Embryo rescue technology plays an important role in seedless grape breeding.  However, the efficiency of embryo rescue, including the embryo formation, germination, and seedling rates, is closely related to the parental genotypes, degree of abortion, growth medium, and plant growth regulators.  In this study, we investigated the effects of different concentrations of paclobutrazol (PAC), a plant growth regulator, and embryo collection times on the embryo formation, germination, and seedling rates for different hybrid combinations of grape breeding varieties used for their aroma and cold-resistance traits.  The results showed that the different PAC concentrations had varying impacts on the development of ovules and embryos from the different grape varieties.  The embryo formation rates of the ‘Sultanina Rose’בBeibinghong’ and ‘Kunxiang Seedless’בTaishan-2’ crosses were the highest under the 5.1 μmol L^–1 PAC treatment.  The 1.0 μmol L^–1 PAC treatment was optimal for the germination and seedling development of the ‘Sultanina Rose’בBeibinghong’ embryos, whereas the 0.2 μmol L^–1 PAC treatment induced the highest germination rate for the ‘Sultanina Rose’בKunxiang Seedless’ cross.  The optimal sampling times for each cross varied as 39 d after pollination (DAP) for the ‘Flame Seedless’בMuscat Hamburg’ cross, 46 DAP for the ‘Kunxiang Seedless’בBeibinghong’ cross, and 41 DAP for the ‘Ruby Seedless’בBeibinghong’ and ‘Fantasy Seedless’בShuangyou’ crosses.  Moreover, the medium modified with 0.5 g L^–1 of indole-3-butyric acid allowed the malformed seedlings to develop into plantlets and achieve larger progenies.  This study provides a useful basis for further studies into grape embryo rescue and could improve breeding efforts for new seedless grape varieties.

Changes in the metabolites of table grapes (Vitis vinifera) reportedly occur during postharvest senescence.  The aim of this study was to determine the metabolomic differences in postharvest table grapes (‘Red Globe’) after being subjected to different senescence periods.  To this end, we used widely targeted metabolomics based on ultra-performance liquid chromatography and tandem mass spectrometry.  A total of 135 differential metabolites were identified.  During postharvest senescence, the levels of most differential flavonoids (e.g., pelargonidin 3-O-glucoside, quercetin-3-O-glucoside, and cyanidin 3-O-glucoside) and L-aspartic acid decreased, while the levels of phenolic acids (e.g., trans-4-hydroxycinnamic acid methyl ester) and pantothenol increased.  During early and late senescence, the levels of most differential lipids, especially LysoPC, as well as those of nucleotides and their derivatives, such as uridine, decreased and increased, respectively.  Collectively, the findings of this study provide fundamental insights into the reasonable control of table grape fruit postharvest senescence and lay a solid foundation for further research.