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1.
In tomato ( Lycopersicon esculentum Mill.) a single dominant gene ( Frl) on chromosome 9 confers resistance to fusarium crown
and root rot (crown rot) incited by Fusarium oxysporum f. sp. radicis-lycopersici. To identify randomly amplified polymorphic
DNA (RAPD) markers linked to Frl, crown rot susceptible and resistant tomato lines were screened for polymorphisms using 1000
random 10-mer primers and three reliable RAPD markers were found linked to Frl (UBC #'s 116, 194, and 655). A codominant polymorphic
PCR marker of TG101, a restriction fragment length polymorphic (RFLP) marker linked to Frl, was developed to facilitate the
linkage studies. Using TG101 and the four RAPD markers, on a Frl segregating backcross population of 950 plants indicated
that all belong to the same linkage group. The polymorphic allele order was found to be TG101 – 655 – 116 – 194 – Frl. UBC
194 was found to be 5.1 cM from Frl in this population. Furthermore, it was the only marker found in the resistant genotypes
‘Mocis’ and Fla 7226, whereas resistant genotypes ‘Momor’, Ohio 89-1, and Fla 7464 all had UBC 194 and UBC #'s 116, 194, and
655.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
RAPD markers linked to a clubroot-resistance locus in Brassica rapa L. 总被引:10,自引:0,他引:10
Yasuhisa Kuginuki Hidetoshi Ajisaka Mamiko Yui Hiroaki Yoshikawa Ken-ichi Hida Masashi Hirai 《Euphytica》1997,98(3):149-154
Linkage of random amplified polymorphic DNA (RAPD) markers with resistance genes to clubroot (Plasmodiophora brassicae Wor.)
in Brassica rapa L. was studied in a doubled haploid (DH population obtained by microspore culture. Thirty-six DH lines were
obtained from F1 plants from a cross between susceptible ‘Homei P09’ and resistant ‘Siloga S2’ plants. ‘Homei P09’ was a DH line obtained
by microspore culture of the Chinese cabbage variety ‘Homei’, which is highly responsive in microspore culture. The resistant
line ‘Siloga S2’ was obtained by two rounds of selfing of the fodder turnip ‘Siloga’. Three RAPD markers, RA12-75A, WE22B
and WE49B, were found to be linked to a clubroot-resistance locus. These three markers were linked in the DH lines and an
F2 population and should be useful for marker-assisted selection in breeding programs.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
K.K. Jena I.C. Pasalu Y.K. Rao Y. Varalaxmi K. Krishnaiah G.S. Khush G. Kochert 《Euphytica》2003,129(1):81-88
An introgression line derived from an interspecific cross between Oryzasativa and Oryza officinalis, IR54741-3-21-22 was found to beresistant to an Indian biotype of brown planthopper (BPH). Genetic analysisof 95 F3 progeny rows of a cross between the resistant lineIR54741-3-21-22 and a BPH susceptible line revealed that resistance wascontrolled by a single dominant gene. A comprehensive RAPD analysisusing 275 decamer primers revealed a low level of (7.1%) polymorphismbetween the parents.RAPD polymorphisms were either co-dominant (6.9%), dominant forresistant parental fragments (9.1%) or dominant for susceptible parentalfragments (11.6%). Of the 19 co-dominant markers, one primer,OPA16, amplified a resistant parental band in the resistant bulk and asusceptible parental band in the susceptible bulk by bulked segregantanalysis. RAPD analysis of individual F2 plants with the primerOPA16 showed marker-phenotype co-segregation for all, with only onerecombinant being identified. The linkage between the RAPD markerOPA16938 and the BPH resistance gene was 0.52 cM in couplingphase. The 938 bp RAPD amplicon was cloned and used as a probe on122 Cla I digested doubled haploid (DH) plants from aIR64xAzucena mapping population for RFLP inheritance analysis and wasmapped onto rice chromosome 11. The OPA16938 RAPD markercould be used in a cost effective way for marker-assisted selection of BPHresistant rice genotypes in rice breeding programs. 相似文献
4.
