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1.
Sledge MK Ray IM Jiang G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(5):980-992
A genetic map constructed from a population segregating for a trait of interest is required for QTL identification. The goal
of this study was to construct a molecular map of tetraploid alfalfa (Medicago sativa.) using simple sequence repeat (SSR) markers derived primarily from expressed sequence tags (ESTs) and bacterial artificial
chromosome (BAC) inserts of M. truncatula. This map will be used for the identification of drought tolerance QTL in alfalfa. Two first generation backcross populations
were constructed from a cross between a water-use efficient, M. sativa subsp. falcata genotype and a low water-use efficient M. sativa subsp. sativa genotype. The two parents and their F1 were screened with 1680 primer pairs designed to amplify SSRs, and 605 single dose alleles (SDAs) were amplified. In the
F1, 351 SDAs from 256 loci were mapped to 41 linkage groups. SDAs not inherited by the F1, but transmitted through the recurrent parents and segregating in the backcross populations, were mapped to 43 linkage groups,
and 44 of these loci were incorporated into the composite maps. Homologous linkage groups were joined to form eight composite
linkage groups representing the eight chromosomes of M. sativa. The composite maps consist of eight composite linkage groups with 243 SDAs from M. truncatula EST sequences, 38 SDAs from M. truncatula BAC clone sequences, and five SDAs from alfalfa genomic SSRs. The total composite map length is 624 cM, with average marker
density per composite linkage group ranging from 1.5 to 4.4 cM, and an overall average density of 2.2 cM. Segregation distortion
was 10%, and distorted loci tended to cluster on individual homologues of several linkage groups.
Electronic Supplementary Material Supplementary material is available for this article at 相似文献
2.
Narasimhamoorthy B Bouton JH Olsen KM Sledge MK 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(5):901-913
Aluminum (Al) toxicity in acid soils is a major limitation to the production of alfalfa (Medicago sativa subsp. sativa L.) in the USA. Developing Al-tolerant alfalfa cultivars is one approach to overcome this constraint. Accessions of wild
diploid alfalfa (M. sativa subsp. coerulea) have been found to be a source of useful genes for Al tolerance. Previously, two genomic regions associated with Al tolerance
were identified in this diploid species using restriction fragment length polymorphism (RFLP) markers and single marker analysis.
This study was conducted to identify additional Al-tolerance quantitative trait loci (QTLs); to identify simple sequence repeat
(SSR) markers that flank the previously identified QTLs; to map candidate genes associated with Al tolerance from other plant
species; and to test for co-localization with mapped QTLs. A genetic linkage map was constructed using EST-SSR markers in
a population of 130 BC1F1 plants derived from the cross between Al-sensitive and Al-tolerant genotypes. Three putative QTLs on linkage groups LG I,
LG II and LG III, explaining 38, 16 and 27% of the phenotypic variation, respectively, were identified. Six candidate gene
markers designed from Medicago truncatula ESTs that showed homology to known Al-tolerance genes identified in other plant species were placed on the QTL map. A marker
designed from a candidate gene involved in malic acid release mapped near a marginally significant QTL (LOD 2.83) on LG I.
The SSR markers flanking these QTLs will be useful for transferring them to cultivated alfalfa via marker-assisted selection
and for pyramiding Al tolerance QTLs. 相似文献
3.
Construction of a basic genetic map for alfalfa using RFLP, RAPD, isozyme and morphological markers 总被引:12,自引:0,他引:12
György B. Kiss Gyula Csanádi Katalin Kálmán Péter Kaló László Ökrész 《Molecular & general genetics : MGG》1993,238(1-2):129-137
The genetic map for alfalfa presented here has eight linkage groups representing the haploid chromosome set of the Medicago species. The genetic map was constructed by ordering the linkage values of 89 RFLP, RAPD, isozyme and morphological markers collected from a segregating population of 138 individuals. The segregating population is self-mated progeny of an F1 hybrid plant deriving from a cross between the diploid (2n=2x=16) yellow-flowered Medicago sativa ssp. quasifalcata and the diploid (2n=2x=16) blue-flowered M. sativa ssp. coerulea. The inheritance of many traits displayed distorted segregation, indicating the presence of lethal loci in the heterozygotic parent plants. In spite of the lack of uniform segregation, linkage groups could be assigned and the order of the markers spanning > 659 centimorgans could be unambiguously determined. This value and the calculated haploid genome size for Medicago (1n=1x=1.0 x 109 bp) gives a ratio of < 1500 kb per centimorgan. 相似文献
4.
