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1.
Jain  R. K.  Jain  Sunita  Nainawatee  H. S.  Chowdhury  J. B. 《Euphytica》1990,48(2):141-152
Summary In vitro selection of salt tolerant plants of Brassica juncea L. (Indian mustard) cv. Prakash has been accomplished by screening highly morphogenic cotyledon explant cultures on high NaCl media. Out of a total of 2,620 cotyledons cultured on high salt medium, 3 survived, showed sustained growth and regenerated shoots. They were multiplied by axillary bud culture on NaCl free medium. The salt-selected shoots retained salt tolerance following 3 month of growth and multiplication on control medium. While two of these somaclones flowered and set seeds, third one grew slowly, had abnormal leaf morphology and was sterile. The seed of the two fertile plants were sown in the field to raise R1 segregating generation. Data were recorded for field, other agronomic components and oil content. The somaclonal lines, both selected salt-tolerant and non-selected, showed tremendous amount of variation for all the characters studied. One of the two tolerant somaclones invariably showed reduced height, longer reproductive phase and higher 1000 seed weight. Based on the agronomic performance of R1 plants of these somaclones, some plants were selected and their progeny were evaluated for agronomic performance under standard field conditions and salt-tolerance in the greenhouse using sand pot culture method. Most of the lines bred true for their specific characteristics. In the greenhouse, selected salt-tolerant somaclones (SR-2 and SR-3) performed better for plant growth, yield and other agronomic traits at higher salt treatments, indicating thereby that salt-tolerance trait selected in vitro was expressed in the whole plants and is genetically stable and transmitted onto the progeny. The two tolerant lines, however, differed in their salt-tolerance during vegetative and reproductive phases as indicated by their salt-tolerance and stress susceptibility indices. The mechanism of salt-tolerance is not clear and needs to be further investigated.  相似文献   

2.
Multiple shoots were efficiently regenerated from cotyledonary node and shoot tip explants of Pisum sativum within 15 days on MS medium containing B5 vitamins and supplelmented with 2.0 mgl-1 6-benzylaminopurine. The elongated shoots produced on the same medium were excised and transferred to MS medium containing half strength ammonium nitrate (8.25 gml-1) and supplemented with auxins (indole-3-butyric acid or naphthalene acetic acid) either alone or in combinations with gibberellic acid. Rooting and flowering were observed on the 7th and 15th day after their transfer to rooting medium. The flowers self-fertilised in vitro and produced mature pods within 25 days of rooting. These seeds were germinable both in vitro and in vivo. In vitro seeds sown in pots under field conditions developed into flowering plants, and subsequently produced pods with viable seeds. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
An in vitro propagation method for female plants of Momordica dioica (Roxb.) has been established. The nodal segments were harvested and the cut ends of the explants were sealed with wax and then surface sterilized and cultured. Bud breaking occurred on Murashige and Skoog’s (MS) agar-gelled medium + 2.0 mg L−1 6-Benzylaminopurine (BAP) + 0.1 mg L−1 Indole-3 acetic acid (IAA). The cultures were amplified by passages on MS medium supplemented with 1.0 mg L−1 BAP + 0.1 mg L−1 IAA. Further, shoot amplification (29.2 shoots per vessel) was achieved by subculturing of in vitro regenerated shoot clump on MS medium + 0.5 mg L−1 BAP + 0.1 mg L−1 IAA. The micropropagated shoots were subsequently transferred for root formation on half-strength MS medium + 2.0 mg L−1 Indole-3 butyric acid (IBA) with 89% success rate. The in vitro-regenerated shoots were also rooted ex vitro with 34% success. These plantlets were hardened in the greenhouse and transferred to the field. The established protocol is suitable for true to type cloning of mature female plant of M. dioica.  相似文献   

4.
The effect of plant growth regulators and natural supplements on the morphogenetic response of Pogostemon cablin Benth. was investigated. Murashige and Skoog (MS) media supplemented with 0.5 mg L?1 benzyl-6-adenine and 0.5 mg L?1 kinetin was effective in inducing multiple shoots (63.20 ± 0.15) with an average shoot length of 5.27 ± 0.15 cm and biomass of 5.20 ± 0.10 g shoot?1. Among the natural supplements, 10% coconut water supplemented to MS media showed a better response in all the morphological parameters studied. The use of 10% tomato extract, 20% banana extract, 10% carrot extract, and 10% papaya extract in MS medium have efficiently increased multiple shoots, shoot length, and fresh weight of the shoots. The natural supplements also effectively increased the chlorophyll content, total protein, and total carbohydrate content in the plant. The frequency of rooting (93%) was highest when shoots were implanted on 1/2 strength MS media with 100 mg L?1 activated charcoal. The in vitro rooted plants were successfully acclimatized and established in soil. Also, RAPD analysis showed no variation suggesting true-to-type nature of the micropropagated plants. Hence, this protocol can effectively reduce the cost of in vitro multiplication of plants.  相似文献   

