bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDIES ON COMBINING ABILITY IN STRAWBERRY (FRAGARIA × ANANASSA). II. FRUIT LENGTH, FRUIT DIAMETER, FRUIT WEIGHT, ASCORBIC ACID, TOTAL SOLUBLE SOLIDS AND FRUIT YIELD
Authors: Lal Shri Dhar , Seth Jitendra Nath
Published: November 2014

A 10 × 10 complete diallel cross was carried out in strawberry (Frageria × ananassa Duch.). Significant general (gca) and specific combining ability (sca) effects were recorded for almost all characters. Variances due to gca exceeded the variances due to sca. Significant reciprocal effects were also observed. The cultivar 'Albritton' was the best general combiner for fruit length, fruit diameter, fruit weight and fruit yield; 'Redcoat' for ascorbic acid and 'Kalimpong Local' for total soluble solids. The best specific combinations for fruit length were 'Premier' × 'Torrey' in F1 and 'Swiss Seedling' × 'Cavalier' in F2. 'Redcoat' × 'Elista' in F1 and 'Premier' × 'Albritton' in F2 for fruit diameter and 'Phenomenal' × 'Swiss Seedling' in F1 and 'Torrey' × 'Albritton' in F1 and F2 were the best for fruit weight. Similarly 'Premier' × 'Kalimpong Local' in F1 and 'Phenomenal' × 'Cavalier' in F2 for ascorbic acid, 'Phenomenal' × 'Jeolikote Local' in F1 and 'Premier' × 'Kalimpong Local' in F2 for T.S.S. and 'Albritton' × 'Kalimpong Local' in F1 and 'Redcoat' × 'Elista' in F2 were best for fruit yield.
EFFECT OF CULTIVAR COMBINATION ON MEIOSIS IN BARLEY-WHEAT HYBRIDS
Authors: Fedak George
Published: November 2014

Hordeum vulgare cultivars Betzes, Bonus, and Emir were crossed with Triticum aestivum cultivars Chinese Spring and Koga. Variable cultivar effects on chiasma frequency in hybrids were observed. Chiasma frequencies per cell varied from 0.38 in the Emir × Chinese Spring hybrid to 3.27 in the Bonus × Koga hybrid. Paired configurations involved homeologous wheat chromsomes.
THE DISTRIBUTION OF CHROMATIN IN THE INTERPHASE NUCLEUS OFZEBRINA PENDULA
Authors: Evans Kirby J. , Filion W. Gary
Published: November 2014

An investigation of nuclear organization in interphase root tip cells of Zebrina pendula Schnizl. showed that: (1) 40% of the BSG (Barium hydroxide/saline/Giemsa) treated nuclei had nonrandomly distributed chromocenters and (2) BrdU-FPG (5′-bromodeoxyuridine-fluorescence plus Giemsa) treated nuclei showed discrete staining patterns when exposed to BrdU for time intervals of two or more cell cycles. These data were interpreted as further evidence for an ordered spatial arrangement of chromosomal regions in the interphase nucleus.
GENIC DIVERSITY OF NATURAL POPULATIONS OF A CLONE- FORMING TREEPOPULUS TREMULOIDES
Authors: Cheliak William M. , Dancik Bruce P.
Published: November 2014

Effects of asexual reproduction as a primary reproductive strategy on population structure and levels of variability were investigated electrophoretically in natural populations of a woody plant species, trembling aspen (Populus tremuloides Michx.), from Alberta. As expected, levels of genic diversity, 42%, and proportion of polymorphic loci, 92%, averaged over all clones are considerably greater than those reported for comparable samples of sexually reproducing plant and animal species. These measures of genic variability of a primarily asexual plant species are similar to those reported for asexual species of insects, fish and bacteria. In addition, each of the 222 clones was electrophoretically unique. Since neutral theory would predict each individual clone to be heterozygous for a unique mutation at each gene locus at equilibrium, these results can be interpreted in a number of ways: (i) insufficient time to reach equilibrium, (ii) inability of electrophoresis to detect all variation at a locus, (iii) periodic establishment of sexually derived propagules in the population, and (iv) selection for similar genotypes at each location or against mutations at particular gene loci. Re-invasion of Pleistocene-glaciated areas by trembling aspen likely was by sexual means, with subsequent reproduction being primarily asexual.
HAPLOIDIZATION ANALYSIS OF HETEROZYGOUS DIPLOIDS OF THE ENTOMOGENOUS FUNGUSMETARHIZIUM ANISOPLIAE
Authors: Bergeron Dominique , Messing-Al-Aidroos Karen
Published: November 2014

All stages of the parasexual cycle required for genetic analysis by haploidization have been demonstrated for Metarhizium anisopliae Metsch. (Sor). Heterokaryons have been synthesized from strains carrying complementing markers, and heterozygotic diploid colonies have been isolated from the heterokaryons. After exposure to benlate or botran, diploid colonies gave rise to a large number of haploid segregants. Analysis of the segregation of eight mutations in three crosses assigned these genes to five possible linkage groups. Use of the parasexual cycle should facilitate genetic analysis of pathogenesis and enhance the usefulness of this fungus for the control of insect pests.
A WHEAT MUTATION CONDITIONING AN INTERMEDIATE LEVEL OF HOMOEOLOGOUS CHROMOSOME PAIRING
Authors: Sears E. R.
Published: November 2014

