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1.
Matthew Darwin Robbins Jack E. Staub 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(4):621-634
Theoretical studies suggest that marker-assisted selection (MAS) has case-specific advantages over phenotypic selection (PHE)
for selection of quantitative traits. However, few studies have been conducted that empirically compare these selection methods
in the context of a plant breeding program. For direct comparison of the effectiveness of MAS and PHE, four cucumber (Cucumis sativus L.; 2n = 2x = 14) inbred lines were intermated and then maternal bulks were used to create four base populations for recurrent mass selection.
Each of these populations then underwent three cycles of PHE (open-field evaluations), MAS (genotyping at 18 marker loci),
and random mating without selection. Both MAS and PHE were practiced for yield indirectly by selecting for four yield-component
traits that are quantitatively inherited with 2–6 quantitative trait loci per trait. These traits were multiple lateral branching,
gynoecious sex expression (gynoecy), earliness, and fruit length to diameter ratio. Both MAS and PHE were useful for multi-trait
improvement, but their effectiveness depended upon the traits and populations under selection. Both MAS and PHE provided improvements
in all traits under selection in at least one population, except for earliness, which did not respond to MAS. The populations
with maternal parents that were inferior for a trait responded favorably to both MAS and PHE, while those with maternal parents
of superior trait values either did not change or decreased during selection. Generally, PHE was most effective for gynoecy,
earliness, and fruit length to diameter ratio, while MAS was most effective for multiple lateral branching and provided the
only increase in yield (fruit per plant).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Comparative analysis of response to phenotypic and marker-assisted selection for multiple lateral branching in cucumber (Cucumis sativus L.) 总被引:2,自引:0,他引:2
Fazio G Chung SM Staub JE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(5):875-883
Yield increase in processing cucumber ( Cucumis sativus L.) is positively correlated with an increase in number of fruit-bearing branches. Multiple lateral branching (MLB) is a metric trait controlled by at least five effective factors. Breeding efficacy might be improved through marker-assisted selection (MAS) for MLB. Experiments were designed to independently confirm previously determined linkage of molecular markers (L18-2-H19A SNP, CSWTAAA01 SSR, CSWCT13 SSR, W7-2 RAPD and BC-551 RAPD) to MLB, and to determine their utility in MAS. These markers were present in significantly higher frequency than expected (1, presence:3, absence; p < 0.001) in BC(2) plants selected based on a high MLB phenotype (BC(2)PHE). However, markers that were considered selectively neutral fit the expected segregation of donor parent DNA in BC(2) progeny. Markers linked to MLB were used in MAS of BC(1) and BC(2) plants to produce BC(2)MAS, and BC(3)MAS progeny. Means for MLB in MAS populations were compared with backcross populations developed through phenotypic selection (BC(2)PHE, BC(3)PHE) and by random mating where no selection had been applied (BC(2)RND, BC(3)RND). Statistical analysis showed no significant differences ( p < 0.001) between means of phenotypic (BC(2)PHE = 3.02, BC(3)PHE = 3.29) and marker-aided selection (BC(2)MAS = 3.12, BC(3)MAS = 3.11) for MLB. However, both phenotypic and MAS population means were significantly higher than the random control (BC(2)RND = 2.27, BC(3)RND = 2.41) for MLB. Thus, given the observed response to selection and the rapid life-cycle of cucumber (4 months), markers linked to MLB when used in MAS will most likely be effective tools in cucumber improvement. 相似文献
3.
