共查询到20条相似文献,搜索用时 0 毫秒
1.
Desmet EM Bulcke R Maeghe L 《Communications in agricultural and applied biological sciences》2004,69(3):83-89
In the growing season 2002-2003 two field experiments were carried out in winter wheat on the heavy clay soil of the coastal polder area at Zevekote to study the response of blackgrass (Alopecurus myosuroides Huds.) resistant or somewhat less sensitive to a wide variety of herbicides (clodinafop-propargyl, fenoxaprop-P-ethy1; flupyrsulfuron-methyl+metsulfuron-methyl, propoxycarbazone-sodium; isoproturon) representing various modes of action. In Experiment 1, preemergence applications of isoproturon+diflufenican (1500+187.5 g/ha) and isoproturon+diflufenican+flurtamone (1250+100+250 g/ha) respectively were followed in mid-March (Zadoks: 23) by one of the following treatments: none, propoxycarbazone-sodium + vegetable oil (42 g/ha + 1 l/ha), mesosulfuron-methyl + iodosulfuron-methyl-sodium (+mefenpyr-diethyl) + vegetable oil (15+3 (+45) g/ha + 1 l/ha), clodinafop-propargyl (+cloquintocet-mexyl) {60 (+15) g/ha} and flupyrsulfuron-methyl+metsulfuron-methyl (10+5 g/ha). Systems based on clodinafop-propargyl, propoxycarbazone-sodium or flupyrsulfuron-methyl+metsulfuron-methyl resulted in poor supplementary control of blackgrass compared to preemergence herbicide application only. On the contrary, systems based on postemergence application of mesosulfuron-methyl + iodosulfuron-methyl-sodium resulted in excellent control. In most cases the few surviving plants failed to produce inflorescences. In Experiment 2, fall applications in the 3 leaves stage (Zadoks: 13) of prosulfocarb + isoxaben (4000+75 g/ha), flufenacet + diflufenican + isoxaben (240+120+75 g/ha) and flufenacet + pendimethalin + chlorotoluron (180+900+1000 g/ha) respectively were followed in mid-March (Zadoks: 23) by one of the following treatments: none, propoxycarbazone-sodium + vegetable oil (42 g/ha+l l/ha), mesosulfuron-methyl + iodosulfuron-methyl-sodium (+mefenpyr-diethyl) + vegetable oil {15+3 (+45) g/ha + 1 l/ha}, clodinafop-propargyl (+cloquintocet-mexyl) {60 (+15) g/ha}, flupyrsulfuron-methyl + metsulfuron-methyl (10+5 g/ha) and isoproturon+diflufenican (1000+125 g/ha). As in Experiment 1, systems based on clodinafop-propargyl, propoxycarbazone-sodium or flupyrsulfuron-methyl+metsulfuron-methyl resulted in poor additional control of blackgrass compared to herbicide application in the fall only. Comparable poor levels of blackgrass control could be observed with isoproturon+diflufenican. Mesosulfuron-methyl + iodosulfuron-methyl-sodium resulted in excellent control comparable to that recorded in Experiment 1. 相似文献
2.
D. F. Lorraine-Colwill S. B. Powles T. R. Hawkes C. Preston 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(4):545-550
Resistance to the non-selective herbicide, glyphosate, has evolved recently in several populations of Lolium rigidum (Gaud.). Based upon the observed pattern of inheritance, glyphosate resistant and susceptible populations are most probably
homozygous for glyphosate resistance and susceptibility, respectively. When these populations were crossed and the F1 progeny treated with glyphosate, the dose response behavior was intermediate to that of the parental populations. This observation,
coupled with an absence of a difference between reciprocal F1 populations, suggests that glyphosate resistance is inherited as an incompletely dominant nuclear-encoded trait. The segregation
of resistance in F1×S backcrosses suggests that the major part of the observed resistance is conferred by a single gene, although at low glyphosate
treatments other genes may also contribute to plant survival. It appears from this study that a single nuclear gene confers
resistance to glyphosate in one population of L. rigidum.
Received: 17 May 2000 / Accepted: 1 September 2000 相似文献
3.
