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1.
In order to explore the domestication and ethnobotany ofLuffa aegyptiaca, collections were made from two regions where wild plants and the domesticate occur: an area in and near southern China, represented by Yunnan Province (China) and northern Laos; and the Indian subcontinent, represented by southeastern Nepal. The allozyme evidence was inconclusive with respect to the region of domestication due to the small sample size of wild accessions from Nepal but suggests a single place of domestication. Principal Components Analysis of morphological characters revealed that some accessions of the domesticate from Yunnan and Laos were more similar to the wild type than were those from Nepal. Compared to the wild type, the domesticate had nonbitter, larger, and indehiscent fruits, flowered earlier, and had thicker fruit vascular bundles. The nutritional content of traditional cultivars was superior to that of a single modern cultivar that was examined.  相似文献   

2.
Benincasa hispida, from tropical Asia, is cultivated primarily for its edible fruit. To explore its domestication and ethnobotany, we made collections from two regions where it may have been domesticated: (1) Southern China/Southeast Asia, represented by southern Yunnan Province (China) and northern Laos; and (2) the Indian subcontinent, represented by southeastern Nepal. Domestication has resulted in diverse fruit sizes, shapes, and colors; seed sizes and shapes; and, in some accessions, the loss of tendrils. Modern cultivars have larger fruit, earlier flowers, and lower nutritional content than traditional cultivars. Allozyme diversity was low, divergence between these two regions was low, and these results do not clarify the place of domestication. The greater morphological diversity of plants from Yunnan and Laos, as compared to Nepal, suggests domestication in the former region. In all accessions, male flowers precede females.Benincasa hispida is prominent in some traditional stories and rituals.  相似文献   

3.
The diploid wheat Triticum monococcum L. (einkorn) was among the first crops domesticated by humans in the Fertile Crescent 10,000 years ago. During the last 5,000 years, it was replaced by tetraploid and hexaploid wheats and largely forgotten by modern breeders. Einkorn germplasm is thus devoid of breeding bottlenecks and has therefore preserved in unfiltered form the full spectrum of genetic variation that was present during its domestication. We investigated haplotype variation among >12 million nucleotides sequenced at 18 loci across 321 wild and 92 domesticate T. monococcum lines. In contrast to previous studies of cereal domestication, we sampled hundreds of wild lines, rather than a few dozen. Unexpectedly, our broad sample of wild lines reveals that wild einkorn underwent a process of natural genetic differentiation, most likely an incipient speciation, prior to domestication. That natural differentiation was previously overlooked within wild einkorn, but it bears heavily upon inferences concerning the domestication process because it brought forth 3 genetically, and to some extent morphologically, distinct wild einkorn races that we designate here as alpha, beta, and gamma. Only one of those natural races, beta, was exploited by humans for domestication. Nucleotide diversity and haplotype diversity in domesticate einkorn is higher than in its wild sister group, the einkorn beta race, indicating that einkorn underwent no reduction of diversity during domestication. This is in contrast to findings from previous studies of domestication history among more intensely bred crop species. Taken together with archaeological findings from the Fertile Crescent, the data indicate that a specific wild einkorn race that arose without human intervention was subjected to multiple independent domestication events.  相似文献   

4.
The extent of 5S and 45S ribosomal DNA (rDNA) variation was investigated in wild and domesticated common beans (Phaseolus vulgaris) chosen to represent the known genetic diversity of the species. 5S and 45S rDNA probes were localized on mitotic chromosomes of 37 accessions by fluorescent in situ hybridization (FISH). The two 5S rDNA loci were largely conserved within the species, whereas a high variation in the number of 45S rDNA loci and changes in position of loci and number of repeats per locus were observed. Domesticated accessions from the Mesoamerican gene pool frequently had three 45S rDNA loci per haploid genome, and rarely four. Domesticated accessions from Andean gene pool, particularly from the race Peru, showed six, seven, eight or nine loci, but seven loci were found in all three races of this gene pool. Between three and eight loci were observed in accessions resulting from crosses between Andean and Mesoamerican genotypes. The presence of two to eight 45S rDNA loci in wild common beans from different geographic locations indicates that the 45S rDNA amplification observed in the Andean lineage took place before domestication. Our data suggest that ectopic recombination between terminal chromosomal regions might be the mechanism responsible for this variation.  相似文献   

