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1.
Salt tolerance in Lycopersicon species. IV. Efficiency of marker-assisted selection for salt tolerance improvement 总被引:1,自引:0,他引:1
A. J. Monforte M. J. Asíns E. A. Carbonell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(5-6):765-772
The usefulness of marker-assisted selection (MAS) to develop salt-tolerant breeding lines from a F2 derived from L. esculentum x L. pimpinellifolium has been studied. Interval mapping methodology of quantitative trait locus (QTL) analysis was used to locate more precisely previously detected salt tolerance QTLs. A new QTL for total fruit weight under salinity (TW) near TG24 was detected. Most of the detected QTLs [3 for TW, 5 for fruit number, (FN) and 4 for fruit weight (FW)] had low R
2 values, except the FW QTL in the TG180-TG48 interval, which explains 36.6% of the total variance. Dominant and overdominant effects were detected at the QTLs for TW, whereas gene effects at the QTLs for FJV and FW ranged from additive to partial dominance. Phenotypic selection of F2 familes and marker-assisted selection of F3 families were carried out. Yield under salinity decreased in the F2 generation. F3 means were similar to those of the F1 as a consequence of phentoypic selection. The most important selection response for every trait was obtained from the F3 to F4 where MAS was applied. While F3 variation was mainly due to the within-family component, in the F4 the FN and FW between-family component was larger than the within-family one, indicating an efficient compartmentalization and fixation of QTLs into the F4 families. Comparison of the yield of these families under control versus saline conditions showed that fruit weight is a key trait to success in tomato salt-tolerance improvement using wild Lycopersicon germplasm. The QTLs we have detected under salinity seem to be also working under control conditions, although the interaction family x treatment was significant for TW, thereby explaining the fact that the selected families responded differently to salinity. 相似文献
2.
A. J. Monforte M. J. Asíns E. A. Carbonell 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):284-293
Salt tolerance was studied comparatively in three families derived from crosses between Lycopersicon esculentum Mill. and two related wild species [two accessions of Lycopersicon pimpinellifolium (Jusl.) Mill. and one accession of Lycopersicon chesmannii f.minor (Hook.f.) Mull.] by means of QTL analysis of fruit yield and earliness under conditions of salinity. From six polymorphic
genomic regions involved in salt tolerance, three contained segregant salt-tolerant QTLs for the three families; two were
found only in both families derived from L.pimpinellifolium; and one, involved in fruit number, was detected only in one of the L.pimpinellifolium families. Some differences regarding the effects of the wild alleles at orthologous QTLs were found. These effects were always
negative in the L. chesmannii family. Comparing both L. pimpinellifolium families, the “wild” alleles at two out of nine common QTLs for fruit number and weight had effects with opposite directions,
and the mode of gene action was clearly different at five of them. QTL analysis of earliness revealed the largest genotypic
differences among families. Most drastic differences were found for the epistatic interactions in which all genomic regions
containing QTLs were involved. These interactions between unlinked genes increased the range of variation of means, mainly
upwards, as compared with genotypes at individual QTLs. Only one (affecting fruit weight) out of 27 interactions was detected
in both L.pimpinellifolium families. Heterotic effects found for salt tolerance in one of the families can be explained by the presence of overdominant
(or pseudo-overdominant) and dominant gene effects at QTLs controlling final fruit yield under conditions of salinity. Allelic
variation at salt-tolerant QTLs exists, changing the additive and, mainly, the non-additive components of the genotypic value.
Consequently, it may negatively affect the general applicability (or efficiency) of marker-assisted selection to improve salt
tolerance in other segregant populations where QTLs were not studied. The use of more informative co-dominant markers, like
microsatelites, might overcome these problems.
Received: 5 August 1996/Accepted: 25 October 1996 相似文献
3.
