biology Article Increases in Genetic Diversity of Weedy Rice Associated with Ambient Temperatures and Limited Gene Flow Hua Kong 1,†, Zhi Wang 2,†, Jing-Yuan Guo 1, Qi-Yu Xia 1, Hui Zhao 1, Yu-Liang Zhang 1, An-Ping Guo 1,* and Bao-Rong Lu 2,* 1 Key Laboratory of Biology and Genetic Resources of Tropical Crops, Hainan Key Laboratory for Biosafety Monitoring and Molecular Breeding in Off-Season Reproduction Regions, Institute of Tropical Bioscience and Biotechnology, CATAS, Haikou 571101, China;
[email protected] (H.K.);
[email protected] (J.-Y.G.);
[email protected] (Q.-Y.X.);
[email protected] (H.Z.);
[email protected] (Y.-L.Z.) 2 Ministry of Education, Key Laboratory for Biodiversity Science and Ecological Engineering, Department of Ecology and Evolutionary Biology, Fudan University, Songhu Road 2005, Shanghai 200438, China;
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[email protected] (B.-R.L.) † These authors are equally contributed to the work. Simple Summary: Increased genetic diversity in plants is probably associated with greater ambient temperatures. To test this hypothesis, we studied genetic diversity and differentiation of weedy rice populations occurring in the early- and late-season rice cultivation fields in Leizhou of southern China. Data collected from 10-year climatic records showed a higher average temperature in the late rice-cultivation seasons than in the early rice-cultivation seasons. Results obtained based on 27 SSR (simple sequence repeat) loci indicated greater genetic diversity in the late-season weedy rice populations, in addition to the considerable genetic differentiation between the early- and late-season weedy rice populations.