bluuebunny/crossref_metadata_2025 huggingface dataset:
IN VITRO CULTURE OF WHEAT TISSUES. I. CALLUS FORMATION, ORGAN REDIFFERENTIATION AND SINGLE CELL CULTURE
Authors: Shimada T. , Sasakuma T. , Tsunewaki K.
Published: November 2014

Callus induction, organ formation from callus and single callus cell culture have been tried in wheat. Though kinetin showed no effects, supplements of 2,4-D (1~10mg/1) or IAA (50mg/1) to the basal media induced calluses from seedling roots of einkorn, emmer and common wheats, and from stem pieces of common wheat. The best callus growth was obtained when casein hydrolysate (1g/1) or coconut milk (1%) was added to the basal media. Callus growth was also vigorous when 2,4-D (0.5~2.0mg/1) was added. Root formation from callus took place in all kinds of tested media, except those containing no growth factors or supplemented with 2,4-D at high concentrations (1~5mg/1). Shoot formation occurred in six cases and no growth factors were found to be specifically effective on shoot differentiation. Two plants were restored and reached maturity. Calluses of common wheat consisted of eudiploid and aneuploid cells at almost the same frequencies. The great majority of aneuploid cells had 42 ± 3 chromosomes. The restored plants showed normal chromosome constitution. Single callus-cell suspensions were obtained by the liquid culture of seeds in a shaker. A filtrate of the single cell suspension was plated on a solid agar medium, and some colonies were formed. However, plating efficiency was very low and colony growth was slow.
THE ORIGIN AND CONSEQUENCES OF SUBCHROMATID ABERRATIONS INGASTERIA ERNESTII-RUSCHII
Authors: Vig B. K.
Published: November 2014

Cytological studies of a plant of Gasteria ernestii ruschii Dtr. revealed the presence of anaphase I bridges with side arms which are usually unaccompanied by fragments. The fragments, when present, were of no regular size and ranged from very small to very large ones. The presence of only fragments or bridges at anaphase II and the above described behaviour of anaphase I chromosomes indicates the presence of subchromatid breakage and reunion. The cytological and genetic consequences of such aberrations are discussed. In a few cases two large chromosomes were interpreted to divide equationally as univalents at metaphase I. Since no univalents for large chromosomes were observed at stages prior to metaphase I their presence may be attributed to 'abortive terminalization' resulting from subchromatid breakage.
CHROMOSOME NUMBER POLYMORPHISM IN AN AUSTRALIAN PONERINE ANT
Authors: Crozier R. H.
Published: November 2014

Southern Victorian populations of Rhytidoponera metallica have n = 22 to 17, with progressive replacement of two acrocentrics at a time by a metacentric to yield numbers lower than 22 (nombre fondamentale = 23). A further collection with n = 12 represents either a further reduction in this Robertsonian system or a sibling species. Related species have n = 21 (victoriae) and 23 (tasmaniensis).
MEIOSIS IN ORNITHOGALUM VIRENS (LILIACEAE): MEIOTIC TIMING AND SEGREGATION OF H3-THYMIDINE LABELED CHROMOSOMES
Authors: Church Kathleen , Wimber Donald E.
Published: November 2014

The timing of meiosis and the segregation of tritium-labeled chromosomes has been studied in Ornithogalum virens. Tritiated thymidine was administered to the inflorescences by a wick feeding process. The length of time required for labeled cells to pass from premeiotic DNA synthesis to the tetrad stage of meiosis is approximately 4 days. The labeled chromosomes display a semiconservative segregation pattern when labeled one division prior to meiosis; however, chromatid exchange events occur prior to, or during meiosis, or both. These exchange events are most likely a combination of crossing over between homologous chromosomes and sister chromatid exchange. The reductional separation of the centromere region at the first meiotic division is confirmed. The observations do not support Sax's two plane theory of crossing over, but are consistent with the theory that chiasmata are the cytological consequences of genetic exchange.
EMBRYOLOGY OF DIPLOID × DIPLOID AND DIPLOID × TETRAPLOID CROSSES IN POINSETTIA
Authors: Milbocker Daniel , Sink Kenneth
Published: November 2014

Hybridization between diploid cultivars of poinsettia results in abundant seed production. However, with the diploid used as the maternal parent in crosses with tetraploids, less than 1% viable seedlings are realized. Cytological observations indicated a 2:3:2 chromosome number ratio of the embryo, endosperm and maternal tissue in diploid crosses with endosperm development completed in about 45 days after pollination. Embryo differentiation in diploid crosses occurred at 26 days and matured in approximately 54 days after pollination. The chromosome number ratio of the embryo, endosperm, and maternal tissue was not firmly established for the diploid × tetraploid cross due to the small number of viable seeds obtained, but the expected 3:4:2 ratio was frequently observed. Endosperm development in most of the ovules examined did not progress beyond the large fragile cell stage. This study suggests that the endosperm may be the determining factor in setting of seed in the diploid × tetraploid cross.
INHERITANCE IN HEXAPLOID WHEAT OF LEAF RUST RESISTANCE AND OTHER CHARACTERS DERIVED FROM AEGILOPS SQUARROSA
Authors: Kerber E. R. , Dyck P. L.
Published: November 2014

