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1.
Summary The green peach aphid (Myzus persicae) is a serious pest of the tomato (Lycopersicon esculentum). Trichome-based host plant resistance of wild Lycopersicon species may offer an alternative to pesticides for management of this pest. Two wild species, Lycopersicon cheesmanii f. minor and L. pennellii, were crossed with L. esculentum and the types and densities of trichomes possessed by the F1 hybrids measured. The effects of these trichomes on M. persicae were assessed by placing nymphs on leaves and, 96 hr later, designating each nymph as either dead, alive, emigrating off the leaf or unaccounted for. A generalised linear model was used to detect relationships between the numbers of nymphs in each designation and the densities of trichomes and leaf area. Mortality of nymphs on L. pennellii hybrids was associated with high densities of type IV and low densities of type I trichomes. Mortality of nymphs on L. cheesmanii f. minor hybrids was associated with high densities of type III trichomes. An increase in the densities of type III trichomes on L. pennellii hybrids was associated with greater numbers of nymphs emigrating off the leaf whilst unaccounted nymphs on L. pennellii hybrids were associated with increased densities of type VII and type I trichomes. Further experimentation using excised leaflets found mortality on L. pennellii hybrids may be due to nymphs being hindered by type I trichomes and increased densities of type V trichomes were associated with greater numbers of unhindered nymphs. Implications of results are discussed in the context of introducing trichome-based host plant resistance into L. esculentum.  相似文献   

2.
K. C. Sink  J. B. Power 《Euphytica》1978,27(3):725-730
Summary Extensive pollinations were made in attempts to produce selected intergeneric or interspecific hybrids using Nicotiana and Petunia species that exhibit potential for somatic hybridization. Pollination between pairs of species was done by standard and bud-pollination methods. Nicotiana alata or N. tabacum when pollinated reciprocally with selected Petunia species failed to produce hybrids. Likewise, no interspecific hybrids were obtained between Petunia parviflora and 4 Petunia species or P. hybrida. The type of incongruity existing between these species is discussed in relation to the production of hybrids by standard In vitro techniques as compared to somatic hybridization.On leave from the Department of Horticulture, Michigan State University, E. Lansing, Michigan, USA. supported by a European Molecular Biology Organization (EMBO) fellowship and The Fred C. Gloeckner Foundation, N. Y., USA.Supported by the Agricultural Research Council.  相似文献   

3.
The results of extensive crosses between the non-tuberous species Solanum brevidens and S. etuberosum on the one hand and ten tuber-bearing Solanum species on the other are presented. Three crosses gave rise to viable progeny. Two progenies consisted of diploid plants only of the strictly self-incompatible species of the mother parent. One cross, viz. S. etuberosum × S. pinnatisectum, produced highly vigorous but fully male sterile F1 hybrids.It is suggested that this hybrid together with those between the tomato, Lycopersicon esculentum, and S, pennellii and S. lycopersicoides constitute piers of a bridge between tomato and potato species which in the future might enable gene transfer between these two crops via their wild relatives. However, such idea has to be treated with all proper reserve.The production of this new hybrid is the first step in making accessible to potato breeding the valuable genes which have been detected in S. brevidens and S. etuberosum, viz. the genes for high resistance to frost, leafroll and Y-virus.  相似文献   

4.
Summary Symmetric somatic hybrids were produced by electrofusion of protoplasts of two dihaploid tuber-bearing potato (Solanum tuberosum L.) lines and Solanum brevidens Phil., a diploid non-tuber-bearing wild potato species. A total of 985 plants was obtained. Verification of nuclear hybridity of putative hybrids was based on additive RAPD patterns, general morphological characteristics and chromosome counts. 53 (90%) calli regenerated into plants which were identified as somatic hybrids. Most of the hybrids were aneuploids at the tetraploid (4×) or hexaploid (6×) level. The 20 hybrids tested expressed a high level of resistance to potato virus Y (PVY N ) characteristic of the S. brevidens parent. Resistance to late blight (Phytophthora infestans (Mont.) de Bary) varied between hybrids, but was on average better than that of the fusion parents. Resistance of hybrids to bacterial stem rot (Erwinia carotovora subsp. atroseptica (van Hall) Dye) was not superior to that of commercial potato cultivars.  相似文献   