Robert Vincent J.M. West Marilyn A.L. Inai Shuji Caines Angela Arntzen Lauren Smith Jodee K. St.Clair Dina A. 《Molecular breeding : new strategies in plant improvement》2001,8(3):217-233
Blackmold, caused by the fungus Alternaria alternata, is a major ripe fruit disease of processing tomatoes. Previously, we found blackmold resistance in a wild tomato (Lycopersicon cheesmanii) and quantitative trait loci (QTL) for resistance were mapped in an interspecific population. Five QTLs were selected for introgression from L. cheesmanii into cultivated tomato using marker-assisted selection (MAS). Restriction fragment length polymorphism and PCR-based markers flanking, and within, the chromosomal regions containing QTLs were used for MAS during backcross and selfing generations. BC1 plants heterozygous at the QTLs, and subsequent BC1S1 and BC1S2 lines possessing different homozygous combinations of alleles at the target QTLs, were identified using DNA markers. Field experiments were conducted in 1998 (with 80 marker-selected BC1S2 lines) and 1999 (with 151 marker-selected BC1S2 and BC1S3 lines) at three California locations. Blackmold resistance was assessed during both years, and horticultural traits were evaluated in 1999. The BC1S2 and BC1S3 lines containing L. cheesmanii alleles at the QTLs were associated with a large genetic variance for resistance to blackmold and moderate heritability, suggesting that significant genetic gain may be achieved by selection in this genetic material. L. cheesmanii alleles at three of the five introgressed QTLs showed a significant, positive effect on blackmold resistance. A QTL on chromosome 2 had the largest positive effect on blackmold resistance, alone and in combination with other QTLs, and was also associated with earliness, a positive horticultural trait. The other four QTLs were associated primarily with negative horticultural traits. Fine mapping QTLs using near isogenic lines could help determine if such trait associations are due to linkage drag or pleiotropy. 相似文献
4.
Yuling Li Yongbin Dong Suzhenniu Niu Dongqun Cui Yanzhao Wang Yanyang Liu Mengguan Wei Xuehui Li 《Molecular breeding : new strategies in plant improvement》2008,21(1):1-14
Specific traits are an important consideration in plant breeding. In popcorn, inferior agronomic traits could be improved
using dent or flint corn backcrossed with popcorn. In this study, we used advanced backcross quantitative trait locus (AB-QTL)
analysis to identify trait-improving QTL alleles from a dent maize inbred Dan232, and compared the detection of QTL in the
BC2S1 population with QTL results using F2:3 families of the same population. Two hundred and twenty BC2S1 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for nine plant traits in replicated
field trials under two environments. Using composite interval mapping (CIM), a total of 28 significant QTL were detected,
and of these, 23 (82.14%) had favorable alleles contributed by the dent corn parent Dan232. Nine QTL (32.14%) detected in
the BC2S1 population were also located in or near the same chromosome intervals in the F2:3 population. All of the favorable QTL alleles from Dan232 could be used in marker-assisted selection (MAS) to improve the
respective plant traits in popcorn breeding. In addition, their near isogenic lines (QTL-NILs) could be obtained through selfing
or another 1–2 backcross with N04. Also, N04 improved for the studied plant traits could be developed from the BC2S1 families used in this study. This study demonstrated that the AB-QTL method can be applied to identify favorable QTL from
dent corn inbred in popcorn breeding and, once identified, the alleles could be used in marker-assisted selection to improve
the respective plant traits. 相似文献
5.
Gandhi SD Heesacker AF Freeman CA Argyris J Bradford K Knapp SJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(4):619-629
Wild populations of common sunflower (Helianthus annuus L.) are self-incompatible and have deep seed dormancy, whereas modern cultivars, inbreds, and hybrids are self-compatible and partially-to-strongly self-pollinated, and have shallow seed dormancy. Self-pollination (SP) and seed dormancy are genetically complex traits, the number of self-compatibility (S) loci has been disputed, and none of the putative S loci have been genetically mapped in sunflower. We genetically mapped quantitative trait loci (QTL) for self-incompatibility (SI), SP, and seed dormancy in a backcross population produced from a cross between an elite, self-pollinated, nondormant inbred line (NMS373) and a wild, self-incompatible, dormant population (ANN1811). A population consisting of 212 BC1 progeny was subsequently produced by backcrossing a single hybrid individual to NMS373. BC1 progeny produced 0–838 seeds per primary capitula when naturally selfed and 0–518 seeds per secondary capitula when manually selfed and segregated for a single S locus. The S locus mapped to linkage group 17 and was tightly linked to a cluster of previously identified QTL for several domestication and postdomestication traits. Two synergistically interacting QTL were identified for SP among self-compatible (ss) BC1 progeny (R2=34.6%). NMS373 homozygotes produced 271.5 more seeds per secondary capitulum than heterozygotes. Germination percentages of seeds after-ripened for 4 weeks ranged from 0% to 100% among self-compatible BC1S1 families. Three QTL for seed dormancy were identified (R2=38.3%). QTL effects were in the predicted direction (wild alleles decreased self-pollination and seed germination). The present analysis differentiated between loci governing SI and SP and identified DNA markers for bypassing SI and seed dormancy in elite × wild crosses through marker-assisted selection.Electronic Supplementary Material Electronic supplementary material is available for this article at 相似文献
6.