Genetic mapping of QTLs conditioning soybean sprout yield and quality 总被引:10,自引:0,他引:10
S. H. Lee K. Y. Park H. S. Lee E. H. Park H. R. Boerma 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(5):702-709
Soybean sprouts have been used as a food in the Orient since ancient times. In this study, 92 restriction fragment length
polymorphism (RFLP) loci and two morphological markers (W1 and T) were used to identify quantitative trait loci (QTLs) associated with soybean sprout-related traits in 100 F2-derived lines from the cross of ’Pureunkong’×’Jinpumkong 2’. The genetic map consisted of 76 loci which covered about 756
cM and converged into 20 linkage groups. Eighteen markers remained unlinked. Phenotypic data were collected in 1996 and 1997
for hypocotyl length, percentage of abnormal seedlings, and sprout yield 6 days after germination at 20°C. Hypocotyl length
was determined as the average length from the point of initiation of the first secondary root to the point of attachment of
the cotyledons. The number of decayed seeds and seedlings, plus the number of stunted seedlings (less than 2-cm growth), was
recorded a s abnormal seedlings. Seed weight was determined based on the 50-seed sample. Sprout yield was recorded as the
total fresh weight of soybean sprouts produced from the 50-seed sample divided by the dry weight of the 50-seed sample. Four
QTLs were associated with sprout yield in the combined analysis across 2 years. For the QTL linked to L154 on the Linkage
Group (LG) G the positive allele was derived from Pureunkong (R
2
= 0.19), whereas at the other three QTLs (A089 on LG B1, A668n on LG K and B046 on LG L) the positive alleles were from Jinpumkong
2. QTLs conditioning seed weight were linked to markers A802n (LG B1), A069 (LG E), Cr321 (LG F) and A235 (LG G). At these
four markers, the Jinpumkong allele increased seed weight. Markers K011n on LG B1, W1 on LG F and A757 on LG L were linked to QTLs conditioning hypocotyl length; and Bng119, K455n and K418n to QTLs conditioning
the abnormal seedlings. The QTLs conditioning sprout yield were in the same genomic locations as the QTLs for seed weight
identified in this population or from previously published research, indicating that QTLs for sprout yield are genetically
linked to seed-weight QTLs or else that seed-weight QTLs pleiotropically condition sprout yield. These data demonstrate that
effective marker-assisted selection may be feasible for enhancing sprout yield in a soybean. The transgressive segregation
of sprout yield, as well as the existence of two QTLs conditioning greater than 10% of the phenotypic variation in sprout
yields provides an opportunity to select for progeny lines with a greater sprout yield than currently preferred cultivars
such as Pureunkong.
Received: 23 August 2000 / Accepted: 23 January 2001 相似文献
4.
Identification and mode of action of quantitative trait loci affecting seedling height and leaf area in Eucalyptus nitens 总被引:6,自引:0,他引:6
M. Byrne J. C. Murrell J. V. Owen P. Kriedemann E. R. Williams G. F. Moran 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(5):674-681
Regions of the genome influencing height and leaf area in seedlings of a three-generation outbred pedigree of Eucalyptus nitens have been identified. Three QTLs affecting height and two QTLs affecting leaf area were located using single-factor analysis
of variance. The three QTLs affecting height each explained between 10.3 and 14.7% of the phenotypic variance, while the two
QTLs for leaf area each explained between 9.8 and 11.6% of the phenotypic variation. Analysis of fully informative marker
loci linked to the QTLs enabled the mode of action of the QTLs to be investigated. For three loci the QTL effect segregated
from only one parent, while for two loci the QTL showed multiple alleles and the effect segregated from both parents in the
pedigree. The two QTLs affecting leaf area were located in the same regions as two of the QTLs affecting height. Analysis
of these regions with fully informative markers showed that both QTLs were linked to the same markers, but one had a similar
size of effects and a similar mode of action for both height and leaf area, whilst the other showed a different mode of action
for the two traits. These regions may contain two closely linked genes or may involve a single gene with a pleiotrophic effect
on both height and leaf area. The QTL with the greatest effect showed multiple alleles and an intra-locus interaction that
reduced the size of the effect. Assessment for two of the QTLs in a second related family did not show an effect associated
with the marker loci; however, this was consistent with the mode of action of these QTLs and the pattern of inheritance in
the second family.
Received: 1 August 1996 / Accepted: 25 October 1996 相似文献
5.