5.
Summary Somatic hybrids between Brassica alboglabra (CC) and B. campestris (AA) were produced through protoplast fusion. Hybrids of this combination have already been produced through sexual crosses and among other traits in the offspring, a CMS of ogura type was discovered. The reason for generating somatic hybrids was to create new nuclear-cytoplasmic combinations and/or cytoplasmic variants, which could be exploited in combination with the sexual hybrids. Mitosis and meiosis were studied and all hybrids were found to be of the AACCCC genomic constitution. The fusion of somatic cells resulted in altered cytoplasmic genomes.  相似文献   

6.
Intraspecific tetraploid somatic and sexual hybrid plants have been resynthesised following protoplast fusion and by sexual crosses between two dihaploid potato (Solanum tuberosum) lines each possessing complementary agronomic traits. The dihaploid PDH 40 possesses good tuber shape and yield but has foliage susceptibility to late blight (Phytophthora infestans). On the other hand, the dihaploid PDH 727 possesses resistance to blight in the foliage but has a low yield of small and irregular shaped tubers. Since it was only possible to use a partial selection strategy based on culture media to facilitate recovery of somatic hybrid plants-further morphological and esterase isozyme based characterisations were performed to identify somatic hybrid plants from amongst the non-hybrid plant material. When the blight resistance of both the intraspecific somatic and sexual hybrid plants was assessed there was no significant difference in the mean resistance value and it was intermediate between those of their parents. However, the range of resistance was much wider among the sexual hybrids than among the plants derived from somatic fusion. An assessment of tuber yield between tetraploid sexual and somatic hybrids showed no significant difference and it was higher than that of either parent value. The implication of these results in the context of potato genetics and breeding is discussed.  相似文献   

7.
Summary Sources of resistance to tomato-yellow-leaf-curl-virus (TYLCV) were investigated in 16 accessions of three Lycopersicon species and 55 commercial tomato hybrids and cultivars. All commercial hybrids and cultivars were highly susceptible. Accessions of L. hirsutum, L. hirsutum f. glabaratum and L. pimpinellifolium showed a wide range of reactions. Those of L. peruvianum, LA 385 of L. peruvianum f. humifusum exhibited very high levels of resistance indicating their potential use in local breeding programs. In contrast to earlier findings, back indexing showed that all symptomless genotypes in this investigation were carriers of the TYLCV.  相似文献   

8.
The wild non-tuberous species Solanumetuberosum is resistant to biotic andabiotic stresses, but is very difficult tocross with cultivated potato. Therefore,interspecific somatic hybrids between adihaploid clone of potato S.tuberosum (2n=2x=24, AA genome) and thediploid species S. etuberosum(2n=2x=24, EE genome) were produced byprotoplast fusion. Among the 7 fertilefusion hybrids analysed by genomic insitu hybridisation (GISH), three groups ofplants were found with the genomicconstitution of AAEE, AAEEEE and AAAAEE.Four fusion hybrids had exactly theexpected chromosome composition, while eachof the three aneuploid hybrids had lost twochromosomes of S. etuberosum. Twobackcross progenies were developed, andGISH analysis was applied to analysetransmission of the parental chromosomesinto the sexual generations. BC1hybrids derived from the crosses of thehexaploid somatic hybrids with tetraploidpotato were pentaploid with thetheoretically expected genomic compositionor with slight deviation from thisexpectation. In the three BC2 hybridsanalysed by GISH seven to 12 chromosomes ofS. etuberosum were detected in thepredominant S. tuberosum background.No recombinant chromosomes in the hybridswere detected. Genome dosage affects tuberformation in hybrids and their progenies,but has less effect on resistance to potatovirus Y (PVY) in fusion hybrids. Severalgenotypes of the fusion hybrids andBC1 progeny did not show viralinfection even in the graftingexperiments.  相似文献   

