共查询到20条相似文献,搜索用时 15 毫秒
1.
M. Byrne J. C. Murrell J. V. Owen E. R. Williams G. F. Moran 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):975-979
Regions of the genome influencing frost tolerance in an outbred family of Eucalyptus nitens have been identified. Two QTLs present on the same linkage group, but located 40 cM apart, were identified using single-factor
analysis of variance. The QTLs explained between 7.7 and 10.8% of the phenotypic variation for frost tolerance in this family.
Analysis of marker loci linked to the QTLs showed one of them to have a simple mode of action with the effect segregating
from the male parent in the family. For the other QTL multiple alleles were identified. This QTL showed segregation from the
female parent which gave a positive effect on frost tolerance; however, an allele segregating from the male parent was identified
which showed a negative interaction with the allele for increased frost tolerance.
Received: 10 May 1997 / Accepted: 2 June 1997 相似文献
2.
D. White Chris Beadle Dale Worledge John Honeysett Maria Cherry 《Trees - Structure and Function》1998,12(7):406-414
Development of the relationship between leaf area (A
l
) and sapwood area (A
s
) was investigated in two important hardwoods, Eucalyptus globulus (Labill) and E. nitens (Deane and Maiden) Maiden, growing in an experimental plantation established in a low rainfall zone (approx. 515 mm year–1) of Tasmania. The experiment compared irrigated controls and a rainfed treatment which was subjected to cyclical summer droughts
from age 1 to 6 years old. Leaf area and sapwood area were determined by destructive sampling at ages 2, 3 and 6 years old.
There was no effect of stand age on A
l
:A
s
when sapwood area was measured at crown break. At age 3 years old A
l
:A
s
was significantly greater in the rainfed than the irrigated trees. It was concluded that this difference was due to earlier
canopy closure in the irrigated trees. When the plantation was 6 years old A
l
:A
s
was significantly greater in the irrigated than the rainfed treatment. An analysis based on an equation which links A
l
:A
s
with transpiration and volumetric flow rate (Whitehead et al. 1984) was used to infer a positive correlation between stem
hydraulic conductivity (k
h
) and water availability. Independent of water availability E. globulus maintained a higher A
l
:A
s
than E. nitens at all ages.
Received: 20 March 1997 / Accepted: 30 December 1997 相似文献
3.
Sebastian RL Kearsey MJ King GJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):601-609
A segregating population of F1-derived doubled haploid (DH) lines of Brassica oleracea was used to detect and locate QTLs controlling 27 morphological and developmental traits, including leaf, flowering, axillary
bud and stem characters. The population resulted from a cross between two very different B. oleracea crop types, an annual cauliflower and a biennial Brussels sprout. A principal component analysis (PCA), based on line means,
allowed all the traits to be grouped into distinct categories according to the first five Principal Components. These were:
leaf traits (PC1), flowering traits (PC2), axillary bud traits (PC3 and 5) and stem traits (PC4). Between zero and four putative
QTL were located per trait, which individually explained between 6% and 43% of the additive genetic variation, using the multiple-marker
regression approach to QTL mapping. For lamina width, bare petiole length and stem length two QTL with opposite effects were
detected on the same linkage groups. Intra- and inter-specific comparative mapping using RFLP markers identified a QTL on
linkage group O8 accounting for variation in vernalisation, which is probably synonymous with a QTL detected on linkage group
N19 of Brassica napus. In addition, a QTL for petiole length detected on O3 of this study appeared to be homologous to a QTL detected on another
B. oleracea genetic map (Camargo et al. 1995).
Received: 28 March 2001 / Accepted: 25 June 2001 相似文献
4.