The inheritance of seedling leaf rust resistance and several morphological characters derived from Aegilops squarrosa (2n = 14 = DD) was investigated in a synthetic hexaploid wheat. The hexaploid was obtained by combining the tetraploid component (2n = 28 = AABB) extracted from the common wheat cultivar Canthatch with Ae. squarrosa var. meyeri R.L. 5289.A major, partially dominant gene was identified that gives good resistance (type 0;1 reaction) to leaf rust races 1, 5, 9, 11, 15, 30, 58 and 126a. This gene was shown to be different from the resistance genes Lr1, Lr2, Lr3, Lr10, Lr16, Lr17 and Lr18. A minor second gene was also detected which gives resistance (type 2 reaction) to race 9 and slight resistance to some of the other races.Each of the characters purple coleoptile, non-waxy foliage, brown glumes, and non-free threshing (tenacious glumes) of the synthetic wheat was monogenically inherited. The gene for threshability may be different from other genetic systems known to affect this character. The gene for brown glumes was linked with the major gene for leaf rust resistance with a recombination value of 3.1 ± 1.1%. The genes for non-waxy foliage and non-free threshing were associated with an estimated linkage value of 15.1 ± 2.6%.The results effectively demonstrated the relative ease with which genetic variation may be incorporated into common hexaploid wheat from its ancestral diploid, Ae. squarrosa, by means of a synthetic hexaploid intermediary. The method avoids the difficulties and complications often encountered with the transfer of genes from more distantly related species which do not have a genome in common with T. aestivum.
MUTAGENIC EFFECTS OF DIETHYL SULPHATE ON CERTAIN MORPHOLOGICAL CHARACTERS OFNICOTIANA TABACUM
Authors: Povilaitis Bronius
Published: November 2014

Dry seed of flue-cured tobacco cultivars Hicks Broadleaf, Yellow Gold, and Canadel were soaked in a freshly mixed saturated solution of the chemical mutagen, diethyl sulphate, at 30 °C for 3 and 5 hours. All the plants with major visible aberrations were eliminated from the tests. Random plants were selected in 1965 and selfed seed was obtained. C2populations were grown in 1966 and C3in 1967.The means for plant height and for length of top and middle leaves of the C2and C3populations were smaller, and the means for number of days to flower were larger than those of the controls. The variances and the ranges of variation of all the treated populations were larger than those of the controls. The frequency distribution in the C3generation was skewed towards lateness to flower for the three cultivars. Negative and significant skewness was found for height in Hicks Broadleaf, and for height and length of the top leaves in Canadel. All the computed values for kurtosis were positive indicating a peaked curve of distribution. The difference between kurtosis values for the 5-hour treated populations and their respective controls was positive and significant in the cultivars Yellow Gold and Canadel for days to flower and for length of both top and middle leaves. Heritability in the broad sense ranged from 27 to 85%.
DURATION OF MITOTIC CYCLE IN BRAIN CELLS OF THE MOSQUITO, AEDES DORSALIS
Authors: Mukherjee Asit B. , Rees Don M.
Published: November 2014

Duration of the mitotic cycle and its various phases in the dividing brain cells of Aedes dorsalis larvae has been determined by high-resolution autoradiography. The length of the cell cycle is 10 hours. The duration of G1 is about 1 hour and 15 minutes, DNA synthetic period (S) is approximately 7 hours, G2 is 1 hour and the duration of mitosis (M) is about 45 minutes.
MEIOTIC RESTITUTION AND THE ORIGIN OF POLYPLOIDY. III. THE CYTOLOGY AND FERTILITY OF EIGHT GENERATIONS OF THE OFFSPRING OF A SPONTANEOUSLY PRODUCED AMPHIPOLYPLOID OF TRITICUM CRASSUM × T. TURGIDUM
Authors: Wagenaar E. B.
Published: November 2014

The pentaploid F1 hybrid (2n = 35) between Triticum crassum (2n = 42 = DDD2D2McrMcr) and T. turgidum (2n = 28 = AABB) produced spontaneous, polyploid F2 offspring with 2n = 70 chromosomes (AABBDDD2D2McrMcr). These offspring were maintained for eight successive generations. From each generation the most fertile plants were selected to serve as parent plants for the next generation.Cytological studies showed that 14 chromosomes were rapidly eliminated in the early generations; the chromosome number became stabilized at 2n = 56 in the F5. The chromosome behavior was very irregular in the meioses of the early generations, but gradually became more regular in the later generations. Pollen mother cells with chromosome mosaics, a very dominant feature of meiosis the F2 and F3 generations, reduced to an occurrence of about 10% in the F7, F8 and F9 generations. The number of univalents decreased while the chiasma frequencies per cell increased. Simultaneous with the improvement of the meiotic behavior of the chromosomes, the fertility increased from an average of less than 10% in the F2 to about 50% in the F7, F8 and F9 generations. The maximum fertility of individual plants was between 80 to 90%. There was thus a clear relationship between the observed pattern in fertility and meiotic chromosome behavior in response to selection for high fertility. This relationship is discussed in detail. The offspring has all characteristics of becoming a separate, polyploid species.
THE ACTION OF ACTINOMYCIN D AND DIEPOXYBUTANE ON RECOMBINATION OF TWO CLOSELY LINKED LOCI INHORDEUM
Authors: Sinha R. P. , Helgason S. B.
Published: November 2014

The effects of applying aqueous solutions of each of actinomycin D (50 μg/ml) and diepoxybutane (0.04%) at the pre-meiotic stage of Hordeum vulgare L. Emend. Lam. were determined with respect to segregation and recombination of the mutants xeand an, closely linked in a region proximal to the centromere in chromosome 3. The solutions were injected into the spike area and the uppermost internode. Recombination in diepoxybutane-treated barley was approximately threefold that of the control for the region tested. A corressponding increase resulted from treatment with actinomycin D. Lethality to culms was considerably greater from the antibiotic than from the alkylating agent. Actinomycin D also reduced the frequency of expression, among progeny plants, of the albino (an) phenotype. Although the effect of the two chemicals on recombination was similar, differences in other effects were considered to indicate different modes of action in raising recombination levels.
THE METAPHASE CHROMOSOMES OF CHINESE HAMSTER LIVER CELLS FOLLOWING PARTIAL HEPATECTOMY
Authors: Brooks A. L. , Mead Diane K.
Published: November 2014