K. Nomura Y. Minegishi C. Kimizuka-Takagi T. Fujioka K. Moriguchi R. Shishido H. Ikehashi 《Plant Breeding》2005,124(4):371-375
Clubroot disease caused by Plasmodiophora brassicae is one of the major diseases of Brassica crops, often devastating to the cultivation of cruciferous crops in temperate regions. In a previous study (Moriguchi et al. 1999) identified three major quantitative trait loci (QTLs) for clubroot resistance, each in a separate linkage group, in a population derived from a cross between a clubroot‐susceptible inbred cabbage line, Y2A and a resistant inbred kale line, K269. In this study, the original random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers were converted into sequence‐characterized amplified region (SCAR) markers to facilitate large‐scale marker‐assisted screening of clubroot resistance in cabbage breeding. Of 15 RAPD markers closely linked to the three QTLs, nine SCARs were developed as dominant markers after cloning and sequencing. In addition, two RAPD markers were converted into co‐dominant cleaved amplified polymorphic sequence (CAPS) markers, and one RFLP marker out of three tested was converted to a dominant SCAR marker. The effect of selection for resistance by the improved markers was evaluated in progeny plants in the F2 and F3. A total of 138 F2 plants were genotyped with nine SCARs and 121 well‐distributed makers consisting of 98 RAPD, 19 RFLP, two isozymes, and two morphological markers in order to estimate the level of resistance and the proportion of undesirable alleles from the kale in non‐target areas in each of the F2 populations. An F2 plant, YK118, had kale alleles at QTL1, QTL3 and QTL9. Three F2 plants, namely, YK107, YK25 and YK51 had kale alleles at only QTL1, QTL3 and QTL9, respectively. These F2 plants were selected for their low proportion of alleles derived from kale in non‐target regions. YK118, like the resistant kale parent, expressed very high resistance to three field isolates of Plasmodiophora brassicae, whereas the mean disease index in the F2 and F3 plants carrying only single QTLs was intermediate. The QTLs showed no differential response to the isolates. These plants with improved resistance will be useful as parental inbred lines for F1 hybrids. 相似文献
5.
Juthaporn Khampila Kamol Lertrat Weerasak Saksirirat Jirawat Sanitchon Nooduan Muangsan Piyada Theerakulpisut 《Euphytica》2008,164(3):615-625
Exserohilum turcicum causes northern corn leaf blight (NCLB), an important disease occurring in maize producing areas throughout the world. Currently,
the development of cultivars resistant to E. turcicum seems to be the most efficient method to control NCLB damage. Marker-assisted selection (MAS) enables breeders to improve
selection efficiency. The objective of this work was to identify random amplified polymorphic DNA (RAPD) and sequence characterized
amplified region (SCAR) markers associated with NCLB resistance. Bulked segregant analysis (BSA) was used to search for RAPD
markers linked to NCLB resistance genes, using F2 segregating population obtained by crossing a susceptible inbred ‘209W’ line with a resistant inbred ‘241W’ line. Two hundred
and twenty-two decamer primers were screened to identify four RAPD markers: OPA07521, OPA16457, OPB09520, and OPE20536 linked to NCLB resistance phenotype. These markers were converted into dominant SCAR markers: SCA07496, SCA16420, SCB09464, and SCE20429, respectively. The RAPD and SCAR markers were developed successfully to identify NCLB resistant genotypes in segregating
progenies carrying NCLB resistant traits. Thus, the markers identified in this study should be applicable for MAS for the
NCLB resistance in waxy corn breeding programs. 相似文献
6.
Summary A Japanese leading cultivar ‘Konafubuki’ has an extreme resistance gene Ry
chc
to Potato virus Y (PVY) in a simplex fashion. To reduce complexity of the highly heterozygous autotetraploid genome and map the Ry
chc
gene, haploid plants were parthenogenetically induced from ‘Konafubuki’. The ratio of 7 resistant: 5 susceptible haploids confirmed the single dominant, simplex genotype of ‘Konafubuki’. A selected resistant haploid 98H20-5 was crossed with a susceptible diploid, resulting in 119 F
1 plants. Using RFLP and RAPD markers, Ry
chc
was mapped to the most distal end of the chromosome 9 where the recovery of recombinant genotypes was extremely reduced in this mapping population possibly due to the linked inferiority factor. The location of Ry
chc
is different from those of the other extreme resistance genes to PVY, but possibly resides in one of resistance gene clusters. 相似文献
7.