Identification of quantitative trait loci contributing to Fusarium wilt resistance on an AFLP linkage map of flax (Linum usitatissimum) 总被引:3,自引:0,他引:3
W. Spielmeyer A. G. Green D. Bittisnich N. Mendham E. S. Lagudah 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(4):633-641
An AFLP genetic linkage map of flax (Linum usitatissimum) was used to identify two quantitative trait loci (QTLs) on independent linkage groups with a major effect on resistance
to Fusarium wilt, a serious disease caused by the soil pathogen Fusarium oxysporum (lini). The linkage map was constructed using a mapping population from doubled-haploid (DH) lines. The DH lines were derived
from the haploid component of F2 haploid-diploid twin seed originating from a cross between a polyembryonic, low-linolenic-acid genotype (CRZY8/RA91) and
the Australian cultivar ‘Glenelg’. The AFLP technique was employed to generate 213 marker loci covering approximately 1400 cM
of the flax genome (n=15) with an average spacing of 10 cM and comprising 18 linkage groups. Sixty AFLP markers (28%) deviated
significantly (P<0.05) from the expected segregation ratio. The map incorporated RFLP markers tightly linked to flax rust (Melamspora lini) resistance genes and markers detected by disease resistance gene-like sequences. The study illustrates the potential of
the AFLP technique as a robust and rapid method to generate moderately saturated linkage maps, thereby allowing the molecular
analysis of traits, such as resistance to Fusarium wilt, that show oligogenic patterns of inheritance.
Received: 8 December 1997 / Accepted: 7 April 1998 相似文献
5.
Identification of quantitative trait loci and epistatic interactions for plant height and heading date in rice 总被引:23,自引:0,他引:23
Yu SB Li JX Xu CG Tan YF Li XH Zhang Q 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):619-625
Appropriate heading date and plant height are prerequisites for attaining the desired yield level in rice breeding programs.
In this study, we analyzed the genetic bases of heading date and plant height at both single- locus and two-locus levels,
using a population of 240 F2:3 families derived from a cross between two elite rice lines. Measurements for the traits were obtained over 2 years in replicated
field trials. A linkage map was constructed with 151 polymorphic marker loci, based on which interval mapping was performed
using Mapmaker/QTL. The analyses detected six QTLs for plant height and six QTLs for heading date; collectively the QTLs for
heading date accounted for a much greater amount of phenotypic variation than did the QTLs for plant height. Two-way analyses
of variance, with all possible two-locus combinations, detected large numbers (from 101 to 257) of significant digenic interactions
in the 2 years for both traits involving markers distributed in the entire genome; 22 and 39 were simultaneously detected
in both years for plant height and heading date, respectively. Each of the interactions individually accounted for only a
very small portion of the phenotypic variation. The majority of the significant interactions involved marker loci that did
not detect significant effects by single-locus analyses, and many of the QTLs detected by single-locus analyses were involved
in epistatic interactions. The results clearly demonstrated the importance of epistatic interactions in the genetic bases
of heading date and plant height.
Received: 5 May 2001 / Accepted: 3 August 2001 相似文献
6.
Leaves of eucalypt species contain a variety of plant secondary metabolites, including terpenoids and formylated phloroglucinol compounds (FPCs). Both terpene and FPC concentrations are quantitative traits that can show large variation within a population and have been shown to be heritable. The molecular genetic basis of this variation is currently unknown. Progeny from a field trial of a three-generation mapping pedigree of Eucalyptus nitens were assayed for terpenes and FPCs. Quantitative trait loci (QTL) analyses were conducted using a map constructed from 296 markers to locate regions of the genome influencing foliar concentrations of these plant secondary compounds. A large number of significant QTL for 14 traits were located across nine linkage groups, with significant clustering of QTL on linkage groups 7, 8 and 9. As expected, QTL for biosynthetically related compounds commonly colocated, but QTL for unrelated monterpenes and FPCs also mapped closely together. Colocation of these QTL with mapped candidate genes from the various biosynthetic pathways, and subsequent use of these genes in association mapping, will assist in determining the causes of variation in plant secondary metabolites in eucalypts. 相似文献
7.