5.
Ramie (Boehmeria nivea) is an economically important natural fiber-producing crop that has been cultivated for thousands of years in China; however, the evolution of this crop remains largely unknown. Here, we report a ramie domestication analysis based on genome assembly and resequencing of cultivated and wild accessions. Two chromosome-level genomes representing wild and cultivated ramie were assembled de novo. Numerous structural variations between two assemblies, together with the genetic variations from population resequencing, constituted a comprehensive genomic variation map for ramie. Domestication analysis identified 71 high-confidence selective sweeps comprising 320 predicted genes, and 29 genes from sweeps were associated with fiber growth in the expression. In addition, we identified seven genetic loci associated with the fiber yield trait in the segregated population derived from the crossing of two assembled accessions, and two of which showed an overlap with the selective sweeps. These findings indicated that bast fiber traits were focused on during the domestication history of ramie. This study sheds light on the domestication of ramie and provides a valuable resource for biological and breeding studies of this important crop.  相似文献   

6.
The predominant view regarding Asian rice domestication is that the initial origin of nonshattering involved a single gene of large effect, specifically, the sh4 locus via the evolutionary replacement of a dominant allele for shattering with a recessive allele for reduced shattering. Data have accumulated to challenge this hypothesis. Specifically, a few studies have reported occasional seed‐shattering plants from populations of the wild progenitor of cultivated rice (Oryza rufipogon complex) being homozygous for the putative “nonshattering” sh4 alleles. We tested the sh4 hypothesis for the domestication of cultivated rice by obtaining genotypes and phenotypes for a diverse set of samples of wild, weedy, and cultivated rice accessions. The cultivars were fixed for the putative “nonshattering” allele and nonshattering phenotype, but wild rice accessions are highly polymorphic for the putative “nonshattering” allele (frequency ~26%) with shattering phenotype. All weedy rice accessions are the “nonshattering” genotype at the sh4 locus but with shattering phenotype. These data challenge the widely accepted hypothesis that a single nucleotide mutation (“G”/“T”) of the sh4 locus is the major driving force for rice domestication. Instead, we hypothesize that unidentified shattering loci are responsible for the initial domestication of cultivated rice through reduced seed shattering.  相似文献   

7.
Gossypium arboreum L. and G. herbaceum L. are the diploid species of cultivated cotton. Little is known regarding the time and place of domestication of either species. Because G. arboreum is known only as a cultigen, others have proposed that it arose from domesticated G. herbaceum during the more than 5,000-year history of Old World cotton cultivation, with wild G. herbaceum subsp. africanum (Watt) Mauer as the putative ancestor of both species. An alternative hypothesis is that the two species have independent origins from progenitors that diverged prior to domestication. The relative merits of these opposing hypotheses were evaluated using data derived from starch gel electrophoresis of enzymes. One hundred and three accessions of G. arboreum and 31 accessions of G. herbaceum were examined for allelic variation at 40 allozyme loci. All measures of genetic variability demonstrated that G. arboreum contains greater diversity than G. herbaceum, although both species have relatively low levels of allozyme variation. In contrast to expectations based on morphology and other chemical data sets, the two species are highly differentiated with respect to allozyme composition. Gossypium arboreum and G. herbaceum each contain a large number of unique alleles and are fixed or nearly fixed for alternate alleles at 8 loci. Five allozyme loci have alleles that are rare in one of the two species but common in the other. Based on restricted occurrence of these alleles to areas with a long history of sympatric cultivation and the geographic distribution of a null allele, we suggest that a significant portion of the allelic diversity in both species results from historical, bidirectional interspecific introgression. The interspecific genetic identity estimate (0.74) is markedly lower than for documented progenitor-derivative and crop-ancestor species pairs. Based on these data, as well as previous cytogenetic data and the observation of F2 breakdown in interspecific crosses, we suggest that cultivated G. arboreum and G. herbaceum were independently domesticated from divergent ancestors.  相似文献   

