bluuebunny/crossref_metadata_2025 huggingface dataset:
GENETIC RELATIONSHIPS BETWEEN DIPLOIDS AND TETRAPLOIDS IN SERIES EUBARBATAE OF AVENA
Authors: Ladizinsky Gideon , Zohary Daniel
Published: November 2014

Diploid (2n = 14) and tetraploid (2n = 28) entities in series Eubarbatae of the genus Avena have been found to be genetically closely linked and are regarded as a single polyploid complex. At both ploidy levels the various morphological types are interfertile. Diploids and tetraploids are largely sympatric in their distribution and converge considerably in their ranges of morphological variation. Contacts between diploids and tetraploids are common and blurred morphological boundaries characterize mixed populations.The possibility of gene flow between diploids and tetraploids has been indicated by the behavior of triploid F1 hybrids. Such hybrids have been found to be partially fertile. In their progeny a conspicuous restoration of fertility is apparent: numerous plants of the F2 generation have been stabilized around the tetraploid level, few around the diploid level. In contact areas, triploids can be regarded as efficient bridges of gene flow between the two ploidy levels.The range of variation found at the tetraploid level is fully explicable by the variation present in the diploid races. Tetraploids are therefore regarded to have had an inter-varietal origin, i.e. have evolved from a single genome. They apparently represent an extreme case of bivalentization, where a full shift from an autotetraploid to an allotetraploid meiotic behavior had occurred. Meiotic behavior of the F2 plants also indicate such origin.
LOCATION AND LINKAGE OF GENES ON WHEAT CHROMOSOME 2D
Authors: Luig N. H. , McIntosh R. A.
Published: November 2014

Two distinct single dominant factors for resistance to wheat leaf rust were located on chromosome 2D. One of these factors, present in Kenya W 1483 and designated Lr15, is closely linked with the stem rust gene Sr6 and less closely with the gene C for compact spike. The second factor, present in Festiguay, is allelic with a factor for leaf rust resistance, in Webster. It is also linked to Sr6 and shows approximately 10 per cent recombination with C.
WHEAT-ALIEN HYBRIDS INVOLVING A CHROMOSOME 5B TRANSLOCATION
Authors: Driscoll C. J. , Quinn C. J.
Published: November 2014

Individuals heterozygous for the reciprocal translocation between chromosomes 5B and 7B, found in the wheat variety Poso, produced a high proportion (8 in sample of 21) of gametes involving duplication and deficiency of segments of those chromosomes. In crosses with Aegilops peregrina it was determined that these gametes are not usually deficient for the segment of the long arm of chromosome 5B that suppresses homoeologous pairing. Translocation aneuploid stocks are being produced which can be expected to give rise to a high degree of wheat-alien homoeologous pairing.
COMPARISONS OF LENGTHS AND AREAS IN KARYOTYPE ANALYSIS OF APHIDIDAE
Authors: Harper A. M. , MacDonald M. D.
Published: November 2014

Total complement lengths and areas of somatic chromosomes varied greatly in two species of aphids. Myzaphis rosarum (Kaltenbach) (2n = 4) and Acyrthosiphum pisum (Harris) (2n = 8). Much smaller coefficients of variation resulted from using relative rather than actual lengths and areas. Both relative measurements compensated for elongation and contraction of chromosomes due to stage of development and technique.There was no difference between two methods of measuring area. The coefficients for relative lengths were greater for short than for long chromosomes. Relative lengths are preferred to relative areas because they are more readily measured. An increase in sample size from 5 to 20 did not decrease the coefficient for relative length.Adoption of the appropriate method of analysis will permit more accurate comparison of aphid species than is possible by simply using chromosome number.
HETEROKARYOTIC TRANSMISSION OF FACTORS AFFECTING RECOMBINATION IN NEUROSPORA CRASSA
Authors: Griffiths A. J. F.
Published: November 2014

Complementation of recombination-inhibiting gene products has been demonstrated in crosses using the heterokaryon as conidial parent. Ways in which this complementation might be effected are examined in the light of corollary experiments.
INCOMPATIBILITY IN RUBUS WITH SPECIAL REFERENCE TO R. IDAEUS L.
Authors: Keep Elizabeth
Published: November 2014

Self-incompatibility is demonstrated in 11 out of 23 Rubus species, including wild raspberry R. idaeus, in which stylar inhibition of self-pollen-tubes occurs. In contrast, nearly all raspberry cultivars are fully self-fertile, probably, as is demonstrated for a derivative of Burnetholm, through mutation of S alleles to the St condition.Unilateral interspecific incompatibility in crosses with the self-compatible R. occidentalis occurs equally with self-incompatible wild raspberry or self-compatible raspberry cultivars as seed parents, showing that the latter retain their stylar activity. This suggests recent aquisition of self-fertility, cultivars being in the 'Sc' condition of Lewis and Crowe.It is suggested that vegetative propagation in R. idaeus provides many of the advantages of inbreeding and this, together with intense selection for vigour, ensures the maintenance of obligate outbreeding in the wild.
RELATIONSHIP OF TAXA IN THE GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. I. M. STRIATA × M. LITTORALIS
Authors: Lesins K. , Erac A.
Published: November 2014