9.
Potato leafroll virus (PLRV; Genus Polerovirus; Family Luteoviridae) is one of the most important virus pathogens of potato worldwide and breeders are looking for new sources of resistance. Solanum etuberosum Lindl., a wild potato species native to Chile, was identified as having resistances to PLRV, potato virus Y, potato virus X, and green peach aphid. Barriers to sexual hybridization between S. etuberosum and cultivated potato were overcome through somatic hybridization. Resistance to PLRV has been identified in the BC1, BC2 and BC3 progeny of the somatic hybrids of S. etuberosum (+) S. tuberosum haploid × S. berthaultii Hawkes. In this study, RFLP markers previously mapped in potato, tomato or populations derived from S. palustre (syn S. brevidens) × S. etuberosum and simple sequence repeat (SSR) markers developed from tomato and potato EST sequences were used to characterize S. etuberosum genomic regions associated with resistance to PLRV. The RFLP marker TG443 from tomato linkage group 4 was found to segregate with PLRV resistance. This chromosome region has not previously been associated with PLRV resistance and therefore suggests a unique source of resistance. Synteny groups of molecular markers were constructed using information from published genetic linkage maps of potato, tomato and S. palustre (syn. S. brevidens) × S. etuberosum. Analysis of synteny group transmission over generations confirmed the sequential loss of S. etuberosum chromosomes with each backcross to potato. Marker analyses provided evidence of recombination between the potato and S. etuberosum genomes and/or fragmentation of the S. etuberosum chromosomes.  相似文献   

10.
Summary Various genes for disease resistance identified in wild Lactuca are difficult, even impossible to exploit in lettuce breeding, due to sexual incompatibility between L. sativa and wild Lactuca sp. We adapted two cellular biology techniques to overcome these interspecific barriers: in vitro embryo rescue and protoplast fusion. In vitro rescue of immature embryos was used successfully for sexual hybridization between L. sativa and L. virosa. Vigorous hybrid plants were produced between L. sativa and seven accessions of L. virosa. Protoplast fusion permitted the regeneration of somatic hybrids between L. sativa and either L. tatarica or L. perennis. Hybrids between L. sativa and L. tatarica were backcrossed to L. sativa.  相似文献   

11.
Summary Asymmetric somatic hybrid plants between Brassica napus L. (oilseed rape genome AACC) and a transgenic line of Brassica nigra L. Koch (black mustard genome BB) were tested for their resistance against rapeseed pathogens Phoma lingam (black leg disease) and Plasmodiophora brassicae (club root disease). The transgenic B. nigra line used (hygromycin-resistant, donor) is highly resistant to both fungi, whereas B. napus (recipient) is highly susceptible. The asymmetric somatic hybrids were produced using the donor-recipient fusion method (with X-irradiation of donor protoplasts) reported by Zelcer et al. (1978) for the production of cybrids. Using hygromycin-B for selection, a total of 332 hybrid calli were obtained. Regenerants, resistant or susceptible to both diseases, were selected. Many hybrids expressed resistance to only one pathogen. Dot blot experiments showed that the asymmetric hybrid plants contained varying amounts of the donor genomic DNA. Furthermore, a correlation was detected between the radiation dose and the degree of donor DNA elimination.  相似文献   

