The Study Of Vigor And Genetic Integrity Of 3 Species Of Forage Seeds Under Different Aging Conditions

In order to prolong the self life of the forage grass seed, to improve and maintain the viability and genetic integrity, the study choose three kinds of forage seed, Aohan alfalfa, Xilinguole Bromus ciliatus and Mengnong sainfoin, as material. Using different aging methods (45℃, RH100% accelerated aging and natural aging) and ISSR Molecular Marker Technique and germination test method were used in this study. We analysised the germination rate, vigor index, genetic similar coefficient, percentage of polymorphic loci and explored the change of seed viability and genetic integrity under different aging state. Then provide the basis of the safety storage and reproduction of the germplasm resources. The main results were as follows:1. Under the condition of 45℃ and RH100%, the changes of viability and vigor of the seeds of three kinds of forage seeds varied with the aging time. The vigor of Xilinguole Bromus ciliatus, Aohan alfalfa and Mengnong sainfoin seed significantly decreased in aging of 108h,96h,48h, respectively,which also reflected the strength of aging resistance. In addition, the viability of three kinds forage seed significantly decreased later than vitality.2. The main factors influenced the safety of storage of Xilinguole Bromus ciliatus and Aohan alfalfa in the process of ageing were seed moisture content and storage temperature. According to the effects of seed moisture content, storage temperature and packaging materials on seed viability and genetic integrity, we determined the more safe and economic storage method of three kinds of forage seeds:Mengnong sainfoin and Xilinguole Bromus ciliatus seed were in 7-8% seed moisture content, with plastic zip lock bags, stored at-18℃. However, Aohan alfalfa was in 4-5% seed moisture content, with plastic zipper bag packaging, stored at 4℃.3. The map of ISSR marker showed that the DNA fragments were concentrated in the regions of high molecular weight and low molecular weight and DNA fragments color gradually became light, disappeared, or had specific DNA fragments. According to the variation of germination rate and genetic integrity, we could initially identified that the standard of germination percentage of three forage seeds were 82%,65% and 75%,respectively.