Abstract: The proper sampling period is one of the most important factors of the grape in ovulo-embryo culture. Through testing the changes of the ovule weight and observing its anatomical structure, the period and mode of ovule(embryo) abortion in crosses between diploid and tetraploid grape cultivars were studied, and the ovules were cultured to determine the proper period of embryo rescue. Unlike the seedless grape varieties, the embryo abortion did not occur at one same time for most seeded varieties crossed with different ploidy, the ovule abortion was only individual action, but not colony one. So the period of sampling had some degree of freedom. The period of ovule(embryo) abortion was correlated with the mature period of the female parent variety. The abortive embryo of early-maturing variety occurred at five weeks after pollination, then the mid-maturing variety and late-maturing variety (with low abortion rate) were at six and nine weeks after pollination comparatively. The proper sampling period was between 6-9 weeks for early-, 7-10 weeks for mid-, and 9-12 weeks for late-maturing varieties after pollination based on the ripenning period of the female parent variety.

Key words: Grapes, Cross between diploid and tetraploid, Embryo rescue, Sampling period