An X-ray-induced mutation in common wheat (Triticum aestivum L.), designated ph2, conditions an intermediate level of homoeologous chromosome pairing in hybrids with Triticum kotschyi var. variabilis. The number of chromosomes paired averaged 9.2 per sporocyte, compared with 2.0 in the control and 27.9 in the same hybrid involving ph1b, an apparent deficiency for Ph1 obtained in the same mutation experiment. The ph2 mutation is located on chromosome 3D and is believed to be a deficiency for a terminal segment of the short arm that includes the locus of Ph2, a minor suppressor of homoeologous pairing. Although no pairing of the ph2-carrying chromosome with telosome 3DS was observed, the mutation is clearly not a deficiency for the entire arm. It has little effect on pairing in wheat itself. Male transmission of the mutation is approximately normal, and fertility, while reduced, is sufficient for easy maintenance of the homozygous line.
GIEMSA C-BAND IDENTIFICATION OF RYE CHROMOSOMES IN SOME ADVANCED LINES OF WINTER TRITICALE
Authors: Ziauddin A. , Kasha K. J.
Published: November 2014

Eight advanced breeding lines of hexaploid winter triticale (× Triticosecale Wittmack) visually selected for high fertility and nonshrivelled seeds were examined for loss of rye chromosomes or their telomeric heterochromatin. The Giemsa C-banding patterns indicated that there were no rye chromosomes lost and that the telomeric heterochromatin normally found in the rye chromosomes was maintained in most of the lines. Similar to a recent report on European winter triticales, high fertility and nonshrivelled seed development of these winter triticale lines could not be associated with the absence of rye chromosomes or their telomeric heterochromatin. Such changes may not be a prerequisite for the improvement of these characteristics in winter triticale.
CELL KINETICS AND RADIOSENSITIVITY OF HUMAN LYMPHOCYTES STIMULATED BY PHYTOHEMAGGLUTININ,WISTARIA FLORIBUNDAORLENTIL LECTIN
Authors: Deknudt G.
Published: November 2014

The cell kinetics and the radiosensitivities of human lymphocytes (four donors) exposed to 200 rads of X-rays and stimulated with phytohemagglutinin (PHA), Wistaria floribunda (WFA) or Lens culinaris (LcH-A) extracts have been compared after cultivation times from 42 up to 54 h. All these mitogens are considered activating primarily T lymphocytes. PHA is a tetrameric molecule, whereas WFA as well as LcH-A are dimeric structures having only two reactive sites. PHA displays a higher mitogenic activity than WFA, while LcH-A is much less active than PHA and WFA. After 42 h of culturing, only metaphases of the first mitosis are found, irrespective of the mitogen used. With increasing cultivation times, however, differences in the cell kinetics have been observed for the different mitogens. Furthermore, no differences in radiosensitivity of lymphocytes stimulated by these mitogens were observed when cells are analyzed exclusively in their first mitosis.
NUCLEAR MUTATIONS INSACCHAROMYCES CEREVISIAECONFERRING MULTIPLE SENSITIVITY TO PETITE-INDUCING TREATMENTS
Authors: Lusena C. V. , James A. P.
Published: November 2014

Eighteen EMS-induced mutant strains of S. cerevisiae with increased sensitivity to petite induction by sulfanilamide-aminopterin treatment have been isolated. Four of these strains demonstrated a concomitant increase in sensitivity to the petite-inducing effects of u.v. irradiation and of growth at an elevated temperature. Of these, two were shown to be a consequence of recessive nuclear mutations at one gene (sas 1-1 and sas 1-2). Expression of the two remaining mutations was too low to permit genetic analysis. All three petite-inducing treatments used in this study are known to reduce the hydrogen bond strength between the two strands of double stranded DNA, and the existence of multiple sensitivity is discussed in terms of an alteration of a mitochondrial endonuclease which acts preferentially at sites of reduced attraction.
Preferential abortion of gametes in wheat induced by an Agropyron chromosome
Authors: Scoles Graham J. , Kibirge-Sebunya I. N.
Published: November 2014

Wheat lines carrying a single Agropyron elongation (Host.) P.B. chromosome either as a monosomic substitution or as a recombined wheat – Agropyron chromosome exhibited an abnormally high frequency of transfer of this chromosome to their progeny. This was due to a high frequency of preferential transmission of the chromosome or the wheat–Agropyron chromosome through the female side which was accompanied by low seed fertility. It is suggested that the chromosome carries a gene which induces preferential abortion of gametes that do not carry it. The occurrence of such genes in a number of species and their significance are discussed.
Mutagen sensitivity of Neurospora meiotic mutants
Authors: Schroeder Alice L. , Olson Loree D.
Published: November 2014

The Neurospora meiotic mutants, mei-1, mei-2, mei-3, and mei-4 were tested for cross sensitivity to mutagens. Mei-2 and mei-3 are sensitive to MMS, γ-irradiation and histidine. Mei-2 is not sensitive to ultraviolet (UV) at 20 °C. Tests with recombinants with crossovers to either side of mei-2 or mei-3 show that these traits are the pleiotropic properties of a single gene which also determines meiotic behavior. The mei-2 gene maps to the right of al-3 on linkage group V. It is not allelic to mus-11. Upon backcrossing, the originally dominant meiotic effect of mei-2 becomes recessive to partially dominant. The histidine sensitivity is recessive.
Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). VII. Location of G6pd in linkage group I, and Alkph in linkage group II
Authors: Gooding R. H.
Published: November 2014

In Glossina morsitans morsitans Westwood the locus for glucose-6-phosphate dehydrogenase, G6pd, was found to be in linkage group I, approximately 35 to 42 map units to the left of ocra, the locus for body color. The locus for midgut alkaline phosphatase, Alkph, was found to be in linkage group II, within 0.41 map units of the locus for xanthine oxidase, Xo. The distance from Xo to the locus for aldehyde oxidase, Ao, was confirmed to be about 42 map units. No evidence for genetical recombination was found in male G. m. morsitans.
Chiasma frequency in male Blattella germanica (Dictyoptera; Blattellidae)
Authors: Keil Clifford B. , Ross Mary H.
Published: November 2014