A cross was made between rice cultivars Katy and Lemont. F3 families were produced from individual F2 plants. Approximately
25 plants of each F3 family were inoculated with each of 8 different strains of Magnaporthe grisea. Each strain of the pathogen was known to have different genes for avirulence on Katy or Lemont. Each F3 family was recorded
as having all plants resistant, segregating for resistance, or all plants being susceptible. The results suggest that the
‘single’ gene for resistance in Katy is a tightly linked cluster of at least seven genes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
The chromosomal location of the resistance gene for green rice leafhopper (GRLH), an injurious insect for rice, has been determined and RFLP markers closely linked to this gene have been identified. The susceptible japonica rice variety ‘Nipponbare’ was crossed with a resistant japonica rice line ‘Aichi42’, in which green rice leaf hopper resistance had been introduced from an indica variety ‘Rantaj‐emas2’, and the 100 F2 plants obtained were used for linkage analysis. The green rice leafhopper resistance gene, Grh3(t), was mapped between RFLP markers C288B and C133A on chromosome 6 and co‐segregated with C81. Of the RFLP markers tightly linked to Grh3(t), C81 was converted to a SCAR marker and C133A to a cleaved amplified polymorphic sequence marker that could distinguish the heterozygous genotype to establish an effective marker‐aided selection system for the GRLH resistance gene. 相似文献
9.
Squash silverleaf (SSL), caused by the silverleaf whitefly [Bemisia argentifolii (formerly known as Bemisia tabaci Gennadius, B strain)], is an important physiological disorder that affects squash (Cucurbita spp.) by reducing yield potential. Breeding squash with resistance to SSL disorder can be facilitated by using marker-assisted
selection (MAS). Resistance to SSL disorder, in Cucurbita pepo, is conferred by a single recessive gene (sl). The objective of this study was to identify molecular markers associated with resistance. A zucchini squash, SSL disorder
resistant breeding line, ‘Zuc76’ (sl/sl) and a SSL disorder susceptible zucchini cultivar ‘Black Beauty’ (Sl/Sl) were screened with 1,152 randomly amplified polymorphic DNA (RAPD) primers and 432 simple sequence repeat (SSR) markers
to identify polymorphisms. Using F2 and BC1 progeny segregating for SSL disorder resistance, three RAPD (OPC07, OPL07 and OPBC16) primers and one SSR (M121) marker were
found associated with sl. Fragments amplified by RAPD primer OPC07 was linked in coupling phase to sl, whereas RAPD primer OPL07 was linked in repulsion phase. RAPD primer OPBC16 and SSR marker M121 were co-dominant. The allelic
order of these loci was found to be M121–sl–OPC07–OPL07–OPBC16. The closest marker to sl is M121 with an estimated genetic distance of 3.3 cM. The markers identified in this study will be useful for breeding summer
squash (C. pepo) for SSL disorder resistance derived from zucchini squash breeding line ‘Zuc76’. 相似文献
10.
H. Kotresh B. Fakrudin S. M. Punnuri B. K. Rajkumar M. Thudi H. Paramesh H. Lohithswa M. S. Kuruvinashetti 《Euphytica》2006,149(1-2):113-120
Summary
Fusarium wilt (Fusarium udum Butler) is a soil borne disease of pigeonpea which causes substantial yield losses. The disease can occur at any stage of plant development, from the young seedling to the pod filling stage. Though resistance is simply inherited, transfer to locally adapted cultivars has been difficult due to linkage drag and difficulty in accurate phenotyping, except in sick plots. An attempt was made to identify RAPD markers associated with wilt phenotype by using F2 populations derived from contrasting parents; GSl (susceptible) ‘ICPL87119 (resistant) and GS1’ ICP8863 (resistant). Parents and F2s were grown in a national Fusarium sick-plot at Gulbarga, India and phenotyped as resistant or susceptible during the entire crop growth period. In both the crosses, resistance to wilt segregated as a monogenic dominant character. DNA samples extracted from sick plot grown, early seedling stage plants of parents and 254 F2 plants of GS1 × ICPL87119 were held separately for marker identification. PCR reactions using 340 random decamer primers with genomic DNA of parents resulted in detection of 45 polymorphic amplicons from 39 primers. PCR testing of bulked DNA from subsets of resistant and susceptible plants revealed the presence of two amplicons at 704 bp and 500 bp (OPM03704 and OPAC11500) with susceptibility. Analysis of individual F2 plants showed a segregation ratio of 3: 1 for the presence: absence of the amplicon in both crosses. Considering the wilt reaction and susceptibility-linked RAPD marker, it was possible to deduce genotype of every F2 plant and the genotypic ratio for wilt reaction was 1RR: 2Rr: 1rr, as expected. 相似文献
11.