A procedure for preparing and observing metaphase chromosomes of the Chinese hamster is described. The technique involved surgical removal of a constant fraction of the liver to stimulate cell division, injection of colchicine to accumulate metaphase cells and a squash technique for spreading the meta-phase chromosomes. A peak in the mitotic index was observed at 54 hours post-partial hepatectomy. Advantages of scoring metaphase as opposed to telophase and anaphase figures are discussed and examples of normal and 144Ce exposed cells are shown. These techniques can be used in the study of internally deposited radioactive material and other toxic agents which have their major effect on the liver.
HETEROSIS IN DIALLEL CROSSES AMONG SIX VARIETIES OF HARD RED SPRING WHEAT
Authors: Knott D. R. , Sindagi S. S.
Published: November 2014

Diallel crosses were made among six varieties of hard red spring wheat that differed considerably in yield and other characteristics. The F1 hybrids were tested at two seeding rates and the F2, hybrids at one. Heterosis was not great in either generation and no cross appeared to be promising. General combining ability was much more important than specific combining ability and parental yields gave reasonable predictions of hybrid yields. Yields of hybrids at the two seeding rates were closely correlated.
RADIATION-INDUCED MUTANTS OF DAHLBOMINUS FUSCIPENNIS (HYMENOPTERA: EULOPHIDAE)
Authors: Baldwin W. F. , Knight P. A. , Chant G. D.
Published: November 2014

Thirteen new mutations of D. fuscipennis are described, bringing the number of mutants described for this species to 25. All the mutations in the haploid males were recessive and arose from irradiation of unmated wild females. Of the 13 mutations, 2 affect eye pigment, 2 body colour and 9 produced morphological changes in the antennae, head, eyes, wings and abdomen. Three of the morphological abnormalities, small head, large eyes and stumpy abdomen did not segregate equally, probably due to lowered viability.
GENETIC RECOMBINATION INCOPRINUS. I. ITS PRECISE TIMING AS REVEALED BY TEMPERATURE TREATMENT EXPERIMENTS
Authors: Lu Benjamin C.
Published: November 2014

A meiotic system that facilitates comparative genetic analysis of recombination and cytological observations of meiosis and chromosome structure by light and electron microscopy is described. Both high (35°C) and low (5°C) temperature treatments can increase genetic recombination in Coprinus lagopus. Cold treatment appears to be more effective than heat treatment. The maximum recombination increase is 220% by cold, and 95% by heat treatment. As revealed by the temperature-treatment experiments, the time that recombination can be modified is determined precisely at a stage defined by light microscopy as pachytene, this period being estimated to be about 4 hr. Temperature treatments do not cause asynapsis or desynapsis. In fact, the chromosomes are very well paired after treatments, and pairing appears to be closer than, that of the controls. It is suggested that temperature treatments induce 'exchange pairing' which is defined as a molecular event leading to the formation of the hybrid DNA.
MUTATION SPECTRUM IN THE FUNGUS CONIOCHAETA VELUTINA
Authors: Paterson M. C. , Tan H. , Cooke F.
Published: November 2014

Auxotrophic, morphological, sensitive and suppressor mutant strains of Coniochaeta velutina are described. Of 1334 auxotrophic mutants isolated, all but 58 have been characterized as to their specific requirements. The mutation spectrum obtained on malt medium differs in several respects from that on complete medium. Arginine, adenine, cysteine, methionine, histidine and pyrimidine requiring mutants were most frequently isolated. Of 12 diauxotrophs tested genetically, 7 proved to be double mutants, but the remaining 5 behaved genetically as single mutants with a double requirement. Four of these required both adenine and histidine for growth and the other both phenylalanine and tyrosine. Cysteine-sensitive mutants and histidine-sensitive strains are described. Other mutants isolated included a variety of morphological, conidial and colour variants, UV-sensitive strains, canavanine-sensitive strains and arginine-suppressor mutations.
COMPONENTS OF GROWTH IN GENETICALLY DIVERSE POPULATIONS OFTRIBOLIUM CASTANEUM
Authors: Englert DuWayne C. , Bell A. E.
Published: November 2014

The growth and developmental patterns of 19 genetically diverse populations of Tribolium castaneum were examined. Measurements were obtained on three primary traits (13-day larval weight, pupation time and pupal weight) and three secondary traits (number of larval molts, adult emergence time and adult weight). The populations were chosen on the basis of their previous selection histories. Selection for different primary traits produced profound effects upon the total growth and development complex.Genetic and environmental relationships between primary traits were estimated within each population, and a consistent asymmetry of correlated responses was observed to be determined by the direction of selection.Possible effects upon the disruption of an intricate balance of the three metamorphosis hormones (activation, molting and juvenile) through selection were postulated.
MORPHOLOGY AND CYTOLOGICAL BEHAVIOR OF ANEUPLOIDS OFSORGHUM BICOLOR
Authors: Lin P. S. , Ross J. G.
Published: November 2014

