Improved in vitro Vitis vinifera L. embryo development of F1 progeny of ‘Delight’ × ‘Ruby seedless’ using putrescine and marker-assisted selection

Production of seedless V. vinifera L. cultivars is one of the major goals of table grape breeding. Traditional methods result in only a low percentage of seedless progeny. Modern techniques, such as embryo rescue, are used to improve production efficiency of seedless cultivars. In this study, the effects of various putrescine concentrations (0, 1, 2, 3, 4, and 5 mmol L −1 ) and different stages of embryo development (globular-, heart-, torpedo-, and cotyledon-shaped embryo) on the success rate of embryo rescue were assessed in three lines of the F 1 Vitis vinifera L., cross ‘Delight’ × ‘Ruby Seedless,’ ‘DR2,’ ‘DR3,’ and ‘DR6’ (with small seed traces). The plant development rates of ‘DR2,’ ‘DR3,’ and ‘DR6’, which contain small seed traces, as female parents, were significantly higher than those of seedless varieties. The rates of embryo development on woody plant medium (WPM) of ‘DR2’ × ‘Thompson Seedless,’ ‘DR3’ × ‘Thompson Seedless,’ and ‘DR6’ × ‘Monukka’ were highest with 2, 2, and 4 mmol L −1 putrescine, respectively. The germination rates of torpedo- and cotyledon-shaped embryos were significantly higher than those of globular- and heart-shaped embryos. Characteristics of the embryo germination progress of ‘DR2’ × ‘Thompson Seedless’ at different developmental stages were recorded. The Grape Seedless gene Probe 1 (GSLP1) marker was used to help identify the seedless descendants; 14 plantlets showed a corresponding electrophoresis band at 569 bp and were preliminarily defined as seedless.