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1.
以秋水仙索为诱变剂，利用茎段浸泡和秋水仙素培养基2种方法对库拉索芦荟进行诱变，结果表明，茎段浸泡秋水仙素法诱导四倍体葡萄的效果优于秋水仙素培养基法，0．2％的秋水仙素处理4d变异效果最好，诱变率达到最高值41.5％。变异株叶片肥厚，叶色深绿，叶片表皮气孔保卫细胞中叶绿体数增多。  相似文献   

2.
Factors affecting reliable plant regeneration from unfertilized ovule culture of gentians (Gentiana spp.) were examined. Cold pretreatment (4°C) of flower buds enhanced or maintained production of embryo-like structure (ELS). When 43 genotypes were surveyed in two different labs, 40 of them produced ELSs ranging from 0.01 to 26.5 ELSs per flower bud. No ELSs could be obtained in three genotypes. A significant correlation (r = 0.64) was observed between the number of ELS per flower and the frequency of responding flower buds. Eight genotypes of G. triflora, which were used as common materials in two different labs, produced ELSs in both labs. The ploidy levels of a total of 1,515 regenerated plantlets were determined, revealing that the majority of these plants consisted of haploids (57.9%) and diploids (34.3%). However, the frequency of haploids and diploids was different between G. triflora and G. scabra, and G. triflora showed higher frequencies of haploids than G. scabra. When haploids were treated with oryzalin for chromosome doubling, diploids and tetraploids were obtained. These results demonstrate that the unfertilized ovule culture technique of gentians is a powerful tool for obtaining haploids and DHs because of its reproducible and reliable nature and application to a wide range of genotypes.  相似文献   

3.
Summary InDactylis glomerata L. subsp.lusitanica, triploid and tetraploid plants were obtained by bilateral sexual polyploidization in crosses between diploid parents known to produce 2n gametes. The polyploid and diploid progeny were compared for allozyme diversity (allele number and heterozygosity), phenological (pollen fertility, inflorescence emergence date), cellular (stomatic cell size) and morphological characters (vegetative biomass, seed weight, total seed number per plant, panicle number and seed number per panicle length) in four contrasting growing conditions. Stomatal cell size and the total number of alleles were significantly lower in diploids than in polyploids which sometimes recovered more than two distinct alleles at a locus via 2n gametes possessing heterozygous loci. Pollen fertility was similar in diploids and tetraploids, but significantly lower in the triploids. Seed weight was significantly higher in polyploids, although the average number of seeds per panicle length and the total number of seeds was higher in the diploid sibs. No phenological differences occurred among ploidy levels whereas such differences were observed inDactylis in all the natural areas of sympatry between diploids and their related polyploids. Our results provide evidence for an instantaneous effect of polyploidization on certain traits and suggest that natural selection would act subsequently on several other traits to allow the establishment of new polyploids.  相似文献   

4.
Mitotic polyploidization in vitro was used in selected wild Solanum species and Solanum tuberosum dihaploids. The efficiency of polyploidization by colchicine was compared with that of oryzalin. Oryzalin was more effective than colchicine (P = 0.1). The rate of non‐affected to mixoploid to tetraploid regenerants was 22 : 2.5 : 1 (colchicine) and 14 : 2 : 1 (oryzalin). Optimal concentrations and durations were 3.5 mm /24 h for colchicine and 25 or 30 μm for 24 or 48 h for oryzalin (variations in concentration and duration are necessary owing to possible diversity of responses in selected genotypes). Tetraploids were obtained from S. berthaultii, S. bulbocastanum, S. pinnatisectum, S. verrucosum and eleven S. tuberosum dihaploids. The yield of tetraploids derived from tbr dihaploids was lower than that from the wild species (P = 0.01). Tetraploid regenerants were tested in intra‐ and inter‐specific crosses. Three of 43 intra‐specific combinations (298 pollinated flowers) were successful and yielded 440 seeds. Inter‐specific crosses (138 combinations, 1672 pollinated flowers) yielded 48 seedless berries.  相似文献   

