共查询到20条相似文献，搜索用时 218 毫秒
1.
Major progress has been made over the last few years in the identification and regulation of tomato ripening genes. At least 25 genes showing elevated expression during ripening have been cloned and several, including polygalacturonase, which modifies fruit textures, have been shown to be ripening-specific. In addition, genes have been cloned for ACC synthase and ACC oxidase, which control the synthesis of ethylene, which plays a critical role in ripening. Inhibition of expression of polygalacturonase, pectinesterase, ACC synthase, ACC oxidase and phytoene synthase has been achieved in transgenic plants, using antisense technology. The expression of several genes has also been inhibited by sense gene suppression. New traits caused by these transgenes are stably inherited. Antisense tomatoes with reduced polygalacturonase have improved textural qualities which are being exploited commercially for the fresh and processed markets. Overexpression of phytoene synthase has been shown to restore carotenoid production in the yellow flesh mutant and can be used to enhance colour in other cultivars. Antisense fruit in which ACC synthase or ACC oxidase are inhibited show slower ripening and reduced over-ripening. ACC oxidase antisense genes have also been shown to delay leaf senescence. It is to be expected that further genes determining other quality traits will be identified and manipulated soon. 相似文献
2.
Summary No antagonistic or synergistic interaction was found between isolates of Uromyces appendiculatus var. appendiculatus and Xanthomonas campestris pv. phaseoli when inoculated to the same plant. A single dominant gene was suggested to control resistance to three isolates of rust in the crosses Pompadour Checa × Chichara and Pompadour Checa × NE W-4. A two-gene model was confirmed for the reaction to the three rust isolates for the crosses Pompadour Checa × GN Tara and Pompadour Checa × San Cristobal; a dominant (Ur
p) gene determined resistance and was epistastic to a dominant gene (Ur
t) for susceptibility. (Ur
t) was expressed only in the presence of recessive (ur
p) alleles. The reaction to common bacterial blight was quantitatively inherited and an association was detected with plant habit but not with rust reaction and leaf variegation. Plants with leaf variegation and crippled growth, were detected in the progeny of the cross Pompadour Checa × GN Tara and were controlled by duplicate recessive genes (mutatorunstable genes) and three genes, acting additively, respectively. The developmental expression of the latter trait varied considerably. Linkage was detected between genes controlling the variegated and the crippling traits.Published as Paper No. 7839, Journal Series, Nebraska Agricultural Experiment Station. Research was conducted under project No. 20-036. 相似文献
3.
G. G. Rowland A. McHughen L. V. Gusta R. S. Bhatty S. L. MacKenzie D. C. Taylor 《Euphytica》1955,85(1-3):317-321
Summary In the early 1980s the phenomenon of somaclonal variation induced by cell culture was exploited to produce genetic variation in linseed. The linseed variety Andro, derived from the widely grown Canadian variety McGregor, was selected in saline culture and was released for production in Canada. Andro possesses traits very different from its parent, such as increased seedling vigour and tolerance to heat stress. Additional stable somaclonal variation in characters such as yield, days to maturity, seed weight and oil content were subsequently induced in McGregor. However, despite extensive screening of the somaclonal variants, no significant variation in the fatty acid profile was found.Chemical mutagenesis using ethyl methanesulphonate was, however, succesful in modifying the fatty acid profile of McGregor. Initial screening of M2 seed by the thiobarbituric acid colourimetric procedure was followed by gas chromatography to select half-seeds with atypical fatty acid profiles. Two independent, partially dominant genes were identified that were responsible for reducing the linolenic acid (18 : 3) from 50% to 2% while increasing linoleic acid (18 : 2) to 70%. A single, partially dominant gene, inherited independently of the linolenic acid genes, increased palmitic acid (16 : 0) from 7% to 30% and palmitoleic acid (16 : 1) from trace amounts to 4%.
Agrobacterium-mediated transformation of linseed has also been successful. Herbicide tolerance genes for glyphosate, sulfonylurea and phosphinothricin have been incorporated into Canadian varieties. Commercially useful levels of tolerance to sulfonylurea herbicides have been achieved with no adverse agronomic affect. It is expected that a transgenic variety containing this resistance will be registered for commercial production in Canada in 1994.Standard breeding techniques, the application of antisense technology and the overexpression of fatty acid synthesis genes are being used to further modify the fatty acid profile of linseed, as well as for the transfer of abiotic stress-related genes identified in bromegrass. 相似文献
4.