Sequence-related amplified polymorphism (SRAP), simple sequence repeats (SSR), inter-simple sequence repeat (ISSR), peroxidase
gene polymorphism (POGP), resistant gene analog (RGA), randomly amplified polymorphic DNA (RAPD), and a morphological marker,
Alternaria brown spot resistance gene of citrus named as Cabsr caused by (Alternaria alternata f. sp. Citri) were used to establish genetic linkage map of citrus using a population of 164 F1 individuals derived between ‘Clementine’ mandarin (Citrus reticulata Blanco ‘Clementine) and ‘Orlando’ tangelo’ (C. paradisi Macf. ‘Duncan’ × C. reticulata Blanco ‘Dancy’). A total of 609 markers, including 385 SRAP, 97 RAPD, 95 SSR, 18 ISSR, 12 POGP, and 2 RGA markers were used
in linkage analysis. The ‘Clementine’ linkage map has 215 markers, comprising 144 testcross and 71 intercross markers placed
in nine linkage groups. The ‘Clementine’ linkage map covered 858 cM with and average map distance of 3.5 cM between adjacent
markers. The ‘Orlando’ linkage map has 189 markers, comprising 126 testcross and 61 intercross markers placed in nine linkage
groups. The ‘Orlando’ linkage map covered 886 cM with an average map distance of 3.9 cM between adjacent markers. Segregation
ratios for Cabsr were not significantly different from 1:1, suggesting that this trait is controlled by a single locus. This locus was placed
in ‘Orlando’ linkage group 1. The new map has an improved distribution of markers along the linkage groups with fewer gaps.
Combining different marker systems in linkage mapping studies may give better genome coverage due to their chromosomal target
site differences, therefore fewer gaps in linkage groups. 相似文献
12.
Takashi Onozaki Natsu Tanikawa Mitsuyasu Taneya Kiyofumi Kudo Takuya Funayama Hiroshi Ikeda Michio Shibata 《Euphytica》2004,138(3):255-262
Bacterial wilt caused by Burkholderia caryophylli is one of the most important and damaging diseases of carnations (Dianthus caryophyllus) in Japan. We aimed to identify random amplified polymorphic DNA (RAPD) markers associated with the genes controlling bacterial wilt resistance in a resistance-segregating population of 134 progeny plants derived from a cross between Carnation Nou No. 1 (a carnation breeding line resistant to bacterial wilt) and Pretty Favvare (a susceptible cultivar). We screened a total of 505 primers to obtain RAPD markers useful for selecting resistant carnation lines: 8 RAPD markers identified by bulked segregant analysis were linked to a major resistance gene; of these, WG44-1050 had the greatest effect on resistance to bacterial wilt. A locus with large effect on bacterial resistance was mapped around WG44-1050 through QTL analysis. The RAPD marker WG44-1050 was successfully converted to a sequence-tagged site (STS) marker suitable for marker-assisted selection (MAS). Five combinations of primers were designed for specific amplification of WG44-1050. In addition, the STS marker we developed was useful and reliable as a selection marker for breeding for resistance to bacterial wilt, using a highly resistant wild species, D. capitatus ssp. andrzejowskianus and a resistant line, Carnation Nou No. 1, as breeding materials. 相似文献
13.
The inheritance of the resistance to Fusarium oxysporum f. sp. melonis (F.o.m.) races 0 and 2 in ‘Tortuga’, a Spanish cantalupensis accession, was studied from crosses of ‘Tortuga’ by the susceptible line ‘Piel de Sapo’ and the resistant one ‘Charentais-Fom1’
that carries the resistance gene Fom-1. The segregation patterns observed in the F2 (‘Tortuga’ × ‘Piel de Sapo’) and the backcross (‘Piel de Sapo’ × (‘Tortuga’ × ‘Piel de Sapo’) populations, suggest that resistance
of ‘Tortuga’ to races 0 and 2 of F.o.m. is conferred by two independent genes: one dominant and the other recessive. In the F2 derived from the cross between accessions
‘Tortuga’ and ‘Charentais-Fom1’, the lack of susceptible plants indicated that the two accessions are carrying the same resistance
gene (Fom-1). The analysis of 158 F2 plants (‘Tortuga’ × ‘Piel de Sapo’) with a Cleaved Amplified Polymorphic Sequence marker 618-CAPS, tightly linked to Fom-1 (0.9 cM), confirmed that ‘Tortuga’ also carries a recessive gene, that we propose to symbolize by fom-4. 相似文献
14.