Graminicide resistance in a blackgrass (Alopecurus myosuroides) population correlates with insensitivity of acetyl-CoA carboxylase 总被引:1,自引:0,他引:1
The appearance of biotypes of the annual grass weed black‐grass (Alopecurus myosuroides L. Huds), which are resistant to certain graminicides, is the most significant example of acquired resistance to herbicides seen so far in European agriculture. An investigation was perfomed into the basis of the specific cross‐resistance to cyclohexanedione (CHD) and aryloxyphenoxypropionoic acid (AOPP) herbicides in the ‘Notts A1’ population of A. myosuroides, which survived treatment of fields with recommended rates of AOPP herbicides. In comparison with the wild‐type ‘Rothamsted’ population, the resistant biotype showed over 100‐fold resistance to these herbicides in a hydroponic growth system. Biosynthesis of fatty acids and activity of crude extracts of acetyl‐CoA carboxylase (ACCase) were commensurately less sensitive to these herbicides in Notts A1 compared with the Rothamsted biotype. These data are consistent with the hypothesis that the highly resistant population has arisen through selection of a mutant ACCase which is much less sensitive to the AOPP and CHD graminicides. Rapidly growing cell suspension cultures established from the Notts A1 population also showed high resistance indices for CHD or AOPP herbicides compared with cultures from the Rothamsted biotype. Fatty acid biosynthesis and ACCase activity in the cell suspensions were similarly sensitive towards the graminicides to those in the foliar tissue counterparts of the resistant and sensitive populations. Moreover, purification of the main (chloroplast) isoform of acetyl‐CoA carboxylase showed that this enzyme from the Notts A1 population was over 200‐fold less sensitive towards the AOPP herbicide, quizalofop, than the equivalent isoform from the Rothamsted population. These data again fully supported the proposal that resistance in the Notts biotype is due to an insensitive acetyl‐CoA carboxylase isoform. Overall, cell suspensions were also demonstrated to be excellent tools for further investigation of the molecular basis of the high level herbicide resistance which is prone to occur in A. myosuroides. 相似文献
4.
Maréchal PY Henriet F Vancutsem F Bodson B 《Communications in agricultural and applied biological sciences》2011,76(3):501-511
Black-grass crossings were conducted outdoor for two successive years in a way to determine the percentage of resistant black-grass that can be engendered in one generation, after the introduction of one target-site resistant individual. After germination, plants were genotyped and couples of resistant and susceptible individuals were formed, then planted outdoor and enclosed with a pollen-proof cloth to avoid any external pollen contamination. Seeds were collected and tested in glasshouses with herbicide spraying. DNA analyses were also performed on surviving plants to distinguish hetero- from homozygotes. The resistance level of the progeny seems to be fairly high and Mendelean distribution is generally confirmed. The offspring of self-crossings was also observed to assess the facultative autogamy ability, according to the genotype and the presence of mutant ALS alleles (position W-574). 相似文献
5.
E. Chevreau S. Leuliette M. Gallet 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):498-506
The polymorphism of 11 enzymes was analysed in 11 progenies from controlled crosses between pear varieties, using acrylamide
and starch electrophoresis gels. Twenty-two loci were identified and segregation was scored for 20 of them. Three pairs of
duplicated loci forming intergenic hybrid bands were detected, these correspond to equivalent duplicated genes in apple. A
total of 49 active alleles and 1 null allele were identified. Joint segregation analysis revealed three linkage groups, which
could all be related to existing groups on the apple map. The conservation of isozyme patterns, duplicated genes and linkage
groups indicates a high degree of synteny between apple and pear.
Received: 8 July 1996 / Accepted: 19 July 1996 相似文献
6.
N. L. McLean J. Nowak 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(4):557-562
Red clover genotypes capable of regenerating plantlets in vitro from non-meristematic tissue-derived callus are rare. Selection
for genotypes capable of somatic embryogenesis identified a clone comprised of a group of plantlets regenerated from a hypocotyl-derived
callus culture on L2-based media and another group of plantlets originating from crown divisions of the epicotyl-derived plant.
The callus-derived plants of this clone were highly regenerative when reintroduced to callus culture, but the epicotyl-derived
plants produced nonregenerative callus cultures. F1, F2 and BC1 populations were evaluated to determine the mode of inheritance of the regeneration trait. Reciprocal crosses did not differ,
indicating a lack of maternal effects. Results were compatible with genetic control of regeneration by two complementary genes.
