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  • Drosophila  (22)
  • Triticum aestivum
  • Springer  (34)
  • Cambridge University Press
  • Frontiers Media
  • 2020-2022
  • 1985-1989
  • 1980-1984
  • 1975-1979  (34)
  • 1977  (34)
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  • Springer  (34)
  • Cambridge University Press
  • Frontiers Media
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  • 2020-2022
  • 1985-1989
  • 1980-1984
  • 1975-1979  (34)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular evolution 9 (1977), S. 279-298 
    ISSN: 1432-1432
    Schlagwort(e): 5S RNA ; Drosophila ; Evolution ; Secondary structure ; Development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleotide sequence ofDrosophila melanogaster 5S RNA has been determined and appears to be homogeneous both in the KC cell line and in the insect at different developmental stages. Experimental evidence on the conformation of this molecule is in agreement with a general class of 5S RNA models.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 182 (1977), S. 107-116 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Salivary glands ; Ecdysone ; Transcriptional control ; Development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Injection of α-ecdysone into the larval haemolymph of late third instar larvae ofD. virilis induces both the extrusion of secretory proteins and the inactivation of the enzyme glutamine-fructose-6-phosphate-aminotransferase (E.C. 2.6.16) in the salivary glands. In the presence of actinomycin D or cycloheximide the hormone is ineffective. If before adding these inhibitors RNA synthesis is allowed to proceed for 1.5h, or protein synthesis for 2h after ecdysone injection, however, the protein extrusion and the enzyme inactivation do occur. It is proposed that ecdysone controls these two cytoplasmic events at the transcriptional level by the activation of specific Correlations with puff activities are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 182 (1977), S. 75-92 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Male foreleg disc ; Dissociation ; Distal transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. The developmental potentials of dissociated cells of the different regions of the male foreleg disc ofDrosophila melanogaster were analysed. To this end, various amounts of foreleg disc material were dissociated together with an excess of heavily irradiated wing discs (“feeding layer”), and the reaggregates were cultured for 10 days in the abdomens of adult hosts prior to metamorphosis. 2. The foreleg disc cells were in most cases unable to regenerate missing structures in a circular direction within the leg segments. Instead they strongly tended to adopt the specifications of more distal leg segments (distal transformation), irrespective of the region of origin of the ancestor cells within the disc. 3. The distal transformation occurred mainly, if not exclusively, during an early phase (“initial phase”) in the reaggregates. 4. The extent of distal transformation was most pronounced in those series in which the foreleg cells were initially least diluted by the “feeding layer” cells. 5. Cells of the lower lateral quadrant were very poor both in proliferative activity and in the extent of distal transformation, compared to cells of the three remaining quadrants. In the experiments with a low initial dilution of the foreleg cells, cells of the lower medial quadrant underwent distal transformation much more distinctly than cells of the upper medial and the upper lateral quadrants. 6. Allotypic structures occurred exclusively in reaggregates of the upper medial and upper lateral quadrants. In these implants, however, the frequency of transdetermination was extremely high. 7. Two alternative mechanisms are discussed which could have led to the general occurrence of distal transformation. They differ in the basic assumption of whether or not the “feeding layer” cells were able to interact with the leg cells to influence their regulative behaviour. In addition, interactions among the leg cells themselves seemed to stimulate proliferation to varying degrees and may account for the observed differences in the degree of distal transformation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 182 (1977), S. 203-211 
    ISSN: 1432-041X
    Schlagwort(e): Germinal mosaicism ; Number of primordial germ cells ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Three-hundred and twenty fertile,pal-induced Y-chromosome mosaic males and females were obtained. Fractional analysis of the sons of 55 somatically mosaic flies that were also germinally mosaic tentatively suggests that the number of functional primordial germ cells inDrosophila melanogaster is variable and that it is seldom greater than 24. From the observed 0.17 frequency of germinal mosaicism it was estimated that the average number of pole cells at the end of blastoderm formation is 45. At present, the germ cells afford the only opportunity to compare genetic estimates of the number of blastoderm or primordial cells with available histological counts. The good agreement between them suggests that both the fractional and the mosaic frequency methods for estimating primordial or blastoderm cell numbers of various larval and imaginal anatomical structures provide reasonably close approximations of the actual values.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Imaginal disc ; Histoblasts ; Adepithelial cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. Histological analyses were made of imaginal discs and histoblasts during the larval development ofDrosophila melanogaster to determine the number of cells, the patterns of cell division and the growth dynamics in these adult primordia. Histological studies were also made of the imaginal rings which are the primordia of the adult salivary gland, fore-and hindgut, the anlage cells of the midgut and several larval and embryonic tissues. 