L.S. Boiteux J.R. Hyman I.C. Bach M.E.N. Fonseca W.C. Matthews P.A. Roberts P.W. Simon 《Euphytica》2004,136(1):37-44
In carrot, two codominant sequence-tagged site (STS) markers, flanking in tight linkage the Meloidogyne javanica resistance (Mj-1) locus, were employed to investigate the association between expression of resistance and locus dosage. Phenotypic expression
of homozygous resistant (R); heterozygous; and homozygous susceptible (S) individuals in an F2 population of 396 F2 plants from ‘Brasília-1252’ (R) × ‘B6274’ (S) was estimated for three resistance criteria: total egg production per plant
(TEP), egg production per gram of fibrous root (EPG) and root gall index (RGI). The homozygous resistant class had average
values of 403.9 for TEP; 147.5 for EPG and 0.8 for RGI. The heterozygous class had 1,673; 477.3; and 0.16 whereas the homozygous
susceptible class had 68,604; 11,877; and 2.54, respectively. The dominance ratio (d/a) indicated that genomic region(s) derived
from the resistant parent encompass genetic factor(s) with almost complete dominance for RGI (d/a = 0.93–0.94) and incomplete
dominance for transformed (TEP)0.25 and (EPG)0.25 (d/a = 0.63–0.65). Broad sense heritabilities were high varying from 72.9% for (EPG)0.25 to 86.0% for RGI. Narrow sense heritability values ranged from 55.9% for RGI to 64.3%for (TEP)0.25. Highly significant orthogonal contrasts were observed between homozygous resistant vs. heterozygous for (TEP)0.25 and (EPG)0.25. Marker-assisted selection could greatly facilitate the incorporation of the Mj-1 allele in both male-fertile and male-sterile counterpart lines in order to obtain F1 hybrids with the most effective levels of resistance.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Benjamin M. Beyer Scott D. Haley Nora L. V. Lapitan Junhua H. Peng Frank B. Peairs 《Euphytica》2011,179(2):247-255
Identification of new sources of resistance to Russian wheat aphid (RWA) (Diuraphis noxia (Kurdjumov) in wheat (Triticum aestivum L.) has become very important with the identification of several new biotypes since 2003. Our objective was to characterize
inheritance and expression of resistance to RWA biotype 2 from three tetraploid wheat landraces (Triticum turgidum L. subsp. dicoccon) during transfer to hexaploid wheat. Resistant tetraploid accessions PI 624903, PI 624904, and PI 624908 were crossed to
the susceptible hexaploid cultivars ‘Len’ and ‘Coteau’. Resistant F1 progeny were advanced to the F2:3 by self-pollination
and to the BC1F2 and BC2F1 by backcrossing. Leaf rolling and chlorosis were recorded in standard seedling screening tests
on F1 and F2:3 individuals while the F2, BC1F1, BC1F2, and BC2F1 were scored as resistant or susceptible. Segregation in the
BC1F1 and BC2F1 fit a 1:1 resistant:susceptible ratio, indicative of control by a single dominant gene. Segregation for resistance
in the F2 did not fit 3:1, 13:3, or 15:1 ratios for any of the resistant accessions. Expression of resistance in homogeneous
resistant F2:3 lines was greater than susceptible checks, similar to the resistant tetraploid accessions, and less than a
line carrying the Dn7 resistance gene. Resistance derived from these tetraploid accessions will be useful to broaden the base of RWA resistance
available for use in wheat breeding. 相似文献
16.
本研究旨在筛选获得与番茄黄化卷叶病毒抗病基因Ty-1紧密连锁的分子标记,为番茄抗病育种提供技术支撑。根据与抗病基因Ty-1紧密连锁的RFLP标记序列设计特异引物,以抗病杂合体(Ty-1/ty-1)、抗病纯合体(Ty-1/Ty-1)和感病纯合体(ty-1/ty-1)材料提取的DNA为模板,进行PCR扩增,而后经不同的核酸内切酶酶切处理,筛选获得与Ty-1基因紧密连锁的CAPS标记。结果显示从4个标记中筛选获得了2个稳定可靠的CAPS标记,即TG97和Mi23。TG97标记在抗病杂合体产生398 bp、303 bp和95 bp 3个特异片段,抗病纯合体产生303 bp和95 bp 2个特异片段,感病纯合体产生398 bp一个特异片段。Mi23标记在抗病杂合体产生402 bp和354 bp 2个特异片段,抗病纯合体产生402 bp一个特异片段,感病纯合体产生354 bp一个特异片段。研究结果表明TG97和Mi23这2个CAPS标记均为共显性标记,可用于番茄抗病育种的辅助选择中。 相似文献
17.
