Changes in barley (Hordeum vulgare L. subsp. vulgare) genetic diversity and structure in Jordan over a period of 31 years

2017 ◽  
Vol 16 (2) ◽  
pp. 112-126 ◽  
Author(s):  
I. Thormann ◽  
P. Reeves ◽  
S. Thumm ◽  
A. Reilley ◽  
J. M. M. Engels ◽  
...  

AbstractIn many regions of the world, the cultivation of landraces is still common, in particular in centres of crop diversity. Significant effort has been put into ex situ conservation of landraces but limited data exist on the changes in genetic diversity that occur over time in farmers’ fields. We assessed temporal changes in barley landrace diversity in Jordan using seed samples collected in 1981 and 2012 from the same locations. We did not observe significant changes in the amount of genetic diversity, but samples collected in 2012 were more homogenous and less locally distinct. In two sites, we observed replacement of the old material. We observed a change in phenotype, and phenotypes were found to be more homogeneous among sites in 2012. Climate changed significantly over the study period, becoming hotter and dryer, but we did not identify any correlation between the changes in climate and genetic and phenotypic variations. While the amount of genetic diversity in terms of allelic richness and number of multi-locus genotypes has been maintained, local distinctiveness among landrace barley populations in Jordan was reduced.

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245965
Author(s):  
Catherine Kiwuka ◽  
Eva Goudsmit ◽  
Rémi Tournebize ◽  
Sinara Oliveira de Aquino ◽  
Jacob C. Douma ◽  
...  

Wild genetic resources and their ability to adapt to environmental change are critically important in light of the projected climate change, while constituting the foundation of agricultural sustainability. To address the expected negative effects of climate change on Robusta coffee trees (Coffea canephora), collecting missions were conducted to explore its current native distribution in Uganda over a broad climatic range. Wild material from seven forests could thus be collected. We used 19 microsatellite (SSR) markers to assess genetic diversity and structure of this material as well as material from two ex-situ collections and a feral population. The Ugandan C. canephora diversity was then positioned relative to the species’ global diversity structure. Twenty-two climatic variables were used to explore variations in climatic zones across the sampled forests. Overall, Uganda’s native C. canephora diversity differs from other known genetic groups of this species. In northwestern (NW) Uganda, four distinct genetic clusters were distinguished being from Zoka, Budongo, Itwara and Kibale forests A large southern-central (SC) cluster included Malabigambo, Mabira, and Kalangala forest accessions, as well as feral and cultivated accessions, suggesting similarity in genetic origin and strong gene flow between wild and cultivated compartments. We also confirmed the introduction of Congolese varieties into the SC region where most Robusta coffee production takes place. Identified populations occurred in divergent environmental conditions and 12 environmental variables significantly explained 16.3% of the total allelic variation across populations. The substantial genetic variation within and between Ugandan populations with different climatic envelopes might contain adaptive diversity to cope with climate change. The accessions that we collected have substantially enriched the diversity hosted in the Ugandan collections and thus contribute to ex situ conservation of this vital genetic resource. However, there is an urgent need to develop strategies to enhance complementary in-situ conservation of Coffea canephora in native forests in northwestern Uganda.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247586
Author(s):  
Christine E. Edwards ◽  
Brooke C. Tessier ◽  
Joel F. Swift ◽  
Burgund Bassüner ◽  
Alexander G. Linan ◽  
...  

Understanding genetic diversity and structure in a rare species is critical for prioritizing both in situ and ex situ conservation efforts. One such rare species is Physaria filiformis (Brassicaceae), a threatened, winter annual plant species. The species has a naturally fragmented distribution, occupying three different soil types spread across four disjunct geographical locations in Missouri and Arkansas. The goals of this study were to understand: (1) whether factors associated with fragmentation and small population size (i.e., inbreeding, genetic drift or genetic bottlenecks) have reduced levels of genetic diversity, (2) how genetic variation is structured and which factors have influenced genetic structure, and (3) how much extant genetic variation of P. filiformis is currently publicly protected and the implications for the development of conservation strategies to protect its genetic diversity. Using 16 microsatellite markers, we genotyped individuals from 20 populations of P. filiformis from across its geographical range and one population of Physaria gracilis for comparison and analyzed genetic diversity and structure. Populations of P. filiformis showed comparable levels of genetic diversity to its congener, except a single population in northwest Arkansas showed evidence of a genetic bottleneck and two populations in the Ouachita Mountains of Arkansas showed lower genetic variation, consistent with genetic drift. Populations showed isolation by distance, indicating that migration is geographically limited, and analyses of genetic structure grouped individuals into seven geographically structured genetic clusters, with geographic location/spatial separation showing a strong influence on genetic structure. At least one population is protected for all genetic clusters except one in north-central Arkansas, which should therefore be prioritized for protection. Populations in the Ouachita Mountains were genetically divergent from the rest of P. filiformis; future morphological analyses are needed to identify whether it merits recognition as a new, extremely rare species.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255418
Author(s):  
Siou Ting Gan ◽  
Chin Jit Teo ◽  
Shobana Manirasa ◽  
Wei Chee Wong ◽  
Choo Kien Wong

