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1.
Summary Lily cv. Harmony was inoculated with several Agrobacterium strains to study its susceptibility to Agrobacterium infection and transformation. Tumorous tissue formation on inoculated stem internodes of sterile-grown plantlets, as well as expression of a -glucuronidase marker gene interrupted by an intron in cells of inoculated stem nodes, indicate that the monocotyledon Lilium is a host for Agrobacterium.  相似文献   

2.
Summary F1 hybrids between short-day photoperiod- sensitive maiwa bulrush millet, Pennisetum americanum (2n=14), and elephant grass, P. purpureum (2n=28), are triploid (2n=21), sterile, and can only be propagated vegetatively. Fertile amphidiploids, (2n=42, with 21 bivalents) were produced by colchicine treatment. Good seed set was obtained upon selfing the amphidiploids and the progeny exhibited variable pollen fertility and bivalent univalent and multivalent formation.Reciprocal crosses between elephant grass and the colchicine-induced amphidiploid failed to produce seeds. The maiwa millet x amphidiploid cross resulted in poor seed set and the reciprocal failed. Maiwa x amphidiploid hybrids were pollen sterile with 2n=21, rather than the expected 2n=28, indicating chromosome elimination.Morphologically, the amphidiploids and maiwa x amphidiploid hybrids closely resembled elephant grass and the F1 hybrid. The amphidiploids showed no superiority over the F1 hybrid and elephant grass in either forage yield or quality but one maiwa x amphidiploid genotype surpassed a promising local elephant grass selection in forage dry matter yield and flowered for a relatively short period.  相似文献   

3.
    
Summary Three random synthetic leaders and three naturally-occurring leaders, the tobacco mosaic virus (TMV) coat protein, the satellite tobacco necrosis virus (STNV) and the plant chlorophyll a/b-binding protein (Cab22L), were shown to modulate the -glucuronidase reporter protein accumulation levels in transient expression experiments. The same chimeric constructs also confer differential distribution patterns of reporter protein accumulation in stably-transformed tobacco calli or regenerated transgenic plants. When the highest expression levels with a given leader are compared, the 31-nucleotide random leader stimulates translation 20- and 100-fold relative to the 9- and 4- nucleotide synthetic leaders respectively. However, this 31-nucleotide random leader is approx. 2 to 3-fold weaker than the 30-nucleotide STNV leader and even 5-fold weaker than both the 79-nucleotide TMV leader and the 66-nucleotide Cab22L leader. These results confirm the findings in transient expression experiments and stress the importance of the 5-untranslated region for the production of heterologous proteins in transgenic plants.  相似文献   

4.
Summary Parent-offspring regression was used to estimate heritability for three traits (-glucan content, groat percentage, and resistance to crown rust (Puccinia coronata Cda. f. sp. avenae Eriks.) in oat (Avena sativa L.). The populations used were derived from two crosses, Nova x Marion QC and Sylva x Marion QC. Marion QC was used as a parent because other research had shown that it is relatively high in -glucan, a trait for which heritability had not previously been estimated. Nova and Sylva are similar in adaptation to Marion QC, and Sylva may be a source of general resistance to crown rust. Random F5 plants were grown in a greenhouse, and their F6 and F7 progeny were grown in replicated field trials. Heritability estimates for the two grain quality traits were based on regression of F6 values on F5 values, F7 values on F6 values, and F7 values on F5 values. Heritability estimates for -glucan content were between 0.27 and 0.45. The highest estimate was the one based on the F6 and F7 generations of Sylva x Marion QC: 0.45, compared to estimates of 0.32 or less for earlier generations of the same cross, and to estimates of 0.35 or less for all generations of Nova x Marion QC. Heritability estimates for groat percentage were all between 0.23 and 0.32. The F6 and F7 generations were evaluated for resistance to crown rust resistance. The Sylva x Marion QC cross seemed to segregate for heritable resistance (h 2=0.31) but the Nova x Marion QC cross did not (h 2=0.07). Several lines from the Sylva x Marion QC cross had low symptoms in both the F6 and F7 generations. There were no strong genetic correlations among the traits.  相似文献   