Ten types of single trisomics were tentatively classified within a progeny of a selfed homozygous triploid plant of Sorghum bicolor Moench using morphological characteristics. Of the 111 offspring obtained, 40 were found to be diploid, 58 trisomic, 11 double trisomic, 1 triple trisomic and 1 plant (because no heads were formed) unknown. Most of these trisomics were less vigorous than the diploids. Trisomics differed in number of tillers, plant height, panicle length, and fertility. Two types of trisomics had abnormalities apparently related to the sterility observed in these types. In Type 8, pollen grains had papilliform appendages and in Type 9 ovaries contained tumorous growths.One double trisomic was tentatively identified as Type 1–4 according to morphological appearances. Cytological analysis of pairing relationships of metaphase I of this plant indicated a close correspondance to the theoretical expectation.The trisomic types (excluding variants) arranged in order of decreasing frequency of occurrence correlated well with their order in decreasing percentage of trivalent formation. This order, therefore, might be interpreted to give an indication of the relative length of the extra chromosome found in each trisomic type.
INHERITANCE OF RESISTANCE TO LOOSE SMUT AND COVERED SMUT IN THE OAT VARIETIES BLACK MESDAG, CAMAS, AND RODNEY
Authors: Cherewick W. J. , McKenzie R. I. H.
Published: November 2014

F3 lines from three smut resistant oat varieties crossed with the susceptible variety Anthony were inoculated with compatible monosporidial lines of two inbred races of Ustilago avenae and one inbred race of U. kolleri. Rodney, Black Mesdag, and Camas each have one gene conferring resistance to two races of U. avenae and to one race of U. kolleri. Black Mesdag and Camas have a second gene, conferring resistance to the U. kolleri race. F3 lines from the Black Mesdag × Anthony cross were inoculated with teliospores of a U. avenae race virulent on all varieties except Black Mesdag. One gene in Black Mesdag conferred resistance to this and the other races used. F3 lines from a cross between Camas and Black Mesdag segregated, indicating that these varieties have genes for smut resistance at different loci.
PATTERN OF SEGREGATION OF LABELED DNA AT THE CHROMATID LEVEL OF CHROMOSOMES WITH DIFFUSE CENTROMERES
Authors: Nelson Janet S. R.
Published: November 2014

After pulse labeling Luzula purpurea shoot meristems with3H-thymidine, the cell cycle and its subdivisions were determined autoradiographically using the labeled mitoses method. The cycle time was 20 hr. G1 = 4.3 hr; C = 9.5 hr; G2 = 2.9 hr; and M = 3.3 hr. In subsequent experiments seedlings were labeled for 4 to 5 hr, long enough to label the chromosomes' full length, eliminating problems associated with asynchronous DNA replication. The longer labeling period did not alter the cell cycle parameters.Cells were designated as being in the first or second division after labeling by the time from the midpoint of the labeling period. Seedlings were placed in 0.1% cycloheximide solution to cause sister chromatids in metaphase cells to separate from each other. Autoradiographs were then made to determine segregation of labeled DNA at the chromatid level. At the first division after labeling all chromatids appeared to be labeled. At the second division after labeling with3H-thymidine the labeling pattern was consistent with semiconservative segregation of labeled DNA and with sister chromatid exchange.These results are discussed in relation to cytological and photometric studies on chromosome strandedness in Luzula and in other organisms with chromosomes with diffuse centromeres.
MITOTIC RECOMBINATION IN BIOCHEMICAL MUTANTS OFUSTILAGO HORDEI
Authors: Kozar F.
Published: November 2014

Data presented indicate the existence of parasexual recombination in U. hordei. Compatible combinations of mutant sporidia were employed to infect the barley host. After some time the parasite was recovered as sporidia or as teliospores. Evidence indicates that the nuclei within the infective dikaryon undergo fusion and produce diploid sporidia characterized by an indefinite Bauch test and biochemical 'wild type' appearance. It is assumed that the diploid infection sporidia may again undergo haploidizarion thereby providing parasexual recombination of parental biochemical markers. These somatic recombinants were observed among sporidia extracted and recovered from the host.
A RE-EXAMINATION OF THE CHROMOSOMES OF THE TETRAPLOID 'AVENA STERILIS' FROM SARDINIA
Authors: Rajhathy Tibor
Published: November 2014

The comparison of the karyotypes of the Sardinian tetraploid 'A. sterilis' reported by Martinoli, and those of A. magna and A. barbata suggested that the chromosomes of the Sardinian tetraploid are more similar to those of A. barbata than to those of A. magna.
INFLUENCE OF DIET ON LACTATIONAL PERFORMANCE AND DAM AND LITTER WEIGHTS IN LINES OF MICE SELECTED AND UNSELECTED FOR INCREASED 12-DAY LITTER WEIGHT
Authors: Eisen E. J. , Hanrahan J. P.
Published: November 2014

Genotypic and dietary (high energy versus standard) influences on lactational performance and on dam and litter weights were studied in lines of mice selected for increased 12-day litter weight and in unselected control lines. There was no evidence that genotype (either among full-sib families within lines or between selected and control lines) × diet interactions were present for 12-day litter weight or correlated traits. The high energy diet led to significant increases in 5- and 12-day litter weights and milk yield 12 days postpartum, but no change in per cent solids or per cent lipid of the milk. Increased milk yield of dams on the high energy diet was sufficient to account for the larger 12-day litter weights. Increased 12-day postpartum weights of dams fed the high energy diet may be related to the increase in milk yield since there was no diet difference in dam weight at parturition. Litter weights at 5 and 12 days of age were significantly larger in the selected lines. However, there were no significant differences in milk yield, per cent solids or per cent lipid between selected and control dams. Body weights of dams in the selected line were larger at 8 weeks of age, at parturition and at 12 days postpartum.
THREE FURTHER STUDIES OF THE CHROMOSOMES OF JAPANESE WEEVILS (COLEOPTERA: CURCULIONIDAE)
Authors: Takenouchi Yasushi
Published: November 2014

