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1.
Xiao-Lan Wang Tzen-Yuh Chiang Nicolas Roux Gang Hao Xue-Jun Ge 《Genetic Resources and Crop Evolution》2007,54(5):1125-1132
Wild banana Musa balbisiana Colla is one of the progenitors of cultivated bananas and plantains. It is native to Southeast Asia and the western Pacific.
South China represents the northern limit of its distribution range. The genetic diversity of Musa balbisiana was assessed by the amplified fragment length polymorphism (AFLP) fingerprinting in 15 populations of China. Four primer
pairs produced 199 discernible loci. High levels of genetic diversity were detected, with P = 78.5%, H
E = 0.241, and H
pop = 0.3684 at population level, and P = 100%, H
T = 0.3362 and H
sp = 0.5048 at species level. Significant genetic differentiation among populations was detected based on Hickory’s analysis
(27.6%), Shannon’s diversity index (27.0%) and AMOVA (27.1%). The AFLP results are discussed and compared with data obtained
by microsatellites method. The estimates of genetic diversity and differentiation between each pair of populations computed
with microsatellites and AFLP markers were not significantly correlated. Conservation strategies for Musa balbisiana in China are proposed. 相似文献
2.
Shao-Qing Tang Xiao-Yun Bin Yun-Tao Peng Jun-Ya Zhou Li Wang Yang Zhong 《Genetic Resources and Crop Evolution》2007,54(5):1053-1061
Genetic variation of wild populations and cultivars of Luohanguo (Siraitia grosvenorii), a plant species endemic to southern China, was assessed using random amplified polymorphic DNA (RAPD) and amplified fragment
length polymorphism (AFLP) markers. Based on the results for 130 individuals from seven populations, a high level of genetic
diversity of Luohanguo was observed at the species level. The percentage of polymorphic loci (P) was 89.4%, Nei’s gene diversity (H
e) was 0.239, and Shannon’s information index (H
o) was 0.373 based on the combined AFLP and RAPD data. There was a high degree of genetic differentiation, with 45.1% of the
genetic variation attributed to differences between the populations. The genetic diversity of the Luohanguo cultivars is much
lower than that of wild populations (P = 41.8%, H
e = 0.141, H
o = 0.211), and a distinct genetic differentiation is observed between the cultivars and wild accessions. The pool of genetic
variation in the wild populations provides an excellent gene resource for Luohanguo breeding. 相似文献
3.
M. A. Islam A. Meister V. Schubert K. Kloppstech E. Esch 《Genetic Resources and Crop Evolution》2007,54(1):149-156
Curcuma zedoaria populations comprise 2n = 63 chromosomes with three satellite chromosomes showing elongated secondary constrictions. Flow
cytometry results inferred that the 2C nuclear DNA values varied between the populations. The largest genome size was found
in the population Chittagong (mean 3.37 pg) and the lowest in the Birganj population (mean 3.15 pg). RAPD based estimations
of genetic diversity revealed that hilly populations maintain higher genetic diversity, which was also found to be distinct
from plainland and plateauland populations. Genome sizes and genetic diversity values of the populations were positively correlated. 相似文献
4.
In the UK, Euphydryas aurinia exists in fragmented habitat patches, and undergoes population fluctuations as a result of a larval parasitoid. Its range is declining in the UK and conservation is thought to require a landscape approach since populations spread over large areas in some years and contract to core breeding patches in others. We examined populations at a range of geographic scales using allozyme electrophoresis to look for evidence of gene flow and differences in genetic diversity among populations. Nationally, our FST value was 0.1542 but between population groups within the suspected colonisation range of the butterfly (ca. 20 km), FST values were not significantly different from zero. Genetic diversity in terms of number of alleles and heterozygosity was reasonably high in natural populations (He=0.267) but low in an introduced, isolated population. We infer that migration between closely spaced subpopulations (in a metapopulation) maintains a high genetic effective population size (large number of individuals in a population that contribute genes to the next generation) which offsets any local reductions in population numbers due to stochastic extinctions or parasitoid effects. We therefore conclude that effective conservation of the species must seek to provide networks of suitable habitat for groups of subpopulations, rather than maintaining habitat for isolated populations. 相似文献
5.
