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1.
Franceli R. Kulcheski Felipe A. S. Graichen José A. Martinelli Ana B. Locatelli Luiz C. Federizzi Carla A. Delatorre 《Euphytica》2010,175(3):423-432
Crown rust, which is caused by Puccinia
coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats (Avena
sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely
great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify
amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F6 genetic map from Pc68/5*Starter × UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in
12 linkage groups. The map covered 409.4 cM of the Avena
sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located
in the linkage group 4_12 in the Kanota × Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes. 相似文献
2.
Thierry Pascal Romain Aberlenc Carole Confolent Mathilde Hoerter Elodie Lecerf Christophe Tuéro Patrick Lambert 《Euphytica》2017,213(6):132
Peach powdery mildew is one of the major diseases of the peach. Various sources of resistance to PPM have thus been identified, including the single dominant locus Vr2 carried by the peach rootstock ‘Pamirskij 5’. To map Vr2, a linkage map based on microsatellite markers was constructed from the F2 progeny (WP2) derived from the cross ‘Weeping Flower Peach’ × ‘Pamirskij 5’. Self-pollinations of the parents were also performed. Under greenhouse conditions, all progenies were scored after artificial inoculations in two classes of reactions to PPM (resistant/susceptible). In addition to Vr2, WP2 segregated for three other traits from ‘Weeping Flower Peach’: Rm1 for green peach aphid resistance, Di2 for double-flower and pl for weeping-growth habit. With their genomic locations unknown or underdocumented, all were phenotyped as Mendelian characters and mapped: Vr2 mapped at the top of LG8, at 3.3 cM, close to the CPSCT018 marker; Rm1 mapped at the bottom of LG1, at a position of 116.5 cM, cosegregating with the UDAp-467 marker and in the same region as Rm2 from ‘Rubira’®; Di2 mapped at 28.8 cM on LG6, close to the MA027a marker; and pl mapped at 44.1 cM on LG3 between the MA039a and SSRLG3_16m46 markers. Furthermore, this study revealed, for the first time, a pseudo-linkage between two traits of the peach: Vr2 and the Gr locus, which controls the red/green color of foliage. The present work therefore constitutes a significant preliminary step for implementing marker-assisted selection for the four major traits targeted in this study. 相似文献
3.
4.
Brent D. McCallum D. Gavin Humphreys Daryl J. Somers Abdulsalam Dakouri Sylvie Cloutier 《Euphytica》2012,183(2):261-274
The wheat (Triticum aestivum L.) gene Lr34/Yr18 conditions resistance to leaf rust, stripe rust, and stem rust, along with other diseases such as powdery mildew. This makes
it one of the most important genes in wheat. In Canada, Lr34 has provided effective leaf rust resistance since it was first incorporated into the cultivar Glenlea, registered in 1972.
Recently, molecular markers were discovered that are either closely linked to this locus, or contained within the gene. Canadian
wheat cultivars released from 1900 to 2007, breeding lines and related parental lines, were tested for sequence based markers
caSNP12, caIND11, caIND10, caSNP4, microsatellite markers wms1220, cam11, csLVMS1, swm10, csLV34, and insertion site based
polymorphism marker caISBP1. Thirty different molecular marker haplotypes were found among the 375 lines tested; 5 haplotypes
had the resistance allele for Lr34, and 25 haplotypes had a susceptibility allele at this locus. The numbers of lines in each haplotype group varied from 1
to 140. The largest group was represented by the leaf rust susceptible cultivar “Thatcher” and many lines derived from “Thatcher”.
The 5 haplotypes that had the resistance allele for Lr34 were identical for the markers tested within the coding region of the gene but differed in the linked markers wms1220, caISBP1,
cam11, and csLV34. The presence of the resistance or susceptibility allele at the Lr34 locus was tracked through the ancestries of the Canadian wheat classes, revealing that the resistance allele was present
in many cultivars released since the 1970s, but not generally in the older cultivars. 相似文献
5.