In crosses between the two taxa Medicago striata Bast, and M. littoralis Rohde a high mortality of gametes and seedlings, and sterility of some plants were noted which were not related to gross chromosomal rearrangements. Although the F1, F2 and F3 generations from reciprocal crosses differed in chlorophyll deficiencies (indicating a cytoplasmic influence) a genic cause became evident from segregations for chlorophyll characters in the F2 and F3. Transference of the cytoplasmic factor by the pollen is indicative.Segregation for pod coiling direction indicated that the character was determined by one or two genetic factors of which the clockwise coiling direction is recessive. The spininess appeared to be determined by one genetic factor, of which the spineless allele is recessive.On the basis of genetic differences (especially on the built-in repulsion systems for normal chlorophyll development of opposite species) the two taxa should be considered two different species.
RECOVERY FROM RADIATION-INDUCED LETHAL SECTORING IN YEAST
Authors: James A. P. , Saunders Alexa S.
Published: November 2014

Recovery from the X-ray-induced damage responsible for lethal sectoring was investigated in diploid yeast. Lethal sectoring, an important factor in lethal damage, is characterized by the sporadic appearance of clusters of dead cells in earlier post-irradiation vegetative generations of surviving cells. Recovery from the instability responsible for sectoring was evident in a gradual decline in the frequency with which sectors were initiated through successive generations. This decline was shown to result from the fact that unstable cells, though able to persist indefinitely, had a propensity for reversion as well as for lethal sectoring. Some lines of descent from unstable cells lost their ability to revert without losing their ability to produce lethal sectors.
GENETIC AND COMPLEMENTATION STUDIES OF A NEW CAROTENOID MUTANT OFNEUROSPORA CRASSA
Authors: Subden R. E. , Threlkeld S. F. H.
Published: November 2014

A spontaneously occurring mutant called "yellow b" has been isolated and mapped on the right arm of linkage group I in Neurospora crassa 0.15 c.o.u. distal to aur and 2 c.o.u. distal to al-2. These three markers complement each other and are involved in the same biosynthetic pathway.
COMB TYPE AND REPRODUCTION IN THE MALE FOWL SEGREGATION OF THE ROSE AND PEA COMB GENES
Authors: Buckland R. B. , Hawes R. O.
Published: November 2014

Segregation ratios from heterozygous males and heterospermic inseminations were studied. There was a deficiency of pea comb offspring from rrPp males, in some cases from RrPp males, as well as from heterospermic inseminations (rrPP plus rrpp semen). Rose and walnut comb chicks were produced in the expected proportions from Rrpp or RrPp males but a significant deficiency of these comb types was found among offspring resulting from heterospermic inseminations (RRpp or RRPP plus rrpp semen).
TEMPERATURE-SENSITIVE MUTATIONS IN DROSOPHILA MELANOGASTER.: II. FREQUENCY AMONG SECOND CHROMOSOME RECESSIVE LETHALS INDUCED BY ETHYL METHANESULFONATE
Authors: Baillie David , Suzuki David T. , Tarasoff Mary
Published: November 2014

Recessive lethal and semilethal mutations induced in chromosome 2 by ethyl methanesulfonate were screened for temperature-sensitivity. Mutants which survive at 17 °C but die at 29° were recovered. At 0.005M EMS, 37.5% of the treated chromosomes were found to be lethal or semilethal from which it is estimated that 10.9% of all EMS-induced lethals are ts. This class of conditional lethals promises to be a useful tool in genetic studies.
THE ANALYSIS OF HERITABLE VARIATION FOR THREE AGRONOMIC TRAITS IN A 6-VARIETY DIALLEL OF GRAIN SORGHUM,SORGHUM VULGAREPERS.
Authors: Liang George H. L. , Heyne E. G. , Chung J. H. , Koh Y. O.
Published: November 2014

Analysis of a six-variety diallel indicates that both general and specific combining ability were important for anthesis time and that specific combining ability seems more important for grain yield. Significant interactions were observed between general combining ability and locations for yield, anthesis time, and protein content while significant interaction between specific combining ability and locations was observed for protein content only.For grain yield, overdominance was indicated by the (H1/D)½ ratio; at least four groups of genes were involved in controlling yield. Heritability estimate was slow. For anthesis time, a partial dominance was indicated. Approximately three groups of genes controlled anthesis; heritability estimate was high. For protein content, a partial dominance was noted. Two groups of genes were estimated for control of protein content; heritability estimate was intermediate.The regression coefficients for the three characters were less than 1, but only that for protein content was significantly so. The deviation of the regression line from unit slope may indicate the ptesence of either epistasis or correlated gene distribution or both in the materials tested.
ANEUPLOIDS FROM TRIPLOID-DIPLOID CROSSES IN THE SERIESTUBEROSAOF THE GENUSSOLANUM
Authors: Vogt G. E. , Rowe P. R.
Published: November 2014