5.
Many diploid rose species and cultivars possess valuable traits that can be introgressed into modern tetraploid cultivars. Interspecific, interploidy crosses are possible, but triploid hybrids typically have limited fertility, hindering further breeding and selection. Tetraploidizing diploids before mating with tetraploids can alleviate fertility barriers. The efficiency of trifluralin was investigated for polyploidization of Rosa chinensis minima (2n = 2x = 14) seedlings. Treatments were trifluralin at 0.086% and 0.0086%, colchicine (0.5%), and distilled water and contained 2% dimethyl sulfoxide and a surfactant. Approximately 5 l of the treatment solution was applied to the apical meristem of seedlings (N = 337, 82–85 per treatment) in the process of cotyledon expansion. Guard cell length, pollen diameter, and root tip squashes of rooted cuttings were used to detect polyploidy in meristematic layer (L)I, LII, and LIII, respectively. Trifluralin (0.086%) was the most effective treatment for polyploidization (LI 20.2%, LII 12.9%, LIII 12.9%), followed by trifluralin (0.0086%) (LI 10.6%, LII 7.1%, LIII 4.7%) and colchicine (LI 2.4%, LII 0%, LIII 0%). Polyploidization consistently occurred from LI inward. Polyploids as a group had reduced pollen stainability and a lower leaflet length to width ratio than diploids. In addition, two diploid seedlings were identified which produce 2n pollen. Considerations in selecting germplasm and generating somatically-induced polyploids from seedlings versus clones for use in breeding are discussed.  相似文献   

6.
The aim of this research was to improve our understanding of how ploidy level influences phenotype and gene expression in Chinese cabbage (Brassica rapa L. ssp. pekinensis). Haploid plants (2n = 10) was induced by 0.2% colchicine to produce diploid (2n = 20) and tetraploid plants (2n = 40). The aneuploid (2n = 24) was also obtained by hybridization between diploid plants as the female and tetraploid plants. The ploidy levels of all plants were identified through chromosome counts and flow cytometry. Leaves and petals became larger as the ploidy level increased from haploid to diploid, and from aneuploid to tetraploid. Similarly, expression of ARGOS was regulated by genome size, increasing in parallel with the level of ploidy. Among the four ploidy types, expression was stronger in the floral buds than in the leaves. Expression by ASY1 also differed according to ploidy level, being highest in diploid plants, followed in order by tetraploids. Expression was similar between haploids and aneuploids at two stages—prior to and after meiosis—but was higher in the haploids during meiosis. When buds were compared within the same ploidy type at different stages, ASY1 expression was obviously higher during meiosis than either before or after. Our study demonstrated the generation and phenotype of a ploidy Chinese cabbage series derived from one haploid. Expression of genes ARGOS and ASY1 were modulated by genome size in this ploidy series, and the regulated patterns of the two genes was different.  相似文献   

7.
P. E. Grimbly 《Euphytica》1973,22(3):479-483
Summary An autotetraploid form of the parthenocarpic variety Butchers Disease Resisting was produced by colchicine treatment. Immersing the seeds in water before treatment in 0.2% colchicine for 24 hours gave the highest percentage of vigorous tetraploids. The yield of fruit from tetraploids was better than the diploids at first but it declined later in the cropping period owing to slow sideshoot production.Self-fertility of autotetraploids was lower than diploids. When crossed with diploids, triploid plants were obtained. These were self-sterile but they could be crossed with diploids to give trisomic plants. Aneuploids with one additional chromosome were found amongst tetraploids and triploids.  相似文献   

8.
This paper describes an efficient colchicine-mediated technique for in vitro induction of octoploids in Pogostemon cablin and its confirmation by flow cytometry and chromosome numbers. The highest octoploid induction ratio was obtained by 0.05% colchicine treatment for 72 h. The chromosome number of octoploid seedlings was 2n = 8x = 128. Colchicine-induced tetraploids and octoploids planted in soil remained stable after 6 months. There were 31 lines of octoploid plants obtained. The leaf characteristics of P. cablin tetraploids and octoploids were compared. The larger leaves and stomata of transplants can be used to identify putative octoploids in P. cablin. Most octoploid lines exhibited higher patchoulic alcohol contents than the controls after 6 months of cultivation. Our results demonstrated that polyploidy induction can be beneficial in improving the medicinal value of P. cablin.  相似文献   

