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1.
Smýkal P Bačová-Kerteszová N Kalendar R Corander J Schulman AH Pavelek M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(7):1385-1397
Retrotransposon segments were characterized and inter-retrotransposon amplified polymorphism (IRAP) markers developed for cultivated flax (Linum usitatissimum L.) and the Linum genus. Over 75 distinct long terminal repeat retrotransposon segments were cloned, the first set for Linum, and specific primers designed for them. IRAP was then used to evaluate genetic diversity among 708 accessions of cultivated flax comprising 143 landraces, 387 varieties, and 178 breeding lines. These included both traditional and modern, oil (86), fiber (351), and combined-use (271) accessions, originating from 36 countries, and 10 wild Linum species. The set of 10 most polymorphic primers yielded 141 reproducible informative data points per accession, with 52% polymorphism and a 0.34 Shannon diversity index. The maximal genetic diversity was detected among wild Linum species (100% IRAP polymorphism and 0.57 Jaccard similarity), while diversity within cultivated germplasm decreased from landraces (58%, 0.63) to breeding lines (48%, 0.85) and cultivars (50%, 0.81). Application of Bayesian methods for clustering resulted in the robust identification of 20 clusters of accessions, which were unstratified according to origin or user type. This indicates an overlap in genetic diversity despite disruptive selection for fiber versus oil types. Nevertheless, eight clusters contained high proportions (70?C100%) of commercial cultivars, whereas two clusters were rich (60%) in landraces. These findings provide a basis for better flax germplasm management, core collection establishment, and exploration of diversity in breeding, as well as for exploration of the role of retrotransposons in flax genome dynamics. 相似文献
2.
Cytokinins antagonize the jasmonates action on the regulation of potato (Solanum tuberosum) tuber formation in vitro 总被引:1,自引:0,他引:1
Debabrata Sarkar Suman Kumar Pandey Sushruti Sharma 《Plant Cell, Tissue and Organ Culture》2006,87(3):285-295
Cucurbita pepo L. (squash, pumpkin) is a highly polymorphic vegetable species of major importance. Our study characterized a spectrum of C. pepo germplasm for the ability to regenerate in vitro by direct organogenesis from cotyledon explants. Cultivars tested included both cultivated subspecies, texana and pepo, and nearly all of their respective cultivar-groups. Direct shoot regeneration occurred in all accessions, and was generally high (56–94%), with a single exception of 22% (‘Bolognese’). There was no significant difference between the percentage regeneration of the two subspecies. Shoot regeneration per responding explant was uniform (1.2–1.6 shoots per explant). Only ‘True French’ produced statistically more shoots (3.9 per explant) than other accessions. The morphology of regeneration varied. Most cultivars produced long shoots, often fasciated, amid a few small buds. Some subspecies pepo cultivars (Beirut, Yugoslavia 7, Ma’yan and True French) produced short, massive, hollow shoots, sometimes accompanied by shoots that were more normal. Two subspecies texana cultivars (Creamy Straightneck and Small Bicolor) produced single (sometimes double) shoots without other buds. The production of chimeric (mixoploid) regenerants varied and there was a tendency to regenerate chimeric plants from the widest-fruited accessions (i.e. lowest length-to-width ratio) in each subspecies. Subspecies pepo Pumpkin Group ‘Tondo di Nizza’ showed significantly greater production of chimeric regenerants. In comparison with the great range of variation observed in fruit shape, the variation of in vitro responses (mostly less than 2-fold in regeneration and shoot production) was less than expected. 相似文献
3.
The majority of Hevea (Hevea brasiliensis Muell. Arg.) genetic resource in Vietnam derived from the IRRDB’81 germplasm collected in the Amazonian habitats of the genus.
Random amplified polymorphic DNA (RAPD) analysis was used to examine the genetic diversity and structure of the IRRDB’81 germplasm.