Evaluation of marker-assisted selection through computer simulation 总被引:20,自引:0,他引:20
M. D. Edwards N. J. Page 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(3-4):376-382
Computer simulation was used to evaluate responses to marker-assisted selection (MAS) and to compare MAS responses with those typical of phenotypic recurrent selection (PRS) in an allogamous annual crop species such as maize (Zea mays L.). Relative to PRS, MAS produced rapid responses early in the selection process; however, the rate of these responses diminished greatly within three to five cycles. The gains from MAS ranged from 44.7 to 99.5% of the maximum potential, depending on the genetic model considered. Linkage distance between markers and quantitative trait loci (QTLs) was the factor which most limited the responses from MAS. When averaged across all models considered, flanking QTLs within two marker loci produced 38% more gain than did selection based on single markers if markers were loosely-linked to a QTL (20% recombination). Flanking markers were much less advantageous when markers were closely-linked to a QTL (5% recombination), producing an advantage over single markers of only 11%. Markers were most effective in fully exploiting the genetic potential when fewer QTLs controlled the trait. Large QTL numbers exacerbated the problem of marker-QTL recombination by requiring more generations for fixation. In annual crop species, MAS may offer a primary advantage of enabling two selection cycles per year versus the 2 years per cycle required by most PRS schemes for the evaluation of testcross progeny. MAS thus appears to allow very rapid gains for the first 2–3 years of recurrent selection, after which time conventional methods might replace MAS to achieve further responses.Publication number 19, 330 of the Minnesota Agricultural Experiment Station 相似文献
7.
Coupling- and repulsion-phase RAPDs for marker-assisted selection of PI 181996 rust resistance in common bean 总被引:1,自引:0,他引:1
E. Johnson P. N. Miklas J. R. Stavely J. C. Martinez-Cruzado 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(5):659-664
The Guatemalan black bean (Phaseolus vulgaris L.) plant introduction (PI) 181996 is resistant to all known US races of the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger var. appendiculatus [syn. U. phaseoli (Reben) Wint.]. We report on two random amplified polymorphic DNA (RAPD) markers OAC20490 tightly linked (no recombinants) in coupling phase and OAE19890 linked in repulsion phase (at 6.2±2.8 cM) to PI 181996 rust resistance. These RAPDs, generated by single decamer primers in the polymerase chain reaction, were identified in near-isogenic bulks of non-segregating resistant and susceptible BC4F2 (NX-040*4/PI 181996) lines. Linkage of the RAPD markers was confirmed by screening 19 BC4F2 and 57 BC4F3 individuals segregating for PI 181996 resistance. Utility of the RAPDs OAC20490 and OAE19890 was investigated in a diverse group of common bean cultivars and lines. All cultivars into which the PI 181996 resistance was introgressed had the RAPD OAC20490. A RAPD similar in size to OAC20490, observed in some susceptible common bean lines, was confirmed by Southern blotting to be homologous to the RAPD OAC20490. Use of the RAPDs OAC20490 and OAE19890 in marker-assisted selection (MAS) is proposed. The coupling-phase RAPD is most useful for MAS of resistant BCnF1individuals during traditional backcross breeding. The repulsion-phase RAPD has greatest utility in MAS of homozygous-resistant individuals in F2 or later-segregating generations.Mention of a trademark or a proprietary product does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other products that may also be suitable. 相似文献
8.