8.
China is rich of germplasm resources of common wild rice (Oryza rufipogon Griff.) and Asian cultivated rice (O. sativa L.) which consists of two subspecies, indica and japonica. Previous studies have shown that China is one of the domestication centers of O. sativa. However, the geographic origin and the domestication times of O. sativa in China are still under debate. To settle these disputes, six chloroplast loci and four mitochondrial loci were selected to examine the relationships between 50 accessions of Asian cultivated rice and 119 accessions of common wild rice from China based on DNA sequence analysis in the present study. The results indicated that Southern China is the genetic diversity center of O. rufipogon and it might be the primary domestication region of O. sativa. Molecular dating suggested that the two subspecies had diverged 0.1 million years ago, much earlier than the beginning of rice domestication. Genetic differentiations and phylogeography analyses indicated that indica was domesticated from tropical O. rufipogon while japonica was domesticated from O. rufipogon which located in higher latitude. These results provided molecular evidences for the hypotheses of (i) Southern China is the origin center of O. sativa in China and (ii) the two subspecies of O. sativa were domesticated multiple times.  相似文献   

9.
Summary Fifty-six accessions of cultivated and wild sorghum were surveyed for genetic diversity using 50 low-copy-number nuclear DNA sequence probes to detect restriction fragment length polymorphisms (RFLPs). These probes revealed greater genetic diversity in wild sorghum than in cultivated sorghum, including a larger number of alleles per locus and a greater portion of polymorphic loci in wild sorghum. In comparison to previously published isozyme analyses of the same accessions, RFLP analysis reveals a greater number of alleles per locus. Furthermore, many RFLP alleles have frequencies between 0.25–0.75, while the vast majority of isozyme alleles are either rare (< 0.25) or near fixation (> 0.75). Correlations between genetic and geographic distances among the accessions were stronger when calculated with RFLP than with isozyme data. Systematic relationships revealed by nuclear and chloroplast restriction site analysis indicate that cultivated sorghum is derived from the wild ssp. arundinaceum. The portion of the wild gene pool most genetically similar to the cultivars is from central-northeastern Africa. Previous published data also suggested that this is most likely the principal area of domestication of sorghum. Introgression between wild and cultivated sorghum was inferred from disconcordant relationships shown by nuclear and chloroplast DNA markers. Introgression apparently occurs infrequently enough that the crop and its wild relatives maintain distinct genetic constitutions.  相似文献   

10.
Archaeobotanical-archaeological, cultural and historical data indicate that grapevine domestication can be dated back from 6000 to 7000 years ago and that it took place in the Caucasian and Middle East Regions. However, events leading to the domestication of this crop species are still an open issue. In this paper, 6 chloroplast microsatellites have been used to assess genetic similarities among, and within, domesticated and wild grapevine accessions representative of 7 distinct geographical regions from the Middle-East to Western Europe. Results show that 2 out of the 6 analyzed chloroplast loci are polymorphic within the 193 domesticated individuals and the 387 samples of 69 wild populations. Allele variants of the Cp-SSR loci combine in a total of 6 different haplotypes. The data show that the haplotype distribution is not homogeneous: the 6 haplotypes are present in the domesticated varieties, but only 5 (haplotype VI is absent) are observed in wild populations. The analysis of haplotype distribution allows discussion of the relationships between the two grape subspecies. The contribution of the wild grape germplasm to the domesticated gene pool still growing in different geographical regions can be, in cases, made evident, suggesting that beside domestication, gene introgression has also played a role in shaping the current varietal landscape of the European viticulture.
  相似文献   

11.
Wild and cultivated barleys show similar affinities for mineral nitrogen   总被引:3,自引:0,他引:3  
Arnold J. Bloom 《Oecologia》1985,65(4):555-557
Summary The kinetics of net ammonium influx were very similar among several cultivars of barley (Hordeum vulgare) and several accessions of the wild taxa H.v. spontaneum and H. jubatum. For net nitrate influx, variation was greater among accessions than among species; accessions from warmer climates had faster rates than those from colder climates. These data indicate that domestication of barley has not reduced its affinity for mineral nitrogen.  相似文献   