2. In the newly-hatched larva, the immature eye-antenna, wing, haltere, leg and genital discs contain about 70, 38, 20, 36–45 and 64 cells respectively. These numbers include cells destined to form cuticular elements as well as peripodial, tracheal and nerve cells and probably the progenitors of adepithelial cells. The number of cells counted in the various imaginal disc anlagen is 1.5 to 4 times higher than the numbers deduced from genetic mosaic analyses by other investigators and reasons for these differences are given. 3. About 12 h after fertilization, mitosis ceases in all tissues of the embryo except the nervous system. After the larva hatches, mitosis resumes in most of the imaginal anlagen and in some larval tissues. The time of resumption of mitosis in the imaginal anlagen was determined after treating the larvae with colchicine for 2 h. 4. Among the imaginal discs, the eye disc is the first to begin cell division, at about 13–15 h after the hatching of the larva (first instar) followed by the wing (15–17 h), the haltere (18–20 h), the antenna, leg, and genitalia (24–26 h, early second instar), and finally the labial and dorsal prothoracic discs (52–54 h, early third instar). The cell doubling time for various discs was calculated from cell counts and the times agree closely with the doubling times deduced from clonal analyses by other workers: e.g., 7.5 h for the cells of the wing disc. 5. The imaginal ring of the hindgut first shows cell division early in the second instar. The imaginal rings of the foregut and salivary glands, the anlage cells of the midgut and the cells of the segmental lateral tracheal branches begin to divide early in the third instar. 6. The histoblasts which are the anlagen of the integument of the adult abdomen do not increase in number from the time of larval hatching until about 5 h after pupation when they begin to divide. Their behaviour contrasts with that of the histoblasts of the other dipterans such asCalliphora, Musca andDacus, which begin to divide during the second instar. 7. The histoblasts are an integral part of the larval abdominal epidermis and, unlike imaginal disc cells, secrete cuticle during larval life. Each hemisegment consists of an anterior dorsal, a posterior dorsal, and a ventral histoblast nest containing about 13, 6 and 12 cells respectively. The 62 histoblasts in each larval segment represent about 7–8% of the total number of cells that form the integument of that segment. 8. The number of cells in a particular type of histoblast nest was constant for both male and female larvae and among the different abdominal segments, except that the anterior dorsal group of the first and the seventh segments contains fewer cells than those of the other segments. Although the male and female adultDrosophila lack the first abdominal sternite and the male lacks the seventh abdominal tergite and sternite, the ventral histoblast nests of the first and the dorsal and ventral nests of the seventh abdominal segments are present in the larval stages as well as in the prepupa and have the same morphology and cell number as similar nests in the rest of the abdominal segments. 9. The cells of the imaginal discs increase in volume about six-fold and their nuclei increase in volume three-fold between the time of hatching and the initiation of mitosis. The histoblasts increase in volume about 60-fold and their nuclei increase in volume about 25-fold between larval hatching and pupariation. 10. Prior to each cell division, the nuclei of the columnar cells of the disc epithelium and of the histoblasts appear to migrate toward the apical surface of the epithelium. The cells round up and shift toward the apical region where mitosis occurs. After cytokinesis, the daughter cells move back to deeper positions in the epithelium. Because the nuclei of the non-dividing cells continue to lie deep in the epithelium, this intermitotic migration of nuclei gives these epithelia a pseudostratified appearance. 11. Analyses of the growth of larval cells and of organs confirmed the observations of earlier investigators that cell division occurs only in a few larval tissues, whereas growth in the rest of the larval tissues is by cell enlargement and polyteny. During larval life, cell division was detected only in the central nervous system, gonads, prothoracic glands, lymph glands and haemocytes. Each tissue began mitosis at a characteristic stage in larval life. The larval cells that did not divide, grew enormously, e.g., epidermal cells increased in volume 150-fold and their nuclei increased in volume 80-fold. 12. The adepithelial cells, which give rise to some of the imaginal muscles, were first identified between the thick side of the imaginal dise epithelium and the basement membrane at the beginning of the third larval instar (50–52 h). The origin of these precursors of mesodermal structures was analysed and evidence is presented that the adepithelial cells come from the disc epithelium. The question of the origin of the mesoderm of cyclorrhaphan Diptera is reviewed and it is suggested that the imaginal disc ectoderm may become segregated from the rest of the embryo before gastrulation has occurred, that is before the mesoderm has been established.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 181 (1977), S. 367-373 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Gynandromorphs ; Genetic mosaics ; Sex determination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The derivatives of 110 mosaic genital discs of gynandromorphs have been analysed microscopically. It has been found that theanalia of both sexes are homologous and derive from a single primordium (see Fig. 1a). Whether male or female anal plates are formed depends on the genetic constitution of the cells. This is analogous to the development of male sex combs versus female transversal rows on the forelegs of gynandromorphs. In contrast, the data for thegenitalia (see Fig. 1 b) are best explained if it is assumed that there are two genital primordia in everyDrosophila embryo: a male primordium that will only develop into genitalia if populated by XY (or XO) nuclei, and a female primordium that will only do so if populated by XX nuclei. This model, as depicted in Figure 2, is compatible with all our gynandromorph data and also with observations onMusca andCalliphora where in fact two separate genital primordia are found.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 182 (1977), S. 305-310 