P. Kaló G. Endre L. Zimányi G. Csanádi G. B. Kiss 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(5):641-657
An improved genetic map of diploid (2n=2x=16) alfalfa has been developed by analyzing the inheritance of more than 800 genetic
markers on the F2 population of 137 plant individuals. The F2 segregating population derived from a self-pollinated F1 hybrid individual of the cross Medicago sativa ssp. quasifalcata ×Medicago sativa ssp. coerulea. This mapping population was the same one which had been used for the construction of our previous alfalfa genetic map. The
genetic analyses were performed by using maximum-likelihood equations and related computer programs. The improved genetic
map of alfalfa in its present form contains 868 markers (four morphological, 12 isozyme, 26 seed protein, 216 RFLP, 608 RAPD
and two specific PCR markers) in eight linkage groups. Of the markers 80 are known genes, including 2 previously cytologically
localized genes, the rDNA and the β-tubulin loci. The genetic map covers 754 centimorgans (cM) with an average marker density
of 0.8/cM. The correlation between the physical and genetic distances is about 1000–1300 kilobase pairs per centiMorgan. In
this map, the linkage relationships of some markers on linkage groups 6, 7, and 8 are different from the previously published
one. The cause of this discrepancy was that the genetic linkage of markers displaying distorted segregation (characterized
by an overwhelming number of heterozygous individuals) had artificially linked genetic regions that turned out to be unlinked.
To overcome the disadvantageous influence of the excess number of heterozygous genotypes on the recombination fractions, we
used recently described maximum-likelihood formulas and colormapping, which allowed us to exclude the misleading linkages
and to estimate the genetic distances more precisely.
Received: 19 October 1998 / Accepted: 15 April 1999 相似文献
5.
Maureira IJ Ortega F Campos H Osborn TC 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(4):775-782
Although unadapted germplasms have been used to improve disease and insect resistance in alfalfa, there has been little effort to use these for improving forage yield. We evaluated genetic diversity and combining ability among two unadapted germplasms (Medicago sativa ssp. sativa Peruvian and M. sativa ssp. falcata WISFAL) and three Northern U.S. adapted alfalfa cultivars. Population structure analyses indicated that the WISFAL and Peruvian germplasms were genetically distinct from the cultivars, although Peruvian was relatively closer to the cultivars. Peruvian and WISFAL germplasms were intermated to generate a novel hybrid population. This population was crossed to the three cultivars as testers, and the testcross progenies were evaluated for forage yield along with the hybrid population, the original germplasms (Peruvian, WISFAL and cultivars), testcrosses of Peruvian and WISFAL to the three cultivars and a three-way hybrid of the cultivars. The experiment was carried out in the field in Temuco, Chile and Arlington, Wisconsin, USA, and forage was harvested during two seasons. Results from these evaluations showed that hybrids between the Peruvian × WISFAL population and the cultivar testers yielded as much as the cultivar testers. Heterosis was observed between Peruvian and WISFAL, and between these germplasms and the cultivar testers, suggesting that each germplasm may contain different favorable alleles. If Peruvian and WISFAL populations contain alleles at different loci that complement cultivar testers, then combining and enriching these alleles in a single population could result in improved combining ability with alfalfa cultivars. 相似文献
6.
D. J. Brouwer T. C. Osborn 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(7-8):1194-1200
A genetic linkage map was constructed for an F1 genotype of auto-tetraploid alfalfa (Medicago sativa L.) using two backcross populations of 101 individuals each and 82 single-dose restriction fragments segregating in each
population. The percentages of marker loci deviating from Mendelian ratios were considerably less than reported for inbred
diploid mapping populations (4–9% compared to 18–54%), probably due to the greater buffering capacity of autotetraploids against
the effects of deleterious recessive alleles. Four homologous coupling-phase cosegregation groups were detected for seven
of the eight linkage groups of diploid alfalfa and aligned using probes in common. No cosegregation groups were found for
linkage group 7 due to the lack of polymorphisms in this cross. A composite map was generated by integrating the four homologous
cosegregation groups and consisted of 88 loci on seven linkage groups covering 443 cM. The locus map-orders and distances
were in general agreement with those found in diploid alfalfa. The mapping population segregates for winterhardiness, fall
dormancy, and freezing tolerance; and the map will be used to locate genomic regions affecting these traits.