A total of 59 accessions from 13 different districts of the Brazilian states namely Acre, Rondonia, and Mato Grosso were brought
into the study using six arbitrarily preselected primers. Sixty-five RAPD band patterns ranging in size from 0.2 to 3.0 kbp
were scored for analysis. Differences in the level of DNA polymorphism among the districts and states were revealed. The percentage
of the polymorphic DNA fragments calculated for 13 individual districts varied from 15.38 to 70.77%. The mean values of heterozygosity
within the district varied from 0.064 to 0.264. Pairwise district Nei’s genetic distance values ranged from 0.046 for Catriquacu
and Itanba of Mato Grosso to 0.304 for Tarauaca of Acre and Aracatuba of Mato Grosso. The estimated values of Shannon’s diversity
index ranged from 0.093 for the Assis-Brasil district of Acre to 0.389 for the Jiparana district of Rondonia. The analysis
of molecular variance (AMOVA) indicated that most of the genetic variations were found among accessions within the districts,
while interdistrict variance component accounted for 14.1% only. The low interdistrict differentiation probably implied an
extensive gene flow among them. Both the principal coordinate analysis and UPGMA cluster analysis based on genetic distance
values revealed a varying degree of separation among the districts and that conformed to geographical origins of Hevea IRRDB’81 collection. 相似文献
4.
M.J. Iqbal O.U.K. Reddy K.M. El-Zik A.E. Pepper 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(4):547-554
Reliable information about the evolutionary and genetic relationships of various germplasm resources is essential to the establishment
of rational strategies for crop improvement. We used AFLPs to study the genetic relationships of 43 cultivars of Gossypium hirsutum representative of the genomic composition of modern ’Upland’ cotton. The study also included representatives of the related
tetraploid species Gossypium barbadense, as well as the diploid species Gossypium raimondii, Gossypium incanum, Gossypium herbaceum and Gossypium arboreum. We tested 20 primer combinations that resulted in a total of 3,178 fragments. At the species level, and above, genetic similarities
based on AFLPs were in agreement with the known taxonomic relationships. Similarity indices ranged from 0.25 to 0.99. Representatives
of the G. hirsutum germplasm resources utilized in North America, including secondary accessions collected by breeders in Central America (’Acala’,
’Tuxtla’, ’Kekchi’) and the southwestern US (’Hopi Moencopi’), formed a single cluster with exceedingly limited genetic diversity
(with many pairwise similarity indices >0.96) We concluded that these accessions were derived from the same genetic pool.
The early maturing or ’latifolium’ or ’Mexican Highlands’ cultigens from which these cultivars were derived appear to have
had extremely limited genetic diversity, perhaps as a result of a severe genetic bottleneck resulting from the selection pressures
of domestication. Outside of the major G. hirsutum cluster, well-supported phylogenies were inferred. Inside this cluster, phylogenies were obscured by limited diversity, reticulation
and lineage sorting. The implications of these findings for cotton improvement are discussed.
Received: 23 May 2000 / Accepted: 23 January 2001 相似文献
5.
Tadeusz Zaj c Stanisław Grzesiak Bogdan Kulig Milan Polá ek 《Acta Physiologiae Plantarum》2005,27(4):549-558
In three year field experiments (2001 – 2003) the growth, yield and productivity of 8 flax cultivars were compared. Cultivars
‘AC Linora’, ‘Flanders’, ‘Linola™ 947’, ‘Norlin’ and ‘Omega’ were obtained from Canada, ‘Barbara’ and ‘Hungarian Gold’ from
Hungary and ‘Opal’ from Poland. Apart from the estimation of the yield of aboveground parts dry matter and seed yield the
determinations of the primary index value of growth analysis were done and on their basis the indices LAI, LAD, RGR, CGR and
HI were calculated.
The obtained yield results of the examined flax cultivars show significant genotypic — environmental relationships pertaining
to the dynamics of dry matter accumulation and the amount of seed yield. Meteorological conditions in the successive years
significantly influenced the particular phases of growth and development of cultivars and the factor which increased the amount
of dry matter was the air temperature during the period of plant emergence — budding. During the vegetative season with a
large amount of rainfall the average seed yield was about 40 % lower than compared with a year of average precipitation and
a warm second part of the second period of flax vegetation. Among the analyzed cultivars a stable yield in all the years was
characteristic for cultivars ‘Flanders’, ‘Barbara’ and ‘AC Linora’ (that cultivar, however, during a wet year yielded at a
low level). The assimilation leaf surface of the linseed quickly increased during the period from budding to flowering and
the accumulation of dry matter of the aboveground parts lasted up to the green maturity. In the successive years of the experiment
there were observed significant (linear or logarithmic regressions) relationship between the yield of dry matter and the indices
of growth analysis. The biggest values of the CGR indicator were observed for the period from budding to flowering. The maintaining
of a high CGR value after plant flowering in the year with a favourable course of climatic parameters was beneficial for a
better yield of all flax cultivars. The low values of the RGR index after flowering of cultivar ‘Hungarian Gold’ and ‘Opal’
strictly corresponded to their low yield of seed and straw biomass. 相似文献
6.
