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1.
Summary Crude protein extracts from single seeds of nondomesticated Mexican bean accessions were analysed by SDS polyacrylamide gel electrophoresis for variability in phaseolin protein. Six new phaseolin types; M1, M2, M3, M4, M5, M6, which contained polypeptides within the same range of molecular weights (51,000 to 45,000 daltons) as occur in the S, T and C phaseolin types of cultivated beans were identified. No T and C types were found among the non-domesticated Mexican accessions, and the S type occurred in less than 7% of the seeds screened. Genetic analyses of F2 progenies from crosses between Sanilac (S), and five of the M types showed that each M phaseolin phenotype was allelic to the S type and expressed codominantly.  相似文献   

2.
A simple method for stimulating and maintaining high in vitro multiplication of Narcissus shoot clump cultures was developed. Shoot clumps were subjected either to normal cutting where leaves were trimmed to 20 mm in length at the beginning of each culture passage or to severe cutting where shoot clumps were cut down to the basal plate region removing all green tissue. Severe cutting at the beginning of each culture passage initially doubled the leaf multiplication, compared to normal cutting, but the difference between cutting treatments declined in successive passages. The improvement in leaf multiplication was maintained when shoot clumps were subjected to severe cutting only at every other culture passage, with no cutting in the alternate recovery passages. In vitro multiplication was increased by severe cutting in all seven Narcissus cultivars which were tested.Abbreviations NAA-1 naphthylacetic acid - BAP benzylaminopurine  相似文献   

3.
Electrophoretic mobilities of three hemoglobins (Hb1, Hb2, and Hb3) were studied in 15 populations of brine shrimps. Genetic segregation data support the model that Hb2 contains n -polypeptides and n -polypeptides; Hb1 contains 2n -polypeptides. Hb3 contains neither - nor -polypeptides. There is no evidence of linkage of and loci with each other or with the locus (or loci) which governs Hb3 or with the nonhomologous portion of the sex chromosomes. Hemoglobins of different populations may be hybridized in vitro by incubation at high temperature. Reversible dissociation to subunits which contain only one ( or ) polypeptide occurs at 40 C (for Hb1) and at 50 C (for Hb2).Supported by Grant HD-11445 from the National Institutes of Health.  相似文献   

4.
The influence of some macronutrients, especially NH4NO3 and KNO3, on root development of microcuttings from 3 apple scion cultivars is discussed. A reduction of the level of NH4NO3 in the medium from full strength to 1/4 strength significantly increased the percentage rooting of Gala and Royal Gala, but not Jonagold. Further reduction of NH4NO3 level from 1/4 strength to zero significantly reduced the percentage of rooting in Gala but not Royal Gala. Jonagold rooted best at zero concentration NH4NO3. Without NH4NO3, rooting percentages were as high as 100% for all 3 cultivars when KNO3 was provided at full strength. The results show that adventitious roots can be induced on apple scion cultivars by media manipulation.  相似文献   

5.
Origin and diversity of North American hard spring wheats   总被引:7,自引:0,他引:7  
Genetic diversity is an important safeguard against crop vulnerability to biotic and abiotic stresses. Coefficient-of-parentage (COP) values of 248 North American hard spring wheat (Triticum aestivum L. em. Thell) cultivars released from 1901 to 1991 were used to estimate the genetic similarity of cultivars. COP values were used: to (1) quantify germ plasm sources and their contributions to the North American hard spring wheat gene pool; (2) measure changes in genetic diversity through time; and (3) identify major groupings of related cultivars. Landraces and local cultivars that contributed to the formation of the gene pool were: spring wheat (64%), winter wheat (16%), T. turgidum var. durum L. (10%), and T. turgidum var. emmer L. (8%). Fife, Hard Red Calcutta, and Turkey Red accounted for 18%, 13%, and 8%, respectively, of the hard spring wheat origins. Era and Butte in the US, and Neepawa and HY 320 in Canada, were the most commonly used named parents of cultivars released from 1981 to 1991. Both Canada and US had the greatest level of similarity among new cultivar releases in the 1930s (Canada: r=0.39, US: r=0.34). Genetic similarity in the US declined to r=0.14 in the 1940s and remained relatively constant thereafter. Similarity among released Canadian cultivars remained relatively high until the 1970s when the introduction of new market classes resulted in a 50% reduction in genetic similarity to approximately the same level of similarity found in the US. Cluster analysis was used to group cultivars released after 1941 into 13 clusters of similar genotypes. The cultivar clusters may have value for the stratified sampling of spring wheat germ plasm or in identifying diverse germ plasm for intermating.Contribution of the Idaho Agric. Exp. Stn. publication no. 95731. Missouri Pub. No. 12338  相似文献   