    ISSN: 1432-041X
    Schlagwort(e): Sterility ; Hybrids ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The females produced in the crossesD. melanogaster×D. simulans andD. melanogaster×D. mauritiana are sterile and have reduced ovaries. Normal and fertile ovaries were produced when genetically marked pole cells ofD. melanogaster were transplanted into eggs which gave rise to the hybrid females. These results eliminate the possibility that the sterility of these hybrids is due to the somatic component, i.e. the follicular cells of the ovaries, or to other physiological causes. The results also suggest that the control of gonadal morphogenesis is dependent mainly on the germ line.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 181 (1977), S. 227-245 
    ISSN: 1432-041X
    Schlagwort(e): Compound eye ; Development ; Cell lineages ; Genetic mosaics ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The generalogical relationships of photoreceptor cells within the compound eye ofDrosophila have been studied using cell labelling, with either3H-thymidine or recessive mutations, during the third larval stage. It has been found that photoreceptor and secondary pigment cells arise from different precursor cells. Under the present experimental conditions, precursors of receptor cells give rise to about 8 elements which differentiate as R cells of two different groups. One of the cells differentiates as R7 and the remaining as any one of the R1 to R6. The last cells behave initially as equivalent, and can differentiate within the same or within different, but neighbouring, ommatidia. The class of R1 to R6 cell in which each one of these elements differentiates, seems to depend on the time of its origin. The implications of these findings for the formation of the ommatidial pattern are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 183 (1977), S. 85-100 
    ISSN: 1432-041X
    Schlagwort(e): Pattern regulation ; Cell death ; Drosophila ; Imaginal discs ; Clonal analysis ; Mitotic recombination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We report on the size distribution of clones marked by mitotic recombination induced by several different doses of X-rays applied to 72 h oldDrosophila larvae. The results indicate that the radiation significantly reduces the number of cells which undergo normal proliferation in the imaginal wing disc. We estimate that 1000 r reduces by 40–60% the number of cells capable of making a normal contribution to the development of the adult wing. Part of this reduction is due to severe curtailment in the proliferative ability of cells which nevertheless remain capable of adult differentiation; this effect is possibly due to radiation-induced aneuploidy. Cytological evidence suggests that immediate cell death also occurs as a result of radiation doses as low as 100 r. The surviving cells are stimulated to undergo additional proliferation in response to the X-ray damage so that the result is the differentiation of a normal wing.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 15 (1977), S. 589-599 
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; isozymes ; selection ; migration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Allozyme polymorphisms at seven loci have been studied in nine natural populations of Drosophila melanogaster from the Saône and Rhône valleys sampled in 1973 and 1974. A great deal of polymorphism was observed; an individual was on the average heterozygous at 20.2% of its loci. The populations were genetically very homogeneous throughout the region sampled. The number of ovariolae per female varied from one group of populations to another depending on their geographical separation. Yet the number of ovariolae remained constant from one year to the next. The results show that migration alone cannot explain the homogeneity of the allozyme frequencies. It seems reasonable to conclude that selection plays a major role in maintaining the homogeneity of populations living in proximal biotopes.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; rudimentary ; aspartate transcarbamylase ; dihydroorotase ; multienzyme complex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The activities of the enzymes aspartate transcarbamylase (ATCase) and dihydroorotase (DHOase) were determined in adult females from a wild-type strain and from eight different alleles of the X-linked mutation rudimentary (r) of Drosophila melanogaster. The alleles chosen span the genetic map of the r locus. The characteristics of the DHOase-catalyzed reaction which converts carbamyl aspartate to dihydroorotate are briefly described. Of all of the r strains tested, only one, r 9, has wild-type levels of aspartate transcarbamylase and dihydroorotase activities. The other seven show either intermediate or very low levels of activity for both enzymes. The lowered ATCase and DHOase activities observed in mutants which do not map in the region of the structural gene for these enzymes are interpreted in light of recent evidence that ATCase and DHOase are part of a three-enzyme complex.