Estimates of chiasma frequency and position for Blattella germanica are presented. Chiasmata occurred in terminal or subterminal positions in the majority of bivalents. Interstitial chiasmata were observed in some instances. A significant maternal age effect on chiasma frequency in the F1 generation is reported. Chiasma frequency declined in males that emerged from a female's subsequent oothecae and the variation within insects became smaller. An argument for the adaptive nature of these variations is presented. A stock heterozygous for a reciprocal translocation was examined for evidence of intra-chromosomal effects on chiasma frequency and insights on bivalent specific rates of crossing-over. It is concluded that chiasma frequency is probably not correlated with increasing chromosome length.
Reverse heteropyknosis between euchromatin and heterochromatin of the X chromosome in meiotic prophase of the cockroach Blaberus discoidalis
Authors: Shi Liming , Hsu T. C. , Pathak Sen
Published: November 2014

The X chromosome and all autosomes of the cockroach Blaberus discoidalis (2n = 37, XO) contain large segments of constitutive heterochromatin (C-bands). From spermatogonial metaphases, the C-bands are found to be located in the middle of most chromosomes, including the X. The C-bands show bright fluorescence when stained with Hoechst 33258. In pachytene, autosomal heterochromatin can be easily identified in acetic orcein squash preparations as condensed segments. In the same preparations the X chromosome exhibits a "closed" appearance with a lightly stained middle loop and two heavily stained terminal segments which lie side-by-side as if they are paired. In C-banded preparations, an opposite reaction is found, i.e., the loop is heavily stained while the tips are lightly stained. In Hoechst 33258 preparations, the loop is brightly fluorescent while the tips are less brightly stained. Thus, in pachytene of conventional orcein preparations the heteropyknotic behavior between euchromatin and heterochromatin of the X chromosome is the reverse of the usual staining pattern; instead of condensed heterochromatin and decondensed euchromatin, euchromatin is condensed whereas heterochromatin is decondensed. The "paired" euchromatic tips may suggest autologous homology between the original X and the original Y which might have been translocated onto the X in the course of karyological evolution.
The addition of Aegilops variabilis chromosomes to Triticum aestivum and their identification
Authors: Jewell D. C. , Driscoll C. J.
Published: November 2014

Nine of the 14 possible single chromosome addition lines of the tetraploid species Aegilops variabilis Eig. (CuCuSvSv) to Triticum aestivum L. cv. Chinese Spring (AA BB DD) have been isolated and identified. The nine Aegilops variabilis addition lines were compared with the available addition lines of Aegilops umbellulata (CuCu) and Aegilops longissima (SvSv) to further elucidate the relationship between these two diploids and the tetraploid Aegilops variabilis. Differences were observed between the same chromosomes isolated from the diploid and the tetraploid and discussed. After taking into account banding pattern polymorphisms, Aegilops umbellulata was confirmed as the donor of the Cu genome, and evidence indicated that Aegilops longissima probably is the donor of the other genome (Sv) in the tetraploid Aegilops variabilis.
Genetics of weather fleck in Nicotiana tabacum
Authors: Aycock Jr. M. K.
Published: November 2014

A 2-year study was conducted to investigate additive, dominance, and epistatic gene effects for weather fleck in Maryland tobacco (Nicotiana tabacum L.). P1, P2, F1, F2, P1F1, and P2F1 population means from each of seven crosses were used to estimate gene effects. In general, additive gene effects were more important in the inheritance of weather fleck than dominance or epistatic effects; however, in three of the seven crosses dominance and (or) epistatic gene effects were important. Adequate additive gene effects were present in five of the seven crosses to allow considerable progress towards selection of more weather fleck resistant lines. In two families, because of significant epistatic gene effects, the development of weather fleck resistant lines could be accomplished by producing doubled haploids from desirable F1 plants or by using a reciprocal recurrent selection program.
Hybrids between Hordeum parodii and H. vulgare
Authors: Fedak George
Published: November 2014

Hybrids between Hordeum vulgare and H. parodii were produced at a frequency of 22% of pollinated florets. Chiasma frequency per cell in the hybrids was 7.46 compared with 3.08 in the polyhaploid of H. parodii. The increased chiasma frequency in the hybrids was attributed to an increase in pairing between homoeologous chromosomes of H. parodii and there was no obvious homology between genomes of the two species.
Inheritance of polyembryony in flax (Linum usitatissimum)
Authors: Green A. G. , Salisbury P. A.
Published: November 2014

The inheritance of polyembryony (haploid–diploid twin seedlings) in the cross between Linum usitatissimum L. cv. Avantgarde (zero twinning) and cv. Rocket 4 (6.6% twins) was examined. It was concluded that the production of polyembryonic seeds is controlled mainly by additive gene action, with a realized narrow-sense heritability of 0.8. The frequency of twinning in the F2 generation displayed substantial transgressive segregation, ranging from zero to 32.0%. It was considered that such transgression could be due to either the presence of residual heterogeneity for twinning alleles in cv. Rocket 4, or the existence of a genetic system suppressing the expression of twinning alleles in cv. Avantgarde. The occurrence of a genotype producing haploid plants from more than 30% of its seeds should enable the efficiency of doubled-haploid line production to be greatly improved, and also lead to a better understanding of the embryological origins of the haploid component of polyembryonic seeds.
Genetic basis for lithium toxicity and its relationship with tissue distribution: a diallel cross analysis of six strains of mice
Authors: El-Kassem M. , Singh S. M.
Published: November 2014

