Improved germination of embryos in seedless grapes

The embryo rescue technique has been widely applied to embryo germination of stenospermic grapes in breeding programs. In the stenospermocarpic genotype, embryos abort after fertilization during development, so the selection of sampling time and growth medium are most crucial to the success of this technique. This study investigated the effect of the best sampling time and media composition on embryo rescue to avoid the high mortality rate. We sampled ovules 6-9 weeks after flowering and tried adding benzyladenine (BA) to the culture medium. The highest percentages were obtained when ovules were harvested at 8 weeks after pollination, indicating that it is suitable to harvest ovules at veraison. The percentage of embryos that developed cotyledons and roots was 22.6% with MS½+BA 0 mM medium, 45.3% with MS½+BA 0.25 mM and 37.7% with MS½+BA 0.5 mM. Therefore, harvest time of 8 weeks after flowering and MS½+BA 0.25 mM medium were selected for use in the embryo rescue protocol in our breeding program.