New sources of nonspecific resistance to rust and common bacterial blight in dry bean landrace Pompadour 总被引：1，自引：0，他引：1
Margaret T. Mmbaga Eladio Arnaud-Santana James R. Steadman Dermot P. Coyne 《Euphytica》1992,65(2):135-144
Summary Inheritance of resistance of five melon lines to two strains of Sphaerotheca fuliginea belonging to races 1 (Sf1) and 2 (Sf2) and to one strain of Erysiphe cichoracearum (Ec) have been studied. PMR 45 possesses one dominant gene controlling only Sf1. WMR 29 has one dominant gene for resistance to Sf1 and another for Sf2 and these genes seem to be linked. In line PMR 5, one dominant gene (or a group of three closely linked genes) is involved in the control of the three strains with one complementary gene for Sf1 and another one for Ec. PI 124112 has one dominant gene or two closely linked loci controlling Sf1 and Sf2 and two complementary different genes controlling Ec. Nantais Oblong has one dominant gene controlling only Ec. A nomenclature of the genes described is proposed. 相似文献
5.
Summary Genetics of parthenocarpy in cv Severianin was tested under natural low-temperature conditions under which only seedless fruits were produced. Results were consistent with the hypothesis that two recessive genes are involved in the expression of parthenocarpy under low-temperature conditions. One gene, pat-2, has major effects on the expression of parthenocarpy. A second gene, mp, in the homozygous form, influences expression of pat-2 in both the homozygous and heterozygous conformation and may be present in non parthenocarpic phenotypes. Linkage tests, using 26 morphological marker genes, located pat-2 between solanifolia, sf (chromosome 3 site 111) and baby-lea syndrome, bls (chromosome 3 L site 74) close to sf. The location of the minor gene for parthenocarpy, mp, was not detected. 相似文献
6.
Summary Phenotypic stability of bacterial leaf spot resistance in peach (Prunus persica (L.) Batsch) regenerants, either selected at the cellular level for insensitivity to a toxic culture filtrate of Xanthomonas campestris pv. pruni or screened at the whole plant level for resistance to X. campestris pv. pruni, was investigated. A detached-leaf bioassay was used to evaluate the original regenerants again after three years in the greenhouse and also after a two to three year cycle of tissue culture propagation. Peach trees derived through micropropagation from the original regenerants were also evaluated after one to three years growth in the field. Although leaf spot resistance was retained in some regenerants over time in the greenhouse, following in vitro propagation, and under field conditions, resistance was either lost or not expressed in others. Regenerants # 19-1 and #156-6, derived from embryo callus of bacterial spot susceptible Sunhigh, were significantly more resistant than Sunhigh. High levels of resistance were exhibited in greenhouse plants and field-grown trees of regenerant #122-1, derived from embryo callus of moderately resistant Redhaven. This research provides additional evidence that selecting or screening for somaclonal variants with disease resistance is a feasible approach to obtaining peach trees with increased levels of bacterial spot resistance.Abbreviations TC
Tissue-Cultured
- TF
Toxic culture Filtrate 相似文献
7.
Summary Inheritance of seedling reactions to cultures of races TLM and MBCT of Puccinia graminis f.sp. tritici was studied in crosses of the resistant durum Reichenbachii with susceptible Marruecos 9623 and DZ04-118. The Chi-square test for goodness of fit was used to analyze segregating populations. Two independent recessive genes appeared to control resistance of Reichenbachii to both TLM and MBCT. Depending upon the cross, the two genes interacted cumulatively to condition immunity or higher levels of resistance than either parent conditioned singly. There was no evidence of maternal influence on the inheritance of resistance. Resistance genes in Reichenbachii were recessive; therefore, breeders should consider the use of relatively large F2 populations to effectively transfer these genes to cultivars with good agronomic characteristics. 相似文献
8.