Hedia Bourguiba Lamia Krichen Jean-Marc Audergon Bouchaib Khadari Neila Trifi-Farah 《Plant Molecular Biology Reporter》2010,28(4):578-587
The impact of mapped microsatellites on the study of genetic diversity of Tunisian apricot accessions was assessed. The genetic
variability of 47 traditional apricot cultivars originating from several areas in Tunisia was investigated with 32 polymorphic
microsatellite loci selected for their location throughout the eight linkage groups of Prunus genome. The higher polymorphism and greater transportability of these markers among Prunus species were proved by the expected heterozygosity (He = 0.56) and Shannon’s index of diversity (I = 1.05), indicating that Tunisian apricot germplasm maintained a substantial level of genetic diversity. According to their
geographical origin, the genetic differentiation among groups (north, center, and south; Fst = 0.04) was lower, while the
gene flow among groups was consequent (Nm = 4.79), attesting a narrow genetic background of apricot in the country. Both unweighted
pair-group method with arithmetic mean dendrogram, based on Nei’s genetic distances and factorial correspondence analysis,
separated northern cultivars from central and southern cultivars, revealing the same molecular basis of apricot material in
the Center and the South of Tunisia. These results revealed the efficiency of mapped markers for genetic variability measurements
compared to randomly ones, however, no advantage was observed considering the genetic relationships among studied accessions. 相似文献
7.
P. K. Subudhi S. Nandi C. Casal S. S. Virmani N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):941-949
The cytoplasmic genetic male-sterile (CMS) lines developed at the International Rice Research Institute are valuable in producing
tropical rice hybrids. Efficient use of CMS lines in hybrid rice production will depend on their level of genetic diversity.
Aside from morphological characterization, molecular analysis based on DNA markers can provide information on the genetic
diversity of the germplasm. The Amplified Fragment Length Polymorphism (AFLP) technique was used to fingerprint 71 CMS lines
and four rice cultivars, ‘IR64’, ‘Azucena’, ‘IR74’, and ‘FR13A’. Eleven primer pair combinations specific to the enzymes PstI and MseI were used to generate 530 AFLP markers, 176 of which were polymorphic. Each CMS line revealed a distinct fingerprint. The
AFLP marker-based dendrogram depicted genetic variation among the CMS lines. The CMS lines developed in japonica background
grouped with ‘Azucena’, a japonica cultivar. None of the CMS lines clustered with ‘FR13A’, a flood-tolerant traditional indica
variety. ‘IR64’ was found to be distinct from the other indica CMS lines and clustered with lines developed in its background.
The grouping of CMS lines into a few groups is useful for breeders in selecting genetically diverse CMS lines for hybrid rice
production and in avoiding test crossing every CMS line empirically. This study demonstrated that AFLP is a powerful and reliable
tool in determining the genetic relationships and in producing distinct fingerprints of rice cultivars.
Received: 20 December 1996 / Accepted: 9 October 1997 相似文献
8.
Lyudmylla Malysheva-Otto Martin W. Ganal John R. Law James C. Reeves Marion S. Röder 《Molecular breeding : new strategies in plant improvement》2007,20(4):309-322
The changes of genetic diversity over time were monitored in 504 European barley cultivars released during the 20th century
by genotyping with 35 genomic microsatellites. For analysis, the following four temporal groups were distinguished: 1900–1929
(TG1 with 19 cultivars), 1930–1949 (TG2 with 40 cultivars), 1950–1979 (237 cultivars as TG3), and 1980–2000 (TG4 consisting
of 208 cultivars). After rarefaction of allelic diversity data to the comparable sample size of 18 varieties, of the 159 alleles
found in the first group (TG1) 134 were retained in the last group (TG4) resulting in a loss of only 15.7% of alleles. On
the other hand 51 novel alleles were discovered in the group representing the last investigated time period (TG4) in comparison
with the TG1. Novel alleles appeared evenly distributed over the genome, almost at all investigated genomic loci, with up
to five such novel alleles per locus. Alleles specific for a temporal group were discovered for all investigated time periods,
however analysis of molecular variance (AMOVA) did not reveal any significant population structure attributable to temporal
decadal grouping. Only 2.77% of the total observed variance was due to differences between the four temporal groups and 1.42%
between individual decades of the same temporal group, while 95.81% of the variance was due to variation within temporal groups.