Selective genotyping to detect quantitative trait loci affecting multiple traits: interval mapping analysis 总被引:3,自引:0,他引:3
Y. I. Ronin A. B. Korol J. I. Weller 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(7):1169-1178
Segregating quantitative trait loci can be detected via linkage to genetic markers. By selectively genotyping individuals
with extreme phenotypes for the quantitative trait, the power per individual genotyped is increased at the expense of the
power per individual phenotyped, but linear-model estimates of the quantitative-locus effect will be biased. The properties
of single- and multiple-trait maximum-likelihood estimates of quantitative-loci parameters derived from selectively genotyped
samples were investigated using Monte-Carlo simulations of backcross populations. All individuals with trait records were
included in the analyses. All quantitative-locus parameters and the residual correlation were unbiasedly estimated by multiple-trait
maximum-likelihood methodology. With single-trait maximum-likelihood, unbiased estimates for quantitative-locus effect and
location, and the residual variance, were obtained for the trait under selection, but biased estimates were derived for a
correlated trait that was analyzed separately. When an effect of the QTL was simulated only on the trait under selection,
a “ghost” effect was also found for the correlated trait. Furthermore, if an effect was simulated only for the correlated
trait, then the statistical power was less than that obtained with a random sample of equal size. With multiple-trait analyses,
the power of quantitative-trait locus detection was always greater with selective genotyping.
Received: 23 February 1998 / Accepted: 15 May 1998 相似文献
8.
Identification and mapping of a new leaf stripe resistance gene in barley (Hordeum vulgare L.) 总被引:2,自引:0,他引:2
G. Tacconi L. Cattivelli N. Faccini N. Pecchioni A. M. Stanca G. Valé 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1286-1291
Pyrenophora graminea is the seed-borne pathogen causal agent of barley leaf stripe disease. Near-isogenic lines (NILs) carrying resistance of
the cv ”Thibaut” against the highly virulent isolate Dg2 were obtained by introgressing the resistance into the genetic background
of the susceptible cv ”Mirco”. The segregation of the resistance gene was followed in a F2 population of 128 plants as well as on the F3 lines derived from the F2 plants; the segregation fitted the 1:2:1 ratio for a single gene. By using NILs, a RAPD marker associated with the resistance
gene was identified; sequence-specific (STS) primers were designed on the basis of the amplicon sequence and a RILs mapping
population with an AFLP-based map were used to position this molecular marker to barley chromosome 1 S (7HS). STS and CAPS
markers were developed from RFLPs mapped to the telomeric region of barley chromosome 7HS and three polymorphic PCR-based
markers were developed. The segregation of these markers was followed in the F2 population and their map position with respect to the resistance gene was determined. Our results indicate that the Thibaut
resistance gene, which we designated as Rdg2a, maps to the telomeric region of barley chromosome 7HS and is flanked by the markers OPQ-9700 and MWG 2018 at distances of 3.1 and 2.5 cM respectively. The suitability of the PCR-based marker MWG2018 in selection- assisted
barley breeding programs is discussed.
Received: 22 June 2000 / Accepted: 16 October 2000 相似文献
9.
Groos C Gay G Perretant MR Gervais L Bernard M Dedryver F Charmet G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(1):39-47
In many wheat (Triticum aestivum L.) growing areas, pre-harvest sprouting (PHS) may cause important damage, and in particular, it has deleterious effects on
bread-making quality. The relationship between PHS and grain color is well known and could be due either to the pleiotropic
effect of genes controlling red-testa pigmentation (R) or to linkage between these genes and other genes affecting PHS. In the present work, we have studied a population of 194
recombinant inbred lines from the cross between two cultivars, ’Renan’ and ’Récital’, in order to detect QTLs for both PHS
resistance and grain color. The variety ’Renan’ has red kernels and is resistant to PHS, while ’Récital’ has white grain and
is highly susceptible to PHS. A molecular-marker linkage map of this cross was constructed using SSRs, RFLPs and AFLPs. The
population was evaluated over 2 years at Clermont-Ferrand (France). PHS was evaluated on mature spikes under controlled conditions
and red-grain color was measured using a chromameter. Over the 2 years, we detected four QTLs for PHS, all of them being co-localized
with QTLs for grain color. Three of them were located on the long arm of chromosomes 3 A, 3B and 3D, close to the loci where
the genes R and taVp1 were previously mapped. For these three QTLs, the resistance to PHS is due to the allele of the variety ’Renan’. Another
co-located QTL for PHS and grain color was detected on the short arm of chromosome 5 A. The resistance for PHS for this QTL
is due to the allele of ’Récital’.
