Study on improving plantlet development and embryo germination rates in in vitro embryo rescue of seedless grapevine

The embryo rescue technique has been proved to be highly effective and become a standard tool in seedless grape breeding. The main factors limiting the success of in vitro embryo rescue are the germination and development of zygotic embryos. Here, we evaluate the effects of different crossing parents, sampling time and culture medium, including different polyamines on development processes of stenospermic grape embryos. Our results indicate that both embryo germination and plantlet development were highly dependent on the crossing parent genotypes, sampling times and improvement of culture medium. Additions of 3 mM putrescine, 0.5 mM spermidine or 0.3 mM spermine significantly increase plantlet development or embryo germination rate in a range of hybrid combinations, including Sultanina Rose x Shuangyou, Ruby Seedless x Zixiang Seedless, Aishenmeigui x Shine-Muscat, Ruby Seedless x Flame Seedless and Blush Seedless x Aishenmeigui, which reveals that appropriate amounts of polyamines are added to the culture medium, the efficiency of in vitro embryo rescue can be significantly increased.