The distinction between two-rowed and six-rowed genetic types accounted for 19.5% of the total observed variance by AMOVA,
whereas the comparison between ‘winter’ and ‘spring’ types accounted for 17% of the total observed variation. The analysis
of linkage disequilibrium did not reveal statistically significant differences between the temporal groups. The results indicated
that the impact of breeding effort and variety delivery systems did not result in any significant quantitative losses of genetic
diversity in the representative set of barley cultivars over the four time periods. 相似文献
9.
A mini core subset for capturing diversity and promoting utilization of chickpea genetic resources in crop improvement 总被引:17,自引:0,他引:17
H. D. Upadhyaya R. Ortiz 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1292-1298
A core collection is a chosen subset of large germplasm collection that generally contains about 10% of the total accessions
and represents the genetic variability of entire germplasm collection. The purpose of a core collection is to improve the
use of genetic resources in crop improvement programs. In many crops the number of accessions contained in the genebank are
several thousands, and a core subset consisting of 10% of total accessions would be an unwieldy proposition. In this article
we have suggested a two-stage strategy to select a chickpea mini core subset consisting of only about 1% of the entire collection
held in trust at ICRISAT’s genebank (16,991 accessions). This mini core subset still represents the diversity of the entire
core collection. The first stage involves developing a representative core subset (about 10%) from the entire collection using
all the available information on origin, geographical distribution, and characterization and evaluation data of accessions.
The second stage involves evaluation of the core subset for various morphological, agronomic, and quality traits, and selecting
a further subset of about 10% accessions from the core subset. At both stages standard clustering procedure was used to separate
groups of similar accessions. A mini core subset consisting 211 accessions from 1,956 core subset accessions, using data on
22 morphological and agronomic traits, was selected. Newman- Keuls’ test for means, Levene’s test for variances, the chi-square
test and Wilcoxon’s rank-sum non-parametric test for frequency distribution analysis for different traits indicated that the
variation available in the core collection has been preserved in the mini core subset. The most important phenotypic correlations
which may be under the control of coadapted gene complexes, were also preserved in the mini core. This mini core subset, due
to its drastically reduced size, will prove to be a point of entry to proper exploitation of chickpea genetic resources.
Received: 20 August 2000 / Accepted: 25 September 2000 相似文献
10.
Shashi Bhushan Choudhary Hariom Kumar Sharma Arroju Anil Kumar Rangappa Thimmaiah Maruthi Jiban Mitra Isholeena Chowdhury Binay Kumar Singh Pran Gobinda Karmakar 《Comptes rendus biologies》2017,340(2):65-75
A total of 130 flax accessions of diverse morphotypes and worldwide origin were assessed for genetic diversity and population structure using 11 morphological traits and microsatellite markers (15 gSSRs and 7 EST–SSRs). Analysis performed after classifying these accessions on the basis of plant height, branching pattern, seed size, Indian/foreign origin into six categories called sub-populations viz. fibre type exotic, fibre type indigenous, intermediate type exotic, intermediate type indigenous, linseed type exotic and linseed type indigenous. The study assessed different diversity indices, AMOVA, population structure and included a principal coordinate analysis based on different marker systems. The highest diversity was exhibited by gSSR markers (SI = 0.46; He = 0.31; P = 85.11). AMOVA based on all markers explained significant difference among fibre type, intermediate type and linseed type populations of flax. In terms of variation explained by different markers, EST-SSR markers (12%) better differentiated flax populations compared to morphological (9%) and gSSR (6%) markers at P = 0.01. The maximum Nei's unbiased genetic distance (D = 0.11) was observed between fibre type and linseed type exotic sub-populations based on EST-SSR markers. The combined structure analysis by using all markers grouped Indian fibre type accessions (63.4%) in a separate cluster along with the Indian intermediate type (48.7%), whereas Indian accessions (82.16%) of linseed type constituted an independent cluster. These findings were supported by the results of the principal coordinate analysis. Morphological markers employed in the study found complementary with microsatellite based markers in deciphering genetic diversity and population structure of the flax germplasm. 相似文献
11.