Combining bacterial blight resistance and Basmati quality characteristics by phenotypic and molecular marker-assisted selection in rice 总被引:1,自引:0,他引:1
Joseph M. Gopalakrishnan S. Sharma R.K. Singh V.P. Singh A.K. Singh N.K. Mohapatra T. 《Molecular breeding : new strategies in plant improvement》2004,13(4):377-387
Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in tropical Asia. Since all the Basmati varieties are highly susceptible and the disease is prevalent in the entire Basmati growing region of India, BB is a severe constraint in Basmati rice production. The present study was undertaken with the objective of combining the important Basmati quality traits with resistance to BB by a combination of phenotypic and molecular marker-assisted selection (MAS). Screening of 13 near-isogenic lines of rice against four isolates of the pathogen from Basmati growing regions identified the Xa4, xa8, xa13 and Xa21 effective against all the isolates tested. Two or more of these genes in combination imparted enhanced resistance as expressed by reduced average lesion length in comparison to individual genes. The two-gene pyramid line IRBB55 carrying xa13 and Xa21 was found equally effective as three/four gene pyramid lines. The two BB resistance genes present in IRBB55 were combined with the Basmati quality traits of Pusa Basmati-1 (PB-1), the most popular high yielding Basmati rice variety used as recurrent parent. Phenotypic selection for disease resistance, agronomic and Basmati quality characteristics and marker-assisted selection for the two resistance genes were carried out in BC1F1, BC1F2 and BC1F3 generations. Background analysis using 252 polymorphic amplified fragment length polymorphism (AFLP) markers detected 80.4 to 86.7% recurrent parent alleles in BC1F3 selections. Recombinants having enhanced resistance to BB, Basmati quality and desirable agronomic traits were identified, which can either be directly developed into commercial varieties or used as immediate donors of BB resistance in Basmati breeding programs. 相似文献
9.
Inheritance of long staple fiber quality traits of Gossypium barbadense in G. hirsutum background using CSILs 总被引:3,自引:0,他引:3
Wang P Zhu Y Song X Cao Z Ding Y Liu B Zhu X Wang S Guo W Zhang T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(8):1415-1428
Gossypium hirsutum is a high yield cotton species that exhibits only moderate performance in fiber qualities. A promising but challenging approach
to improving its phenotypes is interspecific introgression, the transfer of valuable traits or genes from the germplasm of
another species such as G. barbadense, an important cultivated extra long staple cotton species. One set of chromosome segment introgression lines (CSILs) was developed,
where TM-1, the genetic standard in G. hirsutum, was used as the recipient parent and the long staple cotton G. barbadense Hai7124 was used as the donor parent by molecular marker-assisted selection (MAS) in BC5S1–4 and BC4S1–3 generations. After four rounds of MAS, the CSIL population was comprised of 174 lines containing 298 introgressed segments,
of which 86 (49.4%) lines had single introgressed segments. The total introgressed segment length covered 2,948.7 cM with
an average length of 16.7 cM and represented 83.3% of tetraploid cotton genome. The CSILs were highly varied in major fiber
qualities. By integrated analysis of data collected in four environments, a total of 43 additive quantitative trait loci (QTL)
and six epistatic QTL associated with fiber qualities were detected by QTL IciMapping 3.0 and multi-QTL joint analysis. Six
stable QTL were detected in various environments. The CSILs developed and the analyses presented here will enhance the understanding
of the genetics of fiber qualities in long staple G. barbadense and facilitate further molecular breeding to improve fiber quality in Upland cotton. 相似文献
10.
