Study On The Creation Of Seedless Grape Germplasm Materials

Seedless grape breeding is an important direction for the development of grape industry.A large part of the seedless grapes available for fresh food on the market are the seedless varieties obtained after seedlessness,while the proportion of natural seedless varieties is very small.In order to meet the requirements of grape industry development and food health,it is necessary to create green,safe seedless grape germplasm.In this paper,a new seedless grape germplasm was obtained through conventional cross breeding and embryo rescue breeding based on tissue culture technology.In this study,grape varieties with excellent characteristics and rose fragrance traits were selected as parents,and the hybrid combinations of Seed×Seedless,Seedless×Seed（Seedless）were allocated.At the same time,the influence of parental genotype,appropriate sampling time,and the addition of exogenous hormones in the medium on the embryo rescue effect was investigated.The results obtained are as follows:1.A total of 1357 hybrid seedlings were obtained by combinations of Seed×Seedless hybrids.A total of 14674 ovules were inoculated in 22 Seedless×Seed hybrids and 1Seedless×Seedless hybrids,1598 embryos were germinated,and 588 seedlings were formed.2.Parental genotype is one of the factors affecting the efficiency of embryo rescue breeding.The embryo rescue efficiency was better when‘Zicui Seedless’and‘Zitian Seedless’were used as the female parent,and‘Ruidu Xiangyu’,‘Shine Muscat’and‘Jintian Meigui’were used as the male parent.When‘Ruidu Xiangyu’was used as the male parent,‘Zicui Seedless’was used as the female parent,the embryo rescue efficiency was higher,the hybrid ovule development rate was 18.96%,the seedling formation rate was 9.61%.The rate of hybrid ovule development and seedling formation of‘Zitian Seedless’as the female parent was 21.14%and 7.43%respectively.The hybrid ovule development rate of‘Zitian Seedless’as the female parent and‘Jintian Meigui’as the male parent was the highest,reaching 31.88%.The ovule development rate of‘Sweet Sapphire’as the female parent and‘Shine Muscat’as the male parent was the highest,reaching 10.22%,but the seedling formation rate of all the hybrid combinations was slightly lower.It indicates that the embryo rescue efficiency was better when‘Zicui Seedless’and‘Zitian Seedless’were used as the female parent,‘Ruidu Xiangyu’,‘Shine Muscat’and‘Jintian Meigui’are suitable for paternal materials.3.Sampling time is one of the factors affecting the efficiency of embryo rescue breeding.After pollination,5 different sampling times were set to compare ovule development rate and seedling formation rate.The optimal sampling time of‘Zitian Seedless’as the female parent is 42 days after pollination.The optimal sampling time of‘Zicui Seedless’as the female parent is 39-42 days after pollination.The optimal sampling time of‘Sweet Sapphire’as the female parent is 49-52 days after pollination.4.Add appropriate exogenous hormones to improve the efficiency of seedless grape embryo rescue breeding.In the ovule culture stage,when 1.0 mg/L m T and 1.0 mg/L IAA were added into the medium MM₃,the hybrid‘Ruby Seedless’בPearl of Csaba’had the highest ovule development rate,31.85%.When 0.6 mg/L m T was added to the WPM medium,the germination rate of the embryo of the hybrid‘Ruby Seedless’בPearl of Csaba’was up to 31.58%.5.Using KASP marker,a total of 444 hybrid progenies with seedless marker were identified by using conventional hybridization and embryo rescue techniques.