Novel Resistant Downy Mildew Germplasm Innovation Of Seedless Grapes By Embryo Rescue And Technique Improvement

Seedless grape is preferred by consumers in much of the world. However, there are veryfew commercially acceptable downy mildew resistant seedless cultivars. The conventionalseedless grape breeding is hampered by several problems which the frequency of seedlessnessin progenies is very low and the breeding cycle is too long. It is necessary to apply thetechniques of embryo rescue on the creation of downy mildew resistant seedless grapevinegermplasms. In this study, we got the hybrid progeny which cross the European seedlessgrapes with Chinese wild Vitis species (hybrid) and the European resistant grape varietiesthrough embryo rescue technique, and optimize embryo rescue system on the basis of pre-trialsection. The results obtained are as follows:1. We had obtained207lines from22crosses and17lines from2self-pollinationcultivars through embryo rescue technique, which Flame seedless33lines, Delight64lines,Ruby seedless35lines, Heshi seedless11lines, Crimson Seedless4lines, Thompson Seedless2lines, Superior seedless36lines, Emerald seedless3lines. We used molecular markerassociated with seedlessness SCC8to identify the embryo rescue hybrid progeny, which,12individuals showed homozygous SCC8+/SCC8+alleles. Using molecular marker associatedwith downy mildew resistant S294and S382to identify76embryo rescue hybrid progeny,that, we got40clones which contain target alleles.10downy mildew-resistant clones wereobtained after75hybrid progeny was authenticated through inoculate downy mildew inlaboratory.2. The studies show pollen parents have effects on the sampling time of Emerald seedlesswhich sampling time is45-50d postanthesis. The hormone of GA3, BA, ABA and BR addedin MM3medium can contribute to embryo of Superior seedless grape development, however,the IAA showed Inhibition performance on the development of embryos. The bestconcentration of GA3, BR, BA and ABA is1mg l-1,0.5mg l-1,2.5mg l-1,0.08mg l-1. Theresults show that the use of medium with BA0.2mg l-1can promote the development ofglobular-stages embryo and with IAA0.5mg l-1can promote the development ofglobular-stage embryos, which in vitro cultivation developmental rate of Superior seedlessembryo is33.96%. The embryo development rate of Thompson Seedless, Emerald seedless,Delight is highest which use Paper-brideg culture and the three cultivars embryo development rates are6.18%,16.9%and23.08%. Research on young fruit culture showed hormone GA3and IAA on young fruit cultivation has a positive role, culture methods did not show anysignificantly influence on the young fruit in embryo development. Embryo germination testshowed that the germination of embryo is influenced by the concentrations of activatedcarbon and molysite species in the medium. The germination rate of embryo which cultured inthe medium contained2g l-1activated carbon and EDTA-Fe is highest.3. The survival rate and the growth of plants is best with ABT solution soaking for3min.The growth of tube plantlets were inhibited after irrigating1/8MS nutrient solution, andthere’s no significant effect on the survival rate. Survival rate of domestication is highest after4days domesticated began to lid off. Shade treatment after tansplant can not only promote theplant growth but also improve rate of survival.