5.
This study was to determine the agronomic and genetic characteristics of a novel rice dominant dwarf mutant 986083D (japonica) and its potential in breeding. 986083D derived from the anther culture of an autotetraploid indica/japonica hybrid and its progeny segregated into normal and dwarf plants. Homozygous and heterozygous 986083D plants looked similar phenotypically, showing shortened stature, erect leaves, more tillers and poor fertility. The segregation ratio of dwarf to normal plants fit the expected 3:1 by χ2-test in 77 out of 88 tested lines. Crosses between homozygous 986083D and eight other rice varieties had uniform semi-dwarf F1 plants. The F1 plants from crosses between heterozygous 986083D and five other varieties had normal and semi-dwarf plants close to the expected ratio of 1:1. The reduction of plant height in F1 plants ranged from 40.0 to 53.5% in a subtropical environment and from 37.5 to 48.2% in a temperate environment. 986083D showed moderate sensitivity to exogenously applied GA3 in terms of elongation of shoots and induction of α-amylase activity in the endosperm. Linkage analysis showed that the dominant dwarf gene (designated as Dx) in 986083D was not allelic to D53. Dx was roughly mapped to the short arm of chromosome 8. All results showed that 986083D was a novel mutant controlled by single dominant gene, providing a valuable material in rice breeding. Ruizhen Qin, Yang Qiu contributed equally to this work.  相似文献   

6.
Summary To provide a truly genotype-independent transformation system, it is necessary to be able to transform a wide range of potato genotypes. The ability to regenerate shoots in vitro was determined for 34 potato varieties using tuber disc explants. Following a culture regime used extensively in previous studies with the variety Desiree, half of the varieties could be regenerated from tuber discs and half could not. From a sample of varieties that could be regenerated from tuber discs, all but one variety gave transgenic plants. Twelve varieties were evaluated for the capacity to regenerate shoots from leaf and internode explants excised from in vitro grown plants. All of the varieties tested regenerated adventitious shoots. Leaf and internode explants from 5 varieties were subsequently used for transformation, and transgenic plants were produced from two potato varieties that did not give transgenic plants from tuber disc explants. Some varieties could not be transformed by either method, and will require modification of the in vitro regeneration and transformation system to be successful.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - GA3 gibberellic acid - IAA indole-3-acetic acid  相似文献   

7.
Summary Crosses between common bean genotypes from different centres of origin can result in F1 plants with dwarfing that is severe enough to prevent formation of F2 seed. This hybrid dwarfness is controlled by two complementary genes, Dl-1 and Dl-2. The dominant alleles at both loci must be present to cause dwarfing, and an increased dose of either allele increases the severity of the dwarfing. Since dwarfing restricts crossing among gene pools, it holds interests for bean breeding and studies of bean evolution and physiology. Results of grafting studies are described which confirm the previously reported dependance of dwarfing on independent root and shoot effects, and further show that grafting may be used to characterize genotypes for presence of the Dl-1 and Dl-2 alleles and to produce normal shoots in plants which otherwise would have been dwarfed. In the first experiment, two carriers each of Dl-1 and Dl-2 and a non-carrier were grafted reciprocally; of the 25 combinations, only the four combinations of Dl-2-carrying shoots with Dl-1-carrying roots produced dwarfing. In a second experiment, 11 carriers of Dl-1 and 9 of Dl-2 were grafted to Dl-1 roots and Dl-2 shoots. Although most graft combinations where Dl-1 roots were combined with Dl-2 shoots resulted in dwarfed plants, 10 genotypes showed mixed responses or otherwise did not respond as expected. Further experiments confirmed the occurrence of materials giving mixed responses or showing dwarfing irrespective of the graft combination. While grafting has utility as a screening tool, results should be interpreted with caution. There remains a need to determine whether the unexplained results reflect effects of additional alleles or genes affecting the dwarfing response. Grafting was used successfully to obtain normal F1 shoots, and ultimately, to produce F2 seed after two cycles of backcrossing (BC2) for four crosses which otherwise would have given dwarfed plants. Segregation of dwarfed and normal plants in progeny rows of F2 plants derived from the BC2 populations showed 1:3 ratios, this being consistent with the reported inheritance.  相似文献   