Lithium toxicity measured as the time to death following an intraperitoneal injection of a lethal dose (900 mg/kg) of lithium chloride was determined in 8-week-old males from six genetic strains of mice (Balb/c, C3H/S, C57BL/6J, DBA/2, 129/ReJ, and S.W.) and their F1 hybrids. These genotypes were also evaluated for the Li+ distribution in the body 1 h after an i.p. injection of a 200 mg/kg dose of LiCl. Genotype differences in toxicity and lithium concentration in eight tissues, excreta, and urine were all statistically significant. Significant rank correlation with toxicity was found for Li+ levels in three of the tissues (kidney, lung, and blood), excreta, and urine. Diallel cross analysis was used to investigate the genetic properties of the mouse strains in responding to the toxic effects of lithium and in regulating its levels in these tissues, excreta, and urine. Our results suggest that genetically influenced membrane transport which regulates the elimination of the ion via urine and feces is an essential component in determining lithium toxicity. In general, there was a high degree of intra- and inter-genic interaction among genetic determinants of toxicity and its distribution in a number of tissues. The order of dominance of the strains as determined by (Vr, Wr) graph was different for each of the systems analysed. It is realized that the Li+ distribution in the different parts of the body is not the only factor affecting lithium toxicity.
La glutamate déshydrogénase de la luzerne : aspects cytologiques, structuraux et évolutifs
Authors: Vienne D. de
Published: November 2014

The 28 isozymes of the glutamate dehydrogenase (GDH) from Medicago sativa L. pollen result from the random association of three different subunits that form a hexamer enzyme. We show in this paper that: (i) all the isozymes have a mitochondrial localization; (ii) the only mutant that we found in the species (among about 350 individuals) can also be explained by adjusting the distribution of band intensities to a multinomial distribution. The principles of this method are detailed; (iii) the zymograms obtained from other organs accord with the hexamer model of the enzyme; (iv) this mitochondrial GDH is probably homologous to all the mitochondrial GDH, whether they come from plants or animals.
An electron microscope study of the karyotypes of two wolf spiders
Authors: Wise Dwayne
Published: November 2014

Meiosis in two species of wolf spiders, Lycosa georgicola Walckenaer and Lycosa rabida Walckenaer, has been analyzed by light and electron microscopy. Both karyotypes comprise 13 autosomal pairs + X1X2, all except one pair of which are telocentric. The autosomes show a gradual increase in size ranging from 5.6 to 9.9% of the total genome length. The two X chromosomes of L. rabida are not significantly different in length. In both species, the two X chromosomes are loosely aligned at prophase, but never synapse in the true sense; they do not form synaptonemal complexes. This supports the evidence that X1 and X2 are not homologous. In L. georgicola, one of the X's is associated at prophase with one autosomal pair, but this association does not persist to prometaphase.
Genetic analysis of anther-derived plants of rice: independent assortment of unlinked genes
Authors: Chen C. C. , Chiu W. L. , Yu L. J. , Ren S. S. , Yu W. J. , Lin M. H.
Published: November 2014

Haploid and diploid plants produced from anther culture of two hybrids of rice (Oryza sativa), each heterozygous for two unlinked genes, were subjected to genetic analysis. Progeny tests showed that all diploids but one were homozygous for both loci. Chi-square tests of the haploids and homozygous diploids revealed that the two genes in each hybrid segregated in the expected 1:1 ratio and that the four genotypic classes fit a 1:1:1:1 ratio, indicating that independent assortment of marker genes occurred and that the gametes were equally viable in the microspore-derived progeny. One diploid plant produced from anthers of the hybrid of genotype wx+wx lg+lg was found to be homozygous for lg+ but heterozygous for the waxy locus. Indirect evidence suggests that a mutation at the waxy locus in a spontaneously doubled haploid cell during culture may be the cause for occurrence of this unusual plant.
Patterns of variability in DNA content and nuclear volume in regenerating cultures of Nicotiana tabacum
Authors: Berlyn Mary B.
Published: November 2014

The frequency distributions of DNA content per nucleus were examined in five isonicotinic acid hydrazide (INH) resistant callus lines of tobacco and in developing buds and shoots regenerating from the lines. They were compared with the distribution for a diploid plant, with an estimated 2C value of 7.8 pg. The total range of all the callus cultures was between 5 and 40 pg, with modes between 7 and 16 pg. In the oldest (6 years) callus culture, the mean and standard deviation were lower in the buds developing from the culture than in the undifferentiated callus: however, older shoots again showed a higher mean and more disperse distribution. In contrast, for 4-year-old secondary callus cultures from plants simultaneously regenerated from a second INH-resistant (I 24) line, the mean DNA content per nucleus of the developing buds was higher than that of the undifferentiated callus. Less variation and a more nearly diploid distribution were observed in a 2-year-old callus culture of a fertile plant chosen from the progeny of one of these I 24 plants and in the buds and older shoots regenerated from this culture. Thus, in these five moderately heteroploid cultures a consistent pattern of selection for euploid levels of DNA did not occur during the observed stages of regeneration. Examination of volume as well as DNA content of nuclei in the different tissues showed that variability of nuclear volume measurements, as indicated by coefficients of variation, was correlated with variability of DNA content per nucleus, although measurements of volume and DNA content per individual nucleus were not always highly correlated. It is suggested that high coefficient of variation of nuclear volume, in conjunction with large nuclear size, could serve as a rapid preliminary indicator of highly heterogeneous DNA levels in the nuclear population of Nicotiana cultures.
Inheritance and linkage of isozymes in white spruce (Picea glauca)
Authors: King John N. , Dancik Bruce P.
Published: November 2014