Preliminary field observations in our maize breeding nurseries indicated that breeding for improved resistance to gibberella
ear rot (Fusarium graminearum) in maize may indirectly select for resistance to another ear disease, common smut (Ustilago zeae). To investigate this, we compared the disease severity ratings obtained on 189 maize inbreds, eight of which included our
inbreds developed with selection for gibberella ear rot resistance after field inoculation and breeding for 8–10 years. No
correlation was found between disease severities for the 189 inbreds but the eight gibberella-resistant lines were consistently
more resistant to smut. To further examine this relationship and to determine if these eight inbreds would be useful for developing
inbreds with either common smut or fusarium ear rot (F. verticilliodes) resistance, we conducted a Griffing’s diallel analysis on six inbreds of maize, four with high levels of gibberella ear
rot resistance representing all of the pedigree groups in our eight gibberella lines, and two with very low levels. Our most
gibberella ear rot resistant inbreds, CO433 and CO441, had the lowest disease ratings for all three diseases, the consistently
largest general combining ability effects and several significant specific combining ability effects. It was concluded that
some inbreds bred specifically for gibberella ear rot would also be useful in breeding for resistance to common smut and fusarium
ear rot. 相似文献
6.
The Lr56/Yr38 translocation consists primarily of alien-derived chromatin with only the 6AL telomeric region being of wheat origin. To
improve its utility in wheat breeding, an attempt was made to exchange excess Ae. sharonensis chromatin for wheat chromatin through homoeologous crossover in the absence of Ph1. Translocation heterozygotes that lacked Ph1 were test-crossed with Chinese Spring nullisomic 6A tetrasomic 6B and nullisomic 6A-tetrasomic 6D plants and the resistant
(hemizygous 6A) progeny were analyzed with four microsatellite markers. Genetic mapping suggested general homoeology between
wheat chromosome 6A and the translocation chromosomes, and showed that Lr56 was located near the long arm telomere. Thirty of the 53 recombinants had breakpoints between Lr56 and the most distal marker Xgwm427. These were characterized with additional markers. The data suggested that recombinants #39, 157 and 175 were wheat chromosomes
6A with small intercalary inserts of foreign chromatin containing Lr56 and Yr38, located distally on the long arms. These three recombinants are being incorporated into adapted germplasm. Attempts to identify
the single shortest translocation and to develop appropriate markers are being continued. 相似文献
7.
In maize hybrid seed production, some hybrid seed in the field must be harvested before reaching physiological maturity because
of the potential damage from early fall frosts. However, early harvesting can result in poor quality and low vigor of seeds.
To elucidate the genetic basis of seed vigor at different stages of maturity, the seeds of a set of recombinant inbred line
(RIL) populations at three different stages of maturity (32, 40, and 45 days after pollination; DAP), were used to evaluate
the performance of four traits for seed vigor in the field. A genetic linkage map was constructed using 217 SSR makers covering
2438.2 cM with an average interval of 11.2 cM. The results showed that there were significant positive relationships among
the four traits of seed vigor at all three sampling times, and all showed quantitative changes according to the degree of
maturity of the seeds. However, the four traits of seed vigor were not significantly related to the 100-kernel weight. In
total, we detected 16 different QTL for the four measured traits of seed vigor at three sampling times; five QTL were for
germination energy, three for germination percentage, four for germination index, and four for vigor index. Interestingly,
four QTL for seed vigor, which were detected at all three sampling times, were located in the same region on chromosome 7.
This result implies that this region of chromosome 7 is important for seed vigor of seeds harvested before they reach physiological
maturity. 相似文献
8.
Xiao-Ling Wu Jin-Ming Zhao Shi Sun Feng Yang Yuan-Chao Wang Jun-Yi Gai Han Xing 《Euphytica》2010,176(2):261-268
Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease affecting soybean production regions throughout the world. The utilization of resistant cultivars
is the most economical and environmentally safe method for controlling this disease. This work aims to screen the effective
sources of special and partial resistance for the development of resistant cultivars. A total of 611 soybean germplasm lines
from three ecological regions were evaluated for their responses to three P. sojae strains, namely, PNJ1, PNJ3, and PNJ4, using the hypocotyl inoculation technique. The soybean germplasm lines elicited eight
different reaction types with three strains. Among these, 106 were resistant and 253 were susceptible to the three strains.
A total of 123 soybean germplasm lines identified as susceptible to the three strains by the hypocotyl inoculation method
were evaluated for partial resistance to PNJ1 using the slant board assay. Thirty-nine cultivars displayed high levels of
partial resistance to PNJ1. The results of this study can be utilized to plant appropriately resistant cultivars in infected
fields and to provide good breeding materials. 相似文献
9.