Received: 13 December 2000 / Accepted: 24 April 2001 相似文献
10.
Z. Kaya M. M. Sewell D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(3-4):586-592
Quantitative trait loci (QTLs) for annual height- and diameter-increment growth were estimated in each of two three-generation
loblolly pine pedigrees. Annual height-increment was measured in three consecutive years in the BASE pedigree and in four consecutive years in the QTL pedigree. Annual diameter-increment was measured only in the QTL pedigree for two consecutive years. An interval mapping-approach was used to estimate the number of QTLs, the magnitude of
QTL effects, and their position on genetic linkage maps. Thirteen different height-increment and eight different diameter-increment
QTLs were detected, suggesting that the these traits are, at least in part, controlled by a few genes of large effect. Little
evidence was found for the expression of individual QTLs in multiple years or in multiple genetic backgrounds. These results
were discussed in terms of the power of the experiment and their consequences for marker-assisted breeding.
Received: 12 July 1998/Accepted: 5 August 1998 相似文献
11.
C. Xie S. Xu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(6-7):1014-1021
A common problem in mapping quantitative trait loci (QTLs) is that marker data are often incomplete. This includes missing
data, dominant markers, and partially informative markers, arising in outbred populations. Here we briefly present an iteratively
re-weighted least square method (IRWLS) to incorporate dominant and missing markers for mapping QTLs in four-way crosses under
a heterogeneous variance model. The algorithm uses information from all markers in a linkage group to infer the QTL genotype.
Monte Carlo simulations indicate that with half dominant markers, QTL detection is almost as efficient as with all co-dominant
markers. However, the precision of the estimated QTL parameters generally decreases as more markers become missing or dominant.
Notable differences are observed on the standard deviation of the estimated QTL position for varying levels of marker information
content. The method is relatively simple so that more complex models including multiple QTLs or fixed effects can be fitted.
Finally, the method can be readily extended to QTL mapping in full-sib families.
Received: 16 June 1998 / Accepted: 29 September 1998 相似文献
12.
K. Richter J. Schondelmaier C. Jung 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(8):1225-1234
Resistance loci for seedling-stage resistance to net blotch disease (Drechslera teres) in barley were mapped with molecular markers in an F2 population derived from a cross between the susceptible barley cultivar ‘Arena’ and the resistant Ethiopian landrace ‘Hor
9088’. Disease reactions were scored with first and second leaves of 2-week-old plants 7 and 9 days after inoculation with
a single spore-derived isolate. For linkage analysis, 22 RFLP markers and 284 AFLP markers were used. The seven linkage groups
covered 1153.3 cM with an average marker interval of 3.76 cM. The resistance was determined to be inherited in a quantitative
manner. Altogether, 12 QTLs were mapped with positions depending on the leaf used for testing and the time period after infection.
Heritability in the broad sense ranged between 0.21 and 0.37.
Received: 26 May 1998 / Accepted: 9 June 1998 相似文献
13.
A. Börner V. Korzun A. V. Voylokov W. E. Weber 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(6-7):1087-1090
Progenies of an F2 mapping population were analyzed for quantitative traits to detect QTLs by using marker information from F2 plants for chromosome 5R. The mapping population was segregating for the major dwarfing gene Ddw1 and the gene Hp1 for hairy peduncle. The only QTL determining plant height was located between HP1 and Ddw1 on the distal part of chromosome 5RL. At the same position a QTL for peduncle length was found, and this trait was closely
related to plant height (r=0.895). Since Hp1 and Ddw1 are dominant marker loci, no dominance effect could be estimated. The QTLs for spike length and the number of florets were
located near the centromere on 5RL. These two traits were correlated with r=0.824 and showed partial dominance, but these traits were not correlated to plant height and peduncle length. Homoeologous
relationships between the QTLs mapped for the first time in rye and those mapped in other Triticeae members are discussed.