Triploid-diploid crosses yielded nearly 75% aneuploid progeny. Of these, 60% were trisomics (2n = 25) and the rest ranged from 2n = 26 to 2n = 29. The most productive parents were those involving triploid S. maglia and diploid S. berthaultii. The initial trisomics often were not morphologically distinguishable from diploid sibs. Distinctive characteristics – such as slow growth; small, compact habit; lack of interstitial leaflets; and a bilobed stigma — were apparent in the backcross progenies. Most of the trisomics were fertile enough to be used in further genetic studies. Transmission of the extra chromosome through the female for three trisomics was 20–24%. Only primary trisomics were expected but meiotic study of seven clones indicated that all were secondary trisomics. The isochromosome may have originated from the tetraploids involved in the formation of the triploid clones or have been produced during meiosis of the triploid parent.
PHOTOPERIODIC RESPONSE AND ITS EFFECTS ON CERTAIN QUANTITATIVE CHARACTERS IN TOBACCO
Authors: Povilaitis Bronius
Published: November 2014

The effects of the mammoth gene causing a short-day photoperiodic response in a mutant were studied in 1962 and 1966 in six genetic populations (P1, P2, F1, F2, B1 B2) derived from the cross between Mammoth Delcrest, a short-day mutation of the flue-cured tobacco variety Delcrest, and Praecox, a day-neutral pipe tobacco. The data showed the expected monofactorial segregation of day-neutral against short-day plants, the latter being recessive. Considerable amount of positive heterosis was observed for leaf width. In the inheritance of days-to-flower, in addition to the pair of alleles determining the short-day response, one to two gene groups are indicated, operating probably in an additive fashion. Two and three gene groups are indicated for leaf width and leaf length, respectively. Parameters describing additive gene effects were important for all the character tested but none of the parameters for dominance and digenic epistatic effects were significant. Evidently the segregating major gene for the mammoth character did not excessively influence the relationship of gene effects in the remaining genotype as determined by the generation-mean analysis.
ADDITIONAL CHROMOSOME NUMBERS IN THE PHAEOPHYCEAE
Authors: Cole Kathleen
Published: November 2014

Chromosome numbers for 20 species in three orders of the Phaeophyceae are presented in this supplement to an index published in 1967.
EFFECTS OF DIETHYL SULPHATE ON SEED GERMINATION AND SEEDLING GROWTH OF NICOTIANA TABACUM
Authors: Povilaitis Bronius
Published: November 2014

Seeds of three flue-cured tobacco (Nicotiana tabacum L.) varieties, Hicks Broadleaf, Yellow Gold, and Canadel, were soaked for 1, 2, 3 or 5 hours in a saturated solution of diethyl sulphate, a chemical mutagenic agent, to increase variability of plant characteristics. Diethyl sulphate had a detrimental effect on both extent and rate of germination; each decreased with length of soaking period. Seedlings from treated seed grew more slowly than controls.
EXPERIMENTAL EVIDENCE FOR FACTORS AFFECTING THE RELATIVE EFFICIENCY OF INDIRECT TO DIRECT SELECTION IN TRIBOLIUM CASTANEUM
Authors: Scheinberg Eliyahu
Published: November 2014

Uni-stage tandem selection was practiced for three traits in three different populations. An unselected random mating control population was also maintained. These populations, each replicated three times, were selected for ten generations. The three traits measured were: larval weight, developmental time and pupal weight. The factors affecting the genetic gains were discussed. It was demonstrated that indirect selection for larval weight, when selecting directly for pupal weight, is at least as efficient as selecting directly for larval weight. — The genetic gains obtained in the populations under study were compared to their theoretical expectations. They were found to be lower than expected in all selected populations. The results were explained on the basis of development of skewness in the underlying distribution, low realized selection differentials, overestimation of parameters before selection and biased estimates of genetic variances and covariances due to the presence of nonadditive genetic variance. — Further study of this problem, using an index for indirect selection, should be attempted.
ANOTHER ESTERASE VARIANT IN THE KIDNEY OF THE HOUSE MOUSE, MUS MUSCULUS
Authors: Petras Michael L. , Sinclair Patricia
Published: November 2014

Electrophoretic studies of kidney homogenates of the house mouse, Mus musculus, have revealed two patterns in zone II of the esterase zymogram. Animals of inbred strains C3H and C57BL/10 possess seven bands in this region and mice derived from a mating between a wild animal and a C3H mouse have only two bands of considerable activity in zone II. Breeding results are consistent with a two-allele, one-autosomal-locus mode of inheritance, with the allele for the absence of the multiple-band phenotype being dominant. Sensitivity data indicate that the esterases in zone II are aliesterases. Breeding and population data revealed that the zone II esterase-controlling locus is closely linked with but not identical to Es-1, Es-2 and Es-5 loci and so has been tentatively designated Es-6.
THE EFFECTS OF THEEALLELES UPON MELANOCYTE DIFFERENTIATION IN THE FOWL
Authors: Brumbaugh J. A. , Moore J. W.
Published: November 2014

