J Syst Evol ›› 2015, Vol. 53 ›› Issue (4): 330-338.DOI: 10.1111/jse.12152

• Research Articles • Previous Articles     Next Articles

Genetic divergence of weedy rice populations associated with their geographic location and coexisting conspecific crop: Implications on adaptive evolution of agricultural weeds

Zhuo-Jun Song1, Zhe Wang1, Yang Feng1, Nan Yao1,2, Ji Yang1, and Bao-Rong Lu1*   

  1. 1Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Shanghai 200433, China
    2School of Life Science, Chongqing University, Chongqing 401331, China
  • Received:2015-01-04 Published:2015-04-15

Abstract: Weedy rice, the same biological species of cultivated rice, is a noxious weed that infests rice fields worldwide. To determine the genetic diversity, structure, and relationships of weedy rice in China, we applied insertion/deletion (InDel) molecular fingerprints to analyze weedy rice populations from northeastern to southern rice planting regions, using japonica and indica rice cultivars as references. The InDel fingerprints indicated relatively high overall genetic diversity (He = 0.42) for the 240 samples from 14 weedy rice populations. However, much lower within-population diversity was detected, particularly for populations from northeastern and southern China, with the He value ranging from 0.006 to 0.06. Jiangsu populations showed much higher within-population genetic diversity (He = 0.12–0.31) than those from other regions. Analysis of molecular variance and Fst showed ∼88% genetic variation among weedy rice populations. Principal component and structure analyses indicated substantial japonica–indica genetic differentiation of weedy rice populations. Weedy rice from Jiangsu province was undergoing indica–japonicadifferentiation even within populations, which was likely due to the replacement of indica by japonica rice varieties in this region. In conclusion, significant genetic divergence has taken place among weedy rice populations in China, which is associated with their geographic locations and coexisting rice varieties. Introgression from cultivated rice has a critical role in shaping the genetic diversity and structure of weedy rice populations in agro-ecosystems influenced by humans.

Key words: adaptive evolution, agro-ecosystem, genetic differentiation, introgression, molecular markers, weed