Studies On Embryo Rescue For Hybrid Of Diploid And Tetraploid Grapes

In order to obtain new seedless triploid varieties via the use of embryo rescuetechniques,7cross combinations were designed, which were ‘Thompson seedless×Kyoho’,‘Crimson×Kyoho’,‘Flame seedless×Kyoho’,‘Sweet Scarlet×Kyoho’,‘Moldova×Kyoho’,‘Kyoho×Moldova’, and ‘Kyoho×Italia’. First the embryoscontinually developed for about8weeks in vitro, then were transferred onto germinationmedium. When4-5new leaves appeared, the seedlings were cultured under intensive lightcondition for acclimation before were transferred into greenhouse. In addition, effects ofsampling dates of immature embryo, culture medium, plant growth regulators, integument,and culture environment on embryo rescue efficiency were studied. The ploidy of thesurvival progeny was preliminarily determined by using Flow Cytometer. Main resultswere as follows:1. The optimal sampling period for embryo rescue varied from the genotypes of thefemale parent. In this research, it was30d after pollination for ‘Thompson Seedless’,35dfor ‘Sweet Scarlet’, and40d for ‘Flame Seedless’.2The suitable plant growth regulators and concentration used could promote embryodevelopment and germination. The germination medium of immature embryo supplied0.2mg/L IAA could significantly improve the percentage of embryo germination, and thesupplied of BA and IBA had no significant effects on embryo germination.3. Low temperature treatment could effectively relieve seed dormancy and promotethe embryo development and germination. More embryo germinated through4℃treatment on grape fruits for30d. Low temperature after inoculation inhibit thegermination of the embryo.4. The grape integument had negative effect on the hybrid embryo development andgermination. Removed the integument form the embryo led the embryo germinated fasterand increased the seedling survival rate significantly. In ‘Flame Seedless×Kyoho’combination, crosscutting ovule appeared multiple embryo seedlings. After thepolyembryony seedlings were subcultured3times continuously, most of the new budscould sprout and grow up to normal seedlings. 5. Casein hydrolysate promoted the cell growth and development. Supplied500mg/LCH in the embryo development medium could significantly improve the rate of hybridseedling survival.6. Of61hybrid seedlings obtained via embryo rescue techniques,31seedlings weretriploid,29seedlings were diploid, and one was tetraploid, determined by Flow Cytometry.7. After acclimation,87hybrid progeny from five cross combinations of ‘SweetScarlet×Kyoho’,‘Flame Seedless×Kyoho’,‘Thomson Seedless×Kyoho’,‘Kyoho×Moldova’ and ‘Kyoho×Italia’ were transferred into greenhouse. There were74seedlingssurvived with a survival rate of85.59%.