9.
Tetraploid red clover (Trifolium pratense L.) often produces insufficient seed to be economically interesting. Numerous studies have identified poor pollination due to long corolla tubes as its cause, but other studies disagree. Therefore, we investigated seed yield, corolla tube length and flowering traits in 244 plants from five diploid and five tetraploid cultivars during 2 years. Tetraploids produced fewer seeds, fewer flower heads and fewer seeds per head, but an equal number of flowers per head when compared to diploids. Although corolla tubes were longer in tetraploid than in diploid red clover (P < 0.001), no correlation between corolla tube length and seed yield was detected. Therefore, the corolla tube length is likely neither the main nor only cause of low seed yield in tetraploid red clover. Instead, three putative causes for low seed yield were identified: tetraploids produced less inflorescences per plant, possessed a lower degree of determinacy and had markedly less seeds per head when compared to diploids. Possible causes for such differences include lower pollen viability and higher rates of embryo abortion.  相似文献   

10.
Inter-sectional hybrids were successfully obtained by the reciprocal crosses between 11 cultivars (including 6 diploids and 5 tetraploids) of Begonia semperflorens (SS & SSSS genomes) and B. ‘Orange Rubra’ (RR genome) with the aid of in vitro culture of mature or immature seeds on MS medium containing 0.1 mg l−1 α-naphthylacetic acid, 0.1 mg l−1 6-benzyladenine, 10 mg l−1 gibberellic acid, 30 g l−1 sucrose and 2.5 g l−1 gellan gum. Embryo rescue as ovary culture with immature seeds 12th–16th day after pollination (DAP) generally gave higher efficiency of plantlet formation, but in some cross combinations, culture of mature seeds (30 DAP) resulted in higher yield of plantlets. Flow cytometric analysis revealed that they were consisted of the plants with various genomic combinations (RS, RR, RSS, RRS, RRSS and RRRRSS) as estimated by the DNA contents of both parents. Hybridity of these plants with various genomic combinations including RR was confirmed by random amplified polymorphic DNA analysis. These results suggested that unreduced gamete formation and spontaneous chromosome doubling were involved in the hybrid formation of various ploidy levels and genomic combinations. These hybrids showed various levels of intermediate traits between both parents according to the genomic compositions, and some of them had desirable characters of both parents.  相似文献   

11.
Polyploidization and early screening of Rhododendron hybrids   总被引：1，自引：0，他引：1  
Anu Väinölä 《Euphytica》2000,112(3):239-244
Polyploid induction represents a useful tool for breeders of floral crops as larger flowers, longer flowering period and deeper colors can be achieved through chromosome doubling. This study aimed at testing the efficiency of colchicine and oryzalin in inducing polyploidy in three Rhododendroncultivars grown in vitro. The chemicals were used in two concentrations with 24 h and 48 h treatment durations. The survival of the plants was better in colchicine than in oryzalin solutions. The higher concentration of both chemical skilled more plantlets. The treatment duration in oryzalin did not affect the survival, but 48 h in colchicine was more destructive than 24 h. The low survival rate may not be a disadvantage, if the treatment induces desired ploidy. The ploidy levels were screened with flow cytometry. Oryzalin was more efficient than cochicine in inducing polyploidy, the treatment duration and the concentration did not have significant effects as main factors. The biggest proportion of solid tetraploids (18.2% of the survived plants) was obtained from the 24 h treatment in 0.005% oryzalin. Immediately after the treatment the polyploids grew very slowly, whereas most of the unaffected diploids were vigorous from the very beginning. More mixoploids than solid tetraploids were obtained in all treatments. Most of the mixoploids retained their chimerism, one third shifted todiploidy and one single plant to tetraploidy. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
R. Kessel  P. R. Rowe 《Euphytica》1975,24(1):65-75
Summary The variation which persisted in interspecific aneuploids even after one or two generations of backcrossing prevented the morphological distinction of the aneuploids from their diploid sibs. An attempt was made to unmask the effects of aneuploidy by producing aneuploids within the more uniform genetic background of a single species.The procedure to produce trisomics and aneuploids of diploid species was to vegetatively double clones or seed of the species with colchicine, cross the induced tetraploids to diploids to produce triploids, and then cross the triploids to the original diploids. An attempt was made to use the same diploid clone and/or introduction of a species in all successive stages of the procedure in order to obtain as much uniformity as possible. This was largely unsuccessful because self-incompatibility and inbreeding reduced seed set. Seventy-three different tetraploids were obtained from seven species. Tuber treatments were noticeably unsuccessful in producing doubled plants. The two vegetative treatments were most successful and produced 41 different tetraploid clones while 30 doubled plants were obtained from four seed treatments.Morphologically the tetraploids resembled the diploid and there was no noticeable increase in size of leaflets and floral parts in the tetraploid. The average number of chloroplasts in ten pairs of guard cells was a distinctive feature which could efficiently be used in distinguishing the induced tetraploid plants from diploids. The tetraploids were generally less fertile than their diploid counterparts and the majority of them exhibited self-compatibility in comparison to self incompatibility of the diploids.Cooperative investigations of the Agricultural Research Service, U.S. Department of Agriculture and the Wisconsin Agricultural Experiment Station. Supported in part by grants from the Research Committee of the Graduate School, University of Wisconsin.  相似文献   