Osman Gulsen Songul Sever-Mutlu Nedim Mutlu Metin Tuna Osman Karaguzel Robert C. Shearman Terrance P. Riordan Tiffany M. Heng-Moss 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(7):1309-1319
Developing a better understanding of associations among ploidy level, geographic distribution, and genetic diversity of Cynodon accessions could be beneficial to bermudagrass breeding programs, and would enhance our understanding of the evolutionary
biology of this warm season grass species. This study was initiated to: (1) determine ploidy analysis of Cynodon accessions collected from Turkey, (2) investigate associations between ploidy level and diversity, (3) determine whether
geographic and ploidy distribution are related to nuclear genome variation, and (4) correlate among four nuclear molecular
marker systems for Cynodon accessions’ genetic analyses. One hundred and eighty-two Cynodon accessions collected in Turkey from an area south of the Taurus Mountains along the Mediterranean cost and ten known genotypes
were genotyped using sequence related amplified polymorphism (SRAP), peroxidase gene polymorphism (POGP), inter-simple sequence
repeat (ISSR), and random amplified polymorphic DNA (RAPD). The diploids, triploids, tetraploids, pentaploids, and hexaploids
revealed by flow cytometry had a linear present band frequency of 0.36, 0.47, 0.49, 0.52, and 0.54, respectively. Regression
analysis explained that quadratic relationship between ploidy level and band frequency was the most explanatory (r = 0.62, P < 0.001). The AMOVA results indicated that 91 and 94% of the total variation resided within ploidy level and provinces, respectively.
The UPGMA analysis suggested that commercial bermudagrass cultivars only one-third of the available genetic variation. SRAP,
POGP, ISSR, and RAPD markers differed in detecting relationships among the bermudagrass genotypes and rare alleles, suggesting
more efficiency of combinatory analysis of molecular marker systems. Elucidating Cynodon accessions’ genetic structure can aid to enhance breeding programs and broaden genetic base of commercial cultivars.
O. Gulsen and S. Sever-Mutlu contributed equally to this work. 相似文献
12.
Hilde Nybom Artur Mikiciński Larisa Garkava-Gustavsson Jasna Sehic Mariusz Lewandowski Piotr Sobiczewski 《Trees - Structure and Function》2012,26(1):199-213
Fire blight (Erwinia amylovora) causes serious damage to pome fruit orchards, and identification of germplasm with heritable disease resistance is therefore
crucial. Two dominant SCAR (sequence characterised amplified region) marker alleles (AE10-375 and GE-8019), flanking a previously
identified QTL (quantitative trait locus) for resistance to fire blight on ‘Fiesta’ linkage group 7 in apple cultivars related
to ‘Cox’s Orange Pippin’, were screened on 205 apple cultivars. Both marker alleles were present in 22% of the cultivars,
indicating presence of the QTL allele for tolerance, and both were lacking in 25%, indicating homozygosity for absence of
the QTL tolerance allele. However, 33% had only the marker allele AE10-375, while 20% had only GE-8019, suggesting that some
cultivars with the dominant alleles for both of the flanking markers can carry these on separate chromosomes and may lack
the QTL allele for tolerance. In 2009 and 2010, terminal shoots of greenhouse-grown grafted trees of 21 cultivars (only 20
in 2010) were inoculated with Erwinia amylovora. ‘Idared’ (susceptible) and ‘Enterprise’ (tolerant) were included as controls. Disease severity for each cultivar was expressed
as percentage of necrosis in relation to entire length of shoot, and the ranking of cultivars in 2009 and 2010 was compared
with a Spearman rank correlation test, P < 0.01. A relationship between presence of both flanking marker alleles for tolerance and level of fire blight tolerance
was confirmed with a Mann–Whitney U-test, P < 0.01 in 2009, and P < 0.05 in 2010. A PCO (principal coordinate) analysis based on band profiles obtained with 12 SSR (simple sequence repeat)
loci produced three loose clusters, two of which contained known offspring of ‘Cox’s Orange Pippin’, and one with cultivars
that were either unrelated or had an unknown origin. Cases where DNA markers did not predict level of fire blight damage as
expected, were, however, as common among descendants of ‘Cox’s Orange Pippin’ as among apparently unrelated cultivars. Obviously
the ‘Fiesta’ LG 7 QTL has some predictive value, both for known ‘Cox’ relatives and others, but more efficient markers would
be desirable for marker-assisted selection. 相似文献
13.