The time of melanocyte differentiation in embryos and regenerating adult feathers was determined for three alleles at the E pigment locus in the fowl. Melanocytes were identified in dissociated embryonic skin tissue using the dopa reaction. In both embryos and female breast feathers, extended black (E) melanocytes differentiated early and produced eumelanin, while recessive wheaten (ey) melanocytes differentiated significantly later and synthesized pale phaeomelanin. Wild type (e+) melanocytes produced a more intense phaeomelanin and differentiated at an intermediate time. However, melanocytes in the male breast feathers of each genotype differentiated early and produced eumelanin. This suggests that the temporal variation in melanocyte differentiation is related directly to the type of melanin synthesized and only indirectly to genotype. It is suggested that the E allele present interacts with the morphogenetic factors of the growing feather to determine the type of melanin that will be synthesized. The time of observed melanin deposition then becomes a secondary effect of this 'decision', eumelanin being deposited early and phaeomelanins significantly later.
PACHYTENE MORPHOLOGY OF PRUNUS AVIUM L. CV. LAMBERT
Authors: Whelan E. D. P.
Published: November 2014

Analysis of pachytene chromosomes of Prunus avium L. cv. Lambert revealed that only chromosomes 1, 2 and 3 were sufficiently differentiated to be identifiable. These chromosomes were classified as Group A. Chromosome 3 had a large, interstitial deletion involving most of the short arm of one homologue. The remaining five chromosomes, designated as Group B, were primarily achromatic and could not be separated with certainty by morphological characteristics or arm length ratios.The centromeres of all chromosomes were easy to locate, being delimited on both sides by intensely stained chromatic regions. In the Group B chromosomes no other chromatic regions were evident. Telochromomeres were not detected in any chromosome, though the short arm of the Group A chromosomes terminated in a chromatic knob or satellite.Interpretation of pachynema was difficult as the chromosomes failed to spread. They appeared to be associated with each other in the area of chromatic centers.
A LINKAGE STUDY INVOLVING TWO WHEAT-RYE TRANSLOCATION CHROMOSOMES
Authors: Driscoll C. J. , Patil G. D.
Published: November 2014

Two wheat-rye translocation chromosomes involving the same wheat chromosome arm but different rye segments were subjected to a linkage test. Apparently no crossing over occurred between the non-homologous rye segments. The genetic markers possessed by these rye segments showed complete linkage in repulsion. The male transmission rates of the translocation chromosomes agree with those expected on the basis of the male transmission rate of each when competing with the normal wheat chromosome.
RELATIONSHIP BETWEEN MITOTIC EVENTS AND LEAF SPOTTING IN GLYCINE MAX
Authors: Vig B. K.
Published: November 2014

Chromosome analysis of the root tips of Glycine max (L.) Merrill variety T219 revealed several aberrations. Chromosome stickiness, reductional groupings and multiple spindles (as well as multipolar spindles) were observed. In our previous work, we had observed the expression of homozygous genotypes on the heterozygous background in the form of small spots on the leaves of this variety. This paper tends to correlate the two findings. The appearance of some of the spots on the leaves is attributed to the loss of one or more chromosomes, besides somatic crossing-over.
INHERITANCE OF RESISTANCE TO COVERED AND FALSE LOOSE SMUT IN THE BARLEY VARIETIES PANNIER AND EXCELSIOR
Authors: Cherewick W. J. , Buchannon K. W.
Published: November 2014

F3 lines of the barley crosses Odessa × Pannier and Odessa × Excelsior were subjected to tests with compatible monosporidial lines of an inbred race each of covered and false loose smut. The results indicated that both Pannier and Excelsior have one dominant gene for resistance to each of the two races and that the genes in each variety appear to be closely associated.
RELATIONSHIP OF TAXA IN GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. IV. M. HYBRIDA × M. SUFFRUTICOSA
Authors: Lesins K.
Published: November 2014

Medicago hybrida Trautv. and M. suffruticosa Ram. are closely related, as indicated by their ease of hybridization, by the vigor and fertility of the F1, and by good pollen viability (94–98%) in the F1. In the F2, glandular hairs on pods vs. no-hairs segregated in a normal, 1:3 ratio; hairiness of M. suffruticosa was recessive to no-hair condition of M. hybrida. Coiling of pods was determined by six dominant, non-linked factors, A1–A6, with cumulative effect. M. suffruticosa possessed the dominant alleles. Neither M. hybrida nor M. suffruticosa could be hybridized with the M. sativa-falcata group, indicating their membership in different affinity groups. M. leiocarpa Benth. could be crossed with M. hybrida as well as with M. suffruticosa. Further study is needed to determine whether the M. hybrida-suffruticosa group belongs to the genus Medicago or Trigonella.
SOMATIC CONVERSION (PARAMUTATION) AT THE SULFUREA LOCUS OF LYCOPERSICON ESCULENTUM MILL. III. STUDIES WITH TRISOMICS
Authors: Hagemann Rudolf
Published: November 2014