Karen Christin Falke Thomas Miedaner Matthias Frisch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(4):595-603
Computer simulations can be employed to find optimal procedures for developing introgression libraries in rye with marker-assisted
backcrossing. Our objectives were to investigate the effects of the employed (1) breeding scheme, (2) selection strategy,
and (3) population sizes on the donor genome coverage of the library, the number of introgression lines carrying additional
donor chromosome segments outside the target regions, and the number of required marker data points. With respect to these
target criteria, a BC3S2 breeding scheme and increasing population sizes from early to advanced generations were superior to a BC2S3 breeding scheme and constant population sizes. The smallest number of donor segments outside the target regions was reached
with a three-stage selection strategy, which consists on selection for the target segment, selection for recombination at
flanking markers and selection for recurrent parent alleles across the entire genome. Omitting the selection for flanking
markers in generation BC1 reduced considerably the number of required marker data points. A pre-selection of chromosomes consisting completely of donor
genome in BC1 was advantageous, if the effort in the breeding nursery should kept minimum. Adopting the described designs can help rye
breeders to successfully develop introgression libraries. 相似文献
11.
Marker-assisted selection and evaluation of high oil in vivo haploid inducers in maize 总被引:1,自引:0,他引:1
Xin Dong Xiaowei Xu Liang Li Chenxu Liu Xiaolong Tian Wei Li Shaojiang Chen 《Molecular breeding : new strategies in plant improvement》2014,34(3):1147-1158
Doubled haploid technology, which is used to rapidly purify genetic resources, is one of the key technologies in modern maize breeding. In a previous study, the major quantitative trait locus qhir1, which influences in vivo haploid induction, was narrowed down to a 243-kb region, which made it feasible to use marker-assisted selection (MAS) for inducer development. Recently, a new method was developed for haploid identification using oil content (OC). The objective of this study was to develop high oil inducer lines using MAS of the qhir1 locus. We constructed an F2 population, two backcross populations that were backcrossed to the inducer CAU5 (BC1F1-CAU5) and the high oil inbred line GY923 (BC1F1-GY923), respectively, which was derived from the cross GY923 × CAU5, and subjected continuous selfing to develop high oil inducer lines. In each cycle, three different parameters including kernel OC, marker genotype at qhir1 and haploid induction rate (HIR) were used for pedigree selection. Three candidate high oil inducer lines were developed, with an OC of approximately 8.5 %, an HIR of approximately 8 % and superior agronomic performance, which are suitable values for the application of these lines to haploid identification by OC. Our results confirm the notion that HIR selection combined with MAS for qhir1 is an effective approach to haploid inducer breeding. In addition, we determined that the accuracy of haploid identification by OC is influenced by the female germplasm resource and the high oil inducer and that appropriate critical points for OC can balance the false discovery rate and false negative rate. 相似文献
12.
The benefits of marker assisted selection (MAS) are evaluated under realistic assumptions in schemes where the genetic contributions of the candidates to selection are optimised for maximising the rate of genetic progress while restricting the accumulation of inbreeding. MAS schemes were compared with schemes where selection is directly on the QTL (GAS or gene assisted selection) and with schemes where genotype information is not considered (PHE or phenotypic selection). A methodology for including prior information on the QTL effect in the genetic evaluation is presented and the benefits from MAS were investigated when prior information was used. The optimisation of the genetic contributions has a great impact on genetic response but the use of markers leads to only moderate extra short-term gains. Optimised PHE did as well as standard truncation GAS (i.e. with fixed contributions) in the short-term and better in the long-term. The maximum accumulated benefit from MAS over PHE was, at the most, half of the maximum benefit achieved from GAS, even with very low recombination rates between the markers and the QTL. However, the use of prior information about the QTL effects can substantially increase genetic gain, and, when the accuracy of the priors is high enough, the responses from MAS are practically as high as those obtained with direct selection on the QTL. 相似文献
13.
