The Preliminary Selection Of The Salt-tolerant Superior Clones Of Robinia Pseudoacacia And AFLP Analysis Of Genetic Diversity

The Salt-tolerance superior clones of Robinia pseudoacacia is selected in accordance with selection program and the method of selected breeding ,through field investigation, review and registration approaches the Yellow river delta ,the excellent variant plants are selected to conduct the multiple generation propagation by root cutting nursery, the 3 test forest is built at Guangbei farm ,Dongying City, Shandong Province ,Dawenliu test land of Yellow River delta protection zone and high and new technology industrial development zone in Tai'an City, measure the performance index and conduct multiple comparisons to reselect the salt-tolerance superior clones and eventually select 10 salt-tolerant clones: W009, W055, W006, C006, W038, C003, Z012, C045 , C043, C047, using the 10 selected superior clones to constuct the example forest of the Robinia pseudoacacia at the saline and alkaline land by the sea in the Yellow River delta coastal shelterbelt.Use the selected clones planted in pots to conduct salt-resistant test, comprehensively evaluate the resistant capacity to salt of the selected clones the results shows that: different salt stress has different effect on the physiological and biochemical indexes of the clones , the stress under 7g/L alkaline salt and mixed salt results into a damage on the physiological and biochemical index of each clone to the maximum degree, the average rank for the degree of injure is that W037> Shilin> W013> W041> W009> W038> C003, the order of salt tolerance of the clones is: C003> W038> W009>W041> W013>Shilin > W037.the differences of the salt tolerance between W038, W009, C003 is minimal, except in 7g/L alkaline salt stress ,the most obvious symptoms of which under salt stress, emerged later and relatively in small numbers than others, showing highest resistant capacity to salt and alkali, W013,W041 take the second place ,Shilin and W037 is poorest ,which is identical with the performance in the test forest at the saline-alkali land, the evaluation on the resistant character to salt and alkali can provide a consult to that of other clones.The next, put emphasis on the survey of the growing conditions of each clone in the experimental forest in saline land,determine the dynamic changes of soil salinity in the test woodland, salt tolerance to determine the salt -tolerance scope of each clone in the field.Utilize the AFLP molecular marker technology to conduct the in-depth research into the genetic diversity the selected 30 clones of robinia(20 as excellent salt-tolerent clones,10 as poor-growth clones), measure genetic diversity with the purpose of researching into the genetic variation of 30 excellent robinia clones and providing a molecular basis for the identification of the selected clones , From 64 pairs of EcoRI / MseI primers, 9 pairs of primers are selected with the highly polymorphic and clear stripes, these 9- pair primer combinations produce a total of 1944 strips, among which there are 1076 polymorphic strips , accounted for 52.26% the average polymorphism percentage is 55.35% indicating a higher overall polymorphismThe quantity of specific loci generated by different primer combination is diverse, non-specific loci is generated by only one clone, the remaining 29 clones all generate specific loci accounting for 96.67% of all clones, with 213 single strips and 11 absent strips, totally 224 specific strips. the number of the alleles observed is between 1.4120 -1.7500, averaging1.5514, the number of effective alleles is between 1.1795-1.2678, averaging 1.2275, the Nei's genetic diversity index is between 0.1109-0.1780, av eraging 0.1425, the Shannon information index is between 0.1736-0.2890, averaging 0.2237, the genetic diversity level of the 30 selected clones is slightly lower than average genetic diversity level of woody plants and identical with that of the Robinia in china. the similarity between clones is 0.14-0.74, averaging 0.54, indicating that the large genetic differences and complex genetic relationship between the clones,the similarity coefficient between C4 and C19 is a minimum of 0.14, indicating that the largest genetic differences and most distant genetic relationship between 2 clones, the similarity coefficient between C4 and C19 is with a maximum of 0.74, indicating that the smallest genetic differences and most closest genetic relationship between 2 clones, in the threshold of 0.47, the 30 black locust clones could be divided into 3 categories; the research formulates a DNA fingerprinting figure with 29 specific single strips under 3 pairs of primers of 20 superior salt-tolerant and 10 poor-performance clones.Comprehend the superior clone selection , salt-toleracne test and analysis of genetic diversity to evaluated 10 selected clones, the results shows that: the average growth of each clone in test forest is higher than the overall average, each clone belong to different categorieswith high salt-tolerance, the number of specific loci is 2-14, each clone has a large genetic differences.