Andrea Coppi Lorenzo Cecchi Federico Selvi Mauro Raffaelli 《Genetic Resources and Crop Evolution》2010,57(7):1041-1052
DNA sequences from the ITS region of the nuclear genome and Inter-Simple Sequence Repeat markers (ISSR) were used to estimate
genetic diversity among and within populations of the Frankincense tree Boswellia sacra from Dhofar, Oman. This is a culturally and ecologically relevant species that is showing symptoms of decline due to anthropic
factors and, possibly, global warming. ITS sequences were 511 bp long and showed low (6.4%) variation among geographically
different populations. The four selected ISSR primers yielded 93 reproducible bands, of which 91 (97.9%) were polymorphic
in the 97 individual profiles obtained. Total genetic diversity (H
T) and average heterozygosity within populations (H
S) resulted fairly low (0.22 and 0.136, respectively). The accession from Wadi Dowkah, an UNESCO world heritage site, showed
the lowest level of genetic diversity (H
E = 0.107), while the eastern populations from the Hasik area harboured a slightly greater amount of variation. Analysis of
Molecular Variance showed that differentiation among populations was relatively high (38.1%), possibly due to the reduced
gene flow between the largely isolated stands of Boswellia (N
m = 0.39). Genetic distances and AMOVA suggested a clear differentiation between the eastern and western coastal populations,
while those from the internal area did not form a consistent group. For conservation, the eastern sites should be given priority
as core populations harbouring significant amounts of allelic diversity. Reasons for reinforcing the more depauperated stands,
such as Wadi Dowkah, with local plant material only or, alternatively, with the introduction of germplasm from genetically
distinct stands are discussed. 相似文献
6.
There is a need to understand whether weed genetic diversity is the same among different populations, especially between those
exposed to herbicide selection and other without exposure history. Inter-simple sequence repeat (ISSR) were used to assess
level and patterns of genetic diversity in wild Brassica juncea (L.) Czern. et Coss. populations. A total of 93 plants from 24 wild populations in China were analysed by eight primers resulting
in 86 highly reproducible ISSR bands. The analysis of molecular variance (AMOVA) with distances among individuals corrected
for the dominant nature of ISSRs showed that most of the variation (54.09%) occurred among populations, and the remaining
45.91% variance was attributed to differences among individuals within populations. The high differentiation was, perhaps,
due to limited gene flow (Nm < 1.0) of this species. Though highest gene diversity was observed in resistant B. juncea population, the overall distribution of diversity across China was not geographic dependent. High F
ST value (0.541) corroborated AMOVA partitioning and provided significant evidence for population differentiation in wild B. juncea. UPGMA cluster analyses, based on Nei’s genetic distance, revealed grouping pattern geographically. Based on these results,
the factors affect weed population genetic diversity and implication for herbicide resistance evolution were discussed in
the context of transgenic crops advent and increasing herbicide usage in China. 相似文献
7.
Miao-Miao Li Yu-Liang Cai Zeng-Qiang Qian Gui-Fang Zhao 《Genetic Resources and Crop Evolution》2009,56(4):455-464
In this study, the genetic diversity and differentiation of 10 natural Prunus pseudocerasus Lindl. populations were investigated using inter-simple sequence repeat (ISSR) markers. Totally, 18 selected primers generated
150 loci, with an average of 8.33 bands per primer. The results showed that the percentage of polymorphic bands (PPB) was pretty low at the population level (PPB = 1.13–32%), but relatively high at the species level (PPB = 84%). Besides, a high level of genetic differentiation among populations was detected based on the gene differentiation
coefficient (G
ST = 0.7118) and the hierarchical analysis of molecular variance (AMOVA) (Φ
ST = 64.53%, P < 0.001), in line with the low inter-population gene flow (N
m = 0.2025). Moreover, Mantel test revealed a significant correlation between genetic and geographic distances among the populations
(r = 0.5272, P < 0.005). The high level of intraspecific genetic diversity was probably related with its life history traits, while its
small population size and the resultant high levels of genetic drift and inbreeding might explain the low genetic diversity
within populations. The relatively high inter-population genetic differentiation was largely attributed to its small population
size, habitat fragmentation, the mode of pollen and seed dispersal, and geographic isolation. Based on the present study,
conservation strategies were proposed to preserve this valuable natural germplasm resource. 相似文献
8.