Micic Z Hahn V Bauer E Schön CC Knapp SJ Tang S Melchinger AE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(7):1474-1484
In many sunflower-growing regions of the world, Sclerotinia sclerotiorum (Lib.) de Bary is the major disease of sunflower (Helianthus annuus L.). In this study, we mapped and characterized quantitative trait loci (QTL) involved in resistance to S. sclerotiorum midstalk rot and two morphological traits. A total of 351 F3 families developed from a cross between a resistant inbred line from the germplasm pool NDBLOS and the susceptible line CM625 were assayed for their parental F2 genotype at 117 codominant simple sequence repeat markers. Disease resistance of the F3 families was screened under artificial infection in field experiments across two sowing times in 1999. For the three resistance traits (leaf lesion, stem lesion, and speed of fungal growth) and the two morphological traits, genotypic variances were highly significant. Heritabilities were moderate to high (h2=0.55–0.89). Genotypic correlations between resistance traits were highly significant (P<0.01) but moderate. QTL were detected for all three resistance traits, but estimated effects at most QTL were small. Simultaneously, they explained between 24.4% and 33.7% of the genotypic variance for resistance against S. sclerotiorum. Five of the 15 genomic regions carrying a QTL for either of the three resistance traits also carried a QTL for one of the two morphological traits. The prospects of marker-assisted selection (MAS) for resistance to S. sclerotiorum are limited due to the complex genetic architecture of the trait. MAS can be superior to classical phenotypic selection only with low marker costs and fast selection cycles. 相似文献
14.
Kuchel Haydn Ye Guoyou Fox Rebecca Jefferies Stephen 《Molecular breeding : new strategies in plant improvement》2005,16(1):67-78
The advent of molecular markers as a tool to aid selection has provided plant breeders with the opportunity to rapidly deliver superior genetic solutions to problems in agricultural production systems. However, a major constraint to the implementation of marker-assisted selection (MAS) in pragmatic breeding programs in the past has been the perceived high relative cost of MAS compared to conventional phenotypic selection. In this paper, computer simulation was used to design a genetically effective and economically efficient marker-assisted breeding strategy aimed at a specific outcome. Under investigation was a strategy involving the integration of both restricted backcrossing and doubled haploid (DH) technology. The point at which molecular markers are applied in a selection strategy can be critical to the effectiveness and cost efficiency of that strategy. The application of molecular markers was considered at three phases in the strategy: allele enrichment in the BC1F1 population, gene selection at the haploid stage and the selection for recurrent parent background of DHs prior to field testing. Overall, incorporating MAS at all three stages was the most effective, in terms of delivering a high frequency of desired outcomes and at combining the selected favourable rust resistance, end use quality and grain yield alleles. However, when costs were included in the model the combination of MAS at the BC1F1 and haploid stage was identified as the optimal strategy. A detailed economic analysis showed that incorporation of marker selection at these two stages not only increased genetic gain over the phenotypic alternative but actually reduced the over all cost by 40%. 相似文献
15.
Jena KK Jeung JU Lee JH Choi HC Brar DS 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):288-297
Brown planthopper (BPH) is a destructive insect pest of rice in Asia. Identification and the incorporation of new BPH resistance
genes into modern rice cultivars are important breeding strategies to control the damage caused by new biotypes of BPH. In
this study, a major resistance gene, Bph18(t), has been identified in an introgression line (IR65482-7-216-1-2) that has inherited the gene from the wild species Oryza australiensis. Genetic analysis revealed the dominant nature of the Bph18(t) gene and identified it as non-allelic to another gene, Bph10 that was earlier introgressed from O. australiensis. After linkage analysis using MapMaker followed by single-locus ANOVA on quantitatively expressed resistance levels of the
progenies from an F2 mapping population identified with marker allele types, the Bph18(t) gene was initially located on the subterminal region of the long arm of chromosome 12 flanked by the SSR marker RM463
and the STS marker S15552. The corresponding physical region was identified in the Nipponbare genome pseudomolecule 3 through
electronic chromosome landing (e-landing), in which 15 BAC clones covered 1.612 Mb. Eleven DNA markers tagging the BAC clones were used to construct a high-resolution
genetic map of the target region. The Bph18(t) locus was further localized within a 0.843-Mb physical interval that includes three BAC clones between the markers R10289S
and RM6869 by means of single-locus ANOVA of resistance levels of mapping population and marker-gene association analysis
on 86 susceptible F2 progenies based on six time-point phenotyping. Using gene annotation information of TIGR, a putative resistance gene was
identified in the BAC clone OSJNBa0028L05 and the sequence information was used to generate STS marker 7312.T4A. The marker
allele of 1,078 bp completely co-segregated with the BPH resistance phenotype. STS marker 7312.T4A was validated using BC2F2 progenies derived from two temperate japonica backgrounds. Some 97 resistant BC2F2 individuals out of 433 screened completely co-segregated with the resistance-specific marker allele (1,078 bp) in either
homozygous or heterozygous state. This further confirmed a major gene-controlled resistance to the BPH biotype of Korea. Identification
of Bph18(t) enlarges the BPH resistance gene pool to help develop improved rice cultivars, and the PCR marker (7312.T4A) for the Bph18(t) gene should be readily applicable for marker-assisted selection (MAS).