Received: 9 December 1998 / Accepted: 22 June 1999 相似文献
7.
G. Endre P. Kaló M. Hangyel Tárczy G. Csanádi G. B. Kiss 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(7):1061-1065
MnNC-1008(NN) (referred to as MN-1008) is a tetraploid alfalfa mutant with two recessive genes (nn
1
and nn
2
)conditioning the non-nodulating trait. The tetraploid level (2n=4x=32) of this Medicago sativa germ plasm was reduced to the diploid (2n=2x=16) level using the 4x-2x genetic cross originally described as a workable method for the induction of haploidy in alfalfa by T. E. Bingham. In our experiments more than 7000 emasculated flowers of a single non-nodulating MN-1008 mutant alfalfa plant with purple petals were cross-pollinated with pollen from a single, diploid, yellow-flowered alfalfa plant. Mature seeds from these crosses were collected and germinated, after which the plants were subjected to morphological and cytogenetic analyses as well as to DNA fingerprinting. Out of 26 viable progeny, 6 were hybrid plants, 19 proved to be self-mated derivatives of MN-1008, while one descendant turned out to be a diploid (2n=2x=16), purple flowered, non-nodulating plant denoted as M. sativa DN-1008. This diploid, non-nodulating alfalfa plant can serve as starting material to facilitate the comprehensive morphological, physiological and genetic analysis (gene mapping and cloning) of nodulation in order to learn more about the biology of the symbiotic root nodule development. To produce diploid, nodulating hybrid F1 plants, DN-1008 was crossed with a diploid, yellow-flowered M. sativa ssp. quasifalcata plant. An F2 population segregating the nn
1
and nn
2
genes in a diploid manner, in which the genetic analysis is more simple than in a tetraploid population, can be established by self-mating of the F1 plants. 相似文献
8.
Regina Vyšniauskienė Vida Rančelienė Jolanta Patamsytė Donatas Žvingila 《Central European Journal of Biology》2013,8(5):480-491
Alfalfa (Medicago sativa; =M. sativa ssp. sativa) in Lithuania is sown as albuminous forage for cattle due to favourable climatic condition. Over many generations, alfalfa plants have escaped from cultivation fields into natural ecosystems and established wild populations. We collected and analyzed individuals from seventeen wild populations of M. sativa. Using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses, 117 RAPD and 64 ISSR reproducible and highly polymorphic (90.8% for RAPD and 86.3% for ISSR) loci were established. AMOVA showed a high genetic differentiation of M. sativa populations for both types of DNA markers utilized. According to RAPD markers, the genetic variability among populations was 63.1% and 57.0% when ISSR markers were used. Taken together, these results demonstrate that wild populations of M. sativa possess a high potential of genetic variability, that could potentially result in colonization of natural ecosystems. The UPGMA cluster analysis also showed that the DNA markers discovered in this study can distinguish between M. sativa and M. falcata (=M. sativa ssp. falcata) populations and therefore may be used to study the genetic impact of M. sativa on the native populations of M. falcata. 相似文献
9.
The evolution of hemolytic saponin content in wild and cultivated Alfalfa (Medicago sativa,Fabaceae)
Hemolytic saponin content was determined of the leaves of 1213 plants of different variants ofMedicago sativa s.l. (including wild and cultivated alfalfa), and a close ally,M. papillosa. The latter species had a much higher content than any of the groups ofM. sativa. Medicago sativa ssp. caerulea, the most important ancestor of alfalfa, had a very low content of hemolytic saponins. The most primitive forms of cultivated alfalfa examined, from Turkey, and wildM. sativa ssp. sativa of Turkey, also both had very low contents of hemolytic saponins. This is consistent with, and likely explained by, a direct origin of the two Turkish groups from sympatricM. sativa ssp.caerulea. The second most important ancestor of alfalfa,M. sativa ssp.falcata, had the highest content of any of the examined groups ofM. sativa. Modern “Western” (European, NorthAmerican) cultivars and Western ruderal populations had intermediate levels of hemolytic saponins. This is consistent with, and likely explained by, their origin by hybridization and introgression between the low saponin groups noted above andM. sativa ssp.falcata. 相似文献
10.