We propose the genotype Rn1-Rn2- for regenerative plants. Three petiole segment explants were sufficient to evaluate regenerative ability in seedlings. Regenerative
ability was often associated with abnormal leaf morphology in a few to several leaves.
Received: 17 February 1998 / Accepted: 7 April 1998 相似文献
7.
H. D. Mignouna M. M. Abang K. R. Green R. Asiedu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(1):52-55
Colletotrichum gloeosporioides causes anthracnose, the most severe foliar disease of field-grown water yam (Dioscorea alata). The inheritance of resistance to a moderately virulent (FGS) strain of the pathogen was investigated in crosses between
tetraploid D. alata genotypes: TDa 95/00328 (resistant)×TDa 95–310 (susceptible) (cross A), and TDa 85/00257 (resistant)×TDa 92–2 (susceptible)
(cross B). Segregation of F1 progeny fitted genetic ratios of 3:1, 5:1 (crosses A and B) and 7:1 (cross A) resistant:susceptible when inoculated with
the FGS strain, indicating that resistance is dominantly inherited and suggesting that more than one gene controls the inheritance
of resistance to this strain in the accessions studied. When parental and progeny lines of cross A were inoculated with an
aggressive (SGG) strain of the pathogen, all plants expressed a susceptible phenotype, indicating strain-specific resistance
in TDa 95/00328. Screening of 20 cultivars/landraces confirmed the high susceptibility of D. alata accessions to the SGG strain and revealed the presence of apparent strain non-specific resistance in TDa 85/00257. TDa 85/00257
and TDa 87/01091 which were resistant to the SGG strain, will be useful both as sources of resistance and in the development
of a host differential series for D. alata.
Received: 15 May 2000 / Accepted: 18 October 2000 相似文献
8.
G. -H. Bai G. Shaner H. Ohm 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(1):1-8
To study the inheritance of resistance in wheat to Fusarium graminearum, six resistant cultivars from China were crossed to two susceptible cultivars. The parents and their progenies were evaluated
in the greenhouse for resistance to the spread of scab within a spike. A central floret was inoculated by injecting a droplet
of inoculum at the time of anthesis. Inoculated plants were kept in a moist chamber for three subsequent nights. The proportion
of scabbed spikelets was recorded six-times from 3-days to 21-days after inoculation, and the area under the disease progress
curve (AUDPC) was calculated from these proportions. One to three genes, depending on the cultivar, conditioned resistance
to scab as reflected by the AUDPC. A simple additive-dominance effect model fitted the segregation data for 8 of the 11 crosses.
Dominance and epistatic effects were significant in a few crosses. These effects increased resistance in some crosses but
decreased resistance in others. However, relative to additive effects, dominant and epistatic effects accounted for only a
small portion of the genetic effects in the populations evaluated. The importance of additive effects means that it should
be possible to accumulate different genes to enhance resistance to scab in wheat.
Received: 15 December 1998 / Accepted: 17 June 1999 相似文献
9.
Field assessments of gene flow from transgenic to cultivated rice (Oryza sativa L.) using a herbicide resistance gene as tracer marker 总被引:6,自引:0,他引:6
J. Messeguer C. Fogher E. Guiderdoni V. Marfà M. M. Català G. Baldi E. Melé 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(8):1151-1159
Development of plant genetic engineering has led to the deployment of transgenic crops and, simultaneously, to the need for
a thorough assessment of the risks associated with their environmental release. This study investigated the occurrence of
gene flow from transgenic rice to non-transgenic rice plants under agronomic conditions using a herbicide resistance gene
as a tracer marker. Two field experiments were established in the paddy fields of two main Mediterranean rice-growing areas
of Spain and Italy. In both locations analyses of phenotypic, molecular and segregation data showed that pollination of recipient
plants with pollen of the transgenic source occurred at a significant frequency. A gene flow slightly lower than 0.1% was
detected in a normal side-by-side plot design. Similar results were found in a circular plot when the plants were placed at
1-m distance from the transgenic central nucleus. A strong asymmetric distribution of the gene flow was detected among this
circle and highest values (0.53%) were recorded following the direction of the dominant wind. A significant lowest value (0.01%)
was found in the other circle (5 m from the transgenic plants) as was expected according to the characteristics of rice pollen.