8.
Synthetic seed technology is a potential tool for a more efficient and cost effective rapid clonal propagation system. In the present investigation, synthetic seeds were produced by encapsulating nodal segments of Ocimum basilicum in calcium alginate gel. For encapsulation of nodal segment, 3% (w/v) sodium alginate and 75 mM CaCl2.2H2O were found most suitable. The synthetic seeds when cultured on half-strength Murashige and Skoog (MS) medium supplemented with 5.0 μM benzyladenine (BA) and 0.5 μM Indole -3- acetic acid (IAA) produced maximum number of shoots (7.9 ± 0.54) after 8 weeks of culture exhibiting 80% in vitro conversion response. Further, synthetic seeds stored at 4 °C for 4 weeks resulted in maximum conversion response (90%) when placed back to regeneration medium. Both root and shoot formation took place in the same medium but the roots were thin and difficult to handle. Individual elongated shoots were rooted on MS medium supplemented with 1.0 μM Indole -3- butyric acid (IBA). Plants regenerated from the synseeds were hardened, acclimatized, and established in soil with 80% survival rate. Changes in antioxidative enzymes viz., Superoxide dismutase (SOD) and Catalase (CAT) in O. basilicum indicated the adaptation of micropropagated plants to ex vitro conditions.  相似文献   

9.
B. S. Ahloowalia 《Euphytica》1994,75(3):163-172
Summary Production of mini-tubers as a source for seed potato was investigated by growing in soil micropropagated plants and micro-tubers produced from micropropagated plants. Cultures of several cultivars were initiated from indexed tubers and multiplied on modified MS medium. Cultures were micropropagated by using a modular system which allowed batch handling. Micropropagated plants produced mini-tubers in glasshouse after 70–115 days of growth in soil. A large proportion of the mini-tubers produced were between 9 and 15 mm diameter. Several factors, e.g., explant number, duration of in vitro culture and genotype influenced mini-tubers production. Micropropagated plants after culture of 86 days or longer produced micro-tubers ca. 2 to 10 mm diameter. Plants, which formed micro-tubers in vitro, produced less number of mini-tubers in soil. Micro-tubers produced 1 to 3 mini-tubers when grown in soil in chain-type paper pots, but produced conventional sized tubers when grown in soil under plastic polytunnel. Mini-tuber number varied widely between potato cultivars; cvs. Bintje and British Queen produced more mini-tubers than the other cultivars. Mini-tubers developed green hard skins when kept in light for 3 weeks, and could be stored in dark at 4° C upto 6 months. In a field trial, small mini-tubers ca. 5–10 mm diameter produced more but smaller tubers than mini-tubers ca. 15–20 mm diameter. The micropropagated plants and the plants grown from mini-tubers were genetically stable, and did not show any morphological aberrations except for one variegated plant among the several thousand produced. It is concluded that the production of mini-tubers by soil planting of micropropagated plants is a rapid and efficient method for producing seed potato tubers.The use of any trade mark and other commercial products mentioned in this paper does not constitute any recommendation or advertisement for such products on behalf of the Agriculture and Food Development Authority, Dublin, Ireland  相似文献   

10.
Peng Luo  Zequ Lan  Jie Deng  Ziqing Wang 《Euphytica》2000,114(3):217-221
Oil radish (Raphanus sativus var. raphanistroides Makino) is resistant to drought and low temperature. In order to breed more resistant cultivars of rapeseed, the wide cross between rapeseed (Brassica napus L.) and oil radish was made. Rapeseed was not compatible with oil radish, and the frequency of hybrid plants (F1) was very low. Moreover, the hybrid plants were sterile. In order to recover the intergeneric hybrids (F1), the in vitro organ culture technique was applied in our experiments. The frequency of hybrid plants (F1) was increased up to 25.55% by means of in vitro culture of pollinated ovaries. Some fertile amphidiploid hybrid plants were obtained by means of colchicine treatment of small buds obtained from cultured flower receptacle segments of hybrid plants (F1). It is suggested that the technique of in vitro culture of pollinated ovaries and flower receptacle segments is useful in the wide-cross breeding of rapeseed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