Tileye Feyissa Hilde Nybom Igor V. Bartish Margareta Welander 《Genetic Resources and Crop Evolution》2007,54(5):947-958
Genetic diversity within and among 12 populations of the dioecious tropical tree species Hagenia abyssinica (Bruce) J.F. Gmel. in Ethiopia was examined with eight inter simple sequence repeat (ISSR) primers. A total of 104 clearly
scorable bands were generated, among which 84 (81%) were polymorphic. Jaccard similarity coefficient was calculated for pairwise
comparisons among all 120 individuals and ranged from 0.30 to 0.88 while average within-population similarity ranged from
0.53 to 0.66. Within-population variability was estimated as percentage polymorphic loci (ranging from 52% to 87%), Shannon’s
information index (0.30–0.50) and Nei’s genetic diversity (0.21–0.35). The highest variability values were obtained for one
recently planted population and for one wild population growing in an undisturbed primary forest area. Significant overall
differentiation among populations was detected by both Shannon’s information index (0.26) and G
ST (0.25). Relatedness among samples was estimated with a principal coordinate analysis, and relatedness among populations was
estimated with a cluster analysis (UPGMA). A Mantel test indicated a significant association between genetic and geographic
distances, and an autocorrelation analysis showed significant evidence of gene flow over distances up to 30 km. This study
is the first of its kind for H. abyssinica, which has decreased recently in Ethiopia and now must be regarded as an endangered species. Both within-population and between-population
diversity estimates are typical of outcrossing, longlived and late successional species, suggesting that recent anthropogenic
disturbances have not yet had much impact on population genetic parameters. DNA marker data can, however, be used to identify
the most suitable sites for in situ conservation and for collection of material for establishment of genebanks and plant improvement programs. 相似文献
9.
Milene Silvestrini Michele G. Junqueira Andréa C. Favarin Oliveiro Guerreiro-Filho Mirian P. Maluf Maria B. Silvarolla Carlos A. Colombo 《Genetic Resources and Crop Evolution》2007,54(6):1367-1379
Genetic diversity among 115 coffee accessions from the Coffea Germplasm Collection of IAC was assessed using SSR markers. The germplasm represents 73 accessions of Coffea arabica derived from spontaneous and subspontaneous plants in Ethiopia and Eritrea, species center of origin and diversity, 13 commercial
cultivars of C. arabica developed by the Breeding Program of IAC, 1 accession of C. arabica cv. ‘Geisha’, 13 accessions of C. arabica from Yemen, 5 accessions of C. eugenioides, 4 accessions of C. racemosa and 6 accessions of C. canephora. Genetic analysis was performed using average number of alleles per locus (A), proportion of polymorphic loci (P), Shannon’s genetic index (H′ and G′ST) and clustering analysis. All evaluated species were distinguished by a cluster analysis based on Jaccard’s coefficient.
Differentiation between the cultivated plants of C. arabica and accessions derived from spontaneous and subspontaneous plants was observed. Spontaneous and subspontaneous accessions
from Ethiopia were separated according to the geographical origin: east and west of the Great Rift Valley. Cultivated plants
showed a low genetic diversity with a division in two groups: accessions from Yemen (H′=0,028) and Brazilian commercial cultivars (H′=0,030). The results agreed with previously reported narrow genetic basis of cultivated plants of C. arabica and supported the hypotheses about domestication of the species. This study also showed a significant genetic diversity among
accessions from Ethiopia and Eritrea present in the Germplasm Collection of IAC. This diversity is specially observed in accessions
from Sidamo (H′=0,143), Kaffa (H′=0,142) and Illubabor (H′=0,147) indicating their importance as source of genetic variability for coffee breeding programs. 相似文献
10.