    Materialart: Digitale Medien
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  • 12
    ISSN: 1573-4927
    Schlagwort(e): pteridines ; Drosophila ; thin-layer chromatography ; eye pigments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract An improved thin-layer chromatography technique is described for the separation of fluorescent compounds found in extracts of heads of Drosophila melanogaster. Eighteen to twenty fluorescent spots are resolved, two of which are xanthurenic acid and 3-hydroxykynurenine, and the remaining spots are presumably pteridines. Of these, nine have been identified and quantitated directly on the chromatograms with a fluorometer. One of the spots present on the chromatogram apparently has not been described previous to this work. Characteristics of this substance, termed “quench spot,” are presented, several of which indicate that it may be a pteridine or pteridine derivative.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1573-4927
    Schlagwort(e): Drosophila ; eye pigmentation ; 3-hydroxykynurenine accumulation ; white mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Several points of biochemical similarity between white and scarlet mutants suggest that both are defective in the transport of xanthommatin precursors. In both, accumulation of 3-hydroxykynurenine is negligible during larval life and occurs at only a slow rate during adult development. Larvae of both mutants also excrete 3H-3-hydroxykynurenine and 3H-kynurenine rapidly, which probably accounts for the normal levels of kynurenine during larval life. 3-Hydroxykynurenine levels are abnormal in all white mutants which were studied, although in two alleles which are strongly pigmented (w sat and w col) accumulation is enhanced rather than diminished. In w a, larval accumulation is normal but accumulation during adult development is greatly diminished, suggesting that this mutation has a tissue-specific effect. Similar levels were found in zeste females. Of the 11 other eye color mutants tested, abnormal levels of 3-hydroxykynurenine were found in eight. In four of these (claret, light, lightoid, and pink), larval accumulation is negligible, suggesting that these have defects in the kynurenine transport system like scarlet and white. In three others, however (brown, karmoisin, and rosy), accumulation during larval life is enhanced. In cardinal accumulation is normal during larval life but is excessive during adult development. This evidence supports the suggestion that the cd mutation blocks the final step of xanthommatin synthesis.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1573-4927
    Schlagwort(e): pteridines ; Drosophila ; suppression ; eye color mutants ; GTP ; development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The suppressible eye color mutant purple (pr) of Drosophila melanogaster is known to be unable to synthesize a wild-type complement of pteridine eye pigments. This study measures the reduced levels of drosopterins, sepiapterin, and an unidentified presumed pteridine in pr and pr bw. Pteridine analyses in double mutants combining pr with one of three other eye color mutants sepia, Henna-recessive3, and prune2, suggest that the metabolic block in pr occurs prior to sepiapterin biosynthesis. Measurements of GTP and GTP cyclohydrolase in pr showed wild-type levels and indicate the metabolic block in pr to be at one of the steps converting dihydroneopterin triphosphate to sepiapterin. Quantitation of pteridines in suppressed purple [su(s) 2; pr and pr; su(pr) e3] shows restoration of pteridines to wild-type or nearly wild-type levels.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 50 (1977), S. 47-51 
    ISSN: 1432-2242
    Schlagwort(e): Glutamate Oxaloacetate Transaminase ; Isozymes ; Triticum aestivum ; Subunits
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A simple procedure has been developed for the dissociation of active molecules of glutamate oxaloacetate transaminase (GOT: E.C. 2.6.1.1) into protomers and for the reassociation of the subunits into active enzymes. Results of experiments in which the protomers of genetically controlled electrophoretic variants of GOT of Triticum aestivum and of several related species were dissociated and recombined in crude tissue extracts and in partially purified preparations support the hypothesis that the enzyme exists functionally as a dimer in the Triticinae.