12.
W.W. Guo  X.X. Deng 《Euphytica》2001,118(2):175-183
Citrus wild relatives are an untapped germplasm reservoir, which possesses many elite resistance traits. Genetic introgression into Citrus by conventional methods has been greatly hindered by polyembryony, pollen / ovule sterility, sexual / graft incompatibility, long juvenility etc. Somatic hybridization via protoplast fusion may make it possible to transfer genes from wild relatives to Citrus. To date, more than sixty sexually compatible or incompatible intergeneric somatic hybrids between Citrus and its various related wild genera have been produced by PEG - orelectrically - induced fusion. These wide somatic hybrids were identified by morphology, cytology, isozyme, RAPD and RFLP analyses. Genetic variation or recombination was also revealed in some of them. Several sexually compatible combinations have flowered and set fruits. The agronomic performance of these wide somatic hybrids is diverse, and the current results are not conclusive. Somatic hybrids are being tested as rootstocks. The prospects of wide somatic hybridization of Citrus with its wild relatives are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
G. L. Hartman  T. C. Wang 《Euphytica》1993,71(1-2):125-130
Over 540 accessions of wild Lycopersicon species or their crosses with L. esculentum were screened for resistance in a series of trials. Forty-six accessions were selected for the final screening trial based on lower disease ratings in previous trials. Of these, L. hirsutum had the greatest number of resistant accessions, followed by L. esculentum and L. peruvianum. Twenty accessions were quantified for their levels of resistance based on leaf area infected, area under disease progress curve (AUDPC), and the degree of sporulation. There was a significant positive correlation between the AUDPC calculated from 20 accessions evaluated under growth room and field conditions. Five L. hirsutum accessions had no sporulation associated with leaf lesions, whereas L. esculentum accessions had an average of 1.6×104 conidia/cm2 of leaf tissue. There was significant positive correlation between the AUDPC values and the number of conidia per cm2 of leaf tissue.  相似文献   

14.
Summary The past 25 years, 1686 potato accessions, representing 100 species in the genus Solanum L., subgenus Potatoe, section Petota, were evaluated for field resistance to one or more of the following insect pests: green peach aphid, Myzus persicae (Sulzer); potato aphid, Macrosiphum euphorbiae (Thomas); Colorado potato beetle, Leptinotarsa decemlineata (Say); potato flea beetle, Epitrix cucumeris (Harris); and potato leafhopper, Empoasca fabae (Harris). Accessions highly resistant to green peach aphid were identified within 36 species, to potato aphid within 24 species, to Colorado potato beetle within 10 species, to potato flea beetle within 25 species, and to potato leafhopper within 39 species. Resistance levels were characteristic within Solanum species. Insect resistance appears to be a primitive trait in wild potatoes. Susceptibility was most common in the primitive and cultivated Tuberosa. Insect resistance was also characteristic of the most advanced species. The glycoalkaloid tomatine was associated with field resistance to Colorado potato beetle and potato leafhopper. Other glycoalkaloids were not associated with field resistance at the species level. Dense hairs were associated with resistance to green peach aphid, potato flea beetle, and potato leafhopper. Glandular trichomes were associated with field resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Significant correlations between insect score and altitude of original collection were observed in six of thirteen species. Species from hot and arid areas were associated with resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Species from cool or moist areas tended to be resistant to potato aphid.Abbreviations EBN Endosperm Balance Number  相似文献   

15.
Summary Growth analyses were carried out on 88 accessions of five Lycopersicon species. Experiments were conducted in a climate room at 19/14° C day/night temperature which was irradiated at 20 W/m2 for eight hours per day. Large differences in plant weights between wild species and the cultivated tomato were observed from 44 to 84 days after sowing. The increase in plant dry weight could be described by a second order polynomial function. When compared at a standardized plant weight of one gram, the relative growth rates (RGR) of the wild and cultivated accessions ranged from 5.3 to 11.8% and 8.5 to 12.2% per day respectively, limiting the use of wild species as sources for strong growth. When expressed at plant weights of one and three g large differences in decrease of the RGR were observed within L. esculentum. The modern hybrid tomato cultivars were among the fastest growing genotypes, with a relatively slow decrease in RGR.  相似文献   

16.
S. J. Scott  R. A. Jones 《Euphytica》1982,31(3):869-883
Summary Low temperature germination responses were evaluated for 18 high altitude accessions representing five wild Lycopersicon species and 19 accessions of L. esculentum which have reputed ability to germinate in the cold. Survival analysis indicated that one accession of L. chilense germinates better at 10°C than PI 120256, the fastest-germinating L. esculentum genotype, and that PI 120256 germinates as well as PI 126435 (L. peruvianum). Additional wild ecotypes exhibiting rapid germination at 10°C were identified from L. peruvianum and L. hirsutum. These ecotypes may possess genetic potential for introgressing cold germination ability into L. esculentum cultivars.  相似文献   