Variation patterns for 26 loci of white spruce (Picea glauca (Moench) Voss) from 16 enzyme systems were studied using haploid megagametophyte tissue. Inheritance models for 17 polymorphic loci were formulated and tested for deviations from Mendelian segregation. Linkage analyses were conducted for 12 of the polymorphic loci in pairwise comparisons. Significant joint segregation was found for three pairs of loci: Pgi-2 with Aat-1, Gdh with Idh, and one of three families tested with Pgi-2 and 6pg-2,3.
Chromosome distribution between two restitution nuclei in a cell following colchicine treatment
Authors: Davidson D. , Pertens E. , Zhao J.-P.
Published: November 2014

Roots of Zea mays L., Secale cereale L., Vicia faba, L., Allium cepa L., and Hordeum vulgare L. were treated with colchicine. C-metaphases were observed in cells which had chromosomes present in two distinct groups, not the typical single group. Chromosome distribution into two groups was not followed by chromatid segregation: instead, the chromosomes underwent restitution and binucleate-interphase cells were formed. The distribution of chromosomes into two groups is functionally equivalent to chromosome nondisjunction. In some cases, the two groups contained different numbers of chromosomes; these gave rise to aneuploid nuclei. The results support the view that the pattern of chromosome distribution into two groups is not random; it may reflect chromosome position in the interphase or prophase nucleus. The results are related to (i) the formation of genotypic and phenotypic mosaics produced by treatment with other microtubule inhibiting drugs or in response to cell division mutants and (ii) the spatial distribution of chromosomes within the nucleus.
Karyotypic conservatism in the genus Lepus (order Lagomorpha)
Authors: Robinson T. J. , Elder F. F. B. , Chapman J. A.
Published: November 2014

The G- and C-banded chromosomes of six species of hare (genus Lepus) are presented and compared. No variation in gross chromosome morphology or banding pattern was observed indicating that speciation in this widespread genus has not involved karyotypic change.
Centromere orientation at metaphase I of a translocation heterozygote in lentil
Authors: Buruchin Frida , Ladizinsky G.
Published: November 2014

Reciprocal translocation between submetacentric and acrocentric chromosomes of lentil was studied. This interchange did not entail karyotypic changes. Two homomorphic ring bivalents produced by the four chromosomes of the translocation complex indicated that the long arm of the acrocentric chromosome was involved in the interchange. Chiasmata distribution in the native arms, the translocated and interstitial segments in bivalents and quadrivalents, was taken as an indication for two pairing pattern in the translocation complex. Chiasma terminalization in the short arm of the acrocentric chromosome of the translocation complex was faster in bivalents than in quadrivalents. The overwhelming number of cells with alternate-1 compared with alternate-2 orientation was attributed to the similar length of the zigzag diagonals of alternate-1 that apparently induced greater stability. The necessary elements for adjacent-2 orientation were available in the examined material but were practically absent. Pole–centromere specificity was proposed for explaining the absence of adjacent-2 in the present and other studies and the orientation of homologous centromeres to opposite poles even when they were located in different bivalents.
Genetic differentiation for allozymes and fitness characters between mainland and Bogota populations of Drosophila pseudoobscura
Authors: Singh Rama S.
Published: November 2014

We have examined the pattern of hidden allelic variation at 10 loci in mainland and Bogota populations of Drosophila pseudoobscura by various electrophoretic criteria employing gel concentration, pH, and buffer variation. Based on these loci the genetic similarity between mainland and Bogota populations has decreased from 64 to 15%. Bogota is genetically differentiated at 6 of the 10 loci examined (per locus genetic identity less than 5%). We have also made a comparative study of developmental rate, mating speed, sex ratio, fertility, egg-to-adult viability, and ethological differences and found that for all these fitness characters Bogota is polymorphic and shows some genetic differentiation from the mainland populations of D. pseudoobscura. These results are discussed in relation to the current estimates of genetic similarity between species, and the extent of genetic differentiation during species formation.
Genetics of Gibberella fujikuroi. IV. Natural occurrence of compatibility alleles at the mating locus
Authors: Sidhu Gurmel S.
Published: November 2014

Gibberella fujikuroi is a heterothallic bipolar fungus and both mat+ and mat− mating types are found in nature but, they rarely cross under natural conditions. However, mat+ and mat− field isolates cross with the two tester strains under laboratory conditions and show variable degrees of sexual compatibility as measured in terms of number of fertile perithecia. Fifteen mat+ and fifteen mat− field isolates were crossed with the two tester strains. Variable degrees of compatibility, ranging from 2.2 to 47.7 perithecia when crossed with 223 (mat−) and 1.1 to 39.9 perithecia when crossed with 80 (mat+), were obtained. The genetic control of six easily distinguishable degrees of compatibility were studied from testcrosses made with the tester strains using random and unordered tetrad analyses. Three alleles in mat+ and three alleles in mat− were distinguished. Frequency of natural occurrence of mat+ and mat− was found to be 27 and 73%, respectively.
Sources of tertiary trisomics for balanced chromosomal systems in hybrid rye breeding
Authors: Vries J. N. de
Published: November 2014