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Wheat ; Endosperm ; Protein Synthesis ; RNA Level ; Amino Acid Translocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The kinetics of protein accumulation, the variation in RNA, the soluble amino nitrogen content of developing endosperm of two varieties of Triticum aestivum, with high and low protein content in the mature seed, suggest a possible relation between maintenance of the RNA content and the ability to synthesize protein. A sudden halt in protein accumulation is observed as the RNA starts to decrease. The hypothesis is also advanced that maintenance of the RNA content might, in turn, be dependent on the presence, in the endosperm of developing wheat seed, of a certain level of soluble amino nitrogen which could then play the role of limiting factor for protein synthesis.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 50 (1977), S. 125-127 
    ISSN: 1432-2242
    Schlagwort(e): Drosophila ; Mutants ; Radiation ; Lethals ; Dose-Response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The mutagenic efficiency of ionizing radiations has been tested on different lines of Drosophila melanogaster. It has been shown that differential lethal effects are obtained when irradiated females from different lines are mated to flies carrying heterozygous lethal genes. The results seem not to be attributable to differential expression of the lethality in the various crosses performed with the irradiated flies. This might suggest that gene activity is involved in the expression of the mutagenic effects of radiations.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 475-479 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; anthocyanins ; centromere ; chromosome mapping ; crossover units ; dominant genes ; monosomics ; partially dominant ; purple coleoptile ; suppressors ; telocentric chromosome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The association of genes for purple pigment in the coleoptile with the chromosomes of the winter wheat variety Mironovskaya 808 was investigated using monosomic F2 analysis. The segregation ratio for F2 hybrids of Chinese Spring monosomics x Mironovskya 808 seems to indicate that the purple colour of the coleoptile is determined by two dominant genes, Rc3 and Rc4, which are located on the chromosomes 7D and 6B respectively, and which reinforce each other. Apart from these two genes, suppressors found on the chromosomes 2A, 2B, 2D, 4B and 6A also play a role in the intensity of the purple colour. With the aid of a Chinese Spring telocentric chromosome marker it was observed that the Rc3 gene is located on the chromosome arm 7DS, at a distance of 16±4.23 crossover units from the centromere.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 739-744 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; flag leaf area ; grain yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Five spring wheat crosses were evaluated over a 6-year period using comparisons between F2 and F3 data and between near-isogenic F4 populations selected for flag leaf area. Nonsignificant r values for F2 vs. F3 flag leaf measurements may be due to the effect of environment on flag leaf area, but are probably also an indication of low heritability for this plant character. Near-isogenic populations selected on the basis of flag leaf area showed little difference in grain yield, an indication that other plant parts must be more influential in determining grain yield. Flag leaf area, by itself, appears not to be a good index to plant performance.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 565-572 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; pre-harvest sprouting ; Tom Thumb derivatives ; GA3 response index ; apparent α-amylase synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Segŕegating populations of the cross Tordo (a spring white-grained Tom Thumb derivative) and Tr 454-16 (a spring white-grained Sonora-Gabo derivative) were studied for plant height, apparent α-amylase synthesis (AAS) and response to gibberellic acid. Means, variances and heritabilities for these characters were computed and their association was studied by computing correlation coefficients. Plant height showed high heritability while AAS and response to GA3 showed moderate heritability. Plant height was positively correlated with AAS and response to GA3. The results pointed out the importance of using Tom Thumb as a source of pre-harvest sprouting tolerance in a wheat breeding programme, particularly in areas where wheat breeding is restricted to evolving white-grained cultivars.