Received: 8 June 1998 / Accepted: 8 October 1998 相似文献
14.
Identification of quantitative trait loci associated with resistance to cucumber mosaic virus in Capsicum annuum 总被引:5,自引:0,他引:5
A. Ben Chaim R. C. Grube M. Lapidot M. Jahn I. Paran 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1213-1220
QTL analysis for resistance to cucumber mosaic virus (CMV) was performed in an intraspecific Capsicum annuum population. A total of 180 F3 families were derived from a cross between the susceptible bell-type cultivar Maor and the resistant
small-fruited Indian line Perennial and inoculated with CMV in three experiments carried out in the USA and Israel using two
virus isolates. Mostly RFLP and AFLP markers were used to construct the genetic map, and interval analysis was used for QTL
detection. Four QTL were significantly associated with resistance to CMV. Two digenic interactions involving markers with
and without an individual effect on CMV resistance were also detected. The QTL controlling the largest percentage (16–33%)
of the observed phenotypic variation (cmv11.1) was detected in all three experiments and was also involved in one of the digenic interactions. This QTL is linked to the
L locus that confers resistance to tobacco mosaic virus (TMV), confirming earlier anecdotal observations of an association
between resistance to CMV and susceptibility to TMV in Perennial. An advanced backcross breeding line from an unrelated population,
3990, selected for resistance to CMV was analyzed for markers covering the genome, allowing the identification of genomic
regions introgressed from Perennial. Four of these introgressions included regions associated with QTL for CMV resistance.
Markers in two genomic regions that were identified as linked to QTL for CMV resistance were also linked to QTL for fruit
weight, confirming additional breeding observations of an association between resistance to CMV originating from Perennial
and small fruit weight.
Received: 17 July 2000 / Accepted: 16 October 2000 相似文献
15.
M. Byrne G. F. Moran J. C. Murrell W. N. Tibbits 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(4):397-402
The level of polymorphism using genomic and cDNA probes with a number of restriction enzymes and the inheritance of the RFLP loci was investigated in E. nitens. The polymorphism detected with 366 genomic and cDNA probes and three to six restriction enzymes was analysed in three-generation outbred pedigrees. No difference in the level of polymorphism detected with genomic versus cDNA probes was observed. There was a difference in the efficiency of detection of polymorphism with six different restriction enzymes, with three of the enzymes (BglII, DraI and EcoRI) showing substantially more polymorphism than the others. There was no significant correlation between the size of the DNA fragments generated by the enzymes and the detection of polymorphism. Several cases of restriction-site mutations resulting in a polymorphism were observed. The inheritance of 69 loci was analysed in two pedigrees resulting from interpopulational crosses. The majority of the loci segregated according to expected ratios with distortion observed in only 3% of loci. Probes from the cDNA library detected a greater proportion of loci with more than two alleles than did probes from the genomic library. The high polymorphism, large number of alleles, and ease of interpretation of RFLPs in E. nitens means that they will be useful in a range of applications such as genetic linkage maps and paternity analysis. 相似文献
16.