É. C. Dianese M. E. N. Fonseca A. K. Inoue-Nagata R. O. Resende L. S. Boiteux 《Euphytica》2011,180(3):307-319
The genus Tospovirus was considered as monotypic with Tomato spotted wilt virus (TSWV) being the only assigned species. However, extensive studies with worldwide isolates revealed that this genus comprises
a number of species with distinct virulence profiles. The Neotropical South America is one center of Tospovirus diversity with many endemic species. Groundnut ringspot virus (GRSV), TSWV, Tomato chlorotic spot virus (TCSV), and Chrysanthemum stem necrosis virus (CSNV) are the predominant tomato-infecting species in Brazil. Sources of resistance were found in Solanum (section Lycopersicon) mainly against TSWV isolates from distinct continents, but there is an overall lack of information about resistance to other
viral species. One-hundred and five Solanum (section Lycopersicon: Solanaceae) accessions were initially evaluated for their reaction against a GRSV isolate by analysis of symptom expression
and systemic virus accumulation using DAS-ELISA. A subgroup comprising the most resistant accessions was re-evaluated in a
second assay with TSWV, TCSV, and GRSV isolates and in a third assay with a CSNV isolate. Seven S. peruvianum accessions displayed a broad-spectrum resistance to all viral species with all plants being free of symptoms and systemic
infection. Sources of resistance were also found in tomato cultivars with the Sw-5 gene and also in accessions of S. pimpinellifolium, S. chilense, S. arcanum, S. habrochaites, S. corneliomuelleri, and S. lycopersicum. The introgression/incorporation of these genetic factors into cultivated tomato varieties might allow the development of
genetic materials with broad-spectrum resistance, as well as with improved levels of phenotypic expression. 相似文献
10.
The common bacterial blight pathogen [Xanthomonas axonopodis pv. phaseoli (Xap)] is a limiting factor for common bean (Phaseolus vulgaris L.) production worldwide and resistance to the pathogen in most commercial cultivars is inadequate. Variability in virulence
of the bacterial pathogen has been observed in strains isolated from Puerto Rico and Central America. A few common bean lines
show a differential reaction when inoculated with different Xap strains, indicating the presence of pathogenic races. In order
to study the inheritance of resistance to common bacterial blight in common bean, a breeding line that showed a differential
foliar reaction to Xap strains was selected and was crossed with a susceptible parent. The inheritance of resistance to one
of the selected Xap races was determined by analysis of segregation patterns in the F1, F2, F3 and F4 generations from the cross between the resistant parent PR0313-58 and the susceptible parent ‘Rosada Nativa’. The F1, F2 and F3 generations were tested under greenhouse conditions. Resistant and susceptible F3:4 sister lines were tested in the field. The statistical analysis of all generations followed the model for a dominant resistance
gene. The resistant phenotype was found to co-segregate with the SCAR SAP6 marker, located on LG 10. These results fit the
hypothesis that resistance is controlled by a single dominant gene. The symbol proposed for the resistance gene is Xap-1 and for the bacterial race, XapV1. 相似文献
11.
Bárbhara Joana dos Reis Fatobene Vinícius Teixeira Andrade Giulia Stefania Aloise Maria Bernadete Silvarolla Wallace Gonçalves Oliveiro Guerreiro Filho 《Euphytica》2017,213(8):196
Arabica coffee production is based on highly productive cultivars; however, these cultivars are susceptible to infestation by several biotic agents, including root-knot nematodes. Collections of wild Coffea arabica germplasm represent an important source of genetic variability for resistant cultivar development. In this study, 1046 plants derived from 71 wild coffee trees were evaluated with respect to Meloidogyne paranaensis resistance. In addition to information on plants reactions, we also evaluated the genetic parameters related to resistance. Progenies from the five most promising plants were also evaluated regarding resistance to M. incognita and M. exigua. The yield potential of selected plants was estimated through analysis of data for fruits harvested in 4 different years. Forty-seven plants were considered resistant based on reproduction factor values. The estimated heritability was high for all analyzed variables leading to substantial selection gain, mainly at the progeny mean level. On the basis of heritabilities and genetic correlations, we conclude that selection could be performed based on values of the gall and egg mass index. However, higher genetic gain could be obtained based on nematode count variables. A second experiment confirmed the reactions of the selected five plants to M. paranaensis, and multiple resistance was detected in three of them. The resistant accessions also have yield potential. 相似文献
12.