QTL analysis of potato tuberization 总被引:9,自引:1,他引:8
J. H. van den Berg E. E. Ewing R. L. Plaisted S. McMurry M. W. Bonierbale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(3):307-316
Quantitative trait loci (QTLs) affecting tuberization were detected in reciprocal backcrosses between Solanum tuberosum and S. berthaultii. Linkage analyses were performed between traits and RFLP alleles segregating from both the hybrid and the recurrent parent using a set of framework markers from the potato map. Eleven distinct loci on seven chromosomes were associated with variation in tuberization. Most of the loci had small effects, but a QTL explaining 27% of the variance was found on chromosome 5. More QTLs were detected while following alleles segregating from the recurrent S. tuberosum parent used to make the backcross than were detected by following alleles segregating from the hybrid parent. More than half of the alleles favoring tuberization were at least partly dominant. Tuberization was favored by an allele from S. berthaultii at 3 of the 5 QTLs detected by segregation from the hybrid parent. The additive effects of the QTLs for tuberization explained up to 53% of the phenotypic variance, and inclusion of epistatic effects increased this figure to 60%. The most common form of epistasis was that in which presence of an allele at each of 2 loci favoring tuberization was no more effective than the presence of a favorable allele at 1 of the 2 loci. The QTLs detected for tuberization traits are discussed in relationship to those previously detected for trichome-mediated insect resistance derived from the unadapted wild species.Paper number 54 of the Department of Fruit and Vegetable Science, Cornell University 相似文献
6.
QTL analysis of horticultural traits differentiating the cultivated tomato from the closely related species Lycopersicon pimpinellifolium 总被引:3,自引:0,他引:3
S. Grandillo S. D. Tanksley 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(8):935-951
Molecular markers were used to map and characterize quantitative trait loci (QTLs) for several characters of agronomic and biological importance in an interspecific backcross of tomato. The parents of the cross were an elite processing inbred Lycopersicon esculentum cv M82-1-7 and the closely related red-fruited wild species L. pimpinellifolium (LA1589). A total of 257 BC1 plants were grown under field conditions in Ithaca, New York and scored for 19 quantitative traits. A genetic linkage map was constructed for the same population using 115 RFLP, 3 RAPD and 2 morphological markers that spanned 1,279 cM of the tomato genome with an average interval length of 10.7 cM. A minimum of 54 putatively significant QTLs (P<0.001; LOD> 2.4) were detected for all characters with a range of 1–7 QTLs detected per character. Of the total 54 QTLs 11% had alleles with effects opposite to those predicted by the parental phenotypes. The percentage of phenotypic variation associated with single QTLs ranged from 4% to 47%. Multilocus analysis showed that the cumulative action of all QTLs detected for each trait accounted for 12–59% of the phenotypic variation. The difference in fruit weight was controlled largely by a single major QTL (fw2.2). Digenic epistasis was not evident. Several regions of the genome (including the region near sp on chromosome 6) showed effects on more than one trait. Implications for variety improvement and inferences about the domestication of the cultivated tomato are discussed. 相似文献
7.
Identification of quantitative trait loci for plant height, lodging, and maturity in a soybean population segregating for growth habit 总被引:8,自引:0,他引:8
S. H. Lee M. A. Bailey M. A. R. Mian E. R. Shipe D. A. Ashley W. A. Parrott R. S. Hussey H. R. Boerma 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(5):516-523
The use of molecular markers to identify quantitative trait loci (QTLs) has the potential to enhance the efficiency of trait selection in plant breeding. The purpose of the present study was to identify additional QTLs for plant height, lodging, and maturity in a soybean, Glycine max (L.) Merr., population segregating for growth habit. In this study, 153 restriction fragment length polymorphisms (RFLP) and one morphological marker (Dt1) were used to identify QTLs associated with plant height, lodging, and maturity in 111 F2-derived lines from a cross of PI 97100 and Coker 237. The F2-derived lines and two parents were grown at Athens, Ga., and Blackville, S.C., in 1994 and evaluated for phenotypic traits. The genetic linkage map of these 143 loci covered about 1600 cM and converged into 23 linkage groups. Eleven markers remained unlinked. Using interval-mapping analysis for linked markers and single-factor analysis of variance (ANOVA), loci were tested for association with phenotypic data taken at each location as well as mean values over the two locations. In the combined analysis over locations, the major locus associated with plant height was identified as Dt1 on linkage group (LG) L. The Dt1 locus was also associated with lodging. This locus explained 67.7% of the total variation for plant height, and 56.4% for lodging. In addition, two QTLs for plant height (K007 on LG H and A516b on LG N) and one QTL for lodging (cr517 on LG J) were identified. For maturity, two independent QTLs were identified in intervals between R051 and N100, and between B032 and CpTI, on LG K. These QTLs explained 31.2% and 26.2% of the total variation for maturity, respectively. The same QTLs were identified for all traits at each location. This consistency of QTLs may be related to a few QTLs with large effects conditioning plant height, lodging, and maturity in this population. 相似文献
8.