13.
Summary The diploid (2C) amount of DNA in cassava (Manihot esculenta Crantz) is 1.67 picograms (pg) per cell nucleus. This value corresponds to 772 mega-base pairs in the haploid genome. The size of the nuclear genome in cassava is very small in comparison with other Angiosperms. Flow cytometry techniques were used to screen ploidy levels in a large population of in vitro plantlets treated with colchicine and oryzalin (3,5-dinitro-N4,N-dipropylsulphate). Culture of axillary node cuttings for 48 hours in liquid medium supplemented with 2.5 to 5.0 mM colchicine in combination with 2% dimethyl sulfoxide (DMSO) resulted in a high frequency (23 to 42%) of non-chimeric tetraploids in the V3 generation. Although mixoploidy may persist in as many as four cycles of vegetative propagation of node cuttings, solid (non-chimeric) tetraploids can be identified by flow cytometry among in vitro plantlets and then rapidly propagated for field testing. A somatic polyploidization system is proposed for implementation in cassava breeding programmes.Dedicated to the memory of the late Dr. Novak. Correspondence to M. van Duren  相似文献   

14.
F. W. Martin 《Euphytica》1970,19(4):459-464
Summary The kinds and sites of sterility and inviability were noted in induced tetraploids of threeIpomoea species, and of hybrids ofIpomoea lacunosa withI. trichocarpa. Tetraploids were somewhat less fertile than diploids, but seeds were normal appearing and ususally viable. Hybrids were much less fertile. Hybrid sterility occurred as pollen abortion, pollen germination failure, and in failure of pollen tube growth. Small and underdeveloped seeds failed to germinate. The sterility of hybrids (but not of tetraploids) is thus very similar to that of the hexaploid sweet potato. Sterility suggests developmental inbalance, which is probably due to genic and perhaps minor chromosomal differences among the parent species of the sweet potato. Hybrid sterility of the sweet potato may have been fixed by polyploidy, and thus may be impossible to eliminate.  相似文献   

15.
Marie Bragdø 《Euphytica》1962,11(2):143-148
2x, 3x and 4x forms of spinach were compared in 1959, 1960 and 1961.At the same stage of development the tetraploids outyielded the diploids in total green matter and leaf blades in 1959 and 1961. In 1960 there was no significant difference. This year the tetraploids had a very small increase in green matter in the period between the two harvest dates. Yield of dry matter was determined in 1960 and 1961, and in both years the tetraploids outyielded the diploids. The rate of development decreased with increasing degree of ploidy. Compared at the same age, when the diploids were about to start bolting they were superior to the polyploids with regard to total yield, yield of leaf blades and yield of dry matter.The onset of flowering was considerably delayed in the polyploids. Generally the triploids were intermediate between the diploids and the tetraploids. The triploids and tetraploids had a larger proportion of monoecious plants, and a smaller proportion of males than the diploids.Report No. 27  相似文献   

