber and selected wild Cucumis species after intra- and interspecific hybridization, are summarized in this paper. Various culture media and selected genotypes were tested in our experiments. Successful regeneration of mature embryos of some Cucumis spp. was observed on all types of media, and callus or sporadic plant formation from immature embryos and seeds occurred on media with coconut water and gibberellic acid.