Qi Xiaoquan Fufa Fekadu Sijtsma Dick Niks Rients E. Lindhout Pim Stam Piet 《Molecular breeding : new strategies in plant improvement》2000,6(1):1-9
Using AFLP markers, a linkage map was constructed based on a recombinant inbred population of barley derived from a cross between a leaf rust susceptible line, L94, and a partially resistant line, 116-5. The constructed map showed a similar marker distribution pattern as the L94 × Vada map. However, it contained more large gaps, and for some chromosome regions no markers were identified. These regions are most likely derived from L94 because 116-5 was selected from the progeny of a cross of L94 × cv. Cebada Capa. Five QTLs for partial resistance to isolate 1.2.1. were mapped on the L94 × 116-5 map. Three QTLs were effective in the seedling stage, jointly contributing 42% to the total phenotypic variance. Three QTLs were effective in the adult plant stage, collectively explaining 35% of the phenotypic variance. Evidence for two additional linked minor-effect QTLs effective in the adult plant stage was also uncovered. The major-effect QTL, Rphq3, was the only one that was effective in both developmental stages. Moreover, Rphq3, was also identified in the L94 × Vada population, being effective to two rust isolates. The other QTLs were detected in either of the two populations, providing evidence for the existence of many loci for partial resistance to leaf rust on the barley genome. To date, 13 QTLs for partial resistance have been mapped, therefore, a strategy of accumulating many resistance genes in a single cultivar, resulting in a high level of partial resistance, is feasible. 相似文献
9.
Villalta I Bernet GP Carbonell EA Asins MJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(6):1001-1017
Salt tolerance has been analysed in two populations of F7 lines developed from a salt sensitive genotype of Solanum lycopersicum var. cerasiforme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Salinity effects on 19 quantitative traits including fruit yield were investigated by correlation,
principal component analysis, ANOVA and QTL analysis. A total of 153 and 124 markers were genotyped in the P and C populations,
respectively. Some flowering time and salt tolerance candidate genes were included. Since most traits deviated from a normal
distribution, results based on the Kruskal–Wallis non-parametric test were preferred. Interval mapping methodology and ANOVA
were also used for QTL detection. Eight out of 15 QTLs at each population were detected for the target traits under both control
and high salinity conditions, and among them, only average fruit weight (FW) and fruit number (FN) QTLs (fw1.1, fw2.1 and fn1.2) were detected in both populations. The individual contribution of QTLs were, in general, low. After leaf chloride concentration,
flowering time is the trait most affected by salinity because different QTLs are detected and some of their QTL×E interactions
have been found significant. Also reinforcing the interest on information provided by QTL analysis, it has been found that
non-correlated traits may present QTL(s) that are associated with the same marker. A few salinity specific QTLs for fruit
yield, not associated with detrimental effects, might be used to increase tomato salt tolerance. The beneficial allele at
two of them, fw8.1 (in C) and tw8.1 (for total fruit weight in P) corresponds to the salt sensitive parent, suggesting that the effect of the genetic background
is crucial to breed for wide adaptation using wild germplasm. 相似文献
10.
Fanizza G Lamaj F Costantini L Chaabane R Grando MS 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(4):658-664
A segregation population of 184 genotypes derived from a pseudo-testcross of table grapes (Vitis vinifera), together with 203 AFLP and 110 SSR markers was used to detect quantitative trait loci (QTLs) for fruit yield components. Diffferent QTLs, a low percentage of phenotypic variance explained by the QTLs detected and QTL instability over years were detected for each fruit yield component. These results confirm the complex genetic architecture of the yield components in grapevine due to the perennial nature of this species, which has to adapt to yearly variations in climate. Phenotypic correlation analyses between fruit yield components were also performed. The negative correlation between berry weight and the number of berries per cluster seems to have an indirect negative effect on cluster weight, as revealed by the path coefficient analysis; however, this negative correlation was not supported at the molecular level because no coincident QTLs were observed between these traits. Nonetheless, the possibility to select seedless genotypes with large berries without affecting cluster weight needs to be substantiated in future experiments because factors such as sample size and heritability might influence QTL identification in table grapes. 相似文献
11.
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
12.