RFLP variation in diploid and tetraploid alfalfa 总被引:8,自引:1,他引:7
E. C. Brummer G. Kochert J. H. Bouton 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,83(1):89-96
Summary Alfalfa (Medicago sativa L.) is a major forage crop throughout the world. Although alfalfa has many desirable traits, continued breeding is required to incorporate pest resistances and other traits. We conducted this study to determine the amount of restriction fragment length polymorphism (RFLP) variability present within and between diploid and tetraploid alfalfa populations, and whether or not this variability is sufficient for construction of an RFLP map. Diploid plants from M. sativa ssp. falcata, ssp. coerulea, and ssp. sativa and tetraploid spp. sativa cultivars Apollo, Florida 77, and Spredor 2 were included. A total of 19 cDNA clones was probed onto genomic Southern blots containing DNA digested by EcoRI, HindIII, or BamHI. Phylogenetic trees were produced, based on parsimony analysis of shared restriction fragments. Evidence for extensive gene duplication was found; most probes detected complex patterns of restriction fragments. Large amounts of variation are present within all diploid subspecies. M. sativa ssp. falcata plants formed clusters distinct from ssp. sativa or ssp. coerulea plants, which were not distinctly clustered. Some M. sativa ssp. falcata plants were more similar to the other groups than to other plants within ssp. falcata. Variation among tetraploid cultivars showed that Florida 77 and Apollo had more similarities than either showed with Spredor 2. All three cultivars showed large within-population variation, with Apollo being the most diverse and Spredor 2 the least. Based on these results, development of an RFLP map at the diploid level appears possible. Also, differentiation of cultivars, particularly ones of divergent origin, seems possible based on RFLP patterns. 相似文献
11.
Zhang Y Sledge MK Bouton JH 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(8):1367-1378
Allotetraploid white clover (Trifolium repens L.), a cool-season perennial legume used extensively as forage for livestock, is an important target for marker-assisted
breeding. A genetic linkage map of white clover was constructed using simple sequence repeat (SSR) markers based on sequences
from several Trifolieae species, including white clover, red clover (T. pratense L.), Medicago truncatula (Gaertn.) and soybean (Glycine max L.). An F1 population consisting of 179 individuals, from a cross between two highly heterozygous genotypes, GA43 and Southern Regional
Virus Resistant, was used for genetic mapping. A total of 1,571 SSR markers were screened for amplification and polymorphism
using DNA from two parents and 14 F1s of the mapping population. The map consists of 415 loci amplified from 343 SSR primer pairs, including 83 from white clover,
181 from red clover, 77 from M. truncatula, and two from soybean. Linkage groups for all eight homoeologous chromosome pairs of allotetraploid white clover were detected.
Map length was estimated at 1,877 cM with 87% genome coverage. Map density was approximately 5 cM per locus. Segregation distortion
was detected in six segments of the genome (homoeologous groups A1, A2, B1, B2, C1, and D1). A comparison of map locations
of markers originating from white clover, red clover, and alfalfa (M. sativa L.) revealed putative macro-colinearity between the three Trifolieae species. This map can be used to link quantitative trait
loci with SSR markers, and accelerate the improvement of white clover by marker-assisted selection and breeding.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Mapping QTLs for defective female gametophyte development in an inter-subspecific cross in Oryza sativa L. 总被引:3,自引:0,他引:3
Y. S. Liu L. H. Zhu J. S. Sun Y. Chen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1243-1251
The embryo-sac is an essential structure for angiosperm reproduction. The cytological and genetic characterization of embryo-sac
sterility was examined in a cross between Oryza sativa ssp. indica cv. ZYQ8 and ssp. japonica cultivar, JX17. The arrest of embryo-sac development was manifested following meiosis in the F1 hybrid. When the megaspore carried the lethal genotype, the nucleus either failed to divide or divided only once, and the
immature embryo-sac degenerated. Abortion of the embryo-sac in the indica-japonica hybrid background was not observed in their original parents, and an effect of cytoplasmic gene(s) on embryo-sac sterility
in the reciprocal F1 hybrids was not detected. Using a rice molecular linkage map based on a doubled haploid (DH) population from the cross of
ZYQ8 /JX17, we mapped quantitative trait loci (QTLs) for the defective development of the female gametophyte in backcross
progenies from the DH lines. The result demonstrated that a polygenic system is involved in both megagametogenesis and postzygotic
isolation in inter-subspecific hybrid rice.
