Studies On The Genetic And Biological Fundations Of The Sport Plant From Vitis Quinquangularis Rehd

Vitis quinquangularis Rehd was originally produced in China. The wild resources ofVitis quinquangularis Rehd are rich in Guangxi. Its artificial cultivation increasesrapidly along with the developing of grape vintage. But V. quinquangularis Rehd isdioecism with excessive vegetative growth, overblooming, serious physiological fruitdrop, unstable fertility and low yield in artificial cultivation. Therefore, it is importantfor improving the artificial cultivation of V. quinquangularis Rehd to meet therequirement of grape wine industry development in Guangxi by breeding new improvedvarieties which have bisexual flowers, strong resistant ability to diseases and insect pests,high fertility, stable yield, high brewing quality and good adoption to the climate of theSouth. In this study, the sport from V. quinquangularis Rehd was investigated inmorphology, fruit quality, cytobiology and molecular biology. The main results are asfollows:1. Comparisons of the botanical and biological characteristics between the sportand the controlThe sport is very different from the control in surface modality such as leaves,tender treetop, tresses and flower type. The flower type of the sport has mutated frommale to bisexual. The fruit-set rate, juice rate and cuttage survival rate of the sportincreased 168%, 34.6%, 171%, respectively, as compared with the control. Thephenophase of the sport was brought forward for about a month, and the fruit matureperiod for about two month. It only needed 75d from bloom to the berry fruitmaturation for the sport, but 105 d for the control.2. Comparisons of fruit quality between the sport and the controlThe sport is obviously excelled to the control in appearance and vegetativecharacteristics. The average single fruit weight and cluster weight increased by 157.1% and 109.1%, respectively, and the content of titratable acidity dropped by 27.4% overthe control. The content of soluble sugar, reducing sugar, total soluble solids, vitamin Cand tanins were 85.5%, 26.4%, 47.3%, 320.1%, 192.6% higher in the sport than the incontrol. This sport is a fine mutatant in fruit quality.3. Study on the morphologic characteristics and ability of procreation of pollensThe morphologic characteristics of pollens in the bisexual flower of the sport weresimilar to the male but much different from the female flower, especially it hadbourgeoning ditch and hole. In addition, its sprouting rate was 52.4%, similar to 57.4%,that of the male flower, which suggested that the pollens of bisexual flower had strongprocreating ability. The differences in size, figure, characteristics of exine ornamentationand bourgeoning apparatus of pollens between the sport and its mother plant suggestedthat genetic variation had occurred in the sport.4. Analysis of chromosome times of the sportThe sheeting method was used to study the cells in splitting metaphase. The resultshowed that the number of chromosomes in the sport is still 38 and the variation in thesurface of the sport was not caused by the variation of chromosome times.5. Optimization of ISSR conditions for grapeFive essential factors that might affect the results of ISSR were compared and theoptimum ISSR reaction system for grape was established. A 20μL solution with 80 ngtemplate DNA, 0.5～1.0U Taq DNA polymerase, 1×buffer (containing no Mg²⁺), 2.0mmol/L MgCl₂, each 200μmol/L dNTP and 0.25μmol/L ISSR primer was found best foramplification reaction.6. ISSR analyses of the sport and its mother plantTotal 100 ISSR primers were applied with ISSR analysis to study the geneticsubstance differences between the sport and its mother plant, and 16 of the primers (807,810, 812, 815, 822, 825, 826, 828, 835, 845, 848, 851, 855, 856, 857, 859) were found toproduce stable polymorphic segments between the two clones, and 43 of the total 243amplified fragments were distinctive. The similar coefficient between the sport and itsmother plant is 0.7981. These results showed that the changes in appearance of the sportwere consanguineously relative with the change of genetic substances in the mother plant. The regeneration of the sport might be due to the accumulation of gene mutationstime after time or the variation in the structure of the chromosomes.7. Study on partial specific fragments by cloning and sequencingThree specific fragments were cloned and sequenced by using the primer 807. Therewere no functional genes or segments which had high comparability to these fragmentsfound in GenBank. Therefore, the relativity between these specific fragments needsfurther study.