6.
RFLP-based genetic maps of chromosomes 6A and 6B of Triticum turgidum have been constructed using data obtained by the study of Triticum turgidum var durum cv Langdon-T. t. var dicoccoides recombinant substitution lines (RSLs) supplemented with data obtained from F3 families derived from Langdon dicoccoides 6A and 6B disomic substitution lines. The average RFLP frequencies detected for the two chromosomes in a test of 45 DNA clones with six restriction enzymes were 56% and 53%, respectively, and a subset of 32 clones gave frequencies of 75% and 72%, respectively. Seventeen loci were mapped in 6A and 18 in 6B. With the possible exception of 5 loci in the centromeric region of 6A, all of the mapped 6A and 6B loci are located in the same arm as are homologous loci in hexaploid wheat, and the linear order of the loci is the same in the two chromosomes, except possibly close to the centromere. Major differences in genetic distances exist between homologous loci located in the proximal regions of the 6AL and 6BL linkage groups, however, the distances being much larger in the former than in the latter. The 6B maps that were constructed using data from both the RSL and the F2 populations and using data from the RSL population alone closely resemble one another, indicating that the 6B RSL population, composed of 85 lines, can be reliably used for genetic mapping. Additional studies must be conducted before the utility of the 6A RSL population, composed of 66 lines, can be adequately assessed.  相似文献   

7.
The segregation of seven isozyme marker genes was investigated using eight controlled crosses in almond. The cultivar Nonpareil was the maternal parent in all crosses. Pollination was achieved using eight different cultivars, and a total of 3200 individual kernels were assessed. For each isozyme the goodness-of-fit test was used to test for departure from the expected frequencies assuming Mendelian inheritance. Given a higher than expected number of significant results for individual isozymes, independent segregation between pairs of isozymes was tested using the chi-square statistic on the resulting two-way contingency tables. In all crosses a highly significant association (P value< 0.001) was observed between (1) the AAT- 1 and IDH isozymes loci and (2) the LAP-1 and PGM-2 isozymes loci, which leads to the conclusion that the respective isozyme pairs are linked.In addition, a significant association (P value < 0.001) was observed between LAP-1 and GPI-2 when the pollen sources were Fritz, Mission, or Price, but this could not be tested for the remaining five pollen sources, Carmel, Grant, Keane, Ne plus Ultra, Peerless, because they are homozygous at these loci. If LAP-1 is linked with GPI-2 and PGM-2, it might be expected that we should find evidence of linkage between GPI-2 and PGM-2. The lack of a significant association between these two isozymes suggests that LAP-1 is located centrally on the chromosome. These three pairs of linked loci are the first to be reported in almond.  相似文献   

8.
Clostridium sporogenes MD1 grew rapidly with peptides and amino acids as an energy source at pH 6.7. However, the proton motive force (p) was only –25 mV, and protonophores did not inhibit growth. When extracellular pH was decreased with HCl, the chemical gradient of protons (ZpH) and the electrical membrane potential () increased. The p was –125 mV at pH 4.7, even though growth was not observed. At pH 6.7, glucose addition did not cause an increase in growth rate, but increased to –70 mV. Protein synthesis inhibitors also significantly increased . Non-growing, arginine-energized cells had a of –80 mV at pH 6.7 or pH 4.7, but was not detected if the F1F0 ATPase was inhibited. Arginine-energized cells initiated growth if other amino acids were added at pH 6.7, and and ATP declined. At pH 4.7, ATP production remained high. However, growth could not be initiated, and neither nor the intracellular ATP concentration declined. Based on these results, it appears that C. sporogenes MD1 does not need a large p to grow, and p appears to serve as a mechanism of ATP dissipation or energy spilling.Mandatory disclaimer: Proprietary or brand names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product, and exclusion of others that may be suitable.  相似文献   