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  • 21
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; stem rust ; Puccinia graminis tritici ; generalized resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Four morphological characteristics of wheat peduncles were evaluated for genetic and environmental variability. The thickness of the epidermis and the amount and distribution of chlorenchyma tissue in the peduncle were measured. The genetic variability was estimated to be large, whereas the environmental variability was small. It was also concluded that cultivars could be screened for morphological characteristics of the peduncle that contributed to non-specific resistance to stem rust with a minimum sample size of about 10 plants per replication from a single location.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 129-139 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; grain yield ; tall plant ; semidwarf plant ; adaptation ; dryland ; regression analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary With a view to determining the comparative adaptation of semidwarf wheats to rainfed conditions, adaptation analyses were carried out on grain yield data of the 6th and 7th International Spring Wheat Yield Nurseries of the International Maize and Wheat Improvement Centre. Sites were chosen which had not received irrigation: across a combined total of 44 such sites, yield variation was closely related to growing seasonal rainfall. Using these sites, yields of thirty-three common cultivars. Norin 10-derived semidwarf cultivars plus tall ones, were regressed against site mean yield to give a regression slope (b) and deviations from the regression (sd 2) for each cultivar. Semidwarf cultivars generally showed higher mean yields and larger regression slopes (b 〉 0.9) than tall cultivars from lower latitudes. Tall cultivars from higher latitudes showed the lowest mean yields and the lowest b values (〈 0.7). No consistent trends in sd 2 were evident. Despite the greater regression slopes of semidwarf wheats, the best yields under all but the lowest yielding (driest) conditions were given by certain semidwarf cultivars; these had high mean yields and b values close to 1.0 (for example Tobari 66, Inia 66, Pato ArGentino and Sonalika). In contrast other semiwdarfs (notably Chenab 70) of similar mean yield, plant height and phenology, were not well adapted to the drier conditions as indicated by b values close to 1.3. The usefulness of the regression technique and the implications of these results for selection of semidwarf wheats adapted to drier conditions are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 299-308 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; pre-harvest sprouting ; components of resistance to sprouting ; complex resistance (RCP) ; α-amylase synthesis ; GA3 response ; wheat endosperm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The problem of pre-harvest sprouting in wheat is very intricate. New concepts in breeding for resistance to pre-harvest sprouting regard many components such as α-amylase production potential, response to gibberellic acid and inhibition in the bracts as important as dormancy. In the research work carried out at The University of Sydney's Plant Breeding Institute, we found varietal differences for each of these components. We also developed criteria for screening breeding material for these components. The implications of our findings in planning efficient breeding programmes to evolve varieties with multiple resistance to pre-harvest sprouting have been discussed briefly.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; Triticum timopheevi ; fertility restoration ; cytoplasmic male sterile ; percent fertility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Fertility restoration genes in Triticum aestivum L. in Texas Restorer Composite (TRC), D6301, and four CIMMYT restorer lines were studied, and selection was made for higher fertility in TRC. Mean-while, outcrossing percentages of seed set for 27 spring habit cytoplasmic male sterile (cms) varieties were evaluated for 3 to 5 years at Davis. The winter-habit TRC material did not restore reasonably good fertility, and the response to selection for higher fertility seemed to be slow. This poor fertility could be partly due to its late winter growth habit causing flowering at a period of high temperature and low humidity at Davis. The highest F1 fertility was 46.6% in the cross cms Ramona x TRC-6, and its F2 segregated into the ratio of 15 fertile to 1 sterile, with fertility ranging from 3.2 to 100%. Suggested for its improvement was intensive selection in the original TRC material and in the segre-gating F2 population, followed by intercrossing. D6301 has 2 fertility restoration genes with different strengths which restore fertility up to 45.2% when both genes are heterozygous. D6301 is quite likely heterogeneous for these genes. Four CIMMYT restorer lines, D7464, D7465, D7466, and D7467, had satisfactory F1 fertility restoration after crossing with cms Ramona 50. In 1975, the fertilities of the F1's ranged from 71 to 85% and were over 90% in 1976. The F2 population of the cross cms Ramona 50 × D7464 segregated into a ratio of 3 fertile to 1 sterile, indicating that D7464 has a single dominant gene for fertility restoration. The F2's of crosses cms Ramona 50 × D7465, cms Ramona 50 × D7466, and cms Ramona 50 × D7467 gave a ratio of 15 fertile to 1 sterile, indicating that two gene pairs in these three lines were responsible for the fertility restoration. The best of this group was D7467 which restored fertility fully after being crossed with cms Ramona 50 (T. timopheevi cytoplasm). The early-flowering cms male-sterile varieties had higher outcrossing rates (16 to 38%) than late varieties (6 to 30%) over a 5-year period. This was due to hot and dry weather during the late growing season as well as to the rarity of windborne pollen. In 1970, 1971, 1972, and 1976, the variation among varieties was rather great. Some of them such as Roque 66 and Bajio 67, had consistently high outcrossing rates. This outcrossing ability seemed to be inherited and probably associated with the open-flowering characteristics of each variety.