Summary The effect of temperature on fruit set, seed set and seed germination was studied in Sonia × Hadley Hybrid Tea-rose crosses. Sonia mother bushes were grown at constant temperatures (10, 14, 18, 22, 26°C) in the greenhouses of the phytotron until fruit ripening. Fruit set, fruit weight and number of seeds increased as temperature was higher. Optimum temperatures were found for days to fruit ripening (18°C), seed germination (22°C) and number of seedlings per pollinated flower (22°C). Fruit weight and number of seeds were positively correlated. For crossing and the subsequent growing of seed-bearing plants 22°C was the most favourable temperature. Effects of temperature on pollen tube growth, fertilization and seed germination are discussed. 相似文献
9.
Summary Two wheat cultivars, Spica and Lerma 52, which consistently produce high levels of -amylase during the later stages of grain development (late maturity -amylase), were crossed with a set of four near-isogenic lines carrying the tall (rht) allele or one of the dwarfing genes Rht1, Rht2 or Rht3 (GA-insensitive alleles). The F1 and F2 populations were developed and analysed for grain -amylase and plant height. The Rht3 gene exhibited the strongest influence on plant height and strongly inhibited new -amylase synthesis during the later part of grain ripening. By comparison, Rht1 and Rht2 had a less pronounced effect but still significantly reduced the expression of late maturity -amylase. These observations suggest that gibberellic acid is involved either directly or indirectly in this phenomenon. The implications of the effect of dwarfing genes on expression of late maturity -amylase are discussed in relation to cultivar improvement and to the identification and control of high -amylase germplasm. 相似文献
10.
Thanh Tu Chung Gillian West Gregory A. Tucker 《Postharvest Biology and Technology》2006,40(3):250-255
Changes in the activity of the cell wall hydrolases – polygalacturonase (EC 3.2.1.15), pectinesterase (EC 3.2.1.11) and β-galactosidase (EC 3.2.1.23) – have been investigated following wounding of tomato fruit pericarp tissue (Lycopersicon esculentum cv. Ailsa Craig). In ripening fruit wounding appears to arrest the further synthesis of polygalacturonase. β-Galactosidase synthesis may also have been arrested in ripening fruit. The level of pectinesterase declined over the first 24 h following harvest, and since this was apparent in both wounded and unwounded tissue may be related to a harvest, rather than a wounding effect. There was a recovery of activity in intact fruit by 48 h after harvest but this seems to be impaired in wounded tissue. In the case of pectinesterase, this observation was extended to examine the changes in isoform profile and it appeared that the decline of this enzyme may be associated with the reduction of one specific isoform — PE2. In contrast to ripening fruit, wounding of fruit at the fully ripe stage appears to have no significant effects on the activities of any of these three enzymes. 相似文献
11.
Morphological characterisation and agronomic evaluation was conducted on 12 transgenic broccolilines containing a tomato antisense1-aminocyclopropane-1-carboxylic
acid (ACC) oxidase gene. Plants of three cultivars: Shogun (Sh), Green Beauty (Gy) and Dominator (D), were regenerated from
hairy root cultures after co-cultivation with Agrobacterium rhizogenes strain A4T harbouring the binary vector pLN35. The T-DNA of pLN35 contains genes encoding a tomato antisense ACC oxidase
gene (35S-ACC-5′7′) and a neomycin phosphotransferase II gene (NOS-NPTII-NOS) for kanamycin resistance. The transgenic plants
were transferred to a greenhouse and fertile plants obtained. Integration of the foreign DNA into the broccoli genome was
confirmed by the polymerase chain reaction and Southern analyses. Transgenic plants showed evidence of hairy root (HR)-induced
morphological changes to varying degrees. Of the 12 characterised transgenic lines, three lines(Gy/7, D/1 and D/2) performed
within the limits of acceptability for all head quality parameters analysed (size, density, colour, shape and leafiness).