9.
A rapid procedure is described for the separation of CMP-sialic acid:lactosylceramide sialyltransferase reaction components using Sep Pak C18 cartridges. The quantitative separation of the more polar nucleotide sugar, CMP-sialic acid, and its free acid from the less polar GM3-ganglioside is simple and rapid relative to previously described methods. Recovery of GM3 is optimized by the addition of phosphatidylcholine to the reaction mixture prior to the chromatographic step. Using rat liver Golgi membranes as a source of CMP-sialic acid: lactosylceramide sialyltransferase activity (GM3 synthase; ST-1), the transfer of [14C] sialic acid from CMP-[14C] sialic acid to lactosylceramide can be quantified by this assay. The procedure is reliable and may be applicable to the isolation of ganglioside products in otherin vitro glycosyltransferase assays.Abbreviations GM3 GM3-ganglioside - II3NeuAc-LacCer NeuAc2-3Gal1-4Glc1-1Cer - GD1a GD1a-ganglioside, IV3NeuAc, II3NeuAc-GgOse4Cer, NeuAc2-3Gal1-3GalNac1-4(NeuAc2-3)Gal1-4Glc1-1Cer - GD3 GD3-ganglioside, II3(NeuAc)2LacCer, NeuAc2-8NeuAc2-3Gal1-4Glc1-1Cer - GgOse4Cer asialo-GM1 Gal1-3GalNAc1-4Gal1-4Glc1-1Cer - FucGMI fucosyl-GMI-ganglioside, Fuc1-2Gal1-3GalNAc1-4Gal1-4 Glc1-1Cer - ST-1 GM3 synthase, CMP-sialic acid:lactosylceramide sialyltransferase - LacCer lactosylceramide, Gal1-4Glc1-1Cer - CMP-NeuAc cytidine 5-monophospho-N-acetylneuraminic acid - PC phosphatidylcholine - PMSF phenylmethylsulfonyl fluoride  相似文献   

10.
We have developed a polymerase chain reaction (PCR)-based assay that could effectively reduce the time period required to screen and select for Gall Midgeresistant rice lines under field conditions. The primers for the assay were designed on the basis of sequence information of two phenotype specific random amplified polymorphic DNA fragments which were found to be tightly linked to Gall Midge biotype-1 resistance gene (Gm2). The two RAPD fragments, F81700 in the susceptible parent ARC6650 and F10600 in the resistant parent Phalguna, were identified after screening 5450 loci using 520 random primers on genomic DNAs of ARC6650 and Phalguna. These primers, when used in a multiplexed PCR, amplified specifically a 1.7-kb and 0.6-kb fragment in the susceptible and resistant parents, respectively. When this assay was performed on genomic DNAs of 44 recombinant inbred lines derived from ARC6650 x Phalguna and 5 lines derived from other crosses where one of the parents was Phalguna, ARC6650 or their derivatives, the primers amplified a 1.7-kb fragment in all of the susceptible lines or a 0.6-kb fragment in all of the resistant ones. These markers can be of potential use in the marker-aided selection of Gall Midge biotype-1 resistant phenotypes. As screening for resistance can now be conducted independent of the availability of insects, the breeding of resistant varieties can be hastened.  相似文献   

11.
S. U. Wallace 《Plant and Soil》1988,109(1):139-140
Bragg and Cobb soybean [Glycine max (L.) Merr.] seeds were germinated in sand at temperatures ranging from 25 to 40°C. Emergence decreased with increasing temperature above 37°C, with virtually no emergence at 40°C. Emergence of 12 other cultivars at 38°C ranged from 25 to 95%. Foster and Coker 338 were more sensitive to high temperature than the other cultivars.  相似文献   