12.
According to a widely accepted theory on barley domestication, wild barley (Hordeum vulgare ssp. spontaneum) from the Fertile Crescent is the progenitor of all cultivated barley (H. vulgare ssp. vulgare). To determine whether barley has undergone one or more domestication events, barley accessions from three continents have been studied (a) using 38 nuclear SSR (nuSSRs) markers, (b) using five chloroplast SSR (cpSSR) markers yielding 5 polymorphic loci and (c) by detecting the differences in a 468 bp fragment from the non-coding region of chloroplast DNA. A clear separation was found between Eritrean/Ethiopian barley and barley from West Asia and North Africa (WANA) as well as from Europe. The data from chloroplast DNA clearly indicate that the wild barley (H. vulgare ssp. spontaneum) as it is found today in the “Fertile Crescent” might not be the progenitor of the barley cultivated in Eritrea (and Ethiopia). Consequently, an independent domestication might have taken place at the Horn of Africa. Jihad Orabi and Gunter Backes have contributed equally to this work.  相似文献   

13.
The two independent domestication events in the genus Oryza that led to African and Asian rice offer an extremely useful system for studying the genetic basis of parallel evolution. This system is also characterized by parallel de‐domestication events, with two genetically distinct weedy rice biotypes in the US derived from the Asian domesticate. One important trait that has been altered by rice domestication and de‐domestication is hull colour. The wild progenitors of the two cultivated rice species have predominantly black‐coloured hulls, as does one of the two U.S. weed biotypes; both cultivated species and one of the US weedy biotypes are characterized by straw‐coloured hulls. Using Black hull 4 (Bh4) as a hull colour candidate gene, we examined DNA sequence variation at this locus to study the parallel evolution of hull colour variation in the domesticated and weedy rice system. We find that independent Bh4‐coding mutations have arisen in African and Asian rice that are correlated with the straw hull phenotype, suggesting that the same gene is responsible for parallel trait evolution. For the U.S. weeds, Bh4 haplotype sequences support current hypotheses on the phylogenetic relationship between the two biotypes and domesticated Asian rice; straw hull weeds are most similar to indica crops, and black hull weeds are most similar to aus crops. Tests for selection indicate that Asian crops and straw hull weeds deviate from neutrality at this gene, suggesting possible selection on Bh4 during both rice domestication and de‐domestication.  相似文献   

14.
H X Xu  T Jing  N Tomooka  A Kaga  T Isemura  D A Vaughan 《Génome》2008,51(9):728-738
To facilitate the wider use of genetic resources including newly collected cultivated and wild azuki bean germplasm, the genetic diversity of the azuki bean complex, based on 13 simple sequence repeat (SSR) primers, was evaluated and a core collection was developed using 616 accessions originating from 8 Asian countries. Wild germplasm from Japan was highly diverse and represented much of the allelic variation found in cultivated germplasm. The SSR results together with recent archaeobotanical evidence support the view that Japan is one center of domestication of azuki bean, at least for the northeast Asian azuki bean. Cultivated azuki beans from China, Korea, and Japan were the most diverse and were genetically distinct from each other, suggesting a long and relatively isolated history of cultivation in each country. Cultivated azuki beans from eastern Nepal and Bhutan were similar to each other and quite distinct from others. For two primers, most eastern Nepalese and Bhutanese cultivated accessions had null alleles. In addition, wild accessions from the Yangtze River region of China and the Himalayan region had a null allele for one or the other of these primers. Whether the distinct diversity of azuki bean in the Himalayan region is due to introgression or separate domestication events requires further study. In contrast, western Nepalese azuki beans showed an SSR profile similar to that of Chinese azuki beans. The genetic distinctness of cultivated azuki beans from Vietnam has been revealed for the first time. The specific alleles indicate that Vietnamese azuki beans have been cultivated in isolation from Chinese azuki beans for a long time. Wild germplasm from the Himalayan region showed the highest level of variation. Based on the results, Himalayan germplasm could be considered a novel gene source for azuki bean breeding. A comparison with mungbean SSR analysis revealed that the mean gene diversity of cultivated azuki bean (0.74) was much higher than that of cultivated mungbean (0.41). The reduction in gene diversity due to domestication, the domestication bottleneck, in azuki bean is not strong compared with that in mungbean.  相似文献   