Genetic studies carried out since 1958, have revealed at the sulfurea (sulf) locus of Lycopersicon esculentum the occurrence of a particular type of genetic instability: somatic conversion (paramutation). In vegetative cells of sulf+sulf heterozygotes the wild type allele sulf+ is heritably altered under the influence of the mutant sulf allele which is present in the same nucleus.By crossing sulf homozygotes and seven primary trisomics of the tomato (triplo-2, -5, -7, -8, -9, -10, -12) as well as a tertiary trisomic it was proven that the sulf locus is on chromosome 2, the nucleolus chromosome of the tomato.The effects of dosage are shown by the two different heterozygous trisomics which differ with regard to somatic conversion. In sulf+sulf sulf plants somatic conversion takes place very frequently; 60% of the plants (35) are variegated; that is, two conversion-active sulf alleles are very frequently able to convert one sensitive sulf+ allele. However, in sulf+sulf+sulf plants conversion has so far not been found; all plants (52) are entirely green; that is, one conversion-active sulf allele acting against two conversion-sensitive sulf+ alleles is not able to induce somatic conversion.
HEXAPLOID ALFALFA,MEDICAGO SATIVAL.: ORIGIN, FERTILITY AND CYTOLOGY
Authors: Bingham E. T. , Binek A.
Published: November 2014

Two spontaneously occurring hexaploids, 6-1 and 6-2, 2n = 6x = 48, were discovered among tetraploid plants of the variety 'Saranac'. They were selfed, crossed with each other and with diploid (2x), triploid (3x), and tetraploid (4x) alfalfa. Self and cross progeny of 6-1 and 6-2 were all hexaploid; 2x-6x crosses produced a plant with 32 chromosomes; 3x-6x crosses produced hexaploids probably due to unreduced triploid gametes; and 4x-6x crosses produced plants with 32, 34, 35, 36, 37, 38, 40, and 56 chromosomes. Thus many additional hexaploids, two pentaploids, 2n = 40, and a septaploid, 2n = 56, were obtained.Chromosome associations were mostly bivalents, with a low frequency of univalents and quadrivalents in hexaploids with six sativa genomes or five sativa and one falcata genome. Pollen stainability was in excess of 95%, ovule number averaged 12 per carpel, and several grams of hexaploid seed were produced from hand crosses. Five different hexaploid synthetics with narrow and wide genetic bases were produced for future seed increase and field testing. The value of hexaploids in breeding and cytogenetic research was discussed.
CYTOGENETICS OF A BURLEY TOBACCO BREEDING LINE DERIVED FROM A CROSS WITHNICOTIANA LONGIFLORACAV
Authors: Collins G. B. , Legg P. D.
Published: November 2014

Cytological investigations of a burley tobacco (Nicotiana tabacum L.) breeding line designated as L-8 and carrying race 0 black shank resistance derived from a cross with N. longiflora Cav. revealed the regular occurrence of 24 bivalents at metaphase I of meiosis. Instability was apparent at the meiotic anaphase and tetrad stages and from observations of mitotic anaphase and metaphase figures. Pollen viability of L-8 as estimated by a staining technique was very similar to that obtained for a standard burley variety. Comparable cytological observations were extended to the F1hybrids of L-8 with three burley varieties. The findings were similar for L-8 and the F1hybrids. The occurrence of 24 bivalents in meiocytes of F1hybrids provided strong evidence for incorporation of black shank resistance from N. longiflora into N. tabacum by segmental substitution rather than by alien addition of a longiflora chromosome as previously reported.
IDENTIFICATION AND CHROMOMERIC INTERPRETATION OF PACHYTENE BIVALENTS FROM CANIS FAMILIARIS
Authors: Ford Lee
Published: November 2014

Squash techniques were used to spread, the 39 pachytene bivalents from spermatogenic Canis familiaris cells collected by testicular biopsy from normal, healthy male collie dogs. Eight cells in which all bivalents could be identified were photographed, enlarged to 4500 × and cutouts prepared for each chromosome in each of the cells. Characterization and identification were based on relative length, mean percentage length, and number of chromomeres in each bivalent.
END-TO-END, CHAIN-LIKE ASSOCIATIONS OF PAIRED PACHYTENE CHROMOSOMES OF CREPIS CAPILLARIS
Authors: Wagenaar E. B. , Sadasivaiah R. S.
Published: November 2014