Local cultivars adapted to specific environmental conditions are the chief source of seed for farmers in Ethiopia and deserve
research priority. The aim of this study was, therefore, to determine the genetic relationships between different barley landraces,
from north Shewa in Ethiopia so as to differentiate genotypes known by different local names and facilitate their conservation
and use in breeding new varieties. Five AFLP primer combinations were analyzed for 19 barley landraces and five malting varieties.
The number of scoreable fragments amplified by each AFLP primer combination varied from 49 to 118 with an average of 84.5
and polymorphic fragments for each primer combination varied from 27 to 77 with an average of 58.5. The average percent polymorphism
was 69.9% with values ranging from 55.1% to 75.8%. Cluster analysis placed the accessions and malting varieties into one main
group while all the farmers’ cultivars, with the exception of two, were in the other main group. It was shown that sampling
of germplasm at a given locality might not represent the whole array of genetic variability of locally grown famers’ cultivars.
A comprehensive study of all the farmers’ barley cultivars, grown in different parts of Ethiopia, is required to maximize
the efforts of germplasm conservation and utilization in national and regional breeding programs. 相似文献
14.
Bettina Heider Meike S. Andersson Rainer Schultze-Kraft 《Biodiversity and Conservation》2007,16(6):1617-1631
Flemingia macrophylla (Willd.) Kuntze ex Merr., a multi-purpose legume with potential as dry-season forage crop, mainly occurs in subhumid to humid
environments of tropical and subtropical Asia. Despite increasing interest in conservation of germplasm suitable for low-input
production systems information on the genetic diversity of F. macrophylla is extremely scarce. The creation of baseline data is supposed to contribute to more efficient conservation management and
to identify collecting strategies of novel germplasm. Random amplified polymorphic (RAPD) markers were used to investigate
the genetic variation among 37 F. macrophylla accessions. Germplasm analysed in this study originated from Bac Kan province, Northeast Vietnam. Eight primers generated
a total of 47 amplified RAPD loci of which 38 were polymorphic. Jaccard’s similarity coefficients among accessions ranged
from 0.069 to 1 with a mean of 0.67. The UPGMA dendrogram revealed three clusters along with three outliers. No correspondence
between geographic and genetic distance was found (Mantel test: R = 0.21; P = 0.016). Analysis of molecular variance (AMOVA) revealed significant (P < 0.001) differentiation between accessions collected in lowland and upland regions. Results of UPGMA clustering were confirmed
by the pattern of principle coordinates analysis (PCO) plotting. Future collecting strategies should target populations at
large distances and along the altitudinal range. Ex situ conservation should encompass those accessions that showed genetic
divergence. In situ conservation may consist of establishing a system of interconnected population fragments to guarantee
continuing genetic exchange via corridors and of rehabilitating degraded habitats. 相似文献
15.