Oil palm (Elaeis guineensis) germplasm is exclusively maintained as ex situ living collections in the field for genetic conservation and evaluation. However, this is not for long term and the maintenance of field genebanks is expensive and challenging. Large area of land is required and the germplasms are exposed to extreme weather conditions and casualty from pests and diseases. By using 107 SSR markers, this study aimed to examine the genetic diversity and relatedness of 186 palms from a Nigerian-based oil palm germplasm and to identify core collection for conservation. On average, 8.67 alleles per SSR locus were scored with average effective number of alleles per population ranging from 1.96 to 3.34 and private alleles were detected in all populations. Mean expected heterozygosity was 0.576 ranging from 0.437 to 0.661 and the Wright’s fixation index calculated was -0.110. Overall moderate genetic differentiation among populations was detected (mean pairwise population FST = 0.120, gene flow Nm = 1.117 and Nei’s genetic distance = 0.466) and this was further confirmed by AMOVA analysis. UPGMA dendogram and Bayesian structure analysis concomitantly clustered the 12 populations into eight genetic groups. The best core collection assembled by Core Hunter ver. 3.2.1 consisted of 58 palms accounting for 31.2% of the original population, which was a smaller core set than using PowerCore 1.0. This core set attained perfect allelic coverage with good representation, high genetic distance between entries, and maintained genetic diversity and structure of the germplasm. This study reported the first molecular characterization and validation of core collections for oil palm field genebank. The established core collection via molecular approach, which captures maximum genetic diversity with minimum redundancy, would allow effective use of genetic resources for introgression and for sustainable oil palm germplasm conservation. The way forward to efficiently conserve the field genebanks into next generation without losing their diversity was further discussed.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10521
Author(s):  
Núria Garcia-Jacas ◽  
Jèssica Requena ◽  
Sergi Massó ◽  
Roser Vilatersana ◽  
Cèsar Blanché ◽  
...  

Seseli farrenyi (Apiaceae) is an extremely narrow endemic plant, which is considered as one of the species of most conservation concern in Catalonia (NW Mediterranean Basin). Given the accelerated fragmentation and reduction of population size (of over 90%), the environmental agency of Catalonia is currently preparing a recovery plan that includes reinforcements of the extant populations. The present study is aimed at providing the necessary knowledge to carry out genetically-informed translocations, by using microsatellites as genetic markers. Fourteen microsatellites have been specifically developed for S. farrenyi, of which nine have been used. Besides the extant natural populations, the three ex situ collections that are known to exist of this species have also been studied, as they would be the donor sources for translocation activities. Our main finding is that levels of genetic diversity in the natural populations of S. farrenyi are still high (He = 0.605), most likely as a result of a predominantly outcrossing mating system in combination with the limited time elapsed since the population decline. However, population fragmentation is showing the first genetic signs, as the values of genetic differentiation are relatively high, and two well-differentiated genetic lineages have been found even in such a narrow geographic range. These genetic results provide important information when designing conservation management measures.


Botany ◽  
2014 ◽  
Vol 92 (8) ◽  
pp. 579-587 ◽  
Author(s):  
Zhi-Yun Yang ◽  
Ting-Shuang Yi ◽  
Liang-Qin Zeng ◽  
Xun Gong

Aristolochia delavayi Franch. is an endangered species of the dry hot valleys of the Jinsha River, southwestern China. The genetic diversity and structure of the species and the occurrence of gene flow were investigated with eight inter-simple sequence repeat (ISSR) markers and four plastid loci (matK, trnL-trnT, rps4-trnT, and trnC-rpoB). The analysis of ISSR markers indicated that the genetic diversity of the species is relatively high (PPB = 84.71%). Similarly, a high gene diversity of HT = 0.833 was found based on the four plastid loci. It is possible that this species previously maintained a large effective population size and that the current relict distribution of the species is a result of large-scale fragmentation and habitat destruction. The origin of the species at approximately 3.407 million years ago and the ensuing intraspecific divergence are generally consistent with the history of two major glaciations in this region. Conservation measures are urgently needed to increase the genetic diversity and population size of this species through both in- and ex-situ action.


2021 ◽  
Author(s):  
Allo Aman Dido ◽  
B.J.K. Singh ◽  
Ermias Assefa ◽  
M.S.R. Kr ◽  
Dawit Degefu ◽  
...  

