Conservation and genetic diversity of populations of Oryza glumaepatula Steud. in ferruginous mountaintop lakes of the Brazilian Amazonia

To characterize the genetic variability among species and populations of South American wild rice, eleven populations of Oryza glumaepatula, seven of O. grandiglumis, four of O. latifolia and one of O. alta, from Brazil and Argentina, were evaluated. A greenhouse experiment was conducted in completely randomized blocks with 23 treatments. Twenty morphoagronomic traits were assessed. Univariate analyses were performed with 16 quantitative traits with the partitioning of populations within species. Significant differences (p<0.001) between species were observed for all the traits as well as among populations within the species. The most variable was O. glumaepatula followed by O. latifolia. Multivariate discriminant canonical and cluster analyses confirmed the separation of the highly diverse O. glumaepatula populations from the tetraploid species, and the high genetic variation among O. latifolia populations. Morphological differences among the three tetraploid species seemed to be enough to ascribe them at least the condition of species in statu nascendi.

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Genetic structure of Oryza glumaepatula wild rice populations and evidence of introgression from O. sativa in Costa Rica

10.7287/peerj.preprints.1095 ◽

2015 ◽

Author(s):

Eric J Fuchs ◽

Allan Meneses Martínez ◽

Amanda Calvo ◽

Melania Muñoz ◽

Griselda Arrieta-Espinoza

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Costa Rica ◽

Genetic Structure ◽

Wild Species ◽

Wild Rice ◽

Wild Rice Species ◽

Genetic Diversity And Structure ◽

Diversity Estimates ◽

Oryza Glumaepatula

Wild crop relatives are an important source of genetic diversity for crop improvement. However, gene flow from cultivated species into wild species may prove detrimental. Introgression may lead to changes in wild species by incorporating alleles from domesticated species, which may increase the likelihood of extinction. The objective of the present study is to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated if there is evidence of introgression between wild rice and commercial varieties of O. sativa since it is cultivated commonly in close proximity to wild rice populations. Individuals from all known O. glumaepatula populations in Costa Rica were collected. With the aid of 455 AFLP markers, we characterized the genetic diversity and structure among seven populations in northern Costa Rica. Given the dominant nature of our markers, Bayesian estimates of genetic structure were used. We also compared genetic diversity estimates between O. glumaepatula individuals and O. sativa commercial rice. Our results show that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. This is likely a result of large population size. Despite the restricted distributions of this wild species, in Costa Rica most populations are composed of several thousand individuals, thus reducing the effects of drift on genetic diversity. Our results also found low but significant structure (\theta=0.03±0.001) among populations that are separated by ~10 Km within a single river. The position of the population along the river did not influence genetic diversity estimates or differences among populations. This river does not have a strong current and meadows or seeds may easily move upstream, thus homogenizing genetic diversity across populations regardless of river position. Ample gene flow through pollen, seeds or detached culms within the same river reduces genetic structure. A Bayesian structure analysis showed that individuals from two populations share a significant proportion of their genomes with O. sativa genome. These results suggest that the low levels of genetic structure found in these populations are likely the result of introgression from cultivated O. sativa populations. These results expose an important biohazard as recurrent hybridization may reduce genetic diversity of this wild rice species. Introgression may transfer commercial traits into the only populations of O. glumaepatula in Costa Rica, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica.

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Genetic structure of Oryza glumaepatula wild rice populations and evidence of introgression from O. sativa in Costa Rica

10.7287/peerj.preprints.1095v1 ◽

2015 ◽

Cited By ~ 1

Author(s):