The chromosomes of three Japanese weevil species, two parthenogenetic and one bisexual, are described for the-first time. Males of the alate Cyrtepistomus castaneus are unknown. Oogonial metaphases had standard, 3x = 30, and substandard, 3x = 31, chromosome numbers (range ca. 28 — ca. 33). No reduction occurs at meiosis (ca. 30 univalents at MI). This species is therefore considered to be a triploid parthenote. Eight oocyte metaphases of Blosyrus japonicus, which also appears to lack males, showed between 66 and 61 (or 60) univalent chromosomes (two had 66, three had 65). These counts categorize the mothers as thelytokous hexaploids, a degree of polyploidy not previously found in the Curculionidae. The male of the bisexual Ceuthorrhynchus lewisi (2n = 28) possesses an unusually large pair of sex chromosomes. The metacentric X and telocentric Y form an achiasmate, umbrella-like bivalent that is unique among known Coleoptera.
SOME BIOMETRICAL STUDIES ON NINE AGRONOMIC TRAITS IN GRAIN SORGHUM, SORGHUM BICOLOR (L.) MOENCH: I. Variance Components and Heritability Estimates
Authors: Chung Jai H. , Liang George H. L.
Published: November 2014

The investigation was designed to estimate genetic and environmental variability and heritability for a number of agronomic characters in grain sorghum. The study was made in the F3 and F4 generations of three crosses grown at two locations in each of two years. Heritability estimates were computed by three methods: by variance components and by the regression of the F4 generation on the F3, using both conventional and standard-unit methods.In general, the genotypic components of variance were larger than those of the genotype × environment interactions. With few exceptions, second-order interactions were larger than first-order interactions. Although the first-order interactions are of lower magnitude, they should not be interpreted as though the genotype × year and genotype × location interactions did not exist; they may be a reflection of the nature of the lines tested and environments sampled. Most heritability estimates obtained from the three methods were in close agreement. Heritability estimates for half-bloom date, peduncle diameter, and plant height for all crosses were high regardless of the method of calculation. Grain yield, head weight, kernel weight, and kernel number showed moderately high heritability values, while those for head number and threshing percentage appeared to be low.
VARIANCE COMPONENTS IN TOBACCO CULTIVAR TRIALS
Authors: Povilaitis Bronius
Published: November 2014

The data from the Comparative Variety Test of flue-cured tobacco cultivars were available from two locations in south-western Ontario for 1964, 1965 and 1966. Eleven cultivars were in common for the combined analysis of variance. Data for 12 characters were utilized.The main effects, years and locations, were not significant for all characters but the effects for genotypes were significant for yield attributes only. The interaction years × locations was significant for 10 of 12 characters. Variance components for genotype × location interaction were small and significant for only two characters. Genotype × year interaction components were significant for four characters. The components for genotype × location × year interaction were significant only for yield, crop index, number of leaves, and petroleum ether extractives. Total theoretical variance, calculated from the components, was utilized to evaluate the adequacy of the number of years, number of locations, and the number of replications in cultivar tests. It is suggested that three locations with four replications for 2 or 3 years would give an adequate evaluation of a breeding line or cultivar performance. From the ecovalence values of the cultivars it was concluded that specific combinations of environmental conditions, rather than the differences among cultivars, were instrumental in producing significant genotype × location × year interactions.
ABSENCE OF A DETECTABLE CHANGE INDsAT THE A1LOCUS IN MAIZE FOLLOWING MUTAGENIC TREATMENTS
Authors: Mouli Chandra , Notani N. K.
Published: November 2014

Various mutagenically-effective treatments for Sh2locus failed to produce any back mutation of the closely linked [Formula: see text] marker complex. Nor were any Ac-like elements generated. An excision-repair model was proposed to explain the stability of Ds mutations in the absence of Ac and its high mutability in the presence of Ac. A number of other observations on mutable loci in maize were also explained on the basis of this scheme.
CYTOGENETICAL STUDIES OF SOME BACKCROSS DERIVATIVES OF GOSSYPIUM HIRSUTUM × G. ANOMALUM
Authors: Sharif Afsari , Islam A. S.
Published: November 2014

In an attempt to breed for jassid resistance, a hexaploid (F1, G. hirsutum var. M4 × G. anomalum doubled), was backcrossed twice to the cultivar M4. In the first backcross, there were three plants with 60, 62 and 55 chromosomes instead of the expected 65. G. anomalum chromosomes were rapidly eliminated in subsequent generations of both 60- and 62-chromosome plants giving rise to 54- (26 II + 2I) and 53- (26 II + 1I) chromosome plants. These, as well as-some second backcross progeny with 52 and 54 chromosomes (27 II), are considered to be potentially promising breeding material for jassid resistance and length, strength and lustre of fibre.
GENETICS OF A PRIMARY TRISOMIC SERIES IN BARLEY: IDENTIFICATION BY PROTEIN ELECTROPHORESIS
Authors: McDaniel R. G. , Ramage R. T.
Published: November 2014

Disc electrophoresis of seed proteins identified the extra chromosome involved in primary trisomics of barley. Each of the seven primary trisomics could be distinguished from diploids and from each other. Electrophoresis provided a precise biochemical criterion for identification of trisomics.
SOMATIC ASSOCIATION OF CHROMOSOMES IN BARLEY
Authors: Fedak George , Helgason S. B.
Published: November 2014

Distances between pairs of homologous and nonhomologous telocentric chromosomes were measured in root tip cells of barley. The nonhomologous telocentrics were randomly distributed, whereas the homologues were significantly closer than would be expected with random distribution.
GENETICALLY MIXED PERITHECIA AND SOMATIC RECOMBINATION IN A PSEUDO-WILD TYPE STRAIN OFNEUROSPORA CRASSA
Authors: Radford A. , Threlkeld S. F. H.
Published: November 2014