Received: 4 May 2000 / Accepted: 20 September 2000 相似文献
13.
Mapping of simple sequence repeat (SSR) DNA markers in diploid and tetraploid alfalfa 总被引:11,自引:3,他引:8
N. Diwan J. H. Bouton G. Kochert P. B. Cregan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(1-2):165-172
Cultivated alfalfa (Medicago sativa) is an autotetraploid. However, all three existing alfalfa genetic maps resulted from crosses of diploid alfalfa. The current
study was undertaken to evaluate the use of Simple Sequence Repeat (SSR) DNA markers for mapping in diploid and tetraploid
alfalfa. Ten SSR markers were incorporated into an existing F2 diploid alfalfa RFLP map and also mapped in an F2 tetraploid population. The tetraploid population had two to four alleles in each of the loci examined. The segregation of
these alleles in the tetraploid mapping population generally was clear and easy to interpret. Because of the complexity of
tetrasomic linkage analysis and a lack of computer software to accommodate it, linkage relationships at the tetraploid level
were determined using a single-dose allele (SDA) analysis, where the presence or absence of each allele was scored independently
of the other alleles at the same locus. The SDA diploid map was also constructed to compare mapping using SDA to the standard
co-dominant method. Linkage groups were generally conserved among the tetraploid and the two diploid linkage maps, except
for segments where severe segregation distortion was present. Segregation distortion, which was present in both tetraploid
and diploid populations, probably resulted from inbreeding depression. The ease of analysis together with the abundance of
SSR loci in the alfalfa genome indicated that SSR markers should be a useful tool for mapping tetraploid alfalfa.
Received: 10 September 1999 / Accepted: 11 November 1999 相似文献
14.
Phan HT Ellwood SR Hane JK Ford R Materne M Oliver RP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(3):549-558
The first predominantly gene-based genetic linkage map of lentil (Lens culinaris ssp. culinaris) was constructed using an F5 population developed from a cross between the cultivars Digger (ILL5722) and Northfield (ILL5588) using 79 intron-targeted
amplified polymorphic (ITAP) and 18 genomic simple sequence repeat (SSR) markers. Linkage analysis revealed seven linkage
groups (LGs) comprised of 5–25 markers that varied in length from 80.2 to 274.6 cM. The genome map spanned a total length
of 928.4 cM. Clear evidence of a simple and direct macrosyntenic relationship between lentil and Medicago truncatula was observed. Sixty-six out of the 71 gene-based markers, which were previously assigned to M. truncatula genetic and physical maps, were found in regions syntenic between the Lens c. ssp. culinaris and M. truncatula genomes. However, there was evidence of moderate chromosomal rearrangements which may account for the difference in chromosome
numbers between these two legume species. Eighteen common SSR markers were used to connect the current map with the most comprehensive
and recent map that exists for lentil, providing the syntenic context of four important domestication traits. The composite
map presented, anchored with orthologous markers mapped in M. truncatula, provides a strong foundation for the future use of genomic and genetic information in lentil genetic analysis and breeding.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
15.
