Molecular Population Genetic Structure Of Puccinia Striiformis F. SP. Tritici In Tibet And C Migration Relation With Inland

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the mostimportant diseases of wheat in China. Due to Nyingchi of Tibet have special geographiclocation, so it is the main planting area of winter wheat, it is the most serious disease in Tibet.Study on diseases occurrence epidemic rule of wheat stripe rust, integrated control and so onhas been finished, but about molecule population genetic diversity and migration of P.striifornis f. sp. tritici between Tibet and inland are not study until now. Population geneticdiversity of the P. striiformis f. sp. tritici population containing259samples collected fromdifferent areas in Nyingchi was investigated with SSR technique. Compare and analysis therelation of population genetic structure between Tibet with Gansu, Shaanxi, Sichuan. Themain results are summarized as following.1. The results demonstrated that there were about12%of the total variations amongpopulations,88%of the total variation presented within populations, gene flow (Nm) was1.90among different populations, genetic diversity index was H=0.10，information indexI=0.17. The important conclusion is that the populations of P. striifornis f. sp. tritici wasrelatively low level of genetic diversity in Nyingchi of Tibet. There is an extensive gene flowamong the regions in Nyingchi. The main genetic variation presented mainly withinpopulations.2. Study on10populations molecule population genetic diversity and migration of P.striifornis f. sp. tritici between Tibet with inland, the results demonstrated that the geneticdiversity of Tianshui and Longnan populations in Gansu was much higher than that in otherregions. However, the genetic diversity of Southwest of Sichuan, Southeast of Sichuan andNyingchi populations was much lower than that in other regions. AMOVA of SSR resultsshowed that main genetic variation presented mainly within populations with Arlequinsoftware. Populations in inland had extensive gene exchange (Nm>4), and few geneexchange was found between Tibet and inland (Nm<1). Cluster analysis also indicated thatgenetic distance of P. striiformis f. sp. tritici between Tibet and inland was relatively far away, and genetic similarity was lower. The population of P. striiformis f. sp. tritici in Tibet may bea independent genetic population.