17.
Summary 1201 tomato cultivars, breeding lines and accessions of Lycopersicon species were screened for tomato leaf curl virus (TLCV) under field and laboratory conditions during summer seasons of 1986 to 1989. Two lines of L. hirsutum (PI 390658 and PI 390659) and 2 lines of L. peruvianum (PI 127830 and PI 127831) were resistant to TLCV infection. These accessions did not produce any leaf curl symptoms either in field or after inoculation by whitefly Bemisia tabaci with TLCV. Adult whiteflies died within 3 days after releasing on resistant accessions (PI 390658, PI 390659, PI 127830), whereas the whiteflies survived upto 25 days on susceptible tomato cultivars. Under field conditions 0–4 and 5–25 adult whiteflies were observed on resistant and susceptible cultivars respectively. Hybridization was effected using the popular tomato cultivars Arka Sourabh, and Arka Vikas, as the female parents and the resistant Lycopersicon wild species as the pollen parents, to incorporate the resistant gene(s) into the edible tomatoes.  相似文献   

18.
R. A. Jones 《Euphytica》1986,35(2):575-582
Summary The potential to improve seed germination responses to salinity was evaluated for 13 accessions representing six wild Lycopersicon species and 20 accessions of L. esculentum. Germination response times increased in all accessions at 100 mM NaCl. Analysis indicated that one accession of L. peruvianum (PI126435) germinated faster under high salinity than all other accessions and was closely followed by L. pennellii (LA716). The fastest germinating L. esculentum accession, PI174263, ranked third. Additional wild ecotypes exhibiting rapid germination at 100 mM NaCl were identified among L. pimpinellifolium and L. peruvianum.  相似文献   

19.
Summary Density of certain types of trichomes were characterized on leaflets of Lycopersicon hirsutum, L. esculentum and their hybrids. Trichome density covaried with leaflet development, and depending on the species and type of trichome, density also covaried with leaflet surface. Type IV trichomes were not observed on leaflets of L. esculentum and Type V trichomes were not observed on leaflets of L. hirsutum. Type IV and V trichomes were present on F1 hybrids and densities of these two types of trichomes segregated in the F2 population. When corrected for differences of leaflet size between L. hirsutum and L. esculentum, densities of Type VI trichomes were more similar between species than uncorrected densities. There was little difference in Type VI density among F2 individuals. The appearance, lipid and phenol staining properties, and native fluorescence of the multicellular tip of the Type VI trichome differed between L. hirsutum and L. esculentum. F1 hybrids were intermediate for these characters and these characters segregated in the F2 generation.The investigation reported in the paper (84-10-94) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director. This material is based upon work supported, in part, by the U.S. Department of Agriculture, Agreement No. 59-2213-1-1-717-0 (Competitive Research Grants Program).  相似文献   

20.
Since the late 1980s powdery mildew, designated Oidium lycopersicum, frequently invaded the tomato crop in Western Europe. All commercial cultivars are susceptible. To screen for resistance in wild species a reliable and efficient disease test was developed. Young plants with two to three true leaves are inoculated at high relative humidity by spraying with a freshly prepared suspension of 2×104 conidia, ml–1. Symptoms are periodically evaluated according to a scale based on the percentage of leaf area with mycelium.One hundred and twenty seven accessions, representing eight wild Lycopersicon species, were screened for resistance to O. lycopersicum. A large variation in resistance was found between species. L. hirsutum was the most resistant species; L. pennellii was moderately resistant; species of the subgeneric group of L. esculentum and of the peruvianum-complex were all susceptible. L. parviflorum was classified separately due to a large variation between accessions. Except for this species, a low variation was found between accessions within species. High levels of resistance were observed in four accessions of L. hirsutum, in one of L. parviflorum and in one of L. peruvianum. This resistance is characterized by a very low disease incidence and a strongly restricted mycelium growth and lack of sporulation.  相似文献   

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