The ethylene production from stalks of four field-grown transgenic lines of Green Beauty broccoli showed significant reductions
in activity relative to the control 98 h after harvest. The Dominator transgenic lines D/1 and D/2 showed significant improvements
in head colour relative to the control from 48 h after harvest. These results are consistent with the ethylene production
patterns determined previously for these lines. The head colour results are consistent with previous results suggesting that
two enzyme systems may be involved in broccoli senescence, giving two bursts of ethylene production, with only the second
burst inhibited by the antisense ACC oxidase gene used.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Pim Lindhout Sjaak Van Heusden Gerard Pet Johan W. Van Ooijen Hans Sandbrink Ruud Verkerk Ria Vrielink Pim Zabel 《Euphytica》1994,79(3):279-286
In a tomato (Lycopersicon esculentum) breeding programme aimed at earliness, a breeding line, designated IVT-KT1, was developed by several rounds of crossing and selection. Among its ancestors were the two wild relatives L. pimpinellifolium and L. parviflorum. The breeding line flowered and set fruit one to four weeks earlier than old and modern cultivars. To identify QTLs for earliness, an F2 population was obtained by crossing IVT-KT1 with the late true breeding cultivar Premier. In winter and early spring, 690 plants of this F2 population were evaluated for earliness of which 292 were selected for RFLP analysis. Only limited parts of the genomes of IVT-KT1 and Premier were polymorphic and these polymorphisms were likely due to introgression from the ancestor wild species. By using the interval mapping method on the combined data of the greenhouse evaluations and RFLP analyses, three loci were identified that were associated with earliness. One was mainly associated with flowering time, another with fruitset time and a third one with ripening time. Two of these loci were also associated with fruit weight. F3 progenies selected for earliness on the basis of the QTL-data did confirm the F2 results. Two major earliness genes explained a difference in earliness of more than three weeks. The association with reduced fruit weight seemed to be due to pleiotropic effects rather than to linked genes. Consequently, the gain in earliness will cause a reduction in fruit weight that may not be acceptable for breeding applications. 相似文献
13.
Summary Pedigrees of 142 Yugoslavian winter wheat cultivars were traced to 110 ancestral genotypes, of which 41 contributed significantly. In each of the four major Yugoslavian wheat breeding programs, the most important ancestor, as evaluated by mean coefficient of parentage, was Akagomughi, source of the genes Rht8 and Ppd1. The other 13–19 ancestors accounting for the majority of the remaining germplasm, varied considerably among institutions. The relative contributions of ancestors changed little between the periods 1967–76 and 1982–86, with the exception of Neuzucht (source of a 1B/1R translocation), which became much more important in the latter period. 相似文献
14.
Summary Several wheat cultivars/lines were inoculated with isolates of Erysiphe graminis tritici to identify new genes/alleles for resistance. The wheats were tested with 13 isolates that had been characterized from responses on differential lines with known resistance genes. Gene Mlk which occurs in cultivars Kolibri, Syros, Ralle and several other European common wheats was found to be an allele at the Pm3 locus and is now designated Pm3d. The mildew resistance in an old Australian wheat, W150, is conferred by a single gene also allelic to Pm3 and now designated Pm3e. The near-isogenic line Michigan Amber/8*Cc possesses another allele now designated Pm3f. A Syrian land variety of common wheat shows mildew resistance that is conditioned by the combination of genes Pm1 and Pm3a. Finally, two accessions of Triticum aestivum ssp. sphaerococcum appeared to possess the Pm3c allele. 相似文献
15.
Summary The stripe rust resistant spring wheat (Triticum aestivum L.) varieties Anza, Glennson 81, Ollanta, and Yecora Rojo gave 1,2,2, and 2-gene segregations, respectively, in hybrids with susceptible Jupateco 73 when inoculated in field conditions at Davis, California USA with Puccinia striiformis West. pathotype CDL-6 and rated at post-heading stage. Intercrosses of these varieties, Anza/Yecora Rojo was not studied, permitted the following conclusions about the genes expressed in adult plants: Anza, one recessive gene; Glennson 81, two dominant genes; Ollanta, two genes, at least one is dominant; and Yecora Rojo; one dominant and one recessive gene, one of which is common with Ollanta. The resistance genes in these varieties, which expressed resistance in the seedling stage, were believed to be effective at the adult stage. Thus, seven resistance genes were identified in the four varieties. The genotypes were designated for the purposes of this study as follows: Anza, YrA YrH; Glennson 81, Yr9, YrJ, Ollanta YrL YrD; and Yecora Rojo, YrC YrD. It was recommended that these and other Yr genes be used as multiple gene complexes to increase durability of resistance to P. striiformis, an organism known to evolve virulence rapidly in field conditions. The demonstrated durability of Anza in California may be a result of its combination of resistance alleles at two loci. 相似文献
16.