Levels and distribution of allozyme and RAPD variation in populations of Elymus fibrosus (Schrenk) Tzvel. (Poaceae) 总被引:5,自引:0,他引:5
Oscar Díaz Gen-Lou Sun Björn Salomon Roland von Bothmer 《Genetic Resources and Crop Evolution》2000,47(1):11-24
To study the magnitude and nature of genetic variation in E. fibrosus, the levels and distribution of allozyme and RAPD variations were investigated in populations collected from Finland and Russia. The results obtained from the allozyme and RAPD studies were compared to each other in 10 of the populations. The allozyme analysis showed that 6 of 12 presumed loci (50%) were polymorphic within the species, while the mean number of polymorphic loci within populations was 4.8%. The mean number of allele per locus for the species was 1.5 and 1.05 across the populations. Genetic diversity at the species level was low (H
es = 0.025), and the mean population genetic diversity was even lower (H
ep = 0.007). Both these values were much lower than the average for other Elymus and self-fertilising species. The largest proportion of the total allozyme diversity was found among, rather than within the populations (G
ST = 0.70). The allozyme genetic distances between the populations did not reflect geographic distances. Cluster and principal coordinates analyses revealed the same allozyme relationship patterns among the populations. A comparison of allozyme and RAPD variation in 10 of the populations showed differences in the amount of genetic variation. The RAPD analysis revealed higher levels of variation (A
p = 1.19, P
p = 20.3 and H
ep = 0.09) than the allozyme one) A
p = 1.06, P
p = 5.8 and H
ep = 0.008). For both markers, the largest proportion of the total gene diversity was found among the populations studied (G
st = 0.63 for RAPDs and G
st = 0.65 for allozyme). In contrast to the allozyme analysis, the RAPD based genetic distances did reflect geographic distances. The cluster and principal coordinates analyses showed different grouping of populations for each data set. There was a positive, but not significant, correlation (r = 0.41) between the genetic distance matrices resulting from these markers. Regional comparison revealed that the Finnish populations had a higher diversity than the Russian ones. Generally, this study indicates that E. fibrosus contains low genetic variation in its populations. The results are discussed in the context of conservation of the species. 相似文献
11.
O. Ozbek E. Millet Y. Anikster O. Arslan M. Feldman 《Genetic Resources and Crop Evolution》2007,54(7):1587-1598
The aim of the present study was to assess the genetic variation in several Israeli and Turkish populations of wild emmer
wheat, Triticum turgidum ssp. dicoccoides, the progenitor of most domesticated wheat. Single spikes were collected in 2002 from 60 plants that grew in six different
habitats in Ammiad, northeastern Israel (8–12 plants from each habitat), and in 1998 from 56 plants that grew in seven different
habitats in Diyarbakir, southeastern Turkey (8 plants from each habitat). Seeds were planted in a nursery and DNA was extracted
from every plant and analyzed by the fluorescent-based amplified fragment length polymorphism (AFLP) method. Seven primer
combinations produced 788 discernible loci of which 48.6% were polymorphic in Israel and 40.5% in Turkey. The genetic diversity
estimates P (frequency of polymorphic loci) and He (gene diversity) were higher in Ammiad than in Diyarbakir (means of P = 0.34 and He = 0.13 in Ammiad vs. P = 0.20 and He = 0.08 in Diyarbakir). Ammiad populations contained more unique alleles than Diyarbakir populations. The relative genetic
diversity estimates (θ) values were 0.188 in Ammiad and 0.407 in Diyarbakir, suggesting better differentiation of the populations in Turkey. Genetic
distance was larger between Israeli and Turkish populations than between populations of each country. The data indicate that
the Israeli and Turkish populations are considerably diverged and that the Israeli populations are more polymorphic than the
Turkish ones, having a larger within-populations genetic variation than among-populations one. The significance of the results
in relation to the differentiation pattern of wild emmer in the Near East is discussed. 相似文献
12.