Such circular-field trial designs could also prove to be very useful in studying the gene flow to other commercial cultivars
of rice with the aim of establishing strategies to prevent pollen dispersal from commercial transgenic fields to the neighbouring
conventional fields.
Received: 23 February 2001 / Accepted: 31 March 2001 相似文献
10.
T. Krugman A. Korol E. Nevo J. W. Snape O. Levy B. Rubin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):46-51
Chlorotoluron is a selective phenylurea herbicide widely used for broad-leaved and annual grass weed control in cereals. Variation in the response to chlorotoluron (CT) was found in both hexaploid bread wheat (Triticum aestivum L.) and wild tetraploid wheat (Triticum dicoccoides KöRN.). Here, we describe the comparative mapping of the CT resistance gene (Su1) on chromosome 6B in bread and wild wheat using RFLP markers. In bread wheat, mapping was based on 58 F4 single-seed descent (SSD) plants of the cross between a genotype sensitive to chlorotoluron, ‘Chinese Spring’ (CS), and a resistant derivative, the single chromosome substitution line, CS (‘Cappele-Desprez’ 6B) [CS (CAP6B). In T dicoccoides, mapping was based on 37 F2 plants obtained from the cross between the CT-susceptible accession B-7 and the resistant accession B-35. Nine RFLP probes spanning the centromere were chosen for mapping. In bread wheat Su1 was found to be linked to α-Amy-1 (9.84 cM) and Xpsr371 (5.2 cM), both on the long arm of 6B, and Nor2 (2.74 cM) on the short arm. In wild wheat the most probable linkage map was Nor2-Xpsr312-Su1-Pgk2, and the genetic distances between the genes were 24.8cM, 5.3cM, and 6.8cM, respectively. These results along with other published map data indicate that the linear order of the genes is similar to that found in T. aestivum. The results of this study also show that the Su1 gene for differential response to chlorotoluron has evolved prior to the domestication of cultivated wheat and not in response to the development and use of chemicals. 相似文献
11.
Inheritance of resistance to southern corn rust in tropical-by-corn-belt maize populations 总被引:9,自引:0,他引:9
J. B. Holland D. V. Uhr D. Jeffers M. M. Goodman 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(2):232-241
The inheritance of resistance to southern rust (caused by Puccinia polysora Underw.) was investigated in two F2:3 populations derived from crossing two temperate-adapted, 100% tropical maize (Zea mays L.) inbred lines (1416-1 and 1497-2) to a susceptible Corn Belt Dent hybrid, B73Ht×Mo17Ht. The inbred lines possess high levels of resistance to southern rust and may be unique sources of resistance genes. Heritability
for resistance was estimated as 30% and 50% in the two populations from regression of F2:3 family mean scores on F2 parent scores, and as 65% and 75% from variances among F2:3 families on a single-plot basis. RFLP loci on three chromosomal regions previously known to possess genes for resistance
to either southern rust or common rust (P. sorghi Schw.) were used to localize genes affecting resistance to southern rust in selected genotypes of both populations, and to
estimate their genetic effects. A single locus on 10S, bnl3.04, was associated with 82–83% of the variation among field resistance scores of selected F2:3 families in the two populations. Loci on chromosomes 3 (umc26) and 4 (umc31) were significantly associated with resistance in the 1497-2 population, each accounting for 13–15% of the phenotypic variation
for F2:3 field scores. Multiple-marker locus models, including loci from chromosomes 3, 4, and 10 and their epistatic interactions,
accounted for 96–99% of the variation in F2:3 field scores. Similar results were obtained for resistance measured by counting pustules on juvenile plants in the greenhouse.
An attempt was made to determine if the major gene for resistance from 1416-1 was allelic to Rpp9, which is also located on 10S. Testcross families from the cross (1416-1×B37Rpp9)×B14AHt were evaluated for resistance to southern rust in Mexico. Neither source of resistance was completely effective in this environment,
preventing determination of allelism of the two genes; however, both sources of resistance had better partial resistance to
southern rust than did B14AHt.
Received: 6 May 1997/Accepted: 19 September 1997 相似文献
12.