Summary Deep water rice varieties in general have certain peculiar characters which are associated with floating habit. These characters are (i) early nodal differentiation, (ii) nodal rooting, (iii) spreading habit, (iv) awned grains, (v) brown hull colour, (vi) red pericarp (red rice), and (vii) seed dormancy. Inheritance of these characters and linkage relationship of genes governing these characters were studied in a cross between Pankaj (non floating) and Nageribao (floating) rice varieties. Nageribao, a cultivar from Assam possesses these characters.Early nodal differentiation was observed to be controlled by a single dominant gene, designated as Nd. Nodal rooting was controlled by two dominant complementary genes, designated as Nr
1 and Nr
2. We found an inhibitory factor for spreading habit and one for brown hull colour in Pankaj; the operation of two dominant duplicate genes An
1 and An
2 for controlling awning characters, a single dominant gene Rd for red pericarp colour and a single dominant gene Gd for grain dormancy. Joint segregations between these characters resulted in the assignment of genes in the X linkage group of indica rices with estimated map distances based on the cross-over values. The genes An (awning), Es (spreading habit), Nr (nodal rooting) and Nd (nodal differentiation) were observed to be associated with each other. The gene for red pericarp (Rd) was observed to be linked with the grain dormaney gene Gd. 相似文献
17.
Summary The sensitivity of Fragaria seedlings to colchicine is dependent on the plant organ that is treated. Complete immersion of seedlings in a 1.5% colchicine solution results in total lethality, whereas the survival rates were more than 75% even at concentrations of 3.0% when only shoot apices were treated. High proportions of polyploids were isolated by treating shoot apices of seedlings with a 2.0% colchicine solution for 24–28 h. The dropper method is preferred to the tube method as it involves a minimum of manipulation and requires simple equipment. A differential response to colchicine was observed within and between different diploid species, diploid and tetraploid hybrids. 相似文献
18.
Summary Inheritance of resistance to turnip mosaic virus (TuMV) strains C1, C2, C3, C4, and C5 in Chinese cabbage (Brassica campestris subsp. pekinensis) was evaluated using monoclonal antibodies. Crosses were made between a resistant line, 0–2, and four susceptible line. Seoul (SE),SSD31 (SS), Cheongbang (CH), and Yaki 1 ho (YA), to determine the inheritance of resistance of 0–2 in different genetic backgrounds. Resistance to TuMV was controlled by a single dominant gene or double dominant genes depending on the strain and cross. The resistance genes of 0–2 were modified by susceptible parents such that a single dominant gene was involved in the SS×0–2 combination, but double dominant genes in the SE×0–2 against TuMV-C3 or TuMV-C5. ELISA tests using inoculated and noninoculated leaves in the same plant suggested that the dominant resistance genes inhibit virus movement rather than virus multiplication. 相似文献
19.
Jens Weibull 《Euphytica》1994,78(1-2):97-101
Summary Accessions of Hordeum vulgare subsp. spontaneum, the progenitor of cultivated barley, were screened in field and glasshouse trials for resistance to the aphid Rhopalosiphum padi. A few selected lines were furthermore hybridized with a modern barley variety and the resulting populations evaluated. High levels of resistance were found among some of the spontaneum accessions resulting in lower aphid growth rates (maximum reduction 57%). Segregation patterns among siblings in F2 populations were continuous, indicating the presence of several genes with possibly additive effects. The usefulness of H. vulgare subsp. spontaneum for breeding aphid resistant barley is discussed. 相似文献
20.
Summary The inheritance of resistance to Russian wheat aphid Diuraphis noxia (Mordvilko), in two resistant barleys, Hordeum vulgare L., ASE/2CM//B76BB and Gloria/Come, was studied in the field and in the greenhouse. The resistant genotypes were crossed with susceptible genotypes Esperanza and Shyri. Resistance reactions of F1, BC1, and F2 plants, and individual F2 plant derived F3 families indicated that resistance in each genotype was controlled by the same single dominant gene. 相似文献