11.
The first success at interspecific hybridization between cultivated sunflower(H. annuus) and a diploid perennial species, H. simulans is reported. The F1s from both direct and reciprocal directions exhibited dominance of the wild species phenotype and were pollen sterile. Meiosis was irregular in the F1 hybrids and both univalents and multivalents were observed. Multiplication of the interspecific hybrids was achieved through in vitro culture of nodal sections on Murashige & Skoog medium supplemented with 0.5 mg l-1 benzyladenine. Fertility of the interspecific hybrids was improved by subjecting the in vitro proliferating shoots to 0.001% colchicine incorporated in the shoot multiplication medium. The amphiploids serve as fertile bridges and facilitate interspecific gene transfer through conventional breeding. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
Haploid selection for traits related to pollen cold tolerance in tomato was performed in segregating populations derived from a Lycopersicon esculentum × L. pennellii hybrid. BC1 populations were obtained by combining normal and low temperature treatments on two stages of pollen development: pollen formation, and germination and pollen tube growth. F1 hybrids were cultivated under low and normal temperatures and their pollen was used to pollinate L. esculentum plants at low and normal temperatures. The four BC1 populations obtained were tested for the quality and quantity of pollen produced at low temperatures. The population obtained by cold treatment at both stages had a significantly improved pollen germination ability at low temperatures. The two other coldselected BC1 populations showed no differences compared with the unselected BC population. A second cycle of pollen selection, corresponding to BC2, was applied in order to test its persistence in the subsequent generations and the possibility to further improve the character. This second cycle showed no improvement although some plants retained the high pollen germination ability at low temperatures that was observed in the first cycle. Hence, gametophytic selection of some characters related with tomato pollen performance may be feasible, at least for the first cycle of selection.  相似文献   

13.
S.H. Jalikop 《Euphytica》2003,131(3):333-342
Environmentally and developmentally controlled rosette formation is welldocumented in certain crop species. But this report describes a geneticallyinduced rosetting observed in pomegranate (Punica granatum L.).Rosette genotypes were detected at a frequency of 0.12 in the F2 familiesof cv. Ganesh and a recessive rosette mutant clone of cv. Kabul Yellow. Therosetted seedlings had leaves almost touching the ground at emergence, whichwere closely set on a thick, compressed stem with narrow inter-nodes andinactive subapical meristem. They were similar in some certain respects tothe naturally occurring rosetting noticed in lettuce, spinach and lisianthus.The occurrence of rosette type was attributed to a recessive mutant gene ofKabul Yellow and was ascribed the gene symbol rg (rosette growth) whichwas found to alter a host of morphological traits in rosette siblings innursery and field. The foliage colour, pink of Ganesh and yellow of KabulYellow, served as visual marker in distinguishing segregating progeny intopink/yellow normal and rosette types in the nursery. A monogenic segregationin F2 for pink and yellow was evident both in normal and rosette siblings.When a single gene mutation for rosetting was considered a large portion ofthe rosette progeny in F2 was found missing. This has been explained on thebasis of two conditional lethal genes operating in rosette individuals.Moreover, the F2 and BC1 seeds had very low seed fertility indicatingthat F1 possibly carried heavy load of lethal genes. On transplantation,the rosette mutants started to grow tall and erect, like spinach, but had acompact habit with restricted branching and exhibited early leaf senescence,leaving a crown of bushy growth at the tip of almost naked, brittle shoots.Rosettes differed significantly from normal siblings for all the morphologicalcharacteristics studied. The normal progenies flowered and set fruits within13 months, the rosette ones almost failed to do so even after growing for 38months, although they showed relatively loose rosetting than in the nursery.However, one seedling produced 3 small flowers with rudimentary ovary.Moreover, it was observed that the rosette plants had a tendency to regressto normal state, since 9 out of the 31 rosette progeny produced axilary shootsthat had normal stem and leaf attributes. The individuals with both normal androsette shoots should serve the same purpose in research work, as do perfect isogeniclines. Based on the frequency at which the normal shoots appeared the role ofcryptic transposable elements (TEs) was suspected rather than back mutation.Rosette siblings with altered morphology reported here can be secured inabundant number along with the contrasting normal siblings by raising theF2, which provide a good opportunity to gain an insight in the control ofvarious plant developmental processes. Besides, it can be viewed as a valuablemodel system for fundamental research on physiological, biochemical andmolecular genetical bases of rosetting in crop plants.  相似文献   