A phenomenon, loss of heterozygosity (LOH), was discovered in hybrid plants involving a selected plant (named AMR) of the
Chinese rice cultivar ‘ZhongxinNo. 1’ as one parent. In these hybrids and some of their progenies, somatic variations were
manifested by molecular genotypes and/or morphological phenotypes in vegetative parts of the same plant. Random amplified
polymorphic DNA (RAPD) markers for the parents have been followed through the F3 generation. RAPD markers were uniformly present or absent in all plants within some or all F2 panicle rows derived from F1 hybrids involving AMR. In contrast, RAPD markers segregated in the Mendelian manner for dominant markers in panicle rows
derived from control hybrids. Certain F2 panicle rows from F1hybrids involving the special rice became fixed for all assayed RAPD markers. Genotype fixation was confirmed by molecular
assays and field observations of the F3 progenies. We propose a new biological mechanism, called ‘assortment mitosis,’ as being responsible for the observed phenomenon.
The use of this mechanism in plant hybrids allows the development of uniform progenies as early as the F2 generation. Therefore, the time required to obtain fixed non-parental type progenies for subsequent performance trials can
be drastically shortened. Utilizing this mechanism in plant breeding represents a new approach and requires the modification
of conventional plant breeding procedures.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Three segregating F2 populations were developed by self-pollinating 3 black rot resistant F1 plants, derived from across between black rot resistant parent line 11B-1-12 and the susceptible cauliflower cultivar ‘Snow
Ball’. Plants were wound inoculated using 4 isolates ofXanthomonas campestris pv. campestris (Xcc) race 4, and disease severity ratings of F2 plants from the three populations were scored. A total of 860 arbitrary oligonucleotide primers were used to amplify DNA
from black rot resistant and susceptible F2 plants and bulks. Eight RAPD markers amplified fragments associated with completely disease free plants following black rot
inoculation,which segregated in frequencies far lower than expected. Segregation of markers with black rot resistance indicates
that a single, dominant major gene controls black rot resistance in these plants. Stability of this black rot resistance gene
in populations derived from 11B-1-12 may complicate introgression into B. oleracea genotypes for hybrid production.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Bulked segregant analysis (BSA) was used to accumulate RAPD markers near the beet cyst nematode resistance locus Hslpro-1 of sugar beet (Beta vulgaris L.). Graphical genotypes constructed from RFLP data were utilized to select F2 individuals in (1) the construction of pools of plants used in the initial screening for polymorphisms, and (2) the selection of individual plants used to confirm the potential linkage. The pooled DNA samples were screened for polymorphisms using 668 RAPD primers. Forty-four candidate markers potentially linked to the region were analysed further using 14 segregating individuals. Close linkage was confirmed for 17 of the markers. Four of the RAPD markers were assigned map coordinates within the RFLP map. Three of these markers extended the RFLP map by 3cM. Altogether, the 8cM target interval contains 10 RFLP and 17 RAPD markers, corresponding to an average marker density of 0.3cM in the Hslpro-1 region. 相似文献
20.
Expression of resistance to downy mildew at cotyledon and adult plant stages in Brassica oleracea L.
This research compared the expression of resistance to downy mildew at cotyledon and adult plant stages in seven Brassica oleracea genotypes against two P. parasitica isolates of different virulence. Seven day old seedlings were dual inoculated under controlled environment by depositing
two 10 μl droplets of a spore suspension of a different isolate on each cotyledon and the interaction phenotype (IP) evaluated
7 days later using a 0–5 scale of increasing susceptibility. The seedlings were transplanted to 16 cm pots and grown in the
greenhouse for 110 days (15 to 28 leaves). Adult plants were tested using a single leaf inoculation method that allowed the
same plant to be simultaneously inoculated with the two P. parasitica isolates. Leaves were scored 10 days after inoculation using a 0–5 scale of increasing susceptibility. The inoculation of
the same plant with the two isolates produced different combinations of cotyledon (CT) and adult-plant (AP) interaction-phenotype
according to the genotype. CrGC 3.1 was susceptible at CT and AP stages, ‘Algarvia’ resistant at CT and AP stages, and broccoli
‘A’ susceptible at CT and resistant at AP stage against the two isolates. ‘Murciana’ and broccoli ‘B’ were differential at
CT and AP stages. Savoy and Shetland cabbages were differential at CT stage and resistant to both isolates as adult plants.
Cotyledon resistance could not be used to predict adult-plant resistance since the two types of resistance were very poorly
correlated. Resistance can be race specific either at cotyledon or at adult-plant stage.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献