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 89-95 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Heterodera avenae ; cyst nematode ; resistance breeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The use of soil. naturally infested with Heterodera avenae, to select resistant heterozygotes in backcross progenies of wheat, was tested for reliability. Selfed progenies from plants selected as resistant were cultured monoxenically in test tubes with nematodes hatched from single cysts, while backcross progenies from the same parent plants were grown in pots of naturally infested soil. Cyst counts were made after two months' growth. The results showed that over 50% of the backcross lines, screened in previous generations with naturally infested soil, had been erroneously selected as resistant. The test tube cultures clearly differentiated lines carrying resistance from those which were susceptible and corroborated results from pot tests.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 103-112 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; hybrid wheat ; male sterility ; cross pollination ; seed production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Several chemicals were evaluated for their gametocidal properties to control pollination in hybrid wheat (Triticum aestivum L. em Thell.) seed production. In a preliminary study, four chemicals were applied to three cultivars of spring wheat at two application times. RH-532 was the most effective of the four gametocides, reducing fertility to a 0 10% level for all three cultivars. In a second experiment, RH-532 was applied to one cytoplasmic male-sterile and three normal spring wheats at four rates (0.56, 1.12, 2.24, and 4.48 kg/ha) and at two times of application. Alternate strips of pollinator were planted throughout the experiment. All treatments decreased fertility. plant height, and spike length of the three normal wheats. RH-532 did not inhibit spike emergence of two semidwarf cultivars or one of conventional height. Cultivars did not respond similarly to treatments. Yields of cross-pollinated seed were only 1 21% of the normal yield when fertility levels on treated plants reached 0 10%. Hybrid seed content of the harvested seed ranged from 2 55%. On the treated male-sterile line, yield was significantly reduced in comparison with the open-pollinated check. Inhibitory properties of this chemical suppressed the fertilization potential of the female as well as inducing male sterility. The differential response of genotypes to treatments indicates that cultivars should be screened for male and female sensitivity to this chemical. If differential sensitivity is found, breeding and selection to improve this trait may be possible. Different environmental conditions may alter the response of cultivars to this chemical, with less effect on the female structures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; intergeneric cross ; fertilization ; early post-fertilization developments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Fertilization and early seed development was studied in the variety Chinese Spring of common wheat (Triticum aestivum L.) after pollination with rye (Secale cereale L.) and selfing, and in the common wheat variety Hope after selfing. In all three combinations the first pollen tube reached the micropyle in about 40 min after pollination. When pollinated with rye the migration of the sperm nuclei to the egg cell and the polar nuclei was delayed by about an hour. In the subsequent development until 72 hours after pollination the average cellular and nuclear doubling times of embryo and endosperm were about 16 and 8 hours for the interspecific combination. 18 and 9 hours for Chinese Spring selfed and 20 and 12 hours for Hope selfed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 139-146 
    ISSN: 1573-3297
    Schlagwort(e): phototaxis maze ; eye color mutants ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Five different eye color mutations ofDrosophila melanogaster have been tested for their effect on phototactic behavior. All five mutations seem to cause flies to be less photonegative than Canton-S control flies. The mutation sepia was found to produce this effect when heterozygous as well. It was also found that wild-type flies from highly photopositive and photonegative strains seem to be more photoneutral with age.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 349-357 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; sexcombs ; sexual behavior ; strain differences
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The sexcombs were amputated from males of three strains ofDrosophila melanogaster and one strain ofD. simulans in order to assess the importance of these structures in the sexual behavior of these species. InD. melanogaster the sexcombs are important in attempts to copulate with the female. Their removal delays copulation but does not suppress it entirely. Other aspects of courtship are not influenced by removal of the sexcombs. Strain differences in quantitative aspects of courtship were found, and also in the insemination rates of females by males without sexcombs. The present evidence suggests that the sexcombs are primarily structures adapted to grasping the female securely during the act of intromission.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 359-372 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; behavior genetics ; male responses to female physiological state