Studies on the pachytene stage of meiosis of Crepis capillaris showed that the paired chromosomes are attached end-to-end forming chain-like configurations. The arrangements of the chromosomes in these tandem associations are according to the expectations based on the somatogram of this species. These observations make it very likely that the end-to-end chromosome associations present in all somatic interphase cells (Wagenaar, 1969) have their primary significance in the recognition and pairing of homologous chromosomes during early meiotic prophase.
MONOSOMIC ANALYSIS OF FERTILITY RESTORATION IN THREE RESTORER LINES OF WHEAT
Authors: Yen Fu-Sun , Evans L. E. , Larter E. N.
Published: November 2014

Genes conferring fertility restoration, in each of the following three hexaploid restorer lines of common wheat (Triticum aestivum L) carrying cytoplasm of Triticum timopheevi Zhuk, were located using monosomic analyses: [(T. timopheevi × Aegilops squarrosa) × Canthatch3] F7, [(T. timopheevi × Ae. squarrosa) × Dirk3] F6 and (T. timopheevi × Ae. squarrosa) × Karn3] F6.Testcross data revealed that in the Dirk restorer, a major gene (Rf1) conferring fertility restoration was carried on chromosome 1A, while a minor gene (Rf4) was located on chromosome 7D. The restorer line of Canthatch was found to carry a major gene (Rf2) and a minor gene (Rf3) on chromosomes 6B ad 6D respectively. Chromosomes 1A and 6B were found to carry genes for fertility restoration in the Karn restorer. Critical chromosomes carrying genes conferring fertility restoration in each of the three restorer lines were found not to be involved in translocations found in F1 plants of Rescue monosomics × restorer lines. Chromosomes 2A, 6A and 3D of Rescue appeared to carry genes which modified the degree of restoration obtained.
A CHROMOSOMAL ANALYSIS OF EGG PRODUCTION AND ABDOMINAL CHAETA NUMBER INDROSOPHILA MELANOGASTER
Authors: Kidwell J. F.
Published: November 2014

A marked-inversion-outcross technique was used to produce the 81 possible combinations of entire chromosomes (genotypes) resulting from crosses of two isogenic lines. Two metric traits, egg production during the 6th, 7th and 8th day and the number of chaeta on the fourth and fifth abdominal segments, were measured. Heterogeneity of within-genotype variance was found for both traits. There is some evidence of increasing variance with increasing homozygosity, bur it is not conclusive.Egg production is influenced largely by additive and dominance effects of chromosomes 2 and 3 and by epistatic interactions involving all four chromosomes. Chaeta number is determined largely by chromosomes with additive effects. For both traits, however, the three- and four-factor epistatic interactions contributed a real and important fraction of the total variance.The data are consistent with the view that egg production has been subjected to directional selection and that chaeta number has been subjected to stabilizing selection.
SOLUBILISATION D'ENZYMES HYDROLYTIQUES CHEZ GOSSYPIUM HIRSUTUM, G. ANOMALUM ET DES DERIVES DE L'HYBRIDATION ENTRE CES DEUX ESPECES
Authors: Silva J. B. Vieira da , Poisson Ch.
Published: November 2014

Hybrid derivatives between Gossypium anomalum and G. hirsutum, both 2n + 1 aneuploids for chromosome 3 of G. anomalum and euploids derived from this segregating population, exhibit under osmotic stress conditions the same pattern of solubilization of the hydrolytic enzymes, β-fructofuranosidase, β-amylase and acid phosphatase, as the wild parent G. anomalum.This biochemical relationship and the slightly changed phenotype, suggest that the hereditary material could have been transferred from G. anomalum to the euploids.
INHERITANCE OF RESISTANCE TO NET BLOTCH IN BARLEY. II. GENES CONDITIONING RESISTANCE AGAINST RACE W.A.-2
Authors: Khan T. N. , Boyd W. J. R.
Published: November 2014

Resistance to race W.A.-2 of net blotch has been found to be conditioned by a single gene, designated Pta, in each of the three varieties originating from Manchuria: Manchuria (C.I. 2330), Ming (C.I. 4797) and Tifang (C.I. 4407-1). Resistance to the same race, exhibited by each of two varieties of Ethiopian origin (C.I. 5791 and C.I. 9819), has been found to be conditioned by duplicate genes, one of which is allelic to Pta. The relationship of the second gene has not been determined. It was concluded that Pta, differs from the three genes, viz. Pt1, Pt2, and Pt3, previously identified in California, and was shown to segregate independently of the two-row characteristic.Differences were noted in the dominance relationships of gene Pta contributed by the Manchurian varieties. This indicates differences in the genetic background of the sources of resistance from this area which would likely detract from their value as parents in any Western Australian breeding program.
HAPLOID BARLEY FROM CROSSES OF HORDEUM BULBOSUM (2x) × HORDEUM VULGARE (2x)
Authors: Symko Stephan
Published: November 2014