Demissew Sertse Oliver Gailing Nicolas-George Eliades Reiner Finkeldey 《Genetic Resources and Crop Evolution》2011,58(6):849-859
Juniperus procera is economically highly important but threatened tree species. It is the only species among 67 taxa in the genus Juniperus that naturally grows in Africa and south of the equator extending up to 18°S in Zimbabwe. Ethiopia is assumed to host the
largest J. procera populations, which are also believed to have high genetic variation owing to their wide ecological amplitude. This study
assessed genetic variation at AFLPs of J. procera populations in the Ethiopian highlands. In the study six populations, namely Chilimo, Goba, Menagesha-Suba, Wef-Washa, Yabelo
and Ziquala were included. A total of 20–24 trees from each population were investigated based on 128 AFLP band positions.
AMOVA revealed that most of the variation (94%) resided within populations of J. procera suggesting extensive gene flow among populations which is attributable to the outcrossing mating system and effective gene
transport mechanisms of the species. However, genetic differentiation among populations was still significant (P < 0.05), and the differentiation was significantly (P < 0.05) correlated with geographic distance. All population pairs were significantly (P < 0.05) differentiated except for Menagesha-Suba and Wef-Washa. These two populations also showed the highest gene diversity
(H
j = 0.301 and H
j = 0.297, respectively). These results are in accordance with historical records that claim the establishment of the Menagesha-Suba
juniper population as plantation of seedlings from Wef-Washa back in fifteenth century. 相似文献
13.
Thus far, there is little knowledge of the genetic diversity, structure and gene flow dynamics in rare wild and semi-wild soybean mixed populations, and such information is vital for understanding of the origin of semi-wild soybean (Glycine gracilis) and the biosafety protection of wild soybean from transgenic soybeans. Population eco-genetic data are necessary to provide a more coherent and comprehensive understanding of the genetic events that occurred in the natural habitats of wild soybean (Glycine soja). We tested genetic diversity and structure of 11 wild mixed populations of wild soybean (Glycine soja) and semi-wild soybean (G. gracilis), 1 wild soybean population, and 1 cultivated soybean variety population were studied using 20 nuclear microsatellite markers (SSRs). We found based on microsatellite polymorphisms that the mixed populations were characterized by higher mean heterozygosity (H o = 0.029) and outcrossing rate (t m = 6.35 %), and lower fixation index (F is = 0.891), and the semi-wild plants had distinctly higher heterozygosity (H o = 0.081) than that of the wild plants (H o = 0.007). The occurrence of semi-wild plants influenced population genetic structure but not geographical population differentiation. These mixed populations exhibited strong ecogeographical differentiation, which suggests that their original populations were colonized over a long phytogeographical history. The introgression occurred through pollen gene flow from the soybean fields into wild populations and created the semi-wild plants, with significant genetic differentiation from the typical wild ones. Introgressive genes could become established by two possible modes in wild soybean populations by both self-segregation and/or intrapopulation secondary hybridization. The latter deserves attention because of the possibility of rapid transgene escape. 相似文献
14.
Yao Zhao Chengbin Chen Jun Rong Shanshan Dong Hui Liao Fan Lu Baorong Lu Jiakuan Chen Zhiping Song 《Genetic Resources and Crop Evolution》2012,59(1):113-124
Population clonal diversity and fine-scale genetic structure of Oryza officinalis Wall. ex Watt, an endangered species in China recently experiencing habitat degradation, was estimated using inter simple
sequence repeat markers. We analyzed the genetic variations of 440 samples exhaustively collected from nine O. officinalis populations. Relatively rich clonal diversity and poor genetic variation were found in the extant populations. We found that
the number of genets, the percentage of polymorphic loci, and gene diversity decreased with population decline, suggesting
that habitat degradation will lead to further genetic depletion of O. officinalis populations. A pronounced spatial genetic structure occurs at both the ramet and genet levels in several larger populations,
which is the result of clonal growth and concomitant inbreeding. The in situ conserved population PS holds much more genotypes than other populations with the similar population size, which might have more seedling recruitments
from the soil seed bank due to habitat disturbance, suggesting a moderate disturbance combined with habitat degradation-avoiding
measures are effective for in situ conservation of this species. 相似文献
15.