To increase the efficiency of isolating tertiary trisomics, five rye translocations of the Wageningen translocation tester set with exchanged segments of different size were crossed with either a telocentric or a primary trisomic, or with each other. Progenies of two telocentric translocation trisomics, four translocation trisomics, and one double-translocation trisomic thus obtained, were karyotyped, and metaphase I (MI) configurations of the two telocentric translocation trisomics were quantitatively investigated. Tertiary trisomics were obtained with the extra, short translocation chromosome of each of the five interchanges, at frequencies of 0.5–1.0% in the case of the telocentric translocation trisomics. This hardly implies an increase compared with the corresponding interchange heterozygous disomics (maximum 1%, tertiary and translocation trisomics combined). The translocation and double-translocation trisomics yielded higher percentages of tertiary trisomics, the difference being due to the extra chromosome (telocentric or normal) present in the mother plants, and to different ranges of possibilities for MI association and anaphase I (AI) disjunction, respectively. No tertiary trisomics carrying a long translocation chromosome as the extra chromosome were detected. A reduced viability of eggs or zygotes with large amounts of extra chromosomal material, rather than a low frequency of the appropriate MI orientation, is suggested to be the cause.
The effect of homoeologous group 3 chromosomes on chromosome pairing and crossability in Triticum aestivum
Authors: Miller T. E. , Reader S. M. , Gale M. D.
Published: November 2014

Differences in the level of chromosome pairing in hybrids between 'Chinese Spring' wheat homoeologous group 3 aneuploids and rye and in homoeologous group 3 aneuhaploids were studied. Factors affecting chromosome pairing were detected or confirmed on both arms of the chromosomes of homoeologous group 3 in wheat. Effects were also identified on chromosome 3R of rye and a chromosome of Hordeum bulbosum. Factors affecting crossability between 'Chinese Spring' wheat and H. bulbosum were also found on chromosomes 3A, 3B, and 3D. A correlation was shown between increased pairing and reduced crossability.
Role of ions in activation of human lymphocytes
Authors: Pearson J. L. , Ray M.
Published: November 2014

Phytohemagglutinin (PHA)-stimulated lymphocytes were cultured in media containing varying levels of K+, Mg2+, Ca2+. Cell activation was monitored by measuring nuclear diameter and by evaluating the area of nucleolus which reacted with silver nitrate. Decreasing extracellular K+ from normal levels (5.0 mM) to 14% (0.7 mM) and decreasing extracellular Mg2+ from normal levels (1.0 mM) to 14% (0.14 mM) did not affect nuclear diameter or silver nitrate reactivity of PHA-stimulated lymphocytes. Chelation of extracellular Ca2+ with EGTA during the first 24 h after PHA stimulation completely inhibited the increases in silver reactivity and nuclear diameter associated with stimulation. Chelation of extracellular Ca2+ 48 h after PHA stimulation did not inhibit lymphocyte stimulation. Inhibitory effects of EGTA were completely reversed if CaCl2 was added to the medium within 24 h of PHA stimulation. By 48 h the effects were irreversible.
Evaluation of culture media for effects on cell cycle kinetics and incidence of chromosomal aberrations in human blood cells
Authors: Sinha Anil K. , Linscombe V. Ann , Gollapudi B. Bhaskar , Flake Raymond E.
Published: November 2014

Peripheral blood samples from 17 apparently healthy male volunteers were set up in duplicate cultures using three commercially available media: Eagle's MEM, RPMI 1640, and TC 199. BUdR (5-bromo,2-deoxyuridine) (10 μg/mL) was added to one of the cultures from each person in each medium after 24 h of culture initiation. All cultures were harvested at 72 h of incubation in the presence of colcemid. RPMI 1640 stimulated the highest mitotic activity in both BUdR-treated and untreated cultures. Higher numbers of first division metaphases corresponded with the higher frequency of chromosome-type aberrations in cultures with Eagle's MEM as compared with RPMI 1640 media. On the other hand, higher numbers of chromatid-type aberrations were present in cultures with TC 199 as compared with those with Eagle's MEM. When the chromosome- and chromatid-type aberration data were pooled to score total cytogenetic abnormalities, an influence of the medium was demonstrable. While cultures with Eagle's MEM and TC 199 had the greater number of first division cells, third of subsequent division cells were most prevalent in RPMI 1640 cultures. It is inferred that the length of the cell cycle, the mitotic index, and to some degree the incidence of spontaneous cytogenetic abnormalities are variable attributes of culture media.
The behaviour and effects of B chromosomes in the embryo and endosperm of pearl millet, Pennisetum americanum (L.) Leeke
Authors: Rao M. Krishna , Kumari K. Aswani
Published: November 2014

The rate of early seed development was studied in 3B × 3B and 0B × 0B crosses of pearl millet. B chromosomes have a retarding effect on the rate of endosperm development at about the middle of the coenocytic phase (24 h), at the time of and just after cellularization. The increase of endosperm cycle time in 3B versus 0B plants was 27%. The rate of embryo development was similar in both 0B and 3B plants up to 48 h postpollination but was significantly different at 72 h. Here the increase of cycle time in 3B versus 0B plants was 20%. Thus the effect of 3B plants on cell cycle was greater in both the embryo and the endosperm than has been reported previously for the root tip (13%). Nondisjunction of B chromosomes in both embryo and endosperm starts quite early. The mean number of B chromosomes per cell in the endosperm exceeded that of the embryo in all cases, probably owing to a fusion of three nuclei in the former compared with two nuclei in the latter.
Meiotic pairing in wheat–rye addition and substitution lines
Authors: Orellana J. , Cermeño M. C. , Lacadena J. R.
Published: November 2014