15.
The genetic diversity of the Vigna angularis complex in Asia.   总被引:8,自引:0,他引:8  
A selected set of accessions of components of the azuki bean (Vigna angularis) complex comprising 123 cultivated accessions and 23 wild or weedy accessions from Bhutan, China (including Taiwan), India, Japan, Korea, and Nepal was analyzed using amplified fragment length polymorphism (AFLP) methodology. Using 12 AFLP primer pairs, 580 unambiguous bands were generated, 313 (53.9%) of which were polymorphic among azuki bean accessions. All 580 bands were used to assess phenotypic (band) and genetic (nucleotide) diversity among the 146 azuki bean accessions. The results indicate five major groups of azuki bean germplasm primarily associated with geographic origin of accessions and their status: wild, weedy, or cultivated. These five groups are (i) Himalayan wild, (ii) Nepal-Bhutan cultivated, (iii) Chinese wild, (iv) Taiwan wild - Bhutan cultivated, and (v) northeast Asian accessions. Within the northeast Asian accessions, three subgroups are present. These consist of (v1) Japanese complex - Korean cultivated, (v2) Japanese cultivated, and (v3) Chinese cultivated accessions. The results suggest domestication of azuki bean occurred at least twice, once in the Himalayan region of southern Asia and once in northeast Asia. The remarkable diversity of azuki bean germplasm in the Himalayan region compared with other regions suggests this is a rich source of germplasm for plant breeding. The results suggest there are important gaps in the germplasm collections of azuki bean and its close relatives from various parts of Asia and that specific collecting missions for Vigna germplasm related to azuki bean in the highlands of subtropical Asia are needed.  相似文献   

16.
We report reference‐quality genome assemblies and annotations for two accessions of soybean (Glycine max) and for one accession of Glycine soja, the closest wild relative of G. max. The G. max assemblies provided are for widely used US cultivars: the northern line Williams 82 (Wm82) and the southern line Lee. The Wm82 assembly improves the prior published assembly, and the Lee and G. soja assemblies are new for these accessions. Comparisons among the three accessions show generally high structural conservation, but nucleotide difference of 1.7 single‐nucleotide polymorphisms (snps) per kb between Wm82 and Lee, and 4.7 snps per kb between these lines and G. soja. snp distributions and comparisons with genotypes of the Lee and Wm82 parents highlight patterns of introgression and haplotype structure. Comparisons against the US germplasm collection show placement of the sequenced accessions relative to global soybean diversity. Analysis of a pan‐gene collection shows generally high conservation, with variation occurring primarily in genomically clustered gene families. We found approximately 40–42 inversions per chromosome between either Lee or Wm82v4 and G. soja, and approximately 32 inversions per chromosome between Wm82 and Lee. We also investigated five domestication loci. For each locus, we found two different alleles with functional differences between G. soja and the two domesticated accessions. The genome assemblies for multiple cultivated accessions and for the closest wild ancestor of soybean provides a valuable set of resources for identifying causal variants that underlie traits for the domestication and improvement of soybean, serving as a basis for future research and crop improvement efforts for this important crop species.  相似文献   

17.
In 1992, Vaillancourt and Weeden discovered a very important mutation for studying cowpea evolution and domestication. A loss of a BamHI restriction site in chloroplast DNA characterized all domesticated accessions and a few wild (Vigna unguiculata ssp. unguiculata var. spontanea) accessions. In order to screen a larger number of accessions, primers were designed to check this mutation using PCR RFLP or direct PCR methods. Using these new primers, 54 domesticated cowpea accessions and 130 accessions from the wild progenitor were screened. The absence of haplotype 0 was confirmed within domesticated accessions, including primitive landraces from cultivar-groups Biflora and Textilis, suggesting that this mutation occurred prior to domestication. However, 40 var. spontanea accessions distributed from Senegal to Tanzania and South Africa showed haplotype 1. Whereas this marker could not be used to identify a precise center of origin, it did highlight the widely distributed cowpea crop-weed complex. Its very high frequency in West Africa could be interpreted as a result of either genetic swamping of the wild/weedy gene pool by the domesticated cowpea gene pool or as the result of domestication by ethnic groups focusing primarily on cowpea as fodder.  相似文献   