Ru-Qiang Xu Norihiko Tomooka Duncan A. Vaughan Koji Doi 《Genetic Resources and Crop Evolution》2000,47(2):123-134
The present study, using RAPD analysis, was undertaken to characterize genetic variation in three forms of V. angularis, cultivated, wild and weedy forms, and their relationships. The materials used consisted of 171 individuals (plants) or cultivars from 23 populations including 5 wild populations, 6 weedy populations, 6 cultivated populations and 6 populations with plants having wild and weedy or intermediate morphology, denoted here as complex populations. The materials used were collected on Honshu Island, Japan and seeds collected directly from the field were germinated for DNA extraction. In addition, 6 landrace accessions of V. angularis from the genebank were also analyzed. Genetic variation was highest in the wild form (Hg= 0.132; GD = 0.388), followed by the weedy form (Hg= 0.124; GD = 0.341) and the least in the cultivated form (Hg= 0.079; GD = 0.274). Intra-population genetic variation was high in the weedy and in the wild populations. However, inter-population was greater than intra-population genetic variation for all groups of populations studied in the V. angularis complex. 93% of the total diversity in the present study was exhibited by plants from complex populations and specific RAPD bands were found in these populations. Our results provide evidence that complex populations would be a logical focus for efforts to conserve the V. angularis complex in situ. Our results suggest that weedy populations are usually an ecotype of the wild form adapted to a different habitat. 相似文献
16.
Mulatu Geleta Tomas Bryngelsson Endashaw Bekele Kifle Dagne 《Genetic Resources and Crop Evolution》2007,54(3):601-614
Genetic diversity of 70 populations of niger (Guizotia abyssinica) representing all its growing regions in Ethiopia was investigated using random amplified polymorphic DNA (RAPD) to reveal
the extent of its populations genetic diversity. Ninety-seven percent of the loci studied was revealed to be polymorphic for
the whole data set. The within population diversity estimated by Shannon diversity index and Nei gene diversity estimates
was revealed to be 0.395 and 0.158, respectively. The extent of genetic variation of populations from major niger producing
regions was significantly lower than that of populations from other regions; however, it is distributed regardless of altitude
of growth. Genetic differentiation between populations was estimated with Shannon index as G′
ST (0.432), Nei’s G
ST (0.242) and AMOVA based F
ST (0.350) and appears to be equivalent to the average values calculated from various RAPD based studies on outcrossing species.
Higher proportion of the variation detected by AMOVA resided within populations (64.58%) relative to the amount of variation
among populations (35.42%). UPGMA cluster analysis showed that most of the populations were clustered according to their region
of origin. However, some populations were genetically distant from the majority and seem to have unique genetic properties.
It is concluded that the crop has a wide genetic basis that may be used for the improvement of the species through conventional
breeding and/or marker assisted selection. Collection of germplasm from areas not yet covered and/or underrepresented is the
opportunity to broaden the genetic basis of genebank collection. 相似文献
17.
Yang Yang Yuezhi Pan Xun Gong Moutian Fan 《Genetic Resources and Crop Evolution》2010,57(8):1239-1248
Citrus hongheensis is a critically endangered species endemic to the Honghe river region in southeastern Yunnan, China. Its genetic diversity
and differentiation were investigated using Inter-Simple Sequence Repeat (ISSR) markers. One hundred primers were screened,
and a total of 245 loci were amplified from seven natural populations by 13 informative and reliable primers. Of these 245
ISSR loci, 233 were polymorphic and the detected variations revealed a relatively high level of intraspecific genetic diversity.