Phytophthora root and stem rot caused by Phytophthora sojae, is one of the most damaging diseases of soybean, for which management is principally done by planting resistant cultivars
with race specific resistance which are conferred by Rps (Resistance to Phytophthora sojae) genes. The Rps8 locus, identified in the South Korean landrace PI 399073, is located in a 2.23 Mbp region on soybean chromosome 13. In eight
cv. Williams (rps8/rps8) × PI 399073 (Rps8/Rps8) populations, this region exhibited strong segregation distortion. In a cross between the South Korean lines PI 399073 (Rps8/Rps8) and PI 408211B (multiple Rps genes) this region segregated in a Mendelian fashion. In this study, microsporogenesis was evaluated to identify meiotic
abnormalities that may be associated with the segregation distortion of the Rps8 region. Pollen was collected from greenhouse-grown plants of the parental genotypes: Williams, PI 399073, and PI 408211B;
as well as selected Rps8/rps8 RILs from Williams × PI 399073 BC4F2:3 and PI 399073 × PI 408211B F4:5 populations. There were no differences for pollen viability among the genotypes. However, for PI 399073, a mix of dyads,
triads, tetrads and pentads was observed. A high frequency of meiotic abnormalities including fragments, laggards, multinucleated
microspores; and microcytes containing DNA was also observed in Rps8/rps8 Williams × PI 399073 BC4F2:3 RILs. These meiotic abnormalities may contribute to the high degree of segregation distortion present in the Williams × PI
399073 populations. 相似文献
13.
Md. Siddiqur Rahman Abdul Mannan Akanda Ismail Hossain Mian Md. Khurshed Alam Bhuiyan Md. Motaher Hossain 《Journal of Crop Science and Biotechnology》2016,19(3):249-258
Background
Cucumber mosaic virus (CMV) is the most serious virus disease affecting chilli (Capsicum annuum L.) worldwide and the absence of natural resistance makes management of CMV outbreaks difficult. The characterization of improved sources of resistance to CMV in chilli would facilitate the development of commercially acceptable chilli varieties with adequate levels of CMV resistance. A total of 30 chilli genotypes were evaluated for their reaction to CMV in field and artificial inoculated conditions during 2010-2011 and 2011-2012. Large differences were observed among genotypes for disease incidence, severity indexes, and yield losses. Based on observed data, genotype CA23 (Noakhali) was identified as resistant, while CA12 (Comilla-2) was categorized as moderately resistant to CMV both in natural and inoculated conditions. Enzyme-linked immunosorbent assay absorbance values of samples taken from CMV-infected leaves corresponded well with visible viral symptoms for these genotypes. The identified C. annuum CA23 and CA12 genotypes represent previously undescribed and potentially useful sources of CMV resistance.14.
Phytophthora root rot caused by Phytophthora drechsleri Tucker is one of the most devastating sugar beet diseases in tropical areas. To identify genetic resources resistant to this disease, an aggressive isolate of P. drechsleri was selected. Then, a screening method was optimized based on the standard scoring scales of 1–9 (1: no symptoms, 9: complete plant death). Finally, 19 sugar beet lines, three cultivars, and 14 accessions of the wild species Beta vulgaris subsp. maritima, B. macrocarpa, B. procumbens, and B. webbiana were evaluated for resistance to the most aggressive isolate of P. drechsleri by using the optimized method (inoculum included 20 g of rice seed together with superficial wound creation). The isolates of P. drechsleri had significant variation in aggressiveness, and Kv10 was the most aggressive isolate on the susceptible variety Rasoul. The lines O.T.201-15, SP85303-0 (resistant check), and S2-24.P.107 had the lowest disease index with scores of 3.09, 3.13, and 3.27 respectively; they were categorized into the resistant group. The interaction between isolates and genotypes was not significant, which indicated the same response of each genotype to different isolates. Investigating the resistance of different generations of sugar beet revealed that progeny selection would be an effective method for increasing the resistance level of breeding materials to P. drechsleri. Among the wild species, the accession 9402 belonging to B. macrocarpa and the accession 7234 of B. vulgaris subsp. maritima had the lowest disease index (2.29 and 2.60, respectively) and were categorized into the resistant group. 相似文献
15.