14.
Cowpea and kidney bean plants were grown in a hydroponic system, and the effect of calcium silicate supplied to the nutrient solution under salt stress was investigated. The plants were subjected to four different treatments: (1) nutrient solution alone (C), (2) nutrient solution + 40 mmol l−1 NaCl (NaCl), (3) nutrient solution + 40 mmol l−1 NaCl + 0.5 mmol l−1 CaSiO3 (NaCl + Si1) and (4) nutrient solution + 40 mmol l−1 NaCl+1 mmol l−1 CaSiO3 (NaCl + Si2). The results showed that, in both species, salinity reduced all growth variables but silicate supplementation however partly overcame this growth reduction. Addition of silicate in NaCl‐stressed plants maintained membrane permeability. Net photosynthesis, chlorophyll content, stomatal conductance and transpiration were higher in plants under control treatment, and the inclusion of silicate in the nutrient solution resulted in a slight increase in these plant parameters. Intercellular CO2 was slightly higher in plants under silicate treatment than in plants under control or NaCl treatment. Calcium concentration in shoots and roots in both species was slightly higher in the treatments where silicate was added. Potassium concentration for salt treatment was reduced in shoot and root of both species in the absence of silicate. Sodium and chloride concentration in shoots and roots in both species were slightly higher in the presence of NaCl and were slightly reduced in the plants under silicate treatments. The results suggest that, in hydroponically grown plants, the inclusion of silicate in the nutrient solution is beneficial because it improves growth, physiological parameters and may contribute to a more balanced nutrition by enhancing nutrient uptake under NaCl‐stressed conditions. Added calcium silicate may ameliorate the parameters affected by high salinity, may reduce sodium and chloride, and can slightly increase calcium and potassium concentrations in shoots and roots of salt‐stressed cowpea and kidney bean.  相似文献   

15.
The effect of colchicine on induction of embryogenesis andchromosome doubling during microspore culture was evaluated in twoF1 hybrids of spring oilseed rape (Brassica napus L.). Immediatecolchicine treatment of isolated microspores with the concentrations 50 and500 mg/L for 15 h stimulated embryogenesis and produced largeamounts of healthy-looking embryos. These normal embryos germinatedwell at 24 °C after being transferred to solid regeneration mediumand an initial period of low temperature (2 °C) for 10 days, andcould directly and rapidly regenerate vigorous plants. A high doublingefficiency of 83–91% was obtained from 500 mg/L colchicinetreatment for 15 h with low frequency of polyploid and chimeric plants.The present experiment showed that a treatment duration of 30 h revealedless positive effects on embryogenesis and doubling efficiency, especially athigher colchicine concentration (1000 mg/L). Poor embryogenesis andembryo germination were observed from ordinary microspore culturewithout change of induction medium and colchicine treatment, and severalsubcultures were required for induction of secondary embryogenesis andplant regeneration.  相似文献   

16.
Characterization of transgenic male sterility in alfalfa   总被引：6，自引：0，他引：6  
Dependable male sterility would help to make hybrid cultivar development a reality in alfalfa once higher levels of heterosis are attained. Alfalfa plants obtained by genetic transformation with a construct containing the Barnase gene under the control of a tobacco anther tapetum specific promoter were studied. Vacuolization and degeneration of the tapetal cell cytoplasm at a premeiotic stage of development were observed in all five transformed plants (T0)examined, but the severity of the abnormalities varied greatly among pollen sacs of a genotype. During the meiotic stage, some pollen sacs showed reduction in size, and the tapetum generally appeared thinner when compared to those of the non transgenic plants; tapetal cells showed abnormal vacuolization and signs of cytoplasm degeneration. Despite this, some microspores were formed and some pollen grains were shed in all the T0 plants, but these were highly variable in size and had very low in vitro germinability. Self-fertility was negligible. The T0 plants were crossed with one or two unrelated non transgenic male-fertile plants. Mendelian segregation was observed with two exceptions. Instability of the trait in F1 progenies was noticed, varying for different T0 parents. F1 plants exhibiting higher sterility than the primary transformants were observed, indicating that it should be possible to obtain good male sterile plants by backcrossing this trait into different genetic backgrounds. The possible use of this transgenic male sterility in alfalfa breeding is briefly discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
There are many wild species of pigeonpea which are endemic to Australia. These wild species are cross incompatible with cultivated species of Indian origin. Cajanus acutifolius is one such species which does not easily cross with cultivated pigeonpea. Interspecific pollinations lead to hybrid seeds which were semi-shrivelled. Very few seeds germinated to give rise to F1 plants. Backcrossing the hybrid plants to C. cajan, the male parent, gave rise to aborting seeds which did not germinate in vivo hence BC1 plants are obtained after saving the aborting embryos in vitro. BC1 plants showed normal meiotic pairing, but had low pollen fertility. The reasons for embryo abortion and low pollen fertility in spite of normal meiosis could be due to the effect of wild species cytoplasm. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

