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1.
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
2.
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
3.
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
4.
Noelle Giacomini Lemos Alessandro de Lucca e Braccini Ricardo Vilela Abdelnoor Maria Cristina Neves de Oliveira Kazuhiro Suenaga Naoki Yamanaka 《Euphytica》2011,182(1):53-64
Asian rust, caused by the fungus Phakopsora pachyrhizi, is the most severe disease currently threatening soybean crops in Brazil. The development of resistant cultivars is a top
priority. Genetic characterization of resistance genes is important for estimating the improvement when these genes are introduced
into soybean plants and for planning breeding strategies against this disease. Here, we infected an F2 population of 140 plants derived from a cross between ‘An-76’, a line carrying two resistance genes (Rpp2 and Rpp4), and ‘Kinoshita’, a cultivar carrying Rpp5, with a Brazilian rust population. We scored six characters of rust resistance (lesion color [LC], frequency of lesions having
uredinia [%LU], number of uredinia per lesion [NoU], frequency of open uredinia [%OU], sporulation level [SL], and incubation
period [IP]) to identify the genetic contributions of the three genes to these characters. Furthermore, we selected genotypes
carrying these three loci in homozygosis by marker-assisted selection and evaluated their genetic effect in comparison with
their ancestors, An-76, PI230970, PI459025, Kinoshita and BRS184. All three genes contributed to the phenotypes of these characters
in F2 population and when pyramided, they significantly contributed to increase the resistance in comparison to their ancestors.
Rpp2, previously reported as being defeated by the same rust population, showed a large contribution to resistance, and its resistance
allele seemed to be recessive. Rpp5 had the largest contribution among the three genes, especially to SL and NoU. Only Rpp5 showed a significant contribution to LC. No QTLs for IP were detected in the regions of the three genes. We consider that
these genes could contribute differently to resistance to soybean rust, and that genetic background plays an important role
in Rpp2 activity. All three loci together worked additively to increase resistance when they were pyramided in a single genotype
indicating that the pyramiding strategy is one good breeding strategy to increase soybean rust resistance. 相似文献
5.
J. Mei L. Qian J. O. Disi X. Yang Q. Li J. Li M. Frauen D. Cai W. Qian 《Euphytica》2011,177(3):393-399
Stem rot caused by Sclerotinia sclerotiorum is one of the most devastating diseases of rapeseed (Brassica napus L.) which causes huge loss in rapeseed production. Genetic sources with high level of resistance has not been found in rapeseed.
In this study, 68 accessions in six Brassica species, including 47 accessions of B. oleracea, were evaluated for leaf and stem resistance to S. sclerotiorum. Large variation of resistance was found in Brassica, with maximum differences of 5- and 57-folds in leaf and stem resistance respectively. B. oleracea, especially its wild types such as B. rupestris, B. incana, B. insularis, and B. villosa showed high level of resistance. Our data suggest that wild types of B. oleracea possess tremendous potential for improving S. sclerotiorum resistance of rapeseed. 相似文献
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
Using three varieties of Brassica rapa, cv. Hauarad (accession 708), cv. Maoshan-3 (714) and cv. Youbai (715), as the maternal plants and one variety of B. oleracea cv. Jingfeng-1 (6012) as the paternal plant, crosses were made to produce interspecific hybrids through ovary culture techniques. A better response of seed formation was observed when ovaries were cultured in vitro at 9–12 days after pollination on the basal MS and B5 media supplemented with 6-benzylaminopurine (BA) and naphthylacetic acid (NAA). The best response was observed for cross 714×6012 with the rate of seeds per ovary reaching 43.0%. Seeds for cross 715×6012 showed the best germination response (66.7%) on the regeneration medium (MS+1.0 mg l–1 BA+0.05 mg l–1 NAA). In all three cross combinations, good response in terms of root number and length of plants was observed on the root induction medium (MS+1.0 mg l–1 BA+0.1 mg l–1 NAA). A better response was observed for the regenerated plants cultured for 14 days than for 7 days. The ovary-derived plants with well-developed root system were hardened for 8 days and their survival rate reached over 80%. Cytological studies showed that the chromosome number of all plants tested was 19 (the sum of both parents), indicating that these regenerated plants were all true hybrids of B. rapa (n = 10) × B. oleracea (n = 9). The regenerated plants were doubled with colchicine treatment, and the best response in the crosses 708×6012, 714×6012 and 715×6012 was observed when treated with 170 mg l–1 colchicine for up to 30 h and their doubling frequency reached 52, 56 and 62%, respectively. 相似文献
13.