H. D. Mignouna P. Njukeng M. M. Abang R. Asiedu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(8):1196-2000
Yam mosaic virus (YMV) causes the most-widespread and economically important viral disease affecting white yam (Dioscorea rotundata) in West Africa. The genetic basis of resistance in white yam to a Nigerian isolate of YMV was investigated in three tetraploid
D.
rotundata genotypes: TDr 93–1, TDr 93–2 and TDr 89/01444. F1 progeny were produced using TDr 87/00571 and TDr 87/00211 as the susceptible parents. Segregation ratios indicated that a
single dominant gene in a simplex condition governs the resistance in TDr 89/01444, while the resistance in TDr 93–2 is associated
with the presence of a major recessive gene in duplex configuration. Segregation of progeny of the cross TDr 93–1×TDr 87/00211
fitted a genetic ratio of 2.48:1 resistant:susceptible, which can be expected when two simplex heterozygotes are crossed,
indicating the possible modifying effect of the susceptible parent. A triple antibody immunosorbent assay (TAS-ELISA) was
used for virus detection in inoculated plants. Slight mosaic symptoms appeared on most resistant individuals, while asymptomatic
resistant genotypes with high ELISA (A405) values were observed in all crosses. Such a heterogeneous response suggests the influence of additional modifier genes that
segregate in the progeny. The finding that resistance can be inherited as a dominant or recessive character has important
implications for YMV resistance breeding.
Received: 15 August 2000 / Accepted: 12 April 2001 相似文献
13.
G. Besnard Y. Griveau M. C. Quillet H. Serieys P. Lambert D. Vares A. Bervillé 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):131-138
A method based upon targetting of intro-gressed markers in a Phomopsis-resistant line (R) of cultivated sunflower, issuing
from a H. argophyllus cross was used to mark the Phomopsis resistance regions. Our study was based upon 203 families derived from a cross between an inbred line susceptible to Phomopsis (S1) and the introgressed resistant line (R).
Families were checked for Phomopsis resistance level in a design with replicated plots and natural infection was re-inforced
by pieces of contaminated stems. Thirty four primers were employed for RAPD analysis. Out of 102 polymorphic fragments between
(S1) and H. argophyllus, seven were still present in (R) suggesting that they marked introgressions of H. argophyllus into (R). The plants were scored for the presence or absence of 19 fragments obtained from five primers, and the relationships between
the presence/absence of fragments in plants and Phomopsis resistance/susceptiblity in the progenies was determined by using an analysis of variance. We found that at least two introgressed regions, as well as favourable
factors from sunflower, contributed to the level of Phomopsis resistance in cultivated sunflower.
Received: 28 June 1996 / Accepted: 5 July 1996 相似文献
14.
S. B. Verulkar D. P. Singh 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(8):1102-1103
A male-sterile plant was observed in the UPAS-120 cultivar of pigeonpea (Cajanus cajan). The plant was about 5–7 days late-flowering and had white translucent anthers with complete pollen sterility. The inheritance
of this spontaneous male sterility was studied in a cross involving the mutant and fertile UPAS-120, including their F1, F2, BC1F1 and BC2F1 generations. The results suggested that the male sterility was genetic and due to a recessive gene.
Received: 12 November 1996/Accepted: 17 January 1997 相似文献
15.
Inheritance of resistance to beet necrotic yellow vein virus in Beta vulgaris conferred by a second gene for resistance 总被引:1,自引:0,他引:1
O. E. Scholten Th. S. M. De Bock R. M. Klein-Lankhorst W. Lange 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(3-4):740-746
Rhizomania is a serious disease of sugar beet, caused by beet necrotic yellow vein virus (BNYVV). The disease can only be
controlled by the use of resistant cultivars. The accession Holly contains a single dominant gene for resistance, called Rz. The identification of a locus for resistance that differs from Rz would provide possibilities to produce cultivars with multiple resistance to BNYVV. Inheritance of resistance to BNYVV was
studied by screening progenies of crosses between resistant plants of the accessions Beta vulgaris subsp. maritima WB42 and B. vulgaris subsp. vulgaris Holly-1–4 or R104. Observed and expected segregation ratios were compared to elucidate whether the resistance genes in the
three accessions are alleles or situated on different loci. STS markers, linked to the genes for resistance, were used to
study the segregation in more detail. The results demonstrated that the genes for resistance to BNYVV inHolly-1-4 and WB42
are closely linked. The gene for resistance in R104 is at the same locus as in Holly-1-4, and also closely linked to the gene
in WB42. As the Holly resistance gene has been named Rz, the name Rz2 is proposed to refer to the resistance gene in WB42. Consequently, the gene Rz should be referred to as Rz1.