Eric J Fuchs ◽

Allan Meneses Martínez ◽

Amanda Calvo ◽

Melania Muñoz ◽

Griselda Arrieta-Espinoza

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Costa Rica ◽

Genetic Structure ◽

Wild Species ◽

Wild Rice ◽

Wild Rice Species ◽

Genetic Diversity And Structure ◽

Diversity Estimates ◽

Oryza Glumaepatula

Wild crop relatives are an important source of genetic diversity for crop improvement. However, gene flow from cultivated species into wild species may prove detrimental. Introgression may lead to changes in wild species by incorporating alleles from domesticated species, which may increase the likelihood of extinction. The objective of the present study is to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated if there is evidence of introgression between wild rice and commercial varieties of O. sativa since it is cultivated commonly in close proximity to wild rice populations. Individuals from all known O. glumaepatula populations in Costa Rica were collected. With the aid of 455 AFLP markers, we characterized the genetic diversity and structure among seven populations in northern Costa Rica. Given the dominant nature of our markers, Bayesian estimates of genetic structure were used. We also compared genetic diversity estimates between O. glumaepatula individuals and O. sativa commercial rice. Our results show that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. This is likely a result of large population size. Despite the restricted distributions of this wild species, in Costa Rica most populations are composed of several thousand individuals, thus reducing the effects of drift on genetic diversity. Our results also found low but significant structure (\theta=0.03±0.001) among populations that are separated by ~10 Km within a single river. The position of the population along the river did not influence genetic diversity estimates or differences among populations. This river does not have a strong current and meadows or seeds may easily move upstream, thus homogenizing genetic diversity across populations regardless of river position. Ample gene flow through pollen, seeds or detached culms within the same river reduces genetic structure. A Bayesian structure analysis showed that individuals from two populations share a significant proportion of their genomes with O. sativa genome. These results suggest that the low levels of genetic structure found in these populations are likely the result of introgression from cultivated O. sativa populations. These results expose an important biohazard as recurrent hybridization may reduce genetic diversity of this wild rice species. Introgression may transfer commercial traits into the only populations of O. glumaepatula in Costa Rica, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica.

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Highly structured genetic diversity of Bixa orellana var. urucurana, the wild ancestor of annatto, in Brazilian Amazonia

PLoS ONE ◽

10.1371/journal.pone.0198593 ◽

2018 ◽

Vol 13 (6) ◽

pp. e0198593 ◽

Cited By ~ 4

Author(s):

Gabriel Dequigiovanni ◽

Santiago Linorio Ferreyra Ramos ◽

Alessandro Alves-Pereira ◽

Eliane Gomes Fabri ◽

Doriane Picanço-Rodrigues ◽

...

Keyword(s):

Genetic Diversity ◽

Bixa Orellana ◽

Brazilian Amazonia ◽

Wild Ancestor

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Assessing the genetic structure of Oryza glumaepatula populations with isozyme markers

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132008000500001 ◽

2008 ◽

Vol 51 (5) ◽

pp. 873-882 ◽

Cited By ~ 4

Author(s):

Elizabeth Ann Veasey ◽

Daruska Cardin ◽

Rainério Meireles Silva ◽

Eduardo de Andrade Bressan ◽

Roland Vencovsky

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Genetic Differentiation ◽

Mating System ◽

Outcrossing Rate ◽

Structure Parameters ◽

Mato Grosso ◽

Isozyme Markers ◽

Self Fertilization ◽

Oryza Glumaepatula

To assess the genetic diversity and genetic structure parameters, nine populations of Oryza glumaepatula from the Amazon biome, four from the Pantanal biome, and one collected at Rio Xingu, Mato Grosso, totaling 14 populations and 333 individuals were studied with isozyme markers. Six loci were evaluated showing a moderate allozyme variability (A = 1.21, P = 20.7%, Ho = 0.005, He = 0.060). The populations from the Pantanal biome showed higher diversity levels than the Amazon biome. High genetic differentiation among the populations, expected for self-fertilizing species, was observed (F ST=0.763), with lower differentiation found among the Pantanal populations (F ST=0.501). The average apparent outcrossing rate was higher for the Pantanal populations (t a = 0.092) than for the Amazonian populations (t a = 0.003), while the average for the 14 populations was 0.047, in accordance with a self-fertilization mating system.

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