Effect Of Regeneration Population Size And Seed Aging On Genetic Integrity In Tobacco

Tobacco germplasm resoureces are mainly kept by storying seeds in low tempetature, the life ofgermplasm resources could be prolonged, but this can’t stop the change of the genetic integrity. Theseeds aging to a certain degree need regeneration, and the population size is the primary factor. It is ofgreat significance for genetic integrity to study the effect of different population size and seed ageing.N.tabacum germplasm including Honghuadajinyuan, Wankouhongtuyan, Baihuaheiyan, Yunyan87,Heiguzhong and wild tobacco germplasm N.alata were used as materials in this study. The geneticintegrity of different populations was investigated by SSR with constructing mixed DNA pool. Afteraging more tobacco germinations which were selected randomly, we determined the germination rate.The genetic integrity of wild tobacco germplasm N.alata populations having different germinationlevels and Honghuadajinyuan, Wankouhongtuyan kept for different years were analyzed by SSRmarkers. The main results:(1) By scanning the whole-genome, none of polymorphic SSR primers was screened from960SSRprimer pairs of Honghuadajinyuan, Wankouhongtuyan and Baihuaheiyan, but3polymorphic SSRprimers were detected between Yunyan87and Heiguzhong.5,10,20,30plants were selected randomlyfrom80plants of Yunyan87, and5,10,20,30,60plants were selected randomly from96plants ofHeiguzhong, the increase degree of genetic diversity parameters which caused by the increasing ofpopulations is different. Considering the genetic diversity parameters and UPGMA cluster analysisentirely, the population greater than or equal to10plants can represent the genetic integrity ofN.tabacum germplasm.(2) With the scanning of whole-genome,11pairs of primers were selected from the608pairs toanalyze N.alata.5,10,20,30,60plants were selected randomly from96plants of N.alata, the increasedegree of genetic diversity parameters which caused by the increasing of populations is different.Considering the genetic diversity parameters and UPGMA cluster analysis entirely, a sample of no lessthan20plants should represent the genetic integrity of the population.(3) By aging more tobacco germplasms resources stored in genebank, it could be found that withthe extension of aging time, the germination rate of different varieties were reducing differently.(4) Effects of seed artificial aging on genetic integrity in N.alata population having differentgermination levels were analyzed by SSR. It showed that the genetic diversity index of artificially agedpopulation were lower than CK population. The germination rate of regeneration standard should not bebelow50%. SSR markers can be used as a method to research genetic integrity of tobacco agedpopulation, and a low germination percentage standard is disadvantageous for maintaining the geneticintegrity of germplasm resources.(5) Genetic integrity of Honghuadajinyuan and Wankouhongtuyan kept for different years wereanalyzed by SSR, It showed that there was no hereditary difference.