Quantitative trait loci influencing drought tolerance in grain sorghum (Sorghum bicolor L. Moench) 总被引:7,自引:0,他引:7
H. Kebede P. K. Subudhi D. T. Rosenow H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(2-3):266-276
Drought is a major constraint in sorghum production worldwide. Drought-stress in sorghum has been characterized at both pre-flowering
and post-flowering stages resulting in a drastic reduction in grain yield. In the case of post-flowering drought stress, lodging
further aggravates the problem resulting in total loss of crop yield in mechanized agriculture. The present study was conducted
to identify quantitative trait loci (QTLs) controlling post-flowering drought tolerance (stay green), pre-flowering drought
tolerance and lodging tolerance in sorghum using an F7 recombinant inbred line (RIL) population derived from the cross SC56×Tx7000. The RIL lines, along with parents, were evaluated
for the above traits in multiple environments. With the help of a restriction fragment length polymorphism (RFLP) map, which
spans 1,355 cM and consists of 144 loci, nine QTLs, located over seven linkage groups were detected for stay green in several
environments using the method of composite interval mapping. Comparison of the QTL locations with the published results indicated
that three QTLs located on linkage groups A, G and J were consistent. This is considered significant since the stay green
line SC56 used in our investigation is from a different source compared to B35 that was used in all the earlier investigations.
Comparative mapping has shown that two stay green QTLs identified in this study corresponded to stay green QTL regions in
maize. These genomic regions were also reported to be congruent with other drought-related agronomic and physiological traits
in maize and rice, suggesting that these syntenic regions might be hosting a cluster of genes with pleiotropic effects implicated
in several drought tolerance mechanisms in these grass species. In addition, three and four major QTLs responsible for lodging
tolerance and pre-flowering drought tolerance, respectively, were detected. This investigation clearly revealed the important
and consistent stay green QTLs in a different stay green source that can logically be targeted for positional cloning. The
identification of QTLs and markers for pre-flowering drought tolerance and lodging tolerance will help plant breeders in manipulating
and pyramiding those traits along with stay green to improve drought tolerance in sorghum.
Received: 2 June 2000 / Accepted: 15 November 2000 相似文献
17.
A. J. Monforte S. D. Tanksley 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(3-4):471-479
The near-isogenic Line TA523, containing a 40-cM introgression at the bottom of chromosome 1 from Lycopersicon hirsutum acc. LA1777, affects several agronomically important traits. A set of recombinant lines (subNILs) derived from the original
NIL TA523 were developed in order to fine-map, by substitution mapping, the genetic factors included within the original introgression.
In the current experiment, TA523 showed redder, rounded, less pigmented shoulder, lower-weighted fruits and higher brix, whereas
higher yield and brix*yield was observed only in the hybrid TA253×TA209 suggesting heterosis for these traits. By substitution
mapping we mapped independent genetic loci affecting brix, yield and fruit shape, whereas fruit weight, shoulder pigmentation
and external color mapped to a position coincident with the brix locus. Analysis of the subNILs revealed that the gene action
of most of the QTLs was additive or nearly additive. The exception was for the yield QTL which was dominant (d/a=0.7), eliminating
the possibility that yield increase is due to true overdominance at a single gene locus. However, no negative yield effects
were detected in other regions of the introgressed segment, as would be predicted by a dominance complementation model. Therefore,
epistatic interactions among genetic factors along the introgressed segment are suggested as the cause of yield heterosis.
Results from this study, combined with previous experiments involving different tomato wild species, demonstrate that the
base of chromosome 1 of tomato contains multiple QTLs affecting various agronomic and fruit traits and that these effects
can not be attributed to the pleiotropic effects of a single locus.
Received: 21 April 1999 / Accepted: 17 June 1999 相似文献
18.
S. M. Kaeppler 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(4):618-621
Populations derived by multiple backcrosses are potentially useful for quantitative trait locus (QTL) mapping studies. Comparisons
of relative power to detect QTL using populations derived by multiple back-crosses are needed to make decisions when mapping
projects are initiated. The objective of this study was to theoretically compare the power to detect QTL in populations derived
by multiple backcrosses relative to mapping in a recombinant inbred population of equal size. Backcrossing results in a reduction
in genetic variance with each generation and also results in an increasing frequency of the recurrent parent marker genotype.
The relevant outcome for QTL mapping is a reduction in genetic variance to partition between marker genotype classes and increasing
unbalance of the number of individuals contributing to the mean of the marker genotypes. Both of these factors lead to a decrease
in the power to detect a QTL as the number of backcross generations increases. Experimental error was held constant with the
populations compared. From a theoretical standpoint, backcross-derived populations offer few advantages for QTL detection.