Two chloroplast DNA (cpDNA) regions exhibiting a high frequency of intra- or inter-species variation were identified in 12 accessions of the genus Medicago. Restriction maps of both regions were prepared for alfalfa, and the probable nature of the events causing the DNA differences was identified. Specific DNA fragments were then cloned for use in identification of variants in each region. Two each of M. sativa ssp. varia and ssp. caerulea and one of six M. sativa ssp. sativa single plants examined possessed cpDNA heterogeneity as identified by screening extracts for fragments generated by the presence and absence of a specific Xba I restriction site. Three plants of M. sativa ssp. sativa, two of each of sspp. varia and caerulea, and three M. scutellata were also examined for single-plant cpDNA heterogeneity at a hypervariable region where differences resulted from small insertion-deletion events. A single M. scutellata plant with mixed cpDNAs was identified. Sorting out was seen when one spp. sativa plant with mixed plastid types identifiable by the Xba I restriction site difference was vegetatively propagated. This indicated that the initial stock plant was heteroplastidic. Controlled crosses will be required in order to test whether heteroplasmy results from chloroplast transmission in the pollen and to examine the dynamic of sorting out. However, heteroplasmy is apparently not a rare situation in Medicago.Contribution No 88-547-J from the Kansas Agricultural Experiment Station, Manhattan. 相似文献
16.
S. A. Masoud L. B. Johnson E. L. Sorensen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(1):49-55
Summary A high frequency of paternal plastid transmission occurred in progeny from crosses among normal green alfalfa plants. Plastid transmission was analyzed by hybridization of radiolabeled alfalfa plastid DNA (cpDNA) probes to Southern blots of restriction digests of the progeny DNA. Each probe revealed a specific polymorphism differentiating the parental plastid genomes. Of 212 progeny, 34 were heteroplastidic, with their cpDNAs ranging from predominantly paternal to predominantly maternal. Regrowth of shoots from heteroplasmic plants following removal of top growth revealed the persistence of mixed plastids in a given plant. However, different shoots within a green heteroplasmic plant exhibited paternal, maternal, or mixed cpDNAs. Evidence of maternal nuclear genomic influence on the frequency of paternal plastid transmission was observed in some reciprocal crosses. A few tetraploid F1 progeny were obtained from tetraploid (2n=4x=32) Medicago sativa ssp. sativa x diploid (2n=2x=16) M. sativa ssp. falcata crosses, and resulted from unreduced gametes. Here more than the maternal genome alone apparently functioned in controlling plastid transmission. Considering all crosses, only 5 of 212 progeny cpDNAs lacked evidence of a definitive paternal plastid fragment.Contribution No. 89-524-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan 相似文献
17.
G. -W. Xu C. W. Magill K. F. Schertz G. E. Hart 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):139-145
A RFLP linkage map of sorghum composed principally of markers detected with sorghum low-copy-number nuclear DNA clones has been constructed. The map spans 1789 cMs and consists of 190 loci grouped into 14 linkage groups. The 10 largest linkage groups consist of from 10 to 24 markers and from 103 to 237 cMs, and the other 4 linkage groups consist of from 2 to 5 markers and from 7 to 62 cMs. The map was derived in Sorghum bicolor ssp. bicolor by analysis of a F2 population composed of 50 plants derived from a cross of IS 3620C, a guinea line, and BTx 623, an agronomically important inbred line derived from a cross between a zera zera (a caudatum-like sorghum) and an established kafir line. The restriction fragment length polymorphism (RFLP) frequency detected in this population using polymerase chain reaction (PCR)-amplifiable low-copy-number sorghum clones and five restriction enzymes was 51%. A minimal estimate of the number of clones that detect duplicate sequences is 11 %. Null alleles occurred at 13% of the mapped RFLP loci. 相似文献
18.