Chromosome pairing was examined in wheat–rye addition and substitution lines using the C-banding technique. It was found that both rye and wheat chromosomes affect each other's homologous pairing. The strongest diminution of wheat pairing (measured as bound arms per cell) was produced by chromosome 5R of rye (7.5 and 7.2% in 'Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). The weakest diminution of wheat pairing was produced by chromosome 3R in the 'Chinese Spring' – 'Imperial' addition line (1.1%). The diminution of rye chromosome pairing produced by wheat chromosomes ranges from 6.9 to 48.4% ('Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). When put into a wheat background, the rye chromosomes suffer a worse fate than the wheat chromosomes. For example, chromosome 6R reduces the wheat complement pairing in the 'Holdfast' – 'King II' addition line by 3.8% but its own pairing is reduced by 41.4%. The decrease in pairing of both wheat and rye homologous chromosomes in addition and substitution lines is a complex process in which factors such as genes controlling meiotic pairing, constitutive heterochromatin, and cryptic wheat–rye interactions can play important roles.
Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). VIII. Tryptophan oxygenase deficiency, the lesion causing salmon-colored eyes
Authors: Gooding R. H. , Rolseth B. M.
Published: November 2014

Tsetse flies, Glossina morsitans morsitans Westwood, with salmon-colored eyes had less xanthommatin in their heads than did wild-type flies. Wild-type adults excreted kynurenine but adults with salmon-colored eyes excreted tryptophan. Tryptophan oxygenase and kynurenine formamidase were found in pharate, wild-type adults removed from 24- to 27-day-old puparia and in postteneral wild-type adults. The latter enzyme, but not the former, was found in pharate and postteneral adults with salmon-colored eyes. Wild-type phenocopies were produced by administering formylkynurenine or kynurenine sulfate to pharate adults (which were genetically destined to have salmon-colored eyes) in 20- to 22-day-old puparia. The results are interpreted as indicating that the salmon allele sal, which is responsible for producing salmon-colored eyes in G. m. morsitans, causes a biochemical lesion resulting in an absence of tryptophan oxygenase activity.
Heterochromatin content and early endosperm development in 42-chromosome spring triticale
Authors: Gustafson J. P. , Lukaszewski A. J. , Skovmand B.
Published: November 2014

An analysis of several triticales (× Triticosecale Wittmack) from the International Maize and Wheat Improvement Center (CIMMYT) breeding program showed a strong correlation (r = 0.97, p ≤ 0.01) between test weight and the frequency of aberrant-nucleus formation in early endosperm development. The measurements of rye (Secale cereale L.) heterochromatin content indicated that, as compared with an average rye, in substituted triticales it was reduced by 21.4–49.8% and by 9.3 and 30% from that of two complete rye genome triticales analyzed. No correlation was observed between gross heterochromatin content and frequency of aberrant endosperm nucleus production and (or) test weight. However, both percentage heterochromatin and the production of aberrant endosperm nuclei were greatly reduced as compared with the average triticale previously analyzed. In addition, significant correlations were observed between the frequency of aberrant endosperm nuclei and the amount of telomeric heterochromatin on chromosomes 5R (r = −0.60, p ≤ 0.10) and 6R (r = 0.76, p ≤ 0.05). These results suggest that the presence or absence of telomeric heterochromatin on different rye chromosomes on triticale may have different effects on the regularity of early endosperm development and subsequent test weight at maturity. Furthermore, once the total amount of telomeric heterochromatin present on rye chromosomes was greatly reduced it appeared that other genetic factors became visibly involved in irregularities of endosperm development.
Spindle sensitivity to colchicine of the Ph1 mutant in common wheat
Authors: Ceoloni Carla , Avivi Lydia , Feldman Moshe
Published: November 2014

Mitotic spindle sensitivity to colchicine of a common wheat line carrying a mutation at the Ph1 locus which increases homoeologous pairing at meiosis, was studied in treated root-tip cells and compared with that of wild type (Ph1/Ph1) and plants deficient for chromosome 5B. Spindle sensitivity was determined by the percentage of fully affected cells of the overall metaphase cell population. The high-pairing mutant (ph1b/ph1b), which is assumed to be a deficiency for the Ph1 locus on the long arm of chromosome 5B, was found to be significantly more sensitive to colchicine than the corresponding control line, i.e., plants carrying the wild-type allele, Ph1. The sensitivity of the mutant was similar to that of plants deficient for chromosome 5B. It thus becomes highly probable that spindle sensitivity to colchicine, previously found in plants carrying different doses of chromosomal arm 5BL, is indeed determined by the Ph1 gene. This gene presumably exerts its effect on the spindle via modification of some microtubular components. Thus, microtubules are suggested to be a possible target structure for this gene, which is known to affect chromosomal distribution and degree of homologous and homoeologous association in somatic and premeiotic cells, as well as the pattern of meiotic pairing.Key words: spindle, Triticum, microtubules, colchicine.
Spindle sensitivity to isopropyl-N-phenyl-carbamate and griseofulvin of common wheat plants carrying different doses of the Ph1 gene
Authors: Gualandi Giampiero , Ceoloni Carla , Feldman Moshe , Avivi Lydia
Published: November 2014