In a previous study, several quantitative trait loci (QTLs) affecting vegetative propagation traits were detected in a hybrid
cross between Eucalyptus tereticornis and Eucalyptus globulus. The objective of this work was to confirm stable QTL linked markers (detected in different years) for propagation traits
in an independent set of the same segregating population and in two related crosses involving the original E. globulus parent. Phenotypic averages of groups of individuals carrying alternative allelic forms of the stable QTL linked markers
were statistically tested for significant differences. Adventitious rooting and petrification marker–trait associations, detected
previously in the E. tereticornis parent, were verified in an independent sample of the original progeny. In the E. globulus parent, the QTL linked marker was only verified in one related genetic background. Verification was possible only for high-effect
QTL linked markers. This study highlights the importance of sample size in QTL detection for low-heritability traits. 相似文献
13.
Wim van Houten Leo van Raamsdonk Konrad Bachmann 《Plant Systematics and Evolution》1994,190(1-2):49-67
The Chilean annual,Microseris pygmaea, has differentiated in distinct coastal and inland series of populations after long-distance dispersal from western North America. Two plants from the most diverse biotypes were crossed, a large F2 was raised and analysed for segregation of 30 phenotypic characters. Segregation of molecular markers (47 RAPDs, 1 RFLP, 2 isozymes) was determined in a subpopulation of 45 plants which include all extremes for the phenotypic characters. 32 marker/character cosegregations were significant at the 1% level in t-tests between dominant and homozygous recessive marker genotypes. Considering linkage among markers and pleiotropy of certain marker loci, the number of independent quantitative trait loci (QTLs) is reduced to about 18. Interactions among 2 or 3 QTLs affecting one character have been characterized. The phenotypic differentiation ofM. pygmaea during its evolution from a single founder individual begins to be understood at the level of single-gene mutants. 相似文献
14.
Quantitative trait loci (QTLs) affecting body weight were investigated in the backcross population derived from nondiabetic
BB/OK and spontaneously hypertensive rat (SHR) strains. The F1 hybrids were backcrossed onto SHR rats, and QTL analysis was performed separately with the resulting backcross populations
for each sex on Chromosomes (Chrs) 1, 3, 4, 10, 13, and 18. The body weight was determined at the age of 14 weeks, and the
statistical analysis was performed with MAPMAKER/QTL 1.1b computer program. According to the stringent threshold for a lod
score of 3.0, markers on Chr 1 were found to be linked with body weight. The QTL with a peak lod score (5.1) on Chr 1 for
a male population was located within markers Igf2 and D1Mgh12. In contrast, in the female population the body weight affecting QTL (lod = 5.7) on Chr 1 was located between the D1Mit3 and Lsn markers. The existence of QTLs on Chr 1 affecting body weight in the male population was confirmed by congenic BB.Sa rats,
carrying chromosomal region of SHR (Sa-Igf2) on the genetic background of BB rat.
Received: 14 July 1997 / Accepted: 22 December 1997 相似文献
15.
QTL analysis of flower and fruit traits in sour cherry 总被引:2,自引:0,他引:2
D. Wang R. Karle A. F. Iezzoni 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(3-4):535-544
The map locations and effects of quantitative trait loci (QTLs) were estimated for eight flower and fruit traits in sour cherry
(Prunus cerasus L.) using a restriction fragment length polymorphism (RFLP) genetic linkage map constructed from a double pseudo-testcross.
The mapping population consisted of 86 progeny from the cross between two sour cherry cultivars, Rheinische Schattenmorelle
(RS)×Erdi Botermo (EB). The genetic linkage maps for RS and EB were 398.2 cM and 222.2 cM, respectively, with an average interval
length of 9.8 cM. The RS/EB linkage map that was generated with shared segregating markers consisted of 17 linkage groups
covering 272.9 cM with an average interval length of 4.8 cM. Eleven putatively significant QTLs (LOD >2.4) were detected for
six characters (bloom time, ripening time, % pistil death, % pollen germination, fruit weight, and soluble solids concentration).
The percentage of phenotypic variation explained by a single QTL ranged from 12.9% to 25.9%. Of the QTLs identified for the
traits in which the two parents differed significantly, 50% had allelic effects opposite to those predicted from the parental
phenotype. Three QTLs affecting flower traits (bloom time, % pistil death, and % pollen germination) mapped to a single linkage
group, EB 1. The RFLP closest to the bloom time QTL on EB 1 was detected by a sweet cherry cDNA clone pS141 whose partial
amino acid sequence was 81% identical to that of a Japanese pear stylar RNase.