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract MaleDrosophila melanogaster differ in the age at which they reach sexual maturity following eclosion from the pupa. Courtship latency, which is the time taken by a male to initiate courtship of a conspecific female, is related to age. Young males take significantly longer than older males to begin courtship. The probability that a male will initiate courtship is influenced by the physiological state of the female. Males of different genotypes readily court mature (3-day-old) virgin females, but they differ significantly in their reaction to immature (12-hr-old) and fertilized females. Genes located on the third chromosome largely control male courtship latency, but responses to immature and fertilized females have different genetic bases, suggesting that the relevant stimulus inputs governing these responses also differ. The adaptive significance of courtship directed toward immature or fertilized females, which rarely mate, probably depends on the average level of sexual responsiveness of potentially receptive mature virgin females in a given population.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 427-432 
    ISSN: 1573-3297
    Schlagwort(e): allozymes ; Drosophila ; frequency-dependent selection ; rare male mating advantage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Matings betweenDrosophila pseudoobscura strains differeing at the amylase (Amy) locus were observed in Elens-Wattiaux chambers. Males homozygous for eitherAmy 1.00 orAmy 0.84 alleles in the CH gene arrangement enjoyed a mating advantage when moderately rare, but none when quite rare. The minority male advantage for strains differing at theAmy locus, and other loci linked to it, was comparable in size to that observed between strains carrying the ST or CH gene arrangements, and either alike or different at theAmy locus. Although some features of our results are puzzling, there is evidence that theAmy locus and others for which it serves as a marker have effects on mating behavior which include some degree of rare male mating advantage.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 389-402 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; mazes ; phototaxis ; geotaxis ; learning ; strain differences
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Although mazes have been widely used in studying phototaxis, geotaxis, and, more recently, learning inDrosophila, there is no uniformity in maze design, and little is known about the effects such apparatus differences may have on behavior. The new maze design described here is based on T-junctions, molded individually in acrylic, and provides an inexpensive and standardized means of building mazes to any desired specification. The need for uniformity in maze design is demonstrated with an experiment on three variables at the start of a maze that affect the subsequent response of four strains ofD. melanogaster in different ways. Some implications for futureDrosophila research using mazes are considered.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 447-455 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; countercurrent mutants ; geotaxis ; phototaxis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Ten behavioral mutations, originally isolated in the countercurrent fractionation device, were tested in phototaxis and geotaxis mazes. While none of the mutations caused an altered ERG, they all caused photomaze behavior to differ from that seen in Canton-S controls. Eight of the mutants showed altered geotactic behavior. There was no correlation between the kind of change in phototactic behavior and the geomaze behavior of a given mutant. Certain mutations cause flies to be more photopositive and more geonegative than Canton-S; others result in behavior that is photo- and geopositive. The results suggest that certain mutations may be affecting visual components other than the ERG while other mutations may be more centrally or generally acting.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Behavior genetics 7 (1977), S. 457-464 
    ISSN: 1573-3297
    Schlagwort(e): Drosophila ; wild-type larvae ; mutant larvae ; olfactory discrimination ; U-maze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract Wild-type (+B) and compound chromosome mutant(bB) Drosophila melanogaster larvae were tested in a U-maze. FreshDrosophila food or food and larvae were placed in each of the two goals (+B only in goal 1,bB in goal 2) and served as stimulus. Separate trials were conducted using +B andbB larvae to test for preference in the maze. Significantly more test larvae went to the arm of the maze containing their own strain as stimulus when (1) both goals contained larvae, (2) one goal contained homogenetic larvae and the other fresh food only, and (3) the goals contained biotic residues of stimulus larvae. The strength of the stimulus necessary to elicit the response differed for the two strains, the +B strain apparently being more sensitive. As the density of the stimulus larvae was increased, the choices of the test larvae became statistically nonsignificant and the number of larvae remaining in the starting arm of the maze increased. The data suggested that the strains of larvae utilized here have the capacity for olfactory discrimination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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