12.
The regulation of the expression of enzyme activities catalyzing initial reactions in the anoxic metabolism of various aromatic compounds was studied at the whole cell level in the denitrifying Pseudomonas strain K 172. The specific enzyme activities were determined after growth on six different aromatic substrates (phenol, 4-hydroxybenzoate, benzoate, p-cresol, phenylacetate, 4-hydroxyphenylacetate) all being proposed to be metabolized anaerobically via benzoyl-CoA. As a control cells were grown on acetate, or aerobically on benzoate. The expression of the following enzyme activities was determined.Phenol carboxylase, as studied by the isotope exchange between 14CO2 and the carboxyl group of 4-hydroxybenzoate; 4-hydroxybenzoyl-CoA reductase (dehydroxylating); p-cresol methylhydroxylase; 4-hydroxybenzyl alcohol dehydrogenase; 4-hydroxybenzaldehyde dehydrogenase; coenzymeA ligases for the aromatic acids benzoate, 4-hydroxybenzoate, phenylacetate, and 4-hydroxyphenylacetate; phenylglyoxylate: acceptor oxidoreductase and 4-hydroxyphenylglyoxylate: acceptor oxidoreductase; aromatic alcohol and aldehyde dehydrogenases.The formation of most active enzymes is strictly regulated; they were only induced when required, the basic activities being almost zero. The observed whole cell regulation pattern supports the postulate that the enzyme activities play a role in anoxic aromatic metabolism and that the compounds are degraded via the following intermediates: Phenol 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; benzoate benzoyl-CoA; p-cresol 4-hydroxybenzaldehyde 4-hydroxybenzoate 4-hydroxybenzoyl-CoA benzoyl-CoA; phenylacetate phenylacetyl-CoA phenylglyoxylate benzoyl-CoA plus CO2; 4-hydroxyphenylacetate 4-hydroxyphenylacetyl-CoA 4-hydroxyphenylglyoxylate 4-hydroxybenzoyl-CoA plus CO2 benzoyl-CoA.  相似文献   

13.
Summary With the aim of ascertaining the existance of a correlation between in vivo resistance to Fusarium oxysporum f. sp. dianthi and in vitro response to fungal elicitors and toxic substances, phenylalanine ammonialyase and phytoalexin accumulation, on one hand, and resistance to culture filtrate, on the other, were assayed in in vitro cultures of three susceptible and four resistant Dianthus caryophyllus cultivars. Cultivars showing varying degrees of resistance in vivo either tolerated higher culture filtrate concentrations (Niki) or showed high PAL activity and phytoalexin production when treated with Fusarium elicitor (Duca), or responded positively to both treatments (Mei-Ling, Pulcino). No such responses were shown in tissue cultures of susceptible cultivars. The differential response to the fungal elicitor seemed to be highly specific as genetic differences between cultivars were not observed in tissue cultures treated with other biotic (Phytophthora infestans) and abiotic (HgCl2) elicitors.Abbreviations FuCWC cell wall components from Fusarium oxysporum f. sp. dianthi race 2 - PhCWC cell wall components from Phytophthora infestans - PAL phenylalanine ammonia-lyase (EC 4.3.1.5)  相似文献   

14.
Summary The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F1; F2 and F3 progenies of the crosses of 21 resistant varieties with the susceptible variety TN 1 revealed that a single dominant gene governs resistance in Mushkan 41, Santhi, Siahnakidar 195, SM2-34, Tirisurkh 251, Zirijowaian 245, 18, 24A, 39, 76 S, 78, 180, 213 B, 267, 293, CI 6037-4, NP97, S39 JKW and Bansphul. In varieties 65 and 274 A, resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in N 22 revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties 65 and 274 A.  相似文献   