Received: 4 March 1999 / Accepted: 27 August 1999 相似文献
16.
Y. N. Xiao X. H. Li M. L. George M. S. Li S. H. Zhang Y. L. Zheng 《Plant Molecular Biology Reporter》2005,23(2):155-165
Drought accounts for significant yield losses in crops. Maize (Zea mays L.) is particularly sensitive to water stress at reproductive stages, and breeding to improve drought tolerance has been
a challenge. By use of a linkage map with 121 single sequence repeat (SSR) markers, quantitative trait loci (QTLs) for grain
yield and yield components were characterized in the population of the cross X178×B73 under water-stressed and well-watered
conditions. Under the well-watered regime, 2, 4, 4, 1, 2, 2, and 3 QTLs were identified for grain yield, 100-kernel weight,
kernel number per ear, cob weight per ear, kernel weight per ear, ear weight, and ear number per plant, respectively, whereas
under the water-stressed conditions, 1, 5, 2, 6, 1, 3, and 2 QTLs, respectively, were found. The significant phenotypic correlations
among yield and yield components to some extent were observed under both water conditions, and some overlaps between the corresponding
QTLs were also found. QTLs for grain yield and kernel weight per ear under well-watered conditions and ear weight under both
well-watered and water-stressed conditions over-lapped, and all were located on chromosome 1.03 near marker bnlg176. Two other
noticeable QTL regions were on chromosome 9.05 and 9.07 near markers umc1657 and bnlg1525; the first corresponded to grain
yield, kernel weight per ear, and ear weight under well-watered conditions and kernel number per ear under both water conditions,
and the second to grain yield and cob weight per ear under water-stressed conditions and ear number per plant under both water
conditions. A comparative analysis of the QTLs herein identified with those described in previous studies for yield and yield
components in different maize populations revealed a number of QTLs in common. These QTLs have potential use in molecular
marker-assisted selection. 相似文献
17.
The identification of quantitative trait loci (QTLs) based on anchor markers, especially candidate genes that control a trait of interest, has been noted to increase the power of QTL detection. Since these markers can be scored as co-dominant data, they are also valuable for comparing and integrating the QTL linkage maps from diverse mapping populations. To estimate the position and effects of QTLs linked to oil yield traits in African oil palm, co-dominant microsatellites (SSR) and candidate gene-based sequence polymorphisms were applied to construct a linkage map for a progeny showing large differences in oil yield components. The progeny was genotyped for 97 SSR markers, 93 gene-linked markers, and 12 non-gene-linked SNP markers. From these, 190 segregating loci could be arranged into 31 linkage groups while 12 markers remained unmapped. Using the single marker linkage, interval mapping and multiple QTL methods, 16 putative QTLs on seven linkage groups affecting important oil yield related traits such as fresh fruit bunch yield (FFB), ratio of oil per fruit (OF), oil per bunch (OB), fruit per bunch (FB) and wet mesocarp per fruit (WMF) could be identified in the segregating population with estimated values for explained variance ranging from 12.4 % to 54.5 %. Markers designed from some candidate genes involved in lipid biosynthesis were found to be mapped near significant QTLs for various economic yield traits. Associations between QTLs and potential candidate genes are discussed. 相似文献
18.
S. Doganlar S. D. Tanksley M. A. Mutschler 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(2):249-255
Using RAPD marker analysis, two quantitative trait loci (QTLs) associated with earliness due to reduced fruit-ripening time
(days from anthesis to ripening = DTR) were identified and mapped in an F2 population derived from a cross between Lycopersicon esculentum’E6203’ (normal ripening) and Lycopersicon esculentum’Early Cherry’ (early ripening). One QTL, on chromosome 5, was associated with a reduction in both ripening time (5 days)
and fruit weight (29.3%) and explained 15.8 and 13% of the total phenotypic variation for DTR and fruit weight, respectively.
The other QTL, on chromosome 12, was primarily associated with a reduction only in ripening time (7 days) and explained 12.3%
of the total phenotypic variation for DTR. The gene action at this QTL was found to be partially dominant (d/a=0.41). Together,
these two QTLs explained 25.1% of the total phenotypic variation for DTR. Additionally, two QTLs associated with fruit weight
were identified in the same F2 population and mapped to chromosomes 4 and 6, respectively. Together, these two QTLs explained 30.9% of the total phenotypc
variation for fruit weight. For all QTLs, the ’Early Cherry’ alleles caused reductions in both ripening time and fruit weight.