Abstract Characterization of genetic resources maintained at genebanks has important implications for future utilization and collection activities. A total of 49 simple sequence repeat (SSR) or microsatellite markers were used to study genetic diversity and relationships among 376 barley landraces collected from different barley producing parts of Ethiopia and eight cultivars. Overall, 478 alleles with an average of 9.755 alleles per locus were obtained of which 97.07% of the loci were observed to be polymorphic. Nei’s genetic diversity index (h) was 0.654, and the Shannon diversity index (I) was 0.647, indicating that the genetic diversity in barley genotypes studies was moderately high. At the population level, the percentage of polymorphic loci (PPL) averaged 98.37%, h = averaged 0.388, and I = averaged 0.568. The highest level of genetic diversity was observed in the AR population (PPL =100%, h = 0.439, I = 0.624); the lowest was observed in the JM population (PPL = 75.51%, h = 0.291, I =0.430). AMOVA revealed significant genetic differentiation within and between populations (P < 0.001), with 84.21% of the variation occurring within populations and 15.79% occurring among populations. Genetic variation analysis showed a coefficient of gene differentiation of 0.053 and a gene flow value of 4.467 among populations. The 384 barley genotypes were divided into seven genetic clusters according to STRUCTURE, Neighbour joining tree and principal coordinate analysis, correlating significantly with geographic distribution. These results will assist with the formulation of conservation strategies, such as genetic rescue and on-farm in situ and ex situ conservation.


2019 ◽  
Vol 47 (122) ◽  
Author(s):  
Murilo da Serra Silva ◽  
José Cambuim ◽  
Thaysa Yuriko Kuboyama Kubota ◽  
Silvelise Pupin ◽  
Rafael Moyses Alves ◽  
...  

Crustaceana ◽  
2015 ◽  
Vol 88 (1) ◽  
pp. 1-17
Author(s):  
Xiaoying Li ◽  
Zhiguo Dong ◽  
Hongbo Su ◽  
Qingqi Zhang ◽  
Huan Gao ◽  
...  

Using fluorescent AFLP-markers, the genetic diversity and structure of six geographical populations of the swimming crab,Portunus trituberculatus(Miers, 1876), from the coast of China were analysed to assess their genetic resource state. Eight primer combinations generated 925 loci among 85 individuals, and revealed a high polymorphism within these populations that varied from 57.41% (Zhoushan population) to 76.86% (Dalian population). According to the combination of percentage of polymorphic loci (PPL) and Shannon’s information index (I), the populations from Zhangzhou, Dongying and Dalian showed more genetic variation than the Lianyungang, Zhanjiang and Zhoushan populations. The gene flow () and across all populations overall were 1.935 and 0.205, respectively, showing moderate genetic differentiation. Differentiation was highest in the Zhoushan and Zhanjiang populations, and the geographical distribution and UPGMA cluster tree were not fully accordant. Neutrality test results revealed that the Zhangzhou population faced a smaller selective pressure than the other five populations (). In general, a high genetic diversity among theP. trituberculatuspopulations was observed along the coast of China, especially in the Zhangzhou, Dongying, Dalian and Lianyungang populations, while a pronounced level () of genetic differentiation has occurred between the Zhoushan population and the other populations. Therefore, these findings have the following implications for conservation and genetic improvement: (1) high diversity levels and good genetic resources, especially in the Zhangzhou population, which could lay the foundations for breeding research and genetic improvement; (2) the importance of preventing species escape and gene pool contamination in ex-situ conservation and species introduction programs in the Zhoushan population.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 256
Author(s):  
Aida Dervishi ◽  
Jernej Jakše ◽  
Hairi Ismaili ◽  
Branka Javornik ◽  
Nataša Štajner

Olive is considered one of the oldest and the most important cultivated fruit trees in Albania. In the present study, the genetic diversity and structure of Albanian olive germplasm is represented by a set of 194 olive genotypes collected in-situ in their natural ecosystems and in the ex-situ collection. The study was conducted using 26 microsatellite markers (14 genomic SSR and 12 Expressed Sequence Tag microsatellites). The identity analysis revealed 183 unique genotypes. Genetic distance-based and model-based Bayesian analyses were used to investigate the genetic diversity, relatedness, and the partitioning of the genetic variability among the Albanian olive germplasm. The genetic distance-based analysis grouped olives into 12 clusters, with an average similarity of 50.9%. Albanian native olives clustered in one main group separated from introduced foreign cultivars, which was also supported by Principal Coordinate Analysis (PCoA) and model-based methods. A core collection of 57 genotypes representing all allelic richness found in Albanian germplasm was developed for the first time. Herein, we report the first extended genetic characterization and structure of olive germplasm in Albania. The findings suggest that Albanian olive germplasm is a unique gene pool and provides an interesting genetic basis for breeding programs.


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