A. D. Munshi Bishwajit Panda Bikash Mandal I. S. Bisht E. S. Rao Ravinder Kumar 《Euphytica》2008,164(2):501-507
The genetics of resistance to Cucumber mosaic virus (CMV) in Cucumis sativus var. hardwickii R. Alef, the wild progenitor of cultivated cucumber was assessed by challenge inoculation and by natural infection of CMV.
Among the 31 genotypes of C. sativus var. hardwickii collected from 21 locations in India the lowest mean percent disease intensity (PDI) was recorded in IC-277048 (6.33%) while
the highest PDI was observed in IC-331631 (75.33%). All the four cultivated varieties (DC-1, DC-2, CHC-1 and CHC-2) showed
very high PDI and susceptible disease reaction. Based on mean PDI, 8 genotypes were categorized as resistant, 13 as moderately
resistant, 9 as moderately susceptible and one as susceptible. A chi-square test of frequency distribution based on mean PDI
in F2 progenies of six resistant × susceptible crosses revealed monogenic recessive Mendelian ratio 1(R):3(S) to be the best fit.
This monogenic recessive model was further confirmed by 1(R):1(S) ratio as the best fit for back cross with resistant parent
and no fit for either 3:1 or 1:1 in the back cross with the susceptible parent. The results revealed that CMV resistance in
C. sativus var. hardwickii was controlled by a single recessive gene. Considering the cross compatibility between C. sativus var. hardwickii and cultivated cucumber, the resistance trait can be easily transferred to cultivated species through simple backcross breeding. 相似文献
16.
J. B. Hartman D. Vuylsteke P. R. Speijer F. Ssango D. L. Coyne D. De Waele 《Euphytica》2010,172(1):139-148
Crop growth and damage parameters (plant growth and yield, root damage and nematode population densities), believed to be
associated with resistance of Musa genotypes to nematodes under field conditions, were evaluated in a field trial of 24 Musa genotypes inoculated at planting with a combination of Radopholus similis and Helicotylenchus multicinctus with the objective to identify parameters with strong association with nematode resistance and high heritability. Correlation
and path analysis of the association between plant growth, yield, root damage and nematode population densities showed a strong
negative association between percentage dead roots, percentage root necrosis, R. similis and H. multicinctus population densities and yield. The strongest negative association was observed between percentage dead roots and yield.
Broad-sense genotype heritability estimates demonstrated that heritability estimates for percentage dead roots, number of
large lesions and nematode population density were most affected by inoculation with nematodes. These results indicate therefore
that effective selection for nematode resistance under field conditions could be obtained by using an index, that includes
percentage dead roots, the number of large lesions, and nematode population density. 相似文献
17.
Gopesh C. Saha Ashutosh Sarker Weidong Chen George J. Vandemark Fred J. Muehlbauer 《Euphytica》2010,175(2):261-265
Lentil rust caused by Uromyces vicia-fabae (Pers.) Schroet is one of the most important diseases of lentil in South Asia, North Africa and East Africa. This disease
is usually observed during late flowering and early podding stages. Early infection accompanied by favorable environmental
conditions can result in complete crop failure and huge economic losses. Therefore, breeding for resistance against this pathogen
is one of the major challenges for the breeders in those regions. It is important to identify resistance sources and to determine
the location of the genes for resistance in the lentil genome. Since field screening is often difficult due to the unpredictable
nature of the disease, selectable molecular markers can be useful tools to assist lentil breeding and complement field screening
and selection for resistance. To map the genes for resistance, a recombinant inbred line (RILs) population composed of 220
RILs was developed from a cross between a rust resistant line, ILL-4605, and a susceptible line from Bangladesh, ILL-5888.
Phenotyping of the RIL population was carried out during 2006–2007 and 2008–2009 cropping seasons at the Pulse Research Center,
Ishurdi, Bangladesh. There was a lack of uniformity of disease pressure in the 2006–2007 cropping year causing inconsistencies
between replicates. Nevertheless, we were able to choose clearly resistant and clearly susceptible RILs for selective genotyping
using markers previously placed on our lentil genetic map. One of the 62 markers used for selective genotyping proved to be
linked to the gene for resistance. The identified sequence related amplified polymorphism (SRAP) marker, F7XEM4a, was estimated
to be 7.9 cM from the gene for resistance. The F7XEM4a marker could be used for marker assisted selection for resistance;
however, additional markers closer to the resistance gene are needed. 相似文献
18.