K. K. Jena and J. U. Jeung contributed equally to this study. 相似文献
16.
Varshney A Mohapatra T Sharma RP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(1):153-159
White rust, caused by Albugo candida, is a very serious disease in crucifers. In Indian mustard (Brassica juncea), it can cause a yield loss to the extent of 89.9%. The locus Ac2(t) controlling resistance to white rust in BEC-144, an exotic accession of mustard, was mapped using RAPD markers. In the present study, we developed: (1) a more tightly linked marker for the white rust resistance gene, using AFLP in conjunction with bulk segregant analysis, and (2) a PCR-based cleaved amplified polymorphic sequence (CAPS) marker for the closely linked RAPD marker, OPB061000. The data obtained on 94 RILs revealed that the CAPS marker for OPB061000 and the AFLP marker E-ACC/M-CAA350 flank the Ac2(t) gene at 3.8 cM and 6.7 cM, respectively. Validation of the CAPS marker in two different F2 populations of crosses Varuna × BEC-144 and Varuna × BEC-286 was also undertaken, which established its utility in marker-assisted selection (MAS) for white rust resistance. The use of both flanking markers in MAS would allow only 0.25% misclassification and thus provide greater efficiency to selection.Communicated by C. Möllers 相似文献
17.
Ravikumar RL Patil BS Soregaon CD Hegde SG 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(4):619-625
Gametophytic selection can drastically reduce the number of selection cycles during crop improvement programs. The objective
of the present investigation was to test whether the nature of inheritance of two unlinked disease-resistant loci, h
1 and h
2, against Fusarium wilt in chickpea (Cicer arietinum L.) under gametophytic (pollen) selection was similar to that already observed at sporophytic level. A homozygous dominant
(H
1
H
1
H
2
H
2) susceptible genotype JG-62 was crossed to a recessive (h
1
h
1
h
2
h
2) resistant genotype WR-315 to produce 20 F1 hybrid seeds. In the following generation, flower buds of 10 F1 hybrid plants were subjected to toxin stress before anthesis and the remaining ten control F1 plants’ flowers were sprayed with water. Thirty-four selected BC1 plants were generated by test crossing resistant WR-315 individuals with pollen from toxin-stressed F1 individuals. Both control and treated F1 plants were selfed to produce respective F2 generations. Two DNA markers, CS-27700bp and A07C430bp, linked to susceptible alleles H
1 and H
2, respectively, were used to study the inheritance patterns of h
1 and h
2 loci in the F2 and BC1 generations. One hundred and forty-four selected F2, 129 control F2, and 34 selected backcross individuals were tested for the presence or absence of DNA markers. Except for the control F2, observed ratios of selected F2 and BC1 populations exhibited significant chi-square deviations from expected monogenic and digenic ratios. Our results suggest that
gametophytic selection is as effective as that realized at the sporophytic level, and that the gametophytic selection can
be an effective breeding tool for plant breeding programs. 相似文献
18.