In a pseudo-wild heterokaryon of Neurospora, mixed perithecia in a cross in which the heterokaryon is used as the protoperithecial parent may be common. In the present work, 4 out of 22 perithecia contained more than one female nuclear type.A somatic recombinant nucleus, resulting from nondisjunction at anaphase II followed by recombination prior to breakdown of the disomic nucleus has been identified. The recombination event occurred between pyr-1 and tryp-4 on linkage group IV.
MEIOTIC DRIVE IN NATURAL POPULATIONS OFDROSOPHILA MELANOGASTER. IX. SUPPRESSORS OFSEGREGATION DISTORTERIN WILD POPULATIONS
Authors: Hartl D. L.
Published: November 2014

A population of Drosophila melanogaster in Madison, Wisconsin, has been screened for suppressors of segregation distorter (SD), an autosomal meiotic drive element found in the same population. Three kinds of suppressors were tested for: (1) Y-linked suppressors, none were found, (2) X-linked suppressors, whose frequency was found to be 85%, and (3) autosomal dominant suppressors, which occur in 45% of autosome complements.The frequency of X-linked suppressors is comparable to that found in a Japanese population; autosomal suppressors are much more frequent in Madison than in Japan (Katoaka, 1967). The similarity in the frequency of sex-linked suppressors may result from the meiotic drive shown by the suppressor-X itself; the difference in the frequency of autosomal dominant suppressors is possibly related to a higher frequency of SD itself in the Madison population.
CHROMOSOMAL CHANGES IN MAIZE INDUCED BY HYDROGEN FLUORIDE GAS
Authors: Mohamed Aly H.
Published: November 2014

Maize seedlings of the genotype A1A2C1Wx were fumigated in growth chambers with hydrogen fluoride (HF) at a concentration of about 3 μg/m3. The experiment was run for 10 days, with the first group of treated plants removed from the chambers after 4 days and then at intervals of 2 days. Microsporocyte smears from the treated plants revealed chromosomal aberations that included asynaptic regions, translocations, inversions, and bridges plus fragments or fragments by themselves. It is believed that these abnormalities were due to the physiological effect of HF causing the chromosomes to become sticky and/or to the occurrence of chromatid breakage followed by reunion to form structural changes. These findings indicate that HF is a mutagenic agent.
EFFECTS OF GROWTH INHIBITION BY HYDROCORTISONE ACETATE ON VARIANCE IN CHICKENS
Authors: Gavora J. S. , Hodgson G. C.
Published: November 2014

Traditionally genotype by environment interaction studies have dealt with changes in external environment. In this experiment an attempt was made to alter internal environment and keep external environment constant. Cockerels from each of six different commercial stocks were injected with 0,1,2 and 4 mgs hydrocortisone acetate per 100 gms body weight at 14 days of age. This type of hormonal treatment was shown to release additional variability in growth without producing any stock-treatment interaction at the level of means. The results indicate a possible new avenue for future research.
PARACENTRIC INVERSIONS AND DETECTION OF SEX LINKED RECESSIVE LETHALS IN AEDES AEGYPTI
Authors: Bhalla Satish C.
Published: November 2014

Two sex linked paracentric inversions one on m chromosome, marked with bz (bronze body) and the other on M chromosome, marked with w (white eye), were artificially induced with X-irradiation and isolated. The inversions are designated as In. (1)1 and In. (1)2 respectively. The former is more than 23 units long and the later more than 16 units. Both suppress crossing over markedly and are associated with partial sterility. The two inversions are utilized as crossover suppressors in a technique designed for detecting sex linked recessive lethals. The technique works satisfactorily with certain limitations. The possibility of combining inversions with other chromosomal aberrations for genetic control of Aedes aegypti populations is suggested.
CLOSE LINKAGE OF GENES FOR MALE STERILITY AND ANTHOCYANIN SYNTHESIS INBRASSICA OLERACEAPROMISING FOR F1HYBRID SEED PRODUCTION; MULTIVALENTS AT MEIOSIS NOT INVOLVED IN THE LINKAGE
Authors: Sampson D. R.
Published: November 2014

Thirty-two progenies showed a mean of 4.3 ± 0.3% recombination between ms-1, a gene for male sterility and c-1, a seedling marker gene. The closeness of this linkage makes it useful for producing F1hybrid seed of Brassica vegetable crops. Differential viability, acting prior to seed germination and associated with the c-1 locus, resulted in either a deficiency or a surplus of ms-1 ms-1 plants depending on the linkage phase. The mean viability of plants with the C-1 phenotype was 1.26 ± 0.03 times that of c-1 c-1 plants. The genetic stocks studied bred true for a quadrivalent at meiosis I. This presumed duplication was traced through seven generations but was not responsible for the ms-1 c-1 linkage.
STUDIES ON NATURAL POPULATIONS OFDROSOPHILA. XII. HETEROSIS AND FITNESS CHARACTERS IN HYBRIDS BETWEEN DIFFERENT POPULATIONS OFDROSOPHILA MELANOGASTER
Authors: Tantawy A. O. , El-Helw M. R.
Published: November 2014

Three different unrelated natural populations of Drosophila melanogaster from Scotland, Japan and Egypt, as well a highly inbred line, were the basis of the present study. Crosses were made within and between natural populations and between each of the natural populations and the highly inbred line to obtain the parental, F1and F2generations and their relative fitness studied at 15°, 25° and 28 °C.The F1interpopulation hybrids were superior to both parents in egg production, percentage emergence and longevity of adults in most of the crosses. Heterosis tended to be higher at 15° and 28° than at 25 °C. The F2in all crosses was inferior to the F1and also inferior to one or both parents. In crossing the inbred line with any of the natural populations, the F1generally showed higher heterosis than that of the interpopulation hybrids; the F2was also inferior to the F1but superior to the inbred parent.Significant genotype-environment interaction was detected, indicating the differences in sensitivity to temperature in each population. Variance of any-given fitness character of a superior population at a given temperature was often smaller than the poor genotype. There was a decline in the coefficient of variation in the F1generation and an increase in the F2's.
DEVELOPMENT, STRUCTURE AND COMPOSITION OF LAMPBRUSH CHROMOSOMES IN DOMESTIC FOWL
Authors: Ahmad M. Sharif
Published: November 2014