Lines of common wheat cv. 'Chinese Spring' carrying different doses of the Ph1 gene, located on the long arm of chromosome 5B were treated with the antimitotic agents griseofulvin and isopropyl-N-phenyl-carbamate (IPC). Treatments with low griseofulvin concentrations and IPC resulted mainly in the production of a high percentage of cells exhibiting spindle disorganization at metaphase and multipolar cells at anaphase–telophase. These treatments did not differentially affect the tested genotypes. On the other hand, higher griseofulvin concentrations induced the appearance of frequent C-metaphases and C-anaphases because of complete disruption of the spindle microtubules; in such cases, more pronounced sensitivity was observed in a line lacking the Ph1 gene than in lines disomic and tetrasomic for chromosome 5B. From this evidence it can be concluded that subcellular structures regulating microtubule organization and orientation, which are apparently the target of IPC and low griseofulvin concentrations, are not related to the action of the Ph1 gene. Rather, tubulin–microtubules equilibrium, which is affected by colchicine and high griseofulvin concentrations, is influenced by the action of this gene. Thus, the Ph1 gene product may correspond to a tubulin or a microtubule-associated protein which in turn stabilizes microtubule structure. In either case, the equilibrium tubulin–microtubules would be shifted towards microtubules in plants containing two doses of Ph1 and even more in plants containing an extra dose of this gene.Key words: spindle, Triticum, microtubules, antitubulins, griseofulvin.
Karyotypic and chromosome banding studies of the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera, Gelechiidae)
Authors: Bedo D. G.
Published: November 2014

The karyotype of Phthorimaea operculella is similar in both sexes and consists of 29 chromosome pairs. These are of similar size with gradual intergradation except for one pair which is significantly longer. C-banding and fluorescent staining with quinacrine and Hoechst 33258 failed to induce bands in metaphase chromosomes while silver staining clearly showed active nucleoli in all stages except metaphase. The banding results are compared with the few reports available on banding of holocentric chromosomes. It is concluded that considerable variability exists in the heterochromatic structure of holocentric chromosomes.Key words: Lepidoptera, moth, karyotype, C-banding.
Ribosomal RNA genes and the substructure of nucleolar organizing regions in Lilium
Authors: Kalm L. von , Smyth D. R.
Published: November 2014

We have examined the location and organization of nucleolar organizing regions (NORs) in the species Lilium henryi (with four NORs per diploid cell), L. longiflorum, and L. speciosum (each with six NORs), and the hybrids Lilium × 'Black Beauty' (five NORs) and Lilium × parkmannii (eight NORs). The relative number of genes in individual NORs was assayed by in situ hybridization using in vitro labelled ribosomal RNA (rRNA). An estimate of their relative transcriptional activity was obtained by scoring silver band size over the constriction. There was no clear correlation between gene number and activity at specific NORs. Rather, gene number correlated quite well with the relative size of heterochromatin usually found adjacent to NOR constrictions and stained by an acid-banding method. It is possible that many but a variable fraction of the rRNA genes in Lilium NORs are held inactive in nucleolar heterochromatin.Key words: ribosomal RNA genes, Lilium, nucleolus, in situ hybridization, heterochromatin, silver banding.
Evidence for the multiplicity of alleles at Vrn1, the winter–spring habit locus in common wheat
Authors: Roberts D. W. A. , MacDonald M. D.
Published: November 2014

Changes in the number of days to first emergence of the spike head with increasing duration of vernalization were examined in the common wheats (Triticum aestivum L.) 'Rescue,' 'Winalta,' 'Kharkov 22 MC,' and the disomic substitution lines of 'Winalta' and 'Kharkov 22 MC possessing the 5A chromosome from 'Rescue.' The data suggest the existence of three Vrn1 alleles in addition to the Vrn1 allele which occurs in 'Cadet.'Key words: vernalization, Triticum, Vrn alleles, chromosome 5A.
Cytogenetics of a semidwarf phenotype in pearl millet, Pennisetum americanum (L.) Leeke
Authors: Koduru Prasad R. K. , Rao M. Krishna
Published: November 2014

A semidwarf phenotype designated TLD (translocation dwarf) was isolated as a segregant in the selfed progeny of a spontaneously produced interchange heterozygote in the line IP 457 of pearl millet. The mutant is characterised by dark green and erect narrow leaves, early maturity, and a sterile spike tip. Chlorophyll content per unit area of leaf in the mutant is about 29% more than in the control. Results of cytogenetic evaluation of the semidwarf showed that the mutant phenotype is an interchange homozygote. The homozygosity for the interchanged chromosomes and the mutant phenotype are tightly linked; the chromosomes involved are identified as chromosomes 3 and 6. The phenotype is inherited as monogenic recessive. There is normal viability of gametes carrying interchange chromosomes attended by normal viability of zygotes of the three genotypic classes. The potential use of this phenotypic marker as a tester in genetic and breeding experiments concerning the improvement of this crop is stressed.Key words: Pennisetum, pearl millet, translocation, dwarf.
The inheritance of genetic variation in Triticum speltoides affecting heterogenetic chromosome pairing in hybrids with Triticum aestivum
Authors: Chen K. C. , Dvořák J.
Published: November 2014

Triticum speltoides (Tausch) Gren. ex Richter plants which differed in the ability to promote heterogenetic chromosome pairing in hybrids T. aestivum L. × T. speltoides were crossed and a single F1 plant from each cross was hybridized with T. aestivum. The segregation among the hybrids for mean number of chiasmata per cell showed that two gene systems in T. speltoides genotypes were involved in the promotion of heterogenetic pairing. One system was composed of two duplicate gene loci segregating independently of each other. Variation at these loci determined two basic levels of heterogenetic pairing. The other system was composed of several minor genes extensively modifying the effects of the major genes. The minor genes interacted mostly in an additive fashion. Triticum speltoides inbred plants were then crossed with diploid species. T. tauschii (Coss.) Schmal and T. dichasians (Zhuk.) Bowden. Consistent differences in the levels of chromosome pairing were found in these hybrids. However, this variation in chromosome pairing did not coincide with the variation at the major gene loci. This indicated that the major genes were ineffective in the diploid hybrids.Key words: Triticum, pairing regulation, homeologous pairing, heterogenetic pairing.