Chuanxiao Xie Marilyn Warburton Mingshun Li Xinhai Li Muji Xiao Zhuanfang Hao Qi Zhao Shihuang Zhang 《Molecular breeding : new strategies in plant improvement》2008,21(4):407-418
This study analyzes population structure and linkage disequilibrium (LD) among 187 commonly used Chinese maize inbred lines,
representing the genetic diversity among public, commercial and historically important lines for corn breeding. Seventy SSR
loci, evenly distributed over 10 chromosomes, were assayed for polymorphism. The identified 290 alleles served to estimate
population structure and analyze the genome-wide LD. The population of lines was highly structured, showing 6 subpopulations:
BSSS (American BSSS including Reid), PA (group A germplasm derived from modern U.S. hybrids in China), PB (group B germplasm
derived from modern U.S. hybrid in China), Lan (Lancaster Surecrop), LRC (derivative lines from Lvda Reb Cob, a Chinese landrace)
and SPT (derivative lines from Si-ping-tou, a Chinese landrace). Forty lines, which formerly had an unknown and/or miscellaneous
origin and pedigree record, were assigned to the appropriate group. Relationship estimates based on SSR marker data were quantified
in a Q matrix, and this information will inform breeder’s decisions regarding crosses. Extensive inter- and intra-chromosomal
LD was detected between 70 microsatellite loci for the investigated maize lines (2109 loci pairs in LD with D′ > 0.1 and 93 out of them at P < 0.01).This suggests that rapidly evolving microsatellites may track recent population structure. Interlocus LD decay among
the diverse maize germplasm indicated that association studies in QTLs and/or candidate genes might avoid nonfunctional and
spurious associations since most of the LD blocks were broken between diverse germplasm. The defined population structure
and the LD analysis present the basis for future association mapping.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Evaluating genetic relationships between indigenous coconut (Cocos nucifera L.) accessions from Sri Lanka by means of AFLP profiling 总被引:2,自引:0,他引:2
L. Perera J. R. Russell J. Provan J. W. McNicol W. Powell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(3-4):545-550
PCR-based DNA profiling of coconut palms indigenous to Sri Lanka was conducted using amplified fragment length polymorphism
(AFLPs). A total of 322 amplification products were generated from the 42 genotypes with eight pairs of primers (EcoRI and MseI). Overall most variation was detected in the tall (Typica) rather than the intermediate (Aurantiaca) and dwarf (Nana) forms.
A hierarchical analysis of molecular variance (AMOVA) was used to quantify and partition levels of variability into between-
and within-form components. This revealed that for the inbreeding dwarf and intermediate forms most variation was observed
between, rather than within, forms. In contrast, the outbreeding tall forms exhibited as much variation within as between
forms. These observations have important implications for the maintenance and collection of coconut germplasm. This study
also provided insights into the genetic (as opposed to phenotypic) relatedness of coconut accessions. Morphologically the
Aurantiaca group of accessions are considered to be intermediate between the tall and dwarf accessions. Estimation of genetic
relatedness based on AFLP analysis identified the Aurantiaca group as being more similar to the dwarf rather than the tall
group. In addition, putative duplicate accessions were identified in the Aurantiaca group. Information emerging from this
study will facilitate the management of coconut germplasm and optimise the choice of genetically divergent parents for crossing.
Received: 16 June 1997 / Accepted: 14 October 1997 相似文献
17.
Y. M. Charters M. J. Wilkinson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(1):160-166
Theobroma cacao ) genotypes. Six primers were sufficient to distinguish all but three pairs of the 62 accessions examined. A UPGMA dendrogram
was used to provide a measure of the genetic variability between genotypes. The scale was supplied by the inclusion of Theobroma grandiflora as an ’out group’ and also by the use of two contrasting progenies as ’in groups’. The ’in groups’ were obtained from the
self-pollination of one plant (SPEC 54.1) known to be highly homozygous and also of a second, highly heterozygous, clone (P
19B). These reference points allowed several documentation errors to be resolved and provided a basis for identifying unwanted
or low-priority material. Implications of the work for the routine maintenance of large germplasm collections are briefly
discussed.
Received: 20 January 1999 / Accepted: 25 May 1999 相似文献
18.