Rust resistance genes (introgressions S24 and S13) transferred to hexaploid wheat from two Aegilops speltoides accessions could not be used commercially due to associated gametocidal (Gc) genes. Crosses to wheat followed by rigorous selection for increased fertility were employed in an attempt to separate the
unmapped S24 stem rust resistance from the Gc gene(s). However, improved fertility of the better selections could not be maintained in subsequent generations. Since the
S13 introgression (leaf, stripe and stem rust resistances) mapped to chromosome 3A, allosyndetic pairing induction was used
in an attempt to remove the Gc gene(s). This produced putative primary recombinants with improved fertility and plant type, the best of which had exchanged
a small region of Ae. speltoides chromatin, yet was still associated with (reduced) Gc effects. This selection (04M127-3, which appears to have the Su1-Ph1 suppressor) was then crossed with wheat. Surprisingly, the 04M127-3 gametocidal effect differed drastically from that of
the original introgression allowing the recovery of 35 recombinant, leaf rust resistant progeny. Microsatellite and DArT markers
showed that each secondary recombinant had exchanged most of the Ae. speltoides chromatin. Although the data suggested that a complex multigenic interaction may govern the gametocidal response, preliminary
indications are that the Gc effect had largely been removed and it now seems possible to completely separate the gametocidal genes from the S13 leaf
rust resistance gene (here designated Lr66). The associated (S13) stripe rust and stem rust resistance genes were lost during recombination. 相似文献
19.
Coffee varieties with resistance for the plant-parasitic nematodes Pratylenchus coffeae and Radopholus arabocoffeae are limited in Vietnam. A selection of imported varieties and high yield varieties of Arabica coffee in Vietnam were evaluated
for resistance to both plant-parasitic nematode species in Northern Vietnam. The same experiments were carried out with hybrid
arabica coffee, three selected clones of Coffea
canephora and one clone of Coffea excelsa in the Western Highland of Vietnam. The screened coffee accessions from Ethiopia (KH1, KH13, KH20, KH21, KH29, and KH31)
were susceptible and good host for P. coffeae. Also accessions 90P4 (Portugal) and Oro azteca (Mexico) had a reproduction factor Rf > 1. Pluma Hidalgo (Mexico), 90/6 (Vietnam), 90P3 (Portugal), 90P2 (Vietnam), Variedad (Mexico), 90T (Portugal), and Garnica
(Mexico) were poor hosts (Rf < 1) but not tolerant to P. coffeae, expressed by a reduction of root weight compared to untreated control plants. Most of the coffee accessions tested in Northern
Vietnam were intolerant to R. arabocoffeae, except 90T which showed no reduction of root weight, even at high initial nematode densities (4,000/pot). Good hosts for
R. arabocoffeae were Variedad, KH1, KH21, KH29, KH20, KH31, and KH13 with Rf > 1. Pluma Hidalgo, 90/6, 90P3, 90P2, 90T, Oro azteca, and Garnica were poor hosts (Rf < 1). In the Western Highland experiment, all arabica coffee accessions were susceptible for P. coffeae with Rf ranging from 1.41 to 1.59. Tolerance to P. coffeae was found in C. liberica var. Dewevrei, Hong34 and Nhuantren. Coffea excelsa, Hong34, Nhuantren, and H1C19 were tolerant to R. arabocoffeae at the highest inoculation density (4,000 nematodes/pot). The most susceptible accessions were Nhuantren and K55. Resistance
(Rf < 1) to R. arabocoffeae was found in C. liberica var. Dewevrei and Hong34. This article reports on the first screening for resistance and tolerance to P. coffeae and R. arabocoffeae in coffee accessions in Vietnam and shows promising results for enhanced coffee-breeding. 相似文献
20.
Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm−2 leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC1F1 [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on
the parents, F1, F2, BC1F1 and BC1F2 generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant
gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase
chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant
analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately
tested with the 31 BC1F1 individuals. Two RAPD makers, viz., SC10-82360 (primer, GCCGTGAAGT), and SCRI-711000 (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified.
These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably. 相似文献