Landscape-Scale Genetic Structure of Wild Rice Zizania latifolia: The Roles of Rivers, Mountains and Fragmentation

Abstract

Wild rice (Zizania latifolia) is an important genetic resource and it has important ecological functions in aquatic ecosystems as well. Here, we used landscape genetics to investigate how the landscape features, including rivers, mountains and habitat fragmentation, affect the genetic connectivity or create dispersal barriers for Z. latifolia. In this report, seventeen populations from the Sanjiang Plain and its surrounding areas were genotyped by ten microsatellite markers. A high genetic differentiation and genetic discontinuity were found among populations within each river investigated, suggesting that the rivers be not acting as corridors for dispersal. Meanwhile, genetic discontinuity was detected from different sides of the Lesser Khingan and its branch, the Qinghei Mountains, demonstrating that gene flow was blocked by the complex topography of mountains. The results that historical gene flow was much higher than the contemporary gene flow might infer that recent habitat fragmentation resulted in decreased gene flow. For all sampled Z. latifolia populations, the result of low level of genetic variation (n a = 2.3, H E = 0.328) and high genetic divergence (F ST = 0.405, D est = 0.414 and Ø pt = 0.424) was consistent with the decreased gene flow, an inbreeding system and repeated genetic bottlenecks. A conservation strategy for protecting as many populations as possible to maximize genomic representation of the species is proposed. In addition, dredging the watercourses should be carried out to improve habitat stability and to facilitate connectivity among populations.

Species Boundaries Between Three Sympatric Oak Species: Quercus aliena, Q. dentata, and Q. variabilis at the Northern Edge of Their Distribution in China

“…A comparison of different models calculated by Migrate-n based on Bayesian factor values showed that model 2, with three population sizes and two migration rates (from Q. aliena to Q. dentata and from Q. dentata to Q. aliena ) was the best model for evaluating the historical gene flow (Chen et al, 2017 ) among the three oak species. This model verified the occurrence of bidirectional historical gene flow between Q. aliena and Q. dentata (Table 4 , Q. aliena → Q. dentata, M = 56.3; Q. dentata → Q. aliena, M = 57.0).…”

Morphological Characteristics, Nutrients, and Bioactive Compounds of Zizania latifolia, and Health Benefits of Its Seeds

“…Currently, it is rarely cultivated as a crop and mainly survives untended in the wild. It should be noted that Z. latifolia is prevalent throughout China, except in Xinjiang and Tibet, and grows in lakes, ponds, rivers, marshes, and the wetlands [ 6 , 7 ]. It is particularly abundant in the middle and lower Yangtze River basin and Huai River basin [ 5 , 25 , 26 ].…”

“…The reasons for the low genetic diversity of the latter include restricted gene flow among populations, self-fertilization as a mode of reproduction, and genetic drift within populations [ 6 ]. Rivers, mountains, and habitat fragmentation influence the landscape-scale genetic structure of Z. latifolia [ 7 ]. Molecular evidence indicates that Zizania species likely originated in North America, thereafter spreading to East Asia and other parts of the world via the Bering Strait [ 8 ].…”

Gene flow across host‐associated populations of the rice stem borer Chilo suppressalis Walker (Lepidoptera: Crambidae): implications for Bt resistance management in rice

“…Both rice and water oats are often planted next to each other as crops and given that water oats is larger than rice, < 10% land area would likely provide a 10% refuge by volume. In parts of China where water oats is not cultivated, the wild relative of water oats is often found in irrigation canals and ponds close to cultivated rice . Our results show that water oats growing near rice would likely provide suitable refuges for Bt resistance management of this serious rice pest, and structured refuges might be unnecessary.…”