This study analyzed genetic differences of 19 cultivars selected from somaclonal variants of Syngonium podophyllum Schott along with their parents as well as seven additional Syngonium species and six other aroids using amplified fragment length polymorphism (AFLP) markers generated by 12 primer sets. Among the 19 somaclonal cultivars, ‘Pink Allusion’ was selected from ‘White Butterfly’. Tissue culture of ‘Pink Allusion’ through organogenesis resulted in the development of 13 additional cultivars. Self-pollination of ‘Pink Allusion’ obtained a cultivar, ‘Regina Red Allusion’, and tissue culture propagation of ‘Regina Red Allusion’ led to the release of five other cultivars. The 12 primer sets generated a total of 1,583 scorable fragments from all accessions, of which 1,284 were polymorphic (81.9%). The percentages of polymorphic fragments within ‘White Butterfly’ and ‘Regina Red Allusion’ groups, however, were only 1.2% and 0.4%, respectively. Jaccard's similarity coefficients among somaclonal cultivars derived from ‘White Butterfly’ and ‘Regina Red Allusion’, on average, were 0.98 and 0.99, respectively. Seven out of the 15 cultivars from the ‘White Butterfly’ group and three out of six from the ‘Regina Red Allusion’ group were clearly distinguished by AFLP analysis as unique fragments were associated with respective cultivars. The unsuccessful attempt to distinguish the remaining eight cultivars from the ‘White Butterfly’ group and three from the ‘Regina Red Allusion’ group was not attributed to experimental errors or the number of primer sets used; rather it is hypothesized to be caused by DNA methylation and/or some rare mutations. This study also calls for increased genetic diversity of cultivated Syngonium as they are largely derived from somaclonal variants. 相似文献
19.
J. Xu S. V. Constantino G. Magpantay J. Bennett S. Sarkarung N. Huang 《Plant cell reports》1998,17(8):640-645
The polymerase chain reaction (PCR) was used to survey DNA sequence variation among 12 indica and 10 japonica rice cultivars.
Of the 143 primer pairs used, 37 detected amplicon length polymorphism (ALP) and 11 revealed PCR banding patterns paralleled
with the indica/japonica differentiation. Thus the 11 primer pairs were used to discriminate the two rice subspecies. A collection
of 116 accessions representing the breadth of rice germplasm was analyzed for ALP at the 11 loci. Rice accessions with scores
of 0.3 or more were classified as indica while those with –0.3 or less were classified as japonica. Those with scores from
–0.3 to 0.3 were considered intermediate. With this criterion, 70 accessions were classified as indica, 35 accessions as japonica,
and 11 accessions as intermediate. The concept and the approach used here for rice should be equally applicable for classifying
other plant species.
Received: 1 July 1997 / Revision received: 4 December 1997 / Accepted: 29 December 1997 相似文献
20.
Microsatellite-based molecular diversity of bread wheat germplasm and association mapping of wheat resistance to the Russian wheat aphid 总被引:1,自引:0,他引:1
Genetic diversity of a set of 71 wheat accessions, including 53 biotype 2 Russian wheat aphid (RWA2)-resistant landraces and
18 RWA2 susceptible accessions, was assessed by examining molecular variation at multiple microsatellite (SSR) loci. Fifty-one
wheat SSR primer pairs were used, 81 SSR loci were determined, and 545 SSR alleles were detected. These SSR loci covered all
the three genomes, 21 chromosomes, and at least 41 of the 42 chromosome arms. Diversity values averaged over SSR loci were
high with mean number of SSR alleles/locus = 6.7, mean Shannon’s index (H) = 1.291, and mean Nei’s gene diversity (He) = 0.609. The three wheat genomes ranked as A > D > B and the homoeologous groups ranked as 7 > 3 > 1 > 2 > 6 > 5 > 4 based
on the number of alleles per locus. Xgwm136 on chromosome arm 1AS is the most polymorphic SSR locus with the largest number of observed and effective alleles and the
highest H and He. Among all 2485 pairs of wheat accessions, genetic distance (GD) ranged from 0.054 to 1.933 and averaged 0.9832. A dendrogram
based on GD matrix showed that all the wheat accessions could be grouped into distinct clusters. Most of the susceptible cultivars
(13/18) were clustered into groups that contains all or mostly susceptible accessions. Most of the U.S. cultivars belong to
a group that is distinguishable from all the different RWA2 resistant groups. Diversity analysis was also conducted separately
for subgroups containing 53 RWA2-resistant accessions and 18 RWA2-susceptible accessions. Association mapping revealed 28
SSR loci significantly associated with leaf chlorosis, and 8 with leaf rolling. New chromosome regions associated with RWA2
resistance were detected, and indicated existence of new RWA resistance genes located on chromosomes of all other homoeologous
groups in addition to the groups 1 and 7 in bread wheat. This information is helpful for development of mapping populations
for RWA2 resistance genes from different phylogenetic groups, and for wise utilization of the RWA-resistant germplasm in wheat
breeding programs. 相似文献