18.
Summary Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast culture, and their correlations with both phenotypic and GCA-values for anther culture response, were studied using 21 genotypes of perennial ryegrass. Differences between genotypes accounted for approximately 40% of the total variation for callus induction and initial callus growth, and 59 and 83% of the variation in callus culture for regeneration percentage and percentage of green plants. Effects of genotypes were less pronounced in suspension culture, where suspensions from the same genotype often behaved differently. Some suspension cultures retained their capacity for green plant regeneration for almost two years, repeatedly producing 80–100% green regenerants during this period. Genotypes with high regeneration percentage and a large proportion of green plants from callus culture were also superior in suspension culture for both regeneration performance and longevity. Regeneration percentage and percentage of green plants were uncorrelated, and probably under different genetic control. While capacity for green plant formation from the different genotypes showed no correlation between anther culture and somatic in vitro culture, a positive correlation was observed between the regeneration percentages in somatic in vitro culture and anther culture (r=0.44*–0.85***), suggesting some common genetic control of the two systems.  相似文献   

19.
Summary The progeny of 104 regenerated maize plants were screened for tolerance to the safe broad-spectrum herbicide glyphosate during seed germination and early growth. Seven somaclones showed varying degrees of resistance to the application of the herbicide at 1.2 mM (0.1 kg a.i. in 400 1 ha-1 of water). Plants capable of a normal growth following treatment with 2.4 mM (0.2 kg ha-1) glyphosate at the three leaf stage were selfed, and their progeny analyzed. A family able to tolerate the exposure to glyphosate at 2.4 mM was isolated and shown to maintain a photosynthetic rate comparable with control after the application of the herbicide.The selfed progeny of the tolerant somaclone was characterized as to the properties of two targets of glyphosate, the shikimate pathway enzymes 5-enol-pyruvyl-shikimate-3-phosphate (EPSP) synthase and 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase. In vitro tests ruled out the possibility that the tolerance was due to altered forms of these enzymes. Families showed significant variability with regard to EPSP and DAHP synthase levels, measured at different stages during seedling growth; however, not even these traits were correlated with in vivo response to glyphosate. The possible role of other physiological processes in determining the increased tolerance to the herbicide is discussed.Abbreviations DAHP 3-deoxy-D-arabino-heptulosonate-7-phosphate - EPSP 5-enol-pyruvyl-shikimate-3-phosphate - CER carbon-exchange rate - ID50 concentration causing 50% inhibition  相似文献   

20.
N. Inomata 《Euphytica》2003,133(1):57-64
The cytogenetic study was investigated in the intergeneric F1 hybrid, F2and backcross progenies (BC1). The plants used were Brassica juncea(2n=36) and Diplotaxis virgata(2n=18). Three intergeneric F1 hybrids between two species were produced through ovary culture. They showed 36 chromosomes. It might consist one genome of B. juncea and two genomes of D. virgata. The morphology of the leaves resembled that of B. juncea. The color of the petals was yellow that was like in D. virgata. The size of the petal was similar to that of B. juncea. The mean pollen fertility was15.3% and the chromosome associations in the first meiotic division were(0–1)IV+(0–2)III+(8–12)II+(12–20)I. Many F2 and BC1seeds were harvested after open pollination and backcross of the F1 hybrids withB. juncea, respectively. The F2seedlings showed different chromosome constitutions and the range was from 28 to54 chromosomes. Most seedlings had 38chromosomes followed by 36, 40 and 54. The BC1 seedlings also showed different chromosome constitutions and the range was from 29 to 62. Most seedlings had both 40and 54 chromosomes followed by 36, 46 and52. In the first meiotic division of F2 and BC1 plants, a high frequency of bivalent associations was observed in all the various kinds of somatic chromosomes. Many F3 and BC2 seeds were obtained by self-pollination and open pollination of both F2 and BC1 plants, and by backcrossing both F2 and BC1plants with B. juncea, respectively,especially, three type progeny with 36, 40or 54 chromosomes. The somatic chromosomes of the F3 and BC2 plants were further investigated. The bridge plants between B. juncea and D. virgata with 36 chromosomes may be utilized for breeding of other Brassica crops as well as B. juncea. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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