Cassava root rot disease is an increasing problem in Africa where yield losses of about 80% have been recorded. We evaluated
290 African landraces and 306 improved genotypes from the germplasm collections of the International Institute of Tropical
Agriculture (IITA), for sources of resistance using root slice laboratory assay. Disease severity was assessed quantitatively
by direct percentage estimation (PS) and by use of a rating scale (RS). Both methods of assessment were compared for identification
of variability in the germplasm, and genotypes were classified into response groups using an enlarged rank-sum method that
combined the PS and RS assessments. The two scoring methods revealed continuous variation (P < 0.001) for resistance in the sets of germplasm. Disease assessments based on PS and RS were highly correlated in both the
improved germplasm (r = 0.75) and the landraces (r = 0.72). Based on PS assessment, 50 improved genotypes (16.3%) and 53 landraces (18.3%) showed significantly lower disease
scores than the resistant control. The rank-sum method separated each set of collections into highly resistant, resistant,
moderately resistant, moderately susceptible, susceptible and highly susceptible groups. Fifty-nine improved genotypes (16.4%)
and 61 African landraces (16.9%) were identified as either highly resistant or resistant. Generally, these genotypes exhibited
resistance by limiting the growth of the pathogen (reduced amount of invaded surface area). This type of rate-reducing resistance
is highly heritable and a quantitative trait which can be harnessed in breeding. Genotypes subsets were identified for further
studies into the genetic basis of resistance to root rot disease. 相似文献
14.
Pseudomonas syringae is the main pathogen responsible for bacterial blight disease in pea and can cause yield losses of 70%. P. syringae pv. pisi is prevalent in most countries but the importance of P. syringae pv. syringae (Psy) is increasing. Several sources of resistance to Psy have been identified but genetics of the resistance is unknown. In this study the inheritance of resistance to Psy was studied in the pea recombinant inbred line population P665 × ‘Messire’. Results suggest a polygenic control of the resistance and two quantitative trait loci (QTL) associated with resistance, Psy1 and Psy2, were identified. The QTL explained individually 22.2 and 8.6% of the phenotypic variation, respectively. In addition 21 SSR markers were included in the P665 × ‘Messire’ map, of which six had not been mapped on the pea genome in previous studies. 相似文献
15.
Genetic Analysis of Resistance to Soil-Borne Wheat Mosaic Virus Derived from Aegilops tauschii. Euphytica. Soil-Borne Wheat Mosaic Virus (SBWMV), vectored by the soil inhabiting organism Polymyxa graminis, causes damage to wheat (Triticum aestivum) yields in most of the wheat growing regions of the world. In localized fields, the entire crop may be lost to the virus.
Although many winter wheat cultivars contain resistance to SBWMV, the inheritance of resistance is poorly understood. A linkage
analysis of a segregating recombinant inbred line population from the cross KS96WGRC40 × Wichita identified a gene of major
effect conferring resistance to SBWMV in the germplasm KS96WGRC40. The SBWMV resistance gene within KS96WGRC40 was derived
from accession TA2397 of Aegilops taushcii and is located on the long arm of chromosome 5D, flanked by microsatellite markers Xcfd10 and Xbarc144. The relationship of this locus with a previously identified QTL for SBWMV resistance and the Sbm1 gene conferring resistance to soil-borne cereal mosaic virus is not known, but suggests that a gene on 5DL conferring resistance to both viruses may be present in T. aestivum, as well as the D-genome donor Ae. tauschii. 相似文献
16.
Evgenia Dor Biana Alperin Smadar Wininger Bruria Ben-Dor Vishal S. Somvanshi Hinanit Koltai Yoram Kapulnik Joseph Hershenhorn 《Euphytica》2010,171(3):371-380
Orobanche and Phelipanche, commonly known as broomrape, are dicotyledonous holoparasitic flowering plants that cause heavy economic losses in a wide
variety of plant species. Breeding for Orobanche resistance is still one of the most effective management strategies for this weed. However, previous efforts to find broomrape-resistant
tomato (Solanum lycopersicon) genotypes have been unsuccessful. Here, we report on the isolation and characterization of a fast-neutron-mutagenized M-82
tomato mutant, Sl-ORT1. The Sl-ORT1 mutant showed resistance to Phelipanche aegyptiaca as compared to cultivar M-82; segregation analysis suggested a single recessive ort1 allele. Sl-ORT1 broomrape resistance was reflected in a lower number of broomrapes per plant, reduced P. aegyptiaca fresh weight per plant, and the absence of broomrape’s negative effect on plant host growth and yield. Sl-ORT1 was shown to be resistant to high concentrations of P. aegyptiaca seeds, and to another three broomrape species: Phelipanche ramosa, Orobanche cernua, and Orobanche crenata. Grafting experiments demonstrated that roots, rather than shoots, are necessary for Sl-ORT1 broomrape resistance. In addition, Sl-ORT1 was shown to be resistant to broomrape under field conditions. Since yield parameters are slightly affected by the mutation,
this resistance gene should be introduced into tomato varieties with different genetic backgrounds; this newly identified
Orobanche-resistant mutant may be further utilized in breeding programs for Orobanche resistance. 相似文献
17.
