Embryo and ovule cultures in Cucumis species and their utilization in interspecific hybridization

摘要

Cucumis sativus is one of the most economically important crops of the Cucurbitaceae. Recent cucumber cultivars display rather limited genetic variation and are susceptible to some serious diseases and pests (cucumber downy mildew, powdery mildew, nematodes, spider mites etc.). Sources of genetic resistance to these pathogens and pests are known to exist in certain wild Cucumis species. One possible method to introduce these resistance genes to cucumber cultivars is through interspecific hybridization. However, C. sativus is sexually incompatible with nearly all other Cucumis species, because of substantially different chromosome numbers (2n = 14 in C. sativus versus 2n = 24 in Cucumis melo and most wild Cucumis species). One way to overcome this crossability barrier is to use embryo rescue and/or ovule cultures. These techniques have been developed and sometimes used successfuly to obtain interspecific Cucumis hybrids. Recent progress and future trends in this area are summarized and discussed inthis paper.