5.
6.
Summary In order to introduce currently-available genes with agronomical value into banana, two genetic transformation protocols have been optimized.Firstly, regenerable protoplasts isolated from embryogenic cell suspensions of the cultivar Bluggoe have been used for the introduction of several chimaeric uidA gene constructs by electroporation. With the inclusion of polyethylene glycol and heat shock, the frequency of transiently expressing protoplasts reached 1.8% as shown by an in situ -glucuronidase assay. A duplicated 35S promoter with an alfalfa mosaic virus leader sequence (pBI-426) induced the highest expression rate among the constructs tested.Embryogenic cell suspensions of cv. Bluggoe have also been bombarded with accelerated particles coated with a high expression uidA gene construct (pEmuGN) using a biolistic gun. After a partial optimization of the procedure, transient GUS assays reproducibly demonstrated the presence of 400 blue foci in 30 l of settled cell volume (approximately 25 mg cells). Selection and characterization of antibiotic-resistant transformed cultures is in progress.Abbreviations AMV alfalfa mosaic virus - GUS -glucuronidase - TGE transient GUS expression - uidA gene for -glucuronidase  相似文献   

7.
S. B. Teoh  E. C. Ong 《Euphytica》1983,32(3):799-806
Summary The hybrid orchid clones of Aranda Christine show differential meiotic behaviour with respect to meiotic irregularities in the form of non-congressing chromosomes, laggards and complement fractionation. These irregularities occur in significantly variable but high frequencies, which results in the observed sterility of these hybrids. The observed differential meiotic behaviour is probably due to the transmission of a variable set of chromosomes from the third generation hybrid parent, Vanda Hilo Blue. Deviant spores, mainly polysporous and polyploid, are the end products of the meiotic aberrations. Such spores appear to be produced regularly in the intergeneric orchid hybrids.Meiosis in one of the Aranda Christine clones, C80, was found to be highly aberrant and could be unique among orchid hybrids.  相似文献   

8.
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   

9.
Bodo R. Trognitz 《Euphytica》1991,56(2):143-148
Summary The main obstacle in breeding potato (Solanum tuberosum L.) dihaploids is the severe limitation of male fertility. To determine pollen viability assays that correlate well to fertility in crosses, results of five different pollen viability assays were compared by correlation analysis with fruit and seed set characters in test crosses, and to pollen tube growth in situ (PL-test). The methods used were: staining the pollen cells with carmino acetic acid (CAA-test); in vitro pollen germination (PG-test); and detection of pollen staining rates after incubation with fluoresceine diacetate (FDA-test), 2-3-5-triphenyle tetrazolium chloride (TTC-test), and 5-bromo-4-chloro-3-indolyle--galactoside (X-Gal-test).The results of test crosses and pollen tube growth in situ correlated with the results of all other assays with the following ranking, from highest to lowest: enzyme activity assays (X-Gal-test, FDA-test, TTC-test), in vitro pollen germination (PG-test), and pollen staining by CAA. The newly developed X-Gal-test for monitoring -galactosidase activity showed the least variation of all assays investigated. Thus, this highly reproducible simple procedure is recommended for male fertility screening.Abbreviations B/F Berries obtained per 100 flowers - CAA Carmino acetic acid - FDA Fluoresceine diacetate - PG Pollen germination rate in vitro - PL Pollen tube growth in situ - S/B Seeds per berry - S/F Seeds per pollinated flower - TTC 2-3-5-triphenyle tetrazolium chloride - X-Gal 5-bromo-4-chloro-3-indolyle--galactoside  相似文献   

10.
Summary Two wheat cultivars that consistently show high levels of grain -amylase at harvest ripeness, in the absence of preharvest sprouting, were crossed with a control, low -amylase cultivar, and F1, F2 and BC1 populations were developed. Grain of these populations was analysed for -amylase activity at harvest ripeness. Distribution and segregation patterns were consistent with control at a single locus with high -amylase the recessive allele. This mode of inheritance would make it extremely difficult to differentiate homozygous low -amylase lines from heterozygotes (low -amylase phenotype but carriers of high -amylase) and has important implications for wheat breeders. High -amylase, termed late maturity -amylase, was not linked with the awned inhibitor gene, B2, located on the long arm of chromsome 6B.  相似文献   

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