15.
Summary A single dominant factor, Hss, that conditions a rapid lethal necrotic response to soybean mosaic virus (SMV) has been identified in Phaseolus vulgaris L. cv. Black Turtle Soup, line BT-1. Inoculated plants carrying this factor developed pinpoint necrotic lesions on inoculated tissue followed by systemic vascular necrosis and plant death within about 7 days, regardless of ambient temperature. BT-1 also carries dominant resistance to potyviruses attributed to the tightly linked or identical factors, I, Bcm, Cam, and Hsw, so linkage with Hss was evaluated. No recombinants were identified among 381 F3 families segregating for potyvirus susceptibility, thus if Hss is a distinct factor, it is tightly linked to I, Bcm, Cam, and Hsw. BT-1 was also crossed reciprocally with the line Great Northern 1140 (GN 1140) in which the dominant gene, Smv, for systemic resistance to SMV was first identified. Smv and Hss segregated independently and are co-dominant. The (GN 1140 x BT-1) F1 populations showed a seasonal shift of the codominant phenotype. Evaluation of the (GN 1140 x BT-1) F2 population under conditions where Smv is partially dominant allowed additional phenotypic classes to be distinguished. Pathotype specificity has not been demonstrated for either Smv or Hss. Genotypes that are homozygous for both dominant alleles are systemically resistant to the virus and in addition show undetectable local viral replication or and no seed transmission. This work demonstrates that a gene which conditions a systemic lethal response to a pathogen may be combined with additional gene(s) to create an improved resistant phenotype.  相似文献   

16.
Summary The contribution of introgressed regions derived from wild species to the genetic variation within the species of Lycopersicon esculentum was investigated by comparing the RFLP patterns of 2 introgression-free, obsolete cultivars (Moneymaker and Premier) and a modern cultivar (Sonatine) that carries at least 5 introgressed resistance genes. In this analysis 195 mapped nuclear markers were used in combination with 6 restriction enzymes. Among the 1170 probe-enzyme combinations tested, only 3 showed a polymorphism between the 2 introgression-free cultivars. On the other hand 24 probe-enzyme combinations were found to exhibit polymorphisms between Moneymaker and Sonatine. These represented ten polymorphic loci distributed among 5 linkage groups on chromosomes 1, 3, 4, 6, and 9.On the assumption that most of the polymorphic loci corresponded to introgressed chromosome segments of wild species carrying resistance genes, linkages between these loci and the component resistance genes were examined by RFLP analysis of pairs of near-isogenic lines differing only for one particular resistance gene, and a variety of commercial cultivars having different resistance gene compositions. Two of the polymorphic linkage groups could thus be ascribed to resistance genes whose map positions were already known: Cf2 on chromosome 6 and Tm2a on chromosome 9, whereas another marker, TG301 on chromosome 1, could be assigned to the Cladosporium fulvum resistance gene Cf9 with a hitherto disputable map position. By linkage analysis of a segregating F2 population the genetic distance between the Cf9 gene and the marker TG301 was estimated at 5.5 ± 2.3 cM.  相似文献   

17.
The yield of photosynthetic O2 evolution was measured in cultures of Dunaliella C9AA over a range of light intensities, and a range of low temperatures at constant light intensity. Changes in the rate of charge separation at Photosystem I (PS I) and Photosystem II (PS II) were estimated by the parameters PS I and PS II . PS I is calculated on the basis of the proportion of centres in the correct redox state for charge separation to occur, as measured spectrophotometrically. PS II is calculated using chlorophyll fluorescence to estimate the proportion of centres in the correct redox state, and also to estimate limitations in excitation delivery to reaction centres. With both increasing light intensity and decreasing temperature it was found that O2 evolution decreased more than predicted by either PS I or PS II. The results are interpreted as evidence of non-assimilatory electron flow; either linear whole chain, or cyclic around each photosystem.Abbreviations F0 dark level of chlorophyll fluorescence yield (PS II centres open) - Fm maximum level of chlorophyll fluorescence yield (PS II centres closed) - Fv variable fluorescence (Fm-F0) - PS I Photosystem I - PS II Photosystem II - P700 reaction centre chlorophyll(s) of PS I - qN coefficient of non-photochemical quenching of chlorophyll fluorescence - qP coefficient of photochemical quenching of fluorescence yield - qE high-energy-state quenching coefficient - PS I yield of PS I - PS II yield of PS II - S yield of photosynthetic O2 evolution - P intrinsic yield of open PS II centres  相似文献   