16.
Bilateral sexual polyploidization in potatoes   总被引：5，自引：0，他引：5  
Summary Bilateral sexual tetraploidization was achieved by intercrossing diploid Phureja × haploid Tuberosum hybrids. Both parents contribute gametes with the somatic number of chromosomes (diplogynoids and diplandroids). More than 100 tetraploid progeny appeared in nine 2x–2x families. The tetraploids are generally more vigorous and significantly outyield their diploid full-sibs. The superiority of the tetraploids is interpreted on the basis of the mode of diplandroid (2n pollen) formation by first meiotic division restitution (FDR). Heterozygosis, epistasis and genetic diversity, if present in the parental diploid genotype, are largely maintained in the 2n gametes formed by FDR. and syngamy brings about more opportunities for heterotic responses in conjunction with polyploidization. Differences in tuber yield among tetraploid clones within families were found to be statistically significant (P <0.05). Thus, unlike somatic chromosome doubling, which can merely increase chromosome numbers, or somatic hybridization, which could in addition bring about heterosis, sexual polyploidization is also associated with genetic variability. The degree of inbreeding and the genotypic structure in the population of newly arisen tetraploids is discussed. The relationship among asexual reproduction, preservation of favorable nonadditive genetic effects by FDR. restoration of sexuality, and polyploidization is explored. The possible evolutionary significance of these factors is emphasized.  相似文献   

17.
Summary Genetically stable artificial autotetraploids with over 90% seed set were obtained by colchicine treatment of the solanaceous species Hyoscyamus niger L. (2n=4x=68). The tetraploids were vigorous and yielded 22.5% more tropane alkaloid per individual than the source diploids.CIMAP Publication No. 35/90  相似文献   

18.
Summary A 3 hr period of treatment with a 0.2% aqueous solution of colchicine was given to one week old seedlings of 3 inbred lines of perennial ryegrass (Lolium perenne) and 4 lines of Italian ryegrass (L. multiflorum). The surviving plants developed as mixoploids and were self-pollinated. In the following generation (CT1) the seeds were grown without further treatment, and were screened cytologically at the seedling stage to separate out diploids from tetraploids. Only the diploids were kept, and in this CT1 generation comparisons were then made between controls (2x) and colchicine-treated diploids (C2x) for leaf mesophyll cell size and chloroplast number variation. Heritable differences were found such that the cell plan areas and/or the numbers of chloroplasts per cell were significantly greater in the C2x compared with the 2x treatment in 3 and 5 out of the 7 lines. In each case there was enhancement of chloroplast numbers independently of the variation in cell size.  相似文献   

19.
Summary The formation of triploids in 4x×2x crosses was studied in primitive potato varieties from the Andes of Peru and Bolivia. Triploid frequencies were as high as 80–100% in some crosses, although the actual number of seeds was low. The triploid block varied according to the tetraploid parent, and was never entirely absent. The likelihood of triploid formation was studied in 4x×2x crosses where pollen from both tetraploids and diploids of known genotype was used. Even though the diploids were chosen for their non-production of 2n gametes, as detected in pollen grain size, 66% of the hybrids were tetraploid. The amount and probability of gene-flow between the tetraploid and diploid gene-pools, either directly through 2n gametes or through triploid bridges was examined. Most of the 20 cultivars of S. x chaucha produced seed in crosses with tetraploids and diploids, although the fertility of the latter crosses was four times higher. The female fertility of some of the triploids thus allows them to exchange genes with the tetraploids and diploids, although gene-flow occurs more rapidly through direct transfer from diploids to tetraploids via 2n gametes.  相似文献   

20.
甘蓝型油菜作为多倍体起源和发生的历史较短, 遗传背景较为狭窄, 人工合成甘蓝型油菜可作为植物多倍化研究的优选模型, 本文以人工合成的甘蓝型油菜为材料, 通过HPLC分析发现白菜型油菜和甘蓝的甲基化率分别为8.33%和15.88%, 2个杂种株系的全基因组甲基化水平介于双亲之间(分别为10.29%和12.83%)。MSAP分析发现杂种F1代及其亲本的甲基化水平存在明显差异(白菜型油菜<杂种F1<甘蓝), 杂种F1代的甲基化变异(23.71%)中来自A、C基因组的变异分别占6.60%和10.16%。MSAP差异性条带的序列分析发现多倍化过程中与甲基化变化相关的基因参与了多种生物学过程, 且差异甲基化基因在人工合成甘蓝型油菜及其亲本间的表达差异与甲基化修饰模式是一致的。本研究为了解甘蓝型油菜多倍化过程中发生的表观变异奠定了基础。  相似文献   

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