If, however, a backcrossing approach is the most efficient method to achieve a desired breeding objective and if QTL detection
is an objective of equal or less importance, backcross-derived populations are a reasonable approach to QTL detection.
Received: 4 August 1996 / Accepted: 4 April 1997 相似文献
19.
Quantitative trait loci for the stay green trait in sorghum (Sorghum bicolor L. Moench): consistency across genetic backgrounds and environments 总被引:3,自引:0,他引:3
P. K. Subudhi D. T. Rosenow H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):733-741
Stay green in sorghum (Sorghum bicolor L. Moench) is characterized by the plant’s ability to tolerate post-flowering drought stress, thereby delaying the premature
leaf and plant death. It contributes to normal grain filling and reduces the incidence of stalk lodging and charcoal rot disease
during the late stages of grain development. Breeding for improving post-flowering drought tolerance in sorghum hybrids remains
an important objective of sorghum breeders. Since evaluation of the stay green response is difficult and unreliable under
field conditions, due to the timing and intensity of moisture stress and large environmental interaction, progress in improving
drought tolerance by conventional breeding methods has been slow. The objective of the present study was to determine the
consistency of quantitative trait loci (QTLs) controlling stay green in sorghum. We re-evaluated the Recombinant Inbred Line
(RIL)-mapping population from the cross B35 x Tx7000 in two locations over 2 years and compared it with earlier reports. Analysis
using the combined stay green-rating means of seven environments and the expanded molecular map reconfirmed all four stay
green QTLs (Stg1, Stg2, Stg3 and Stg4) that were identified earlier by Xu et al. (2000). Similarly, comparison of the stay green QTL locations with earlier reported
results indicated that all four stay green QTLs showed consistency across different genetic backgrounds. Examination of the
stay green QTL profiles of the best and poorest stay-green lines indicated that three stay green QTLs, Stg1, Stg2 and Stg3, appear to be important for the expression of this trait when the percent phenotypic variation, and the consistency in different
backgrounds and different environments, are considered. A significant epistatic interaction involving Stg2 and a region on linkage group C was also identified for the stay green and chlorophyll content. We concluded that Stg2 is the most important QTL controlling stay green, explaining the maximum amount of phenotypic variation. This report further
strengthens our view to target the Stg2 QTL region for gene discovery in order to improve the basic understanding of the stay green phenomenon, which might be helpful
in manipulating this trait not only in sorghum but also in other cereal crop species.
Received: 12 January 2000 / Accepted: 12 February 2000 相似文献
20.
K. D. Jermstad D. L. Bassoni N. C. Wheeler T. S. Anekonda S. N. Aitken W. T. Adams D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1152-1158
Quantitative trait loci (QTLs) affecting fall and spring cold-hardiness were identified in a three-generation outbred pedigree
of coastal Douglas-fir [Pseudotsuga meniziesii (Mirb.) Franco var. menziesii]. Eleven QTLs controlling fall cold-hardiness were detected on four linkage groups, and 15 QTLs controlling spring cold-hardiness
were detected on four linkage groups. Only one linkage group contained QTLs for both spring and fall cold-hardiness, and these
QTLs tended to map in close proximity to one another. Several QTLs were associated with hardiness in all three shoot tissues
assayed in the spring, supporting previous reports that there is synchronization of plant tissues during de-acclimatization.
For fall cold-hardiness, co-location of QTLs was not observed for the different tissues assayed, which is consistent with
previous reports of less synchronization of hardening in the fall. In several cases, QTLs for spring or fall cold-hardiness
mapped to the same location as QTLs controlling spring bud flush. QTL estimations, relative magnitudes of heritabilities,
and genetic correlations based on clonal data in this single full-sib family, supports conclusions about the genetic control
and relationships among cold-hardiness traits observed in population samples of Douglas-fir in previous studies.
Received: 20 July 2000 / Accepted: 19 October 2000 相似文献