Stained sections of developing ovaries and hand-isolated oocyte nuclei and lampbrush chromosomes of domestic fowl were studied. The observations suggest a synchronous transformation from the diplotene chromosomes to the lampbrush stage of chromosomal development and an asynchronous breakdown of recognizable chromosomes in larger oocytes.Before the appearance of lampbrush chromosomes a series of nucleo-cytoplasmic changes were observed in the developing oocytes. Formation and dispersal of the Balbiani-body complex in the cytoplasm appears to be associated with the movement of chromosomes and the initiation of lampbrush formation.The lampbrush chromosomes are developed early in life, in about 18-day chicks, and continue to be observed in active oocytes (above 150 μ diam) of mature birds. The lateral loops of lampbrush chromosomes appear to contain nucleoprotein chromatic granules in linear array. Using enzyme treatment it is conceived that the protein composition of the lampbrush chromosome is relatively higher than is observed in other species and that nucleoprotein synthesis can take place in several segments of a single loop of the avian lampbrush chromosome.
ESTIMATION OF THE MITOTIC CYCLE IN LARVAL BRAIN CELLS OF THE HOUSE FLY
Authors: Jan K. Y. , Boyes J. W.
Published: November 2014

An attempt to estimate the mitotic cycle in brain cells of the house fly was made by injecting thymidine-methyl-H3into third instar larvae. The G2 period plus prophase was about 1.5 hours for some of the XX and XY cells. The graph of the percentages of metaphases labelled deviated considerably from the theoretical expectation, preventing a valid estimation of the duration of G1, S, mitosis and total cell cycle. The probable causes of such deviation have been discussed.
GENETIC CONTROL OF VARIATION IN A SELECTED POPULATION OF LOLIUM PERENNE L.
Authors: Hayward M. D. , Lawrence T.
Published: November 2014

Progenies from a five genotype diallel cross in Lolium perenne L. were studied to assess the pattern of genetic control for seed weight, a number of seedling characters, and two adult plant characters.Variation in seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Gene action was additive, but some specific genetic effects were also present, suggesting possible interaction between the haploid pollen genome with a diploid ovular genome in the triploid endosperm, or alternatively between the developing seed and the female parent plant.Of the seedling characters (total germination, rate of germination, rate of leaf and tiller production, length of fifth leaf, and seedling dry matter production) only length of fifth leaf showed any additive variation which might be easily exploited.Adult plant production showed considerable variation which interacts with the season of assessment. However, the relative order of merit remained the same and only the magnitude of the differences in productivity between the families altered. This response was itself under simple genetic control.
GENETIC AND ACCUMULATION STUDIES IN SULFITE-REQUIRING MUTANTS OFASPERGILLUS NIDULANS
Authors: Gravel R. A. , Käfer E. , Niklewicz-Borkenhagen A. , Zambryski P.
Published: November 2014

Using complementation tests and genetic mapping, mutants of two new genes, sE (sulfite less) and sF (thiosulfateless) were identified among 145 nitroso-guanidine-induced mutants of the sulfur metabolism in Aspergillus nidulans. Most of the other mutants (134) turned out to be alleles of the four established 'sulfite' genes, sA - sD. The new genes were found to be unlinked to any other s-gene; sE was mapped in linkage group VIII distal to cha and sF in VII. Mapping of several mutants allelic to one or the other of the closely linked sA or sC genes showed that these loci are two cistrons 1.1 cMo units apart.Results from studies using radioactive sulfate as a substrate for the different mutants showed35S-accumulation profiles by electrophoresis consistent with the assignment of the five sulfite genes to the following steps: sB(3), sulfate transport; sC(12), sulfurylation of ATP to produce APS; sD(50 or 205), phosphorylation of APS to PAPS; and sA(6) and sE(15), PAPS reduction to sulfite. Although the last two genes appear to control the same step, their35S-accumulation profiles are distinct. In addition, it was found that mutants of all previously established genes, including sA, are epistatic to sE(15) when single and double mutants are tested for resistance on selenate medium.
THE ISOLATION OF CROSSOVER SUPPRESSORS ON HOUSE FLY AUTOSOMES AND THEIR POSSIBLE USE IN ISOLATING RECESSIVE GENETIC FACTORS
Authors: McDonald Ian C.
Published: November 2014

A test procedure was devised to isolate crossover suppressors on autosomes of the house fly, Musca domestica L. Adult males from a wild-type strain were X-rayed and mated to virgin females carrying two mapped markers on a particular chromosome. F1females heterozygous for an unmarked test chromosome and a marker chromosome were then backcrossed to appropriate marker males and the F2progeny scored for reduced recombination frequencies. Two suppressors were recovered for chromosome III using this technique. One suppressor was recovered for each of chromosomes II, IV, and V. Cytological analyses of testicular tissues from suppressor heterozygotes revealed unpaired regions or loop configurations between autosomal homologues of interest in each suppressor strain. Three of the suppressors were lethal in the homozygous condition. One suppressor homozygote was viable and fertile; one appeared to be viable but sterile. Intrastrain matings between suppressor heterozygotes were usually less fertile than intrastrain matings between wild-type males and females. Lowered egg hatches were almost always recorded in heterozygous suppressor outcrosses to wild-type flies. Male suppressor outcrosses were usually less fertile than their corresponding female outcrosses. The data indicate that the crossover suppressors can be used to isolate recessive genetic factors in the house fly.
A DEVELOPMENTAL MUTANT THAT AFFECTS ASCOSPORE DELIMITATION IN NEUROSPORA TETRASPERMA
Authors: Novak Dennis R. , Srb Adrian M.
Published: November 2014