Xie W Ben-David R Zeng B Distelfeld A Röder MS Dinoor A Fahima T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(5):911-922
Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most important wheat diseases worldwide. Wild emmer wheat, Triticum turgidum ssp. dicoccoides, the tetraploid ancestor (AABB) of domesticated bread and durum wheat, harbors many important alleles for resistance to various
diseases, including powdery mildew. In the current study, two tetraploid wheat mapping populations, derived from a cross between
durum wheat (cv. Langdon) and wild emmer wheat (accession G-305-3M), were used to identify and map a novel powdery mildew
resistance gene. Wild emmer accession G-305-3M was resistant to all 47 Bgt isolates tested, from Israel and Switzerland. Segregation ratios of F2 progenies and F6 recombinant inbred line (RIL) mapping populations, in their reactions to inoculation with Bgt, revealed a Mendelian pattern (3:1 and 1:1, respectively), indicating the role of a single dominant gene derived from T. dicoccoides accession G-305-3M. This gene, temporarily designated PmG3M, was mapped on chromosome 6BL and physically assigned to chromosome deletion bin 6BL-0.70-1.00. The F2 mapping population was used to construct a genetic map of the PmG3M gene region consisted of six simple sequence repeats (SSR), 11 resistance gene analog (RGA), and two target region amplification
polymorphism (TRAP) markers. A second map, constructed based on the F6 RIL population, using a set of skeleton SSR markers, confirmed the order of loci and distances obtained for the F2 population. The discovery and mapping of this novel powdery mildew resistance gene emphasize the importance of the wild emmer
wheat gene pool as a source for crop improvement. 相似文献
19.
Wang L Wang A Huang X Zhao Q Dong G Qian Q Sang T Han B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(2):327-340
Mapping chromosome regions responsible for quantitative phenotypic variation in recombinant populations provides an effective
means to characterize the genetic basis of complex traits. We conducted a quantitative trait loci (QTL) analysis of 150 rice
recombinant inbred lines (RILs) derived from a cross between two cultivars, Oryza sativa ssp. indica cv. 93-11 and Oryza sativa ssp. japonica cv. Nipponbare. The RILs were genotyped through next-generation sequencing, which accurately determined the recombination
breakpoints and provided a new type of genetic markers, recombination bins, for QTL analysis. We detected 49 QTL with phenotypic
effect ranging from 3.2 to 46.0% for 14 agronomics traits. Five QTL of relatively large effect (14.6–46.0%) were located on
small genomic regions, where strong candidate genes were found. The analysis using sequencing-based genotyping thus offers
a powerful solution to map QTL with high resolution. Moreover, the RILs developed in this study serve as an excellent system
for mapping and studying genetic basis of agricultural and biological traits of rice. 相似文献
20.
F. Veronesi A. Mariani E. T. Bingham 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(1):37-41
Summary In the genus Medicago, it is known that 2n gametes have been important in the evolution and breeding of cultivated alfalfa, which is a natural polysomic polyploid (2n=4x=32), however little is known on the frequency of male and female 2n gametes in diploid relatives of alfalfa. To obtain data on the frequency of 2n gametes, more than 12,000 2x–4x and 4x–2x crosses were made in 1982 at Madison (USA). Diploid parents in crosses were from four populations of M. coerulea, two of M. falcata and one diploid population of cultivated M. sativa which was derived by haploidy. The tetraploid seed parent in the crosses was a male-sterile M. sativa clone and vigorous tetraploid M. sativa plants were used as pollen parents. Each of 274 diploid plants was utilized both as male and as female. Of the 548 cross combinations, 266 crosses produced variable quantities of seeds which were sown in 1983 in a greenhouse at Perugia (Italy); the plants were subsequently space transplanted in the field in 1984. The identification of ploidy level of these genotypes was made on the basis of morphological characters, plant fertility, pollen stainability and chromosome counts.Of the 515 plants analyzed, the majority behaved as normal tetraploids indicating that many diploid plants produced 2n gametes. Diplogynous and diplandrous gamete production was not correlated with each other, which indicated a different genetic control of 2n sporogenesis in the 2 sexes. Only 4 F1 triploid plants confirmed the presence of a very effective triploid block in alfalfa. In consequence, bilateral sexual polyploidization is a more likely alternative for the origin of tetraploid alfalfa than triploid bridges. The present study showed that it is possible to efficiently identify genotypes able to produce high frequencies of 2n gametes within natural populations of diploids Medicago that are useful in alfalfa breeding.Part of this study was conducted at the Agronomy Department, University of Wisconsin, Madison, Wis, USA, while one of us (F. Veronesi) was in receipt of financial assistance provided by the National Research Council of Italy; part was conducted at Centro di Studio per il Miglioramento Genetico delie Piante Foraggere, C.N.R., Perugia, Italy. The paper was presented at the Eucarpia Fodder Crops Section Meeting, Svalöv, Sweden, 16–19th September 1985 相似文献