Awang Maharijaya Ben Vosman Greet Steenhuis-Broers Asep Harpenas Agus Purwito Richard G. F. Visser Roeland E. Voorrips 《Euphytica》2011,177(3):401-410
Thrips are damaging pests in pepper worldwide. They can cause damage directly by feeding on leaves, fruits or flowers, and
also indirectly by transferring viruses, especially tomato spotted wilt virus (TSWV). Although thrips are among the most damaging
pests in pepper, until now there is no commercial variety with a useful level of resistance to thrips. This is at least partly
due to the lack of knowledge on resistance levels in pepper germplasm of QTLs and/or genes for resistance, and of information
about resistance mechanisms to thrips in pepper. This paper describes our research aimed at developing practical and reliable
screening methods for thrips resistance in pepper and at identifying pepper accessions showing a strong resistance to thrips.
Thirty-two pepper accessions from four species of pepper (Capsicum annuum, C. baccatum, C. chinense and C. frutescens) and two species of thrips (Frankliniella occidentalis and Thrips parvispinus) were used in this study. Our results indicate that the laboratory based leaf disc test and the detached leaf test can be
used as reliable screening methods for thrips resistance in pepper. We observed a large variation for resistance to thrips
in Capsicum that can be exploited in breeding programs. 相似文献
18.
Jinfa Zhang S. Sanogo R. Flynn Jit B. Baral S. Bajaj S. E. Hughs Richard G. Percy 《Euphytica》2012,187(2):147-160
Verticillium wilt (VW, Verticillium dahliae) is a worldwide destructive soil-borne fungal disease and employment of VW resistant cultivars is the most economic and efficient method in sustainable cotton production. However, information concerning VW resistance in current commercial cotton cultivars and transfer of VW resistance from Pima (Gossypium barbadense) to Upland (Gossypium hirsutum) cotton is lacking. The objective of the current study was to report findings in evaluating commercial cotton cultivars and germplasm lines for VW resistance in field and greenhouse (GH) experiments conducted in 2003, 2006, and 2007. In the study, 267 cultivars and germplasm lines were screened in the GH, while 357 genotypes were screened in the field. The results indicated that (1) VW significantly reduced cotton yield, lint percentage, 50% span length and micronaire, but not 2.5% span length and fiber strength, when healthy and diseased plants in 23 cultivars were compared; (2) some commercial cotton cultivars developed by major cotton seed companies in the US displayed good VW resistance; (3) many Acala cotton cultivars released in the past also had good VW resistance, but not all Acala cotton germplasm are resistant; (4) Pima cotton possessed higher levels of VW resistance than Upland cotton, but the performance was reversed when the root system was wounded after inoculation; (5) VW resistance in some conventional cultivars was transferred into their transgenic version through backcrossing; and (6) some advanced backcross inbred lines developed from a cross between Upland and Pima cotton showed good VW resistance. The successful development of VW resistant transgenic cultivars and transfer of VW resistance from Pima to Upland cotton implies that VW resistance is associated with a few genes if not a major one. 相似文献
19.
20.
Data presented herein provides a rapid and efficient method for Agrobacterium rhizogenes-mediated genetic transformation of Arnebia hispidissima for hairy root cultures as well as for enhancing Shikonin production. Etiolated explants viz. shoot tip, nodal, leaf and
internodal segments were co-cultivated with Agrobacterium rhizogenes for induction of hairy root. Among the various explants employed, leaf explant showed maximum 70.7% response followed by
shoot tip 48.3%, nodal segment 38.7% and internodal segment 9.3%. Integration of Ri plasmid rolB gene in the transformed hairy root cultures was confirmed by PCR analysis using forward (FrolB) and reverse (RrolB) primers of rolB gene resulting in the amplification of 0 ∼ 0.8 kb fragments. Medium compositions have been optimized for in vitro induction
of Shikonin in hairy root cultures of Arnebia hispidissima. Hairy roots on hormonefree MS medium showed red spots in the older part of the tissues which turned white after a second
subculture. Whereas hairy roots cultured on RC medium showed faster growth and produced large amount of Shikonin. The Shikonin
content in transformed hairy root culture was estimated by recording absorbance at 620 nm and quantified against authentic
sample of Shikonin. Shikonin content was estimated to be 0.85 mg g−1 fresh weight of tissue at the end of the 50 days of culture. The results presented herein will help to design strategies
for bridging the gap between ever increasing demand and supply of raw products necessary for obtaining Shikonin for cosmetic,
dyeing, food, medicinal, and pharmaceutical industries. 相似文献