18.
Annual wild soybean (Glycine soja Sieb. et Zucc.) is believed to be a potential gene source for future soybean improvement in coping with the world climate change for food security. To evaluate the wild soybean genetic diversity and differentiation, we analyzed allelic profiles at 60 simple-sequence repeat (SSR) loci and variation of eight morph-biological traits of a representative sample with 196 accessions from the natural growing area in China. For comparison, a representative sample with 200 landraces of Chinese cultivated soybean was included in this study. The SSR loci produced 1,067 alleles (17.8 per locus) with a mean gene diversity of 0.857 in the wild sample, which indicated the genetic diversity of G. soja was much higher than that of its cultivated counterpart (total 826 alleles, 13.7 per locus, mean gene diversity 0.727). After domestication, the genetic diversity of the cultigens decreased, with its 65.5% alleles inherited from the wild soybean, while 34.5% alleles newly emerged. AMOVA analysis showed that significant variance did exist among Northeast China, Huang-Huai-Hai Valleys and Southern China subpopulations. UPGMA cluster analysis indicated very significant association between the geographic grouping and genetic clustering, which demonstrated the geographic differentiation of the wild population had its relevant genetic bases. In comparison with the other two subpopulations, the Southern China subpopulation showed the highest allelic richness, diversity index and largest number of specific-present alleles, which suggests Southern China should be the major center of diversity for annual wild soybean. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

19.
Crop evolution is a long‐term process involving selection by natural evolutionary forces and anthropogenic influences; however, the genetic mechanisms underlying the domestication and improvement of fruit crops have not been well studied to date. Here, we performed a population structure analysis in peach (Prunus persica) based on the genome‐wide resequencing of 418 accessions and confirmed the presence of an obvious domestication event during evolution. We identified 132 and 106 selective sweeps associated with domestication and improvement, respectively. Analysis of their tissue‐specific expression patterns indicated that the up‐regulation of selection genes during domestication occurred mostly in fruit and seeds as opposed to other organs. However, during the improvement stage, more up‐regulated selection genes were identified in leaves and seeds than in the other organs. Genome‐wide association studies (GWAS) using 4.24 million single nucleotide polymorphisms (SNPs) revealed 171 loci associated with 26 fruit domestication traits. Among these loci, three candidate genes were highly associated with fruit weight and the sorbitol and catechin content in fruit. We demonstrated that as the allele frequency of the SNPs associated with high polyphenol composition decreased during peach evolution, alleles associated with high sugar content increased significantly. This indicates that there is genetic potential for the breeding of more nutritious fruit with enhanced bioactive polyphenols without disturbing a harmonious sugar and acid balance by crossing with wild species. This study also describes the development of the genomic resources necessary for evolutionary research in peach and provides the large‐scale characterization of key agronomic traits in this crop species.  相似文献   

20.
The domestication of plants frequently results in a high level of genetic differentiation between domesticated plants and their wild progenitors. This process is counteracted by gene flow between wild and domesticated plants because they are usually able to inter‐mate and to exchange genes. We investigated the extent of gene flow between wild barley Hordeum spontaneum and cultivated barley Hordeum vulgare, and its effect on population structure in wild barley by analysing a collection of 896 wild barley accessions (Barley1K) from Israel and all available Israeli H. vulgare accessions from the Israeli gene bank. We compared the performance of simple sequence repeats (SSR) and single nucleotide polymorphisms (SNP) marker data genotyped over a core collection in estimating population parameters. Estimates of gene flow rates with SSR markers indicated a high level of introgression from cultivated barley into wild barley. After removing accessions from the wild barley sample that were recently admixed with cultivated barley, the inference of population structure improved significantly. Both SSR and SNP markers showed that the genetic population structure of wild barley in Israel corresponds to the three major ecogeographic regions: the coast, the Mediterranean north and the deserts in the Jordan valley and the South. Gene flow rates were estimated to be higher from north to south than in the opposite direction. As has been observed in other crop species, there is a significant exchange of alleles between the wild species and domesticated varieties that needs to be accounted for in the population genetic analysis of domestication.  相似文献   

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