Self-fertile mycelia of N. tetrasperma containing normal nuclei and nuclei with a previously undescribed mutation (Gsp-1) yield perithecia bearing asci most of which contain a single giant ascospore. The mutation can be maintained in a self-fertile heterokaryon. All attempts to recover Gsp-1 nuclei from the heterokaryon have failed, although complementary nuclei (that is, those not carrying the Gsp-1 mutation) are easily recovered. Hence, in addition to its effect on ascospore delimitation, Gsp-1 is a recessive lethal. Data are presented to show that Gsp-1 is linked to mating type and probably arose as a spontaneous mutation.
QUANTITATIVE GENETIC NATURE OF VEGETATIVE GROWTH IN ALFALFA
Authors: Singh S. M. , Lesins K.
Published: November 2014

Seven selected clones of cultivated alfalfa, superior in forage yield, were used in the complete diallel crossing system. The crosses were made after complete emasculation of the flowers and the progenies, single planted in the field, were studied for vegetative growth at various stages for 3 years. The data was subjected to Griffing's (1956) method of diallel cross analysis and it was noted that though the general and specific combining ability variances for all these traits were significant, the genetic factors responsible for the specific combining ability, namely allelic and nonallelic interactions, were more prominent. This could be due to the fact that the material was subjected to several selection cycles for high yield. Similar conclusions were also derived from the heritability studies for growth during the year of establishment (1968), growth in spring and fall, and total vegetative yield in 1969 and 1970. In the light of the above genetic estimates, it may be proposed that additional gain in vegetative growth might be obtained by using these clones in the hybrid combinations.
CYTOGENETICS OF A UNIVALENT CHROMOSOME INBSDROSOPHILA MELANOGASTERMALES
Authors: Johnsen R. C.
Published: November 2014

Bsmales bearing a modified X:4 translocation in which one of the members, XPYL∙YS, is an invariable univalent show that the univalent-bearing gametes from males raised at 26.0 °C are recovered only half as frequently as from those raised at 18.0 °C (Zimmering, 1963).Such males were raised at 26.0 °C (Experiments I and II) and at 18.0 °C (Experiment III) and upon eclosion were mated to three yellow free-X females for 3 days at 26.0 °C. Testes of sib males were squashed and examined with phase optics to follow the meiotic behavior of the univalent. All tests were carried out over a 3-year period.The genetic results confirm those of Zimmering (1963) and show that the univalent is recovered with a frequency of 22.5 ± 0.9% and 18.5 ± 0.9% in Experiments I and II, whereas it is recovered with a frequency of 36.7 ± 1.6% in Experiment III. However, the cytological results show that while the univalent lags at A I with a frequency of 9.4, 28.7, and 32.2%, respectively, cells with and without XPYL∙YSare observed with equal frequency at M II and A II in all experiments. The post meiotic stages also appear to be normal at the level of the light microscope. Although negligible loss of the univalent is not excluded, it is clear that the frequency of XPYL∙YSlag is unrelated to temperature or to the distorted genetic ratios from males raised at 26.0 °C. Degeneration of XPYL∙YS-bearing sperm beyond the level of the light microscope remains as a possible explanation for the observed genetic distortion.
HYBRIDS BETWEEN A DIPLOID AGROPYRON ELONGATUM AND AEGILOPS SQUARROSA
Authors: Dvořák J.
Published: November 2014

Hybrids were obtained in crosses between Aegilops squarrosa and Agropyron elongatum (2x) but not in crosses between Ag. elongatum and Ae. speltoides and T. boeoticum, respectively. Chromosome pairing revealed a rather high degree of homoeology between the genomes of Ae. squarrosa and Ag. elongatum. The average pairing was 10.7′ + 1.5″ + 0.027″′ per cell with a range of from 0 to 5 pairs. All F1 hybrid plants were sterile with very low pollen fertility.It is proposed that the A and D genomes of wheat are more closely related to the genomes of section Elytrigia of the genus Agropyron than is the B genome.
RESISTANCE IN WHEAT TO FORMAE SPECIALES TRITICI AND SECALIS OF PUCCINIA GRAMINIS
Authors: Sanghi A. K. , Luig N. H.
Published: November 2014

Nine genes conditioning resistance to cultures of P. graminis tritici (possessing unusual genes for avirulence), P. graminis secalis, and sexual or somatic hybrids between these formae speciales were found in the wheat cultivars Mentana and Yalta. In Mentana, Sr8 operated against all six cultures utilized; but in Yalta, Sr11 conditioned resistance to only two hybrid cultures. In addition, four other genes in Mentana and three genes in Yalta operated against the cultures.The present study indicates that hybridization between wheat stem rust and rye stem rust can be important in producing new combinations of virulence genes which can attack known genes for resistance in wheat. The implications of such hybridization in relation to the transference to wheat of resistance in rye to P. graminis tritici are discussed.
MORPHOLOGIE DU CORPUSCULE FLUORESCENT INTERPHASIQUE MIS EN EVIDENCE PAR LA QUINACRINE CHEZ L'HOMME
Authors: Gagné Richard , Laberge Claude
Published: November 2014

In man, the distal part of the long arms of the Y chromosome and a corresponding interphase body fluoresce brightly when stained by quinacrine, an acridine derivative. We confirmed these observations, but we have found that this interphase body varies in size from one individual to another and that a multicorpuscular structure is often seen, which may correspond to a functional state.