Studies On Genetic Relationships Among The Jujube (Ziziphus Jujuba Mill.) In Sichuan By Using Issr Technique And Agronomic Characters

Jujube (Ziziphus Jujuha Mill.) which genus Rhamnaceae are deciduous shrubs or climbers. About 98% of the jujube plant resources all around the world are focused in China, and extensively distributed throughout north-south. It is one of the important economic trees in China which has many advantages such as rapidly fertility in a short time, strong resistance, less investment, quickly earnings. It has a large planting scale in the central hilly region of Sichuan. For further investigation we found a batch of excellent varieties in this area, such as ’mizao’ ’tiaoyuanzao’, ’youzao’, and introduced varieties, such as ’fengmiguanzao’,’zhanhuadongzao’. The resources of ’mizao:are concentration distributed in ZhanShan village in Mianyang Santai, Changqiu village in Chengdu PuJiang, and Qishan village in Meishan, which have certain differences in morphological characteristics. In the population of ’zhanshanmizao’,we found two strains that have differences with the original species of big fruit type and apple type.In this study, the methods of ISSR molecular marker and agronomic traits are used to analysis the genetic relationships of 22 jujube materials from some of Sichuan, including three areas of ’mizao’, three strains in ’zhanshanmizao’ population, other local jujube resources and introduced varieties, aimimg to find out the genetic links among the Chinese jujube germplasm across Sichuan, and providing reference for germplasm identification, selection superior resources and new variety breeding. The results are as follows:1. Obtained high quality DNAs using improved CTAB method for ISSR amplification, and setting up a suitable ISSR PCR amplification reaction system for jujube, the system including 0.8μmol/L primer,80ng DNA,10.OμL 2×Taq PCR Master Mix, the total volume of 20 μL.2. Special amplification bands based on ISSR markers were obtained in 22 jujube materials.11 ISSR primers were selected in 100 primers of Columbia University, which has clear and rich polymorphism for amplification. Totally,80 polymorphic alleles were revealed, among which 50 bands were polymorphic, with an average of 7.21 for each primer, and the percentage of polymorphism was 68.75%.3. Similarity coefficients and UPGMA clustering dendrograms were obtained based on ISSR data. The ISSR similarity coefficients were ranged from 0.59 to 1.00, and divided the 22 materials into four groups with the 0.73 coefficient. 1-5with 15 to 17 is the first group, 6-14 is the second group,18 and 20 to 22 is the third group,19 were grouped separately.4. Variation of quantitative charaters were analyzed which showed that years before fruiting, tirtable acidity content ranked the top two with variation coefficients of 2.588, and 2.346, respectively, while ratio of edibility ranked the lowest with variation coefficients of 0.022. From 25 quantitative charaters, a total of 22 characters are extracted, they are divided into nine main components, combined contribution rate reached 71.869%. And the average of stone weight, vertical length of stone, vertical length of fruit, growing shoot length, cross length of leaf, growing shoot diameter and cross length of stone are contributed larger.5. Euclidean distances between 22 materials based on 22 quantitative charaeters and 17 qualitative charaeters were analyzed 3(the grafting tree of’Qishanmizao’) and 5(the tillering tree of’Changqiumizao’) showed smallest Euclidean distance of 1.039, while 5(the seeding tree of’Zhanshanmizao’) and 15(cultiva ’zhanhuadongzao’) showed biggest Euclidean distance of 4.589.The average Euclidean distance was 2.746. Clustering analysis were used by Ward’s method and the linkage between group method. Both of them are clustered 1-5,16 and 17 for the first group; and 6-14 for the forth group. Difference between two methods are 18,19 firstly to be a group and then 21 join, and the remaining 15,20,22 to be the third group in Ward’s method, while the linkage between group method is only gathered 18 and 19 for a group, as the rest are respectively gathered for a group.6. Comprehensive morphology clustering analysis and molecular clustering results showed that the two kinds of methods are very strong consistency, and only have a small difference that put 15 (’zhanhuadongzao’) to the first group which have large stone including 1-5,16 and 17, explained close relatives; separated the 18 (’tailihongzao’) and 19 (’fengmiguanzao’) and joined in 20 to 22 (’jinsixiaozao’,’hetianyuzao’,’junzao’) group. The results showed greater genetic differences in different materials. In addition, ’qishanmizao’ and ’changqiumizao’ should be the same germplasm, and ’zhanshanmizao’ is not of them which should be a new germplasm. In the population of ’zhanshanmizao", the three strains didn’t showed genetic difference, it may only happened environmental modification, not the nature of genetic differences.