Ninety-seven hybrid seeds were obtained from seven crosses of Hordeum bulbosum (2x) × H. vulgare (2x), using embryo culture. Cytological examination revealed that all plants had 2n = 7 chromosomes. The vegetative characters of most of these haploids were intermediate between those of the two parental species whereas all haploids had the spike characters of H. vulgare. Possible origins from true nuclear gene hybridity followed by somatic reduction or by male parthenogenesis with differences in plasmagene activity are discussed.
NEW DUPLICATION-GENERATING INVERSIONS INNEUROSPORA
Authors: Turner Barbara C. , Taylor Cecile W. , Perkins David D. , Newmeyer Dorothy
Published: November 2014

Inversion In(ILR)NM176 has one break point at the extreme right end of linkage group I and the other distal to mating type in the left arm. In crosses of Inversion × Normal the products of single crossing over within the inversion are complementary duplication-deficiency classes. One crossover product is viable, with a large segment of IL duplicated and the dispensable right tip presumably deficient. This class has low fertility and distinctive morphology. The complementary product has a large deficiency which results in a pair of white, inviable ascospores. Single exchanges within the heterozygous inversion thus produce asci with 6 Black: 2 White spores; four-strand double exchanges produce 4 B:4 W; and non-exchanges produce asci with 8 B:0 W. Approximate mapping of break points was accomplished by three-point crosses. Precise placement of the left break point between ser-3 and un(55701t), just left of mating type, is based on coverage of markers by the heterozygous duplication. No crossover has been obtained between mating type and the break point, despite extensive efforts. In(ILR)NM176 differs from the inversion In(ILR)H4250 described by Newmeyer and Taylor (1967) in one main respect: the mating type locus is included in the inverted segment of NM176. Consequently, when duplications are generated, the progeny are unisexual and do not have the unstable inhibited phenotype characteristic of H4250 duplication progeny, which are heterozygous for the mating type alleles A and a. Three other inversions which originated independently of In(ILR)NM176 resemble it closely and have similar or identical break points.
INBREEDING AND HETEROSIS IN AUTOTETRAPLOID ALFALFA. I. FERTILITY
Authors: Dessureaux L. , Gallais A.
Published: November 2014

Certain aspects in the quantitative genetics of autotetraploid populations have been developed into a deterministic model. The use of two mating systems, inbreeding and hybridization, on the fertility of two alfalfa clones gave results which were in close agreement with the proposed model. The interactions between more than two alleles, whether identical or not, were important in the expression of heterosis. Performance of hybrids became weaker and weaker as the parents were more and more inbred. It was possible to evaluate the influence of the various genotypic structures on seed setting.
REVERSION OF SPONTANEOUSLY ARISING RESPIRATORY DEFICIENCY INSACCHAROMYCES CEREVISIAE
Authors: Rank Gerald H. , Person Clayton
Published: November 2014

Reversion of naturally-arising cytoplasmically-inherited respiratory deficiency in Saccharomyces cerevisiae was indicated by the occurrence of colonies with a respiratory sufficient apex arising from a respiratory deficient base. The basal respiratory deficient cells were shown to contain the suppressive factor. It was suggested that genetic information for the suppressive factor resided in abnormal mitochondrial DNA and that mosaic colonies arose from a heteroplasmic cell containing both normal and abnormal mitochondrial DNA.
CHROMOSOMAL POLYMORPHISM INPISSODES WEEVILS: FURTHER ON INCOMPATIBILITY IN P.TERMINALS
Authors: Smith S. G. , Takenouchi Y.
Published: November 2014

The North American Pissodes terminalis exhibits dual sexual dichotomy of its karyotype. Whereas females are invariably homozygous both for the sex chromosomes and a pair of metacentric autosomes (XC/XC), all males are double heterozygotes (XC/Ycc), one C being replaced by its corresponding twin acrocentrics. Consequently females produce only X/C eggs but, since meiotic orientation of the XY II and the Ccc III is random, males should produce four types of spermatozoa in equal proportions. If so, to render the dual dichotomy permanent, effective fertilization must perforce be solely by XC and Ycc sperms.Hybrids have been obtained between different taxa that are monomorphic either for two C-metacentrics or for their equivalent twin c-acrocentrics. When the cs in hybrid males are of paternal origin, the semi-incompatibility system (SIS), as seen in terminalis, is immediately synthesized and thereafter faithfully perpetuated. When, however, they are of maternal origin, free recombination ensues both in the F2and backcrosses. An identical alternate scheme of inheritance is displayed when terminalis is one or the other parent. Egg viability, sex ratio, late mortality, and family size in SIS hybrids show no significant deviation relative to those of monomorphic species or non-SIS hybrids. It is therefore concluded that the autosomal heterozygosity of SIS males is a consequence not of a balanced lethal mechanism but of selective fertilization. This system can be formally ascribed to translocation of a factor from one of the twin acrocentrics to the Y (Xcc: Ycc → Xcc/Y+c−c); thereby these two mutually compensating chromosomes became permanently linked in heredity and concomitantly excluded from females.The synthesis of the SIS in intra-complex hybrids demonstrates that the seeming random recombination in c-acrocentric species is illusory. They likewise possess a built-in SIS, one that is only exposed after crossing to C-metacentric females. Significantly, other species complexes in the genus also have an innate SIS, but they fail to conceal it because in males their c/c−II is readily visible. Thus it follows that the mutation did not originate in terminalis, a species of obvious recent origin.The absence of the system from C-metacentric taxa, we attribute to their obvious Robertsonian origin from c-acrocentric SIS species by centric fusion of nonhomologues. Such a fusion, by arising in the female, exempts the male c−from direct participation and, following introduction of the newly formed C chromosome into males(v. terminalis), merely await loss of the plus factor from the Y+to ensure the free recombination currently seen in C:C taxa, for Yc−c gametes should thereby be totally incapacitated.
INFLUENCE OF CHROMOSOME SIZE ON THE RADIOSENSITIVITY OF LINUM SPECIES
Authors: Bari G. , Godward M. B. E.
Published: November 2014