At the population level, the mean percentage of polymorphic loci (PPB) was 36.50%, while the average expected heterozygosity (He) and Shannon diversity index (Ho) were 0.1327 and 0.1972, respectively. At the species level (across all populations), PPB was 95.10%, while He and Ho were 0.3520 and 0.5195, respectively. A high Gst value (0.6247) indicated that there is significant differentiation among populations, which was confirmed by AMOVA analysis
(Φst = 0.6420). Pairwise genetic identity (I) values among populations ranged from 0.6341 to 0.7675, with a mean of 0.7008. We propose that the high level of genetic
differentiation may be the result of habitat fragmentation and limited gene flow (Nm = 0.1502). For effective in situ conservation and population restoration of C. hongheensis it will be important to maintain historical processes, including high outbreeding rates, sufficient gene flow, and large
effective population sizes. 相似文献
18.
Sonia?Marghali Olivier?Panaud Fran?oise?Lamy Salma?Ghariani Aboubakry?Sarr Mohamed?Marrakchi Neila?Trifi-Farah
Amplified fragment length polymorphism (AFLP) markers were used to characterize the genetic diversity within and among natural populations and cultivars of Hedysarum coronarium. Twelve populations within Tunisia were evaluated with three AFLP primer combinations. A total of 207 reproducible bands was detected of which 178 (86%) were polymorphic. The great discriminative power of AFLP markers and their ability to represent genetic relationships among Hedysarum plants was demonstrated. Genetic diversity within and among populations was assessed through Principal Component Analysis (PCA) and cluster analysis by using the Neighbor-joining clustering algorithm. AFLP technology has provided evidence of a high degree of intra- and inter-population genetic diversity in H. coronarium. AFLP banding patterns provided molecular markers correlated with the plants’ geotropism. In addition, AFLP markers can differentiate wild accessions from cultivars. Moreover, geographical origins did not correspond to population clustering. 相似文献
19.
Orychophragmus violaceus, a ground covering plant that is widely distributed in China. It has both high economical value in food, forage, health care
and ornamental value in gardening. In this study, the genetic diversity of 245 individuals from nine populations in China
were investigated using the inter-simple sequence repeat markers. Of the 100 primers screened, eight were highly polymorphic.
Using these primers, 162 discernible DNA fragments were generated with 150 (92.59%) being polymorphic, indicating a pronounced
genetic variation at the species level. Also, there were high levels of polymorphism at the population level with the percentage
of polymorphic bands ranging from 85.74 to 90.06%. Analysis of molecular variance showed that the genetic variation within
populations was 80.80% and the variance among populations was 16.43%. The Nei’s G
ST (0.1643) and gene flow among populations (Nm = 2.5760) revealed large gene exchanges among populations. O. violaceus belongs to out-crossing plants. It is capable of reproducing by self-sowing, thus can influence population genetic structure.
The pronounced genetic variation within populations tells us that O. violaceus is a proper plant for genetic research and that there is great potential of breeding this species for gardening. 相似文献
20.
American ginseng (Panax quinquefolius) is a native North American medicinal plant that is becoming increasingly vulnerable despite government harvest restrictions. To better understand the genetic diversity and gene flow of American ginseng, we studied RAPD variation in cultivated and wild populations. Classical and Bayesian analogues of genetic diversity statistics were estimated in seven wild and two cultivated populations. The wild populations were more highly structured (G stβ = 0.41) than the cultivated populations (G stβ = 0.24). The genetic diversity within populations ranged from H eβ = 0.05 to 0.38. Based on genetic pairwise distances, six of the wild populations clustered with the locally-derived cultivated population, while one wild population was more similar to the non-local cultivated population than the local populations. This wild population was highly diverse (P = 1.0; U = 1.0) suggesting that it was supplemented from exotic seed. A set of eight RAPD markers was identified that differentiated plants of local and non-local origin. As a conservation strategy, we recommend that regional gene banks be established based on molecular and geographic diversity to preserve the locally adapted germplasm. These regional gene banks would serve as a conservation tool and also provide a source of genes for genetic improvement of cultivated ginseng. 相似文献