18.
RFLP analysis was conducted on a population derived from a three-way cross to determine the location of the hybrid sterility locus, S-5, in relation to mapped molecular markers and to identify markers that would be useful for selection in breeding. S-5 is of interest to rice breeders because it is associated with spikelet sterility of F1 hybrids in Indica/Japonica crosses. Identification of an S-5 allele which confers fertility in Indica/Japonica hybrids when introgressed into either the Indica or the Japonica parent has been reported. Varieties carrying this S-5 n allele are known as wide compatibility varieties (WCV). Our data suggests that RFLP marker RG213 on chromosome 6 is closely linked to the S-5 locus and can be efficiently used to identify wide compatibility (WC) lines. RG213 is a single-copy genomic clone that detects three bands of different molecular weights in DNA from Japonica (Akihikari) and Indica (IR36) varieties and WC line (Nekken 2). We demonstrate that the three alleles detected by this marker could be used to trace the inheritance of the wide compatible phenotype in breeders' material.  相似文献   

19.
Summary A simple viscoelastic film model is presented, which predicts a breakdown electric potential having a dependence on the electric pulse length which approximates the available experimental data for the electric breakdown of lipid bilayers and cell membranes (summarized in the reviews of U. Zimmermann and J. Vienken, 1982,J. Membrane Biol. 67:165 and U. Zimmermann, 1982,Biochim. Biophys. Acta 694:227). The basic result is a formula for the time of membrane breakdown (up to the formation of pores): =(/C)/( m 2 0 2 U 4/24Gh 3+T 2/Gh–1), where is a proportionality coefficient approximately equal to ln(h/20),h being the membrane thickness and 0 the amplitude of the initial membrane surface shape fluctuation ( is usually of the order of unity), represents the membrane shear viscosity,G the membranes shear elasticity modules, m the membrane relative permittivity, 0=8.85×10–12 Fm,U the electric potential across the membrane, the membrane surface tension andT the membrane tension. This formula predicts a critical potentialU c ;U c =(24Gh 3/ m 2 0 2 )1/4 (for = andT=0). It is proposed that the time course of the electric field-induced membrane breakdown can be divided into three stages: (i) growth of the membrane surface fluctuations, (ii) molecular rearrangements leading to membrane discontinuities, and (iii) expansion of the pores, resulting in the mechanical breakdown of the membrane.  相似文献   

20.
In a previous study, cDNA microsatellite markers were described in apricot (Prunus armeniaca L.). Specific PCR primers were designed to amplify the microsatellite-containing regions from genomic DNA in different Prunus species. In the present work, cDNA microsatellite markers were developed in the hexaploid Prunus domestica L. species and polymorphism was ascertained in a segregating plum population. Co-dominant mendelian segregation of alleles was demonstrated and microsatellite polymorphism displayed up to 6 alleles per SSR locus per individual. Parentage lineage of three full-sib European plum cultivars (cv. Cacanska najbolja, Cacanska rana and Cacanska lepotica) was reconstructed by the analysis of the above nuclear SSR markers, completed by four chloroplastic microsatellite loci. The six most informative nuclear loci enabled discrimination between the three Cacak cultivars and unrelated individuals as well as the previously proposed parents, Wangenheim and Pozegaca. Data obtained support previous evidence that these cultivars originated from the Stanley cultivar. However, SSR analysis finally excluded Wangenheim as the other possible parent. Based on the results obtained with nuclear and chloroplast SSR loci, we propose the origin of those three Cacak cultivars in a cross between Stanley as the mother plant and Ruth gerstetter as the pollinator. Furthermore, we demonstrate the utility of these apricot SSR markers for genotype fingerprinting of the hexaploid plum cultivars.  相似文献   

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