Several factors have been shown to influence the radiosensitivity of plants. Gustafsson (1944) reported that the seeds of oleiferous plants were highly resistant to X-rays, and considered that the resistance was due to some physiological properties inside the cell and the nucleus, and suggested that the resistance was associated with the fat content. Sparrow and Evans (1961), and Evans and Sparrow (1961) have discussed the nuclear factors affecting radio-sensitivity, and Konzak et al. (1961) have reviewed the physiological and morphological factors involved in the response of plants to radiation.Gustafsson (1944) studied the radiosensitivity of cultivated flax over a period of two years by X-irradiating the seeds with doses ranging from 5 kR to 45 kR. But the variation between his results of two years is so very great that it seemed desirable to undertake fresh studies with a wider range of radiation dosage. In addition to the cultivated flax, Linum usitatissimum, 10 other species of the genus Linum were included in these studies.
RADIATION-INDUCED SPERMATOGONIAL EXCHANGE BETWEEN THE X AND Y CHROMOSOMES IN THE GUPPY
Authors: Schröder Johannes Horst
Published: November 2014

Irradiation of male germ cells in newborn guppies, Lebistes reticulatus Peters, causes an increase in the exchange frequency between the X and Y chromosomes in comparison to unirradiated controls among the offspring of the irradiated males, provided the offspring are produced during an interval between 161 and 283 days after irradiation. No significant increase of crossing-over frequency was obtained among offspring produced during the interval between 59 and 145 days after irradiation. It is concluded that irradiation of early spermatogonia (59 to 145 days postirradiation) does not increase the exchange frequency between sex chromosomes whereas the irradiation of stem cells (161 to 283 days) provides a significantly higher incidence of crossing-over events in the irradiated series than in the controls. The excess of crossovers in the irradiated stem cells of spermatogenesis is due only to clusters of crossovers in the irradiated series, since on excluding the clusters no difference between irradiated and control series could be found.
THE PATHWAY OF INFECTION OF USTILAGO HORDEI
Authors: Kozar F.
Published: November 2014

Biochemical mutants of Ustilago hordei (Pers.) Lagerh were used to infect barley seeds in a study of the pathway of infection and the development of the parasite within the host. Microscopic studies in which the parasite was recovered from pieces of host tissue, identified and grown in vitro confirmed earlier views that the parasite mycelium was present throughout the spike primordia of the barley host.From genetically marked infections, it became evident that diploidization and subsequent recombination and haploidization may follow the dikaryotic stage of the parasite.
DNA BASE COMPOSITION OF SOME FREE-LIVING NEMATODE SPECIES
Authors: Behme R. , Pasternak J.
Published: November 2014

The mean base compositions (% GC) of DNA samples from five free-living nematodes were determined by CsCl equilibrium buoyant-density centrifugation and thermal denaturation studies. Both methods gave similar results indicating that there is no extensive replacement of the usual bases in nematode DNA. From the ultracentrifugation studies the % GC content of the DNA of Caenorhabditis briggsae (Dougherty and Nigon, 1949) Dougherty, 1953, Turbatrix aceti (Müller, 1783) Peters, 1927, Rhabditis (Rhabditis) anomala Hertwig, 1922 (Dougherty 1955), Panagrellus redivivus (Linn, 1767) T. Goodey, 1945, and Panagrellus silusiae (de Man, 1913) T. Goodey, 1945 was 36, 40, 42, 44 and 44, respectively.The sample of DNA from T. aceti showed two distinct ultraviolet absorbing bands in a CsCl gradient. The band at 1.688 g/cm3 proved to be a polysaccharide. It gave a distinctive refractive index pattern when viewed with the schlieren optical system, was insensitive to DNase treatment and was removed by a-amylase treatment. On the other hand, the material banding at 1.699 g/cm3 was shown to be DNA. This band produced no disturbance in the refractive index gradient. It was not altered by a-amylase treatment, but it was DNase sensitive.Since P