Assessing Genetic Diversity and Population Structure of Prunus Davidiana From China Using Simple Sequence Repeat (SSR) Markers

Prunus davidiana, a wild species related to peach (Prunus persica L. Batsch), represents an important source of pest and disease resistance in peach breeding programs.  It is native to China, and in the Northern China it is used as rootstock for peach and nectarine and as a core germplasm source of new traits for peach improvement.  Distribution of P. davidiana in China has been investigated and several collecting trips were organized during past few years, and tissue samples from more than thirty accessions were collected from each natural population.  Genetic variation and population structure of P. davidiana populations was assessed using a set of microsatellite (SSR) markers selected from Prunus reference map.  A subset of 192 accessions representing seven populations collected from different environments from more than four Chinese provincial areas were assayed using 20 SSR markers evenly distributed throughout peach genome. All primer pairs produced amplification products in P. davidiana except for pchcms2.  Number of alleles observed ranged from 2 for CPPCT002 to 9 for UDP96-001 and UDP96-005, with average of 5.3.  Allele frequency per natural population ranged from 2.4 to 3.6 with average of 3.1.  The size range of the amplification product varied from 50 to 500bp.  Genetic diversity and population structure, as well as observed special alleles and their distribution will be discussed.  The obtained results should provide guidance for conservation and further utilization of P. davidiana germplasm.