Abstract: Male and female gametophytes development in an interspecific hybrid F1 of Cucumis hystrix Chakr.×C. sativus L. (NC4406) were studied through meiotic analysis and paraffin section observation. And meanwhile, the fertile level and potential value of this hybrid in the breeding programs were assessed. Variable chromosome configurations were observed in the pollen mother cells (PMCs) of hybrid F1 at metaphase I, e.g. univalent, bivalents, trivalents and quadrivalents, et al. At anaphase I and Ⅱ, chromosome lagging and bridges resulted from irregular chromosome separation and asynchronization between the different genomes were frequently observed as well, which led to formation of polyads and only partial microspores could developed into fertile pollen grains (about 23.3%). Observations of paraffin sections observed lots of degenerated and abnormal embryo sacs during the female gametophytes development. And only 40% female gametophytes could develop into normal 8 – nuclear megaspore. Fertility test indicated that the male and female gametophytes were partially fertile. On average, 22.8 and 6.3 seeds per fruit could be obtained from the reciprocal backcross, respectively, indicating that this hybrid is a useful germplasm for transferring exotic gene at diploid level.

Key words: Cucumis, interspecific hybrid, male gametophytes, female gametophytes