Received: 29 October 1998 / Accepted: 12 March 1999 相似文献
16.
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
17.
18.
Inheritance of resistance to covered smut in barley and development of a tightly linked SCAR marker 总被引:3,自引:0,他引:3
Ardiel GS Grewal TS Deberdt P Rossnagel BG Scoles GJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):457-464
Inheritance of resistance to covered smut in the barley line Q21861 was studied using a doubled-haploid population produced
by crossing Q21861 with the line SM89010. Based on 3 years of screening in the field and two seasons in the greenhouse, segregation
for resistance/susceptibility fits a one-gene ratio, indicating a single major gene for resistance in Q21861. Of 440 random
10-mer primers tested using bulked segregant analysis, one primer (OPJ10) resulted in a reproducible polymorphic band. RAPD
marker OPJ10450 co-segregated in repulsion with the covered smut resistance. This marker was converted to a sequence-characterized amplified
region (SCAR) marker linked in coupling (5.5 cM) with the covered smut resistant gene in Q21861. The SCAR marker was amplified
in the line TR640 which is also resistant to covered smut, but not in the other resistant lines. The SCAR marker will be useful
for marker-assisted selection for covered smut in barley breeding programs.
Received: 9 January 2001 / Accepted: 31 May 2001 相似文献
19.
Black‐grass (Alopecurus myosuroides) is an allogamous grass weed common in cereal fields of northern Europe, which developed resistance to a widely used family of herbicides, the ACCase‐inhibiting herbicides. Resistance is caused by mutations at the ACCase gene and other, metabolism‐based, mechanisms. We investigated the genetic structure of 36 populations of black‐grass collected in one region of France (Côte d’Or), using 116 amplified fragment length polymorphism (AFLP) loci and sequence data at the ACCase gene. The samples were characterized for their level of herbicide resistance and genotyped for seven known ACCase mutations conferring resistance. All samples contained herbicide‐resistant plants, and 19 contained ACCase mutations. The genetic diversity at AFLP loci was high (HT = 0.246), while differentiation among samples was low (FST = 0.023) and no isolation by distance was detected. Genetic diversity within samples did not vary with the frequency of herbicide resistance. A Bayesian algorithm was used to infer population structure. The two genetic clusters inferred were not associated with any geographical structure or with herbicide resistance. A high haplotype diversity (Hd = 0.873) and low differentiation (GST = 0.056) were observed at ACCase. However, haplotype diversity within samples decreased with the frequency of ACCase‐based resistance. We suggest that the genetic structure of black‐grass is affected by its recent expansion as a weed. Our data demonstrate that the strong selection imposed by herbicides did not modify the genome‐wide genetic structure of an allogamous weed that probably has large effective population sizes. Our study gives keys to a better understanding of the evolution of successful, noxious weeds in modern agriculture. 相似文献
20.
W. Wicki M. Winzeler J. E. Schmid P. Stamp M. Messmer 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(7-8):1265-1272
Sixteen crosses between eight winter wheat cultivars were screened for resistance to Septoria nodorum leaf and glume blotch in the F1 and F4 generations using artificial inoculation in the field. The F1 of most crosses showed dominance for susceptibility on both ear and leaf. The effects of general combining ability were of
similar magnitude as the effects for specific combining ability. On the basis of the phenotypic difference of the parents,
no prediction was possible about the amount and the direction of genetic variance in the segregating populations. The variation
observed in this study both within and among the segregating populations suggests a quantitative inheritance pattern influencing
the expression of the two traits. The components of variance between F2 families within a population were as high as (for S. nodorum blotch on the ear) or higher (for S. nodorum blotch on the leaf) than those between populations. Therefore, strong selection within a few populations may be as effective
to obtain new resistant genotypes as selection in a large number of populations. In almost all crosses, progenies were found
that were more resistant than the better parent. Thus transgression breeding may be a tool to breed for higher levels of resistance
to S. nodorum blotch. Highly resistant genotypes were found even in combination with two susceptible parents. The genetic source for Septoria resistance is probably broader than is generally assumed and could be used to improve S. nodorum resistance by combination breeding followed by strong selection in large populations.
Received: 18 January / Accepted: 30 April 1999 相似文献