The polymorphic band for the most significant RAPD marker (OPAB-06), linked to the reduced ripening time QTL on chromosome
12, was converted to a cleaved amplified polymorphism (CAP) assay for marker-aided selection and further introgression of
early ripening time (DTR) into cultivated tomato.
Received: 15 March 1999 / Accepted: 29 April 1999 相似文献
19.
D. Crouzillat E. Lerceteau V. Petiard J. Morera H. Rodriguez D. Walker W. Phillips C. Ronning R. Schnell J. Osei P. Fritz 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(1-2):205-214
A genetic linkage map of Theobroma cacao (cocoa) has been constructed from 131 backcross trees derived from a cross between a single tree of the variety Catongo and an F1 tree from the cross of Catongo by Pound 12. The map comprises 138 markers: 104 RAPD loci, 32 RFLP loci and two morphologic loci. Ten linkage groups were found which cover 1068 centimorgans (cM). Only six (4%) molecular-marker loci show a significant deviation from the expected 11 segregation ratio.The average distance between two adjacent markers is 8.3 cM. The final genome-size estimates based on two-point linkage data ranged from 1078 to 1112 cM for the cocoa genome. This backcross progeny segregates for two apparently single gene loci controlling (1) anthocyanidin synthesis (Anth) in seeds, leaves and flowers and (2) self-compatibility (Autoc). The Anth locus was found to be 25 cM from Autoc and two molecular markers co-segregate with Anth. The genetic linkage map was used to localize QTLs for early flowering, trunk diameter, jorquette height and ovule number in the BC1 generation using both single-point ANOVA and interval mapping. A minimum number of 2–4 QTLs (P<0.01) involved in the genetic expression of the traits studied was detected. Coincident map locations of a QTL for jorquette height and trunk diameter suggests the possibility of pleiotropic effects in cocoa for these traits. The combined estimated effects of the different mapped QTLs explained between 11.2% and 25.8% of the phenotypic variance observed in the BC1 population. 相似文献
20.
Mapping QTLs for Phosphorus-Deficiency Tolerance at Wheat Seedling Stage 总被引:13,自引:0,他引:13
Junying Su Yanmei Xiao Ming Li Quanyou Liu Bin Li Yiping Tong Jizeng Jia Zhensheng Li 《Plant and Soil》2006,281(1-2):25-36
Soil phosphorus (P) deficiency is one of the major limiting factors to crop production throughout the world. It is an important
strategy to breed varieties with improved P-deficiency tolerance for sustainable agriculture. The objective of this study
was to map QTLs for P-deficiency tolerance in wheat, and develop molecular marker assisted selection in breeding wheat with
improved P-deficiency tolerance. A doubled haploid (DH) population, consisting of 92 DH lines (DHLs) derived from P-deficiency
tolerant wheat variety Lovrin 10 and P-deficiency sensitive variety Chinese Spring, was developed for mapping QTLs for P-deficiency
tolerance. A genetic linkage map consisting of 34 linkage groups was constructed using 253 SSR markers. Shoot dry weight (SDW),
tiller number (TN), shoot P uptake (SPU), and shoot P utilization efficiency (PUE) were investigated at seedling stage under
P deficiency (−P) and sufficiency (+P) condition in two pot trials in 2002 and 2003, respectively. All traits segregated continuously
in the population under either −P or +P condition. Significant positive correlations were found in between TN, SDW and SPU,
whereas significant negative correlations were observed between PUE and SPU and between PUE and TN. Twenty and 19 QTLs were
detected under −P and +P condition, respectively. The 39 QTLs were distributed on 21 chromosomal regions. There were three
clusters of QTLs, which were associated with Xgwm25l (on chromosomes 4B), Xgwm271.2 (on chromosome 5A), and Xgwm121 (on chromosome 5D), respectively. Compared to the DHLs with all Chinese Spring alleles at the three loci, those with all
Lovrin 10 alleles had, on average, much higher SPU, SDW and TN under −P condition in both trials, suggesting the importance
of the three loci in controlling P-deficiency tolerance. It was interesting to find that two of the above three loci were
closely linked with vernalization requirement genes VRN-A1 (on chromosome 5A) and VRN-D1 (on chromosome 5D). Potential implication of the linkage between P-deficiency tolerance and VRN genes was discussed. 相似文献