Population genetic divergence in Lycium chinense Mill. (Solanaceae) is driven by both hybridization and geo-environmental factors

Abstract

The population genetic structure of plants is affected by both genetic and geo-environmental factors. Dissecting the relationship between these factors is important for conservation and breeding applications of plant natural resources. Lycium chinense Mill., is a perennial shrub long-term used as both medicinal herbs and vegetables. Here we investigated the population genetic variation and structure of L. chinense (including two varieties L. chinense var. chinense and L. chinense var. potaninii Pojark. A. M. Lu) and its closely related species Lycium barbarum L. using EST-SSR markers. We found a moderate level of genetic variation presented in the L. chinense populations, which was lower than that of L. barbarum. Both STRUCTURE and PCoA analyses showed that the variety of L. chinense var. potaninii samples was potentially hybrid derived with possible donor parents of L. chinense var. chinense and L. barbarum. We also found positive relationships presented between the genetic and geographical distance, as well as between the genetic distance and annual mean temperature in populations of L. chinense and in populations only from L. chinense var. chinense, suggesting potentially isolation by distance and isolation by adaptation effects. A core collection of L. chinense that included 37 accessions was finally constructed. Hybridization and introgression has affected genetic variation of L. chinense populations. The population genetic structure of L. chinense has been driven by both hybridization and geo-environmental factors. This genetic information and core collection will facilitate the conservation and breeding of L. chinense in future.