Boron (B) is an essential micronutrient for higher plant, but toxic levels can seriously diminish grain yield in cereal crops by affecting root growth, and thus restricting water extraction from the subsoil. Amelioration of high concentrations in soils is expensive and not always feasible, so breeding for B tolerance is the most viable alternative. This article reports the marker-assisted (MAS) transfer of favourable alleles from an unadapted six-rowed barley (Hordeum vulgare L.) variety, Sahara 3771, into two-rowed lines adapted to southern Australia. During the backcrossing process, the SSR marker, EBmac679, located on chromosome 4H was used to control the target region in foreground selection, but no background selection was applied. Gene introgression was confirmed with 40 BC6F1-derived doubled haploid lines segregating for the SSR marker EBmac679. We used a combination of molecular and conventional assays to unequivocally classify the 40 BC6F1-derived DH lines as B tolerant or sensitive, and then compared their means for grain yield measured over 2 years and four locations. Results showed modest improvements in grain yield of lines carrying B tolerance genes at some B toxic environments, and negative impact at others. Our results also showed that malting quality profile was not adversely affected through the introgression of the B tolerance allele from Sahara 3771, allowing the newly developed material to be used by breeding programs without risk of a penalty on malt quality. 相似文献
19.
M. Bohn S. Groh M. M. Khairallah D. A. Hoisington H. F. Utz A. E. Melchinger 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):1059-1067
Cross validation (CV) and validation with an independent sample (IV) are new biometric approaches in QTL analysis to obtain
unbiased estimates of QTL effects and the proportion of the genetic variance explained by the detected marker-QTL association
(p). Our objective with these methods was to obtain a realistic picture on the prospects of marker-assisted selection (MAS)
for improving the resistance of maize against the tropical stem borer species Diatraea grandiosella (SWCB) and Diatraea saccharalis (SCB). Published QTL mapping studies on leaf-damage ratings (LDR) with populations of F2:3 lines and recombinant inbred lines (RIL) from crosses CML131×CML67 and Ki3× CML139 of tropical maize inbreds were re-analyzed
with CV and IV. With CV, the reduction in p for LDR compared to p obtained with the whole data set varied between 41.0 and 79.6% in the populations of F2:3 lines and between 30.1 and 65.2% in the two populations of RIL. Estimates of p for SCB LDR were similar for CV and IV. For SWCB LDR, p estimates obtained with IV were larger than those obtained with CV in CML131× CML67. The reverse was observed for Ki3×CML139.
Under the assumption of identical selection intensities, and based on the re-estimates of p, MAS using only molecular marker information is less-efficient than conventional phenotypic selection (CPS). MAS combining
marker and phenotypic data increases the relative efficiency by only 4% in comparison to CPS. In conclusion, MAS for improving
SWCB and SCB LDR seems not-promising unless additional QTLs with proven large effects are available or the costs of marker
assays are considerably reduced.
Received: 7 December 2000 / Accepted: 5 February 2001 相似文献
20.
Nikita Baliyan Rekha Malik Reema Rani Kirti Mehta Urvashi Vashisth Santosh Dhillon Khazan Singh Boora 《Comptes rendus biologies》2018,341(1):1-8
Bacterial leaf blight (BB), caused by the bacterium Xanthomonas oryzae pv. Oryzae (Xoo), is the major constraint amongst rice diseases in India. CSR-30 is a very popular high-yielding, salt-tolerant Basmati variety widely grown in Haryana, India, but highly susceptible to BB. In the present study, we have successfully introgressed three BB resistance genes (Xa21, xa13 and xa5) from BB-resistant donor variety IRBB-60 into the BB-susceptible Basmati variety CSR-30 through marker-assisted selection (MAS) exercised with stringent phenotypic selection without compromising the Basmati traits. Background analysis using 131 polymorphic SSR markers revealed that recurrent parent genome (RPG) recovery ranged up to 97.1% among 15 BC3F1 three-gene-pyramided genotypes. Based on agronomic evaluation, BB reaction, aroma, percentage recovery of RPG, and grain quality evaluation, four genotypes, viz., IC-R28, IC-R68, IC-R32, and IC-R42, were found promising and advanced to BC3F2 generation. 相似文献