Studies On Primary Core Collection Of Wild Actinidia Eriantha Of Jiangxi And Genetic Diversity By ISSR

Actinidia eriantha Benth is a unique germplasm resource of kiwifruit in China. The wild A. eriantha germplasm resources, which distributed in Magu Mountain and surrounding areas in Nancheng county of Jiangxi province, were collected and studied to explore the classification standard of the main quantitative characters of the fruit and also propose the reference germplasm. It can provide reference for the normalization and standardization of the description of wild A.eriantha resources. Using the correlated character data of wild A.eriantha fruit and the method of stepwise clustering to study the construction strategy of primary core collection of wild A.eriantha from different sampling ratio, sampling method and clustering method, and finally obtained the best construction method to construct the primary core collection of A.eriantha. At the same time, the genetic diversity of special germplasm resources of A.eriantha fruits collected from the Actinidia resources nursery in Fengxin County was analyzed using ISSR markersto reveal the genetic diversity at molecular level and the differences and genetic relationships within the germplasm resources of wild A.eriantha, and will provide theoretical basis for the protection and rational development and utilization of the germplasm resource. The main results are as follows:(1) The coefficients of variation of 7 main quantitative characters of 118 wild A.eriantha in the test were more than 10%. Fruit weight has the maximum variation coefficient(33.65%), followed by soluble sugar, fruit shape index, AsA, dry matter content, acid and soluble solids content(SSC), and the average coefficient of variation was up to 20.77%. K-S normality test result showed that most of the characters showed the normal distribution. According to the results of the analysis, the classification criteria of grade 5 quantitative characters were proposed, and two different germplasm resources were proposed as a reference per level.(2) According to the DUS national standard of Actinidia, 20 fruit related traits were selected to study the construction strategies of the primary core collection of118 wild A.eriantha materials. Comparing of 3 sampling methods(random sampling,deviation sampling and preferential sampling) showed that the preferential sampling method was superior to the other two sampling methods. Comparing of 4 clustering methods(the average method, the distance square sum method, the longest distance method and the shortest distance method) showed that the average method is better than the other three clustering methods. And the comparing of 6 sampling ratios(15%, 20%, 25%, 30%, 40%, and 35%) showed that the optimal sampling ratio was30%. Using principal component analysis to evaluate the primary core collection,and the result showed that the primary core collection was able to retain the genetic information of the original germplasm at the maximum extent.(3) The wild A.eriantha resources saved in the Actinidia resources nursery in Fengxin County were as materials and the main factors affecting the ISSR Reaction system were optimized using orthogonal experiment. The optimal reaction system of ISSR-PCR for the A.eriantha was obtained: The total volume is 20 ?l, 2 ?l buffer without Mg2+, 1mmol/L Mg2+,1 U Taq enzyme,0.25 mmol/L dNTPs, 1?mol/L primerand 80 ng template DNA.Amplification program as following:Pre-denaturation at 94? for 3 min,denaturation at 94?for 30 s,anneal at 50-60? for45 sand extend at 72? for 1 min,40 cycles, and finally extend at 72? for 7min,then saved at 12? forever. The optimum annealing temperature of the primers UBC842 was 58??(4) The genetic diversity of wild A.eriantha resources saved in the Actinidia resources nursery in Fengxin County was analyzed using ISSR molecular markers. Total of 83 bands were amplified using 11 ISSR primers, and containing 77 polymorphic bands. The percentage of polymorphic bands was 92.66%. Per primer amplified an average of 7.55. The average effective number of alleles(Ne) was 1.58,Nei's gene diversity(He) was 0.34, and the Shannon index(I) was 0.51. The average genetic similarity coefficient of each material was 0.6161, and the range was0.0738-0.8623. The materials could be divided into 5 groups(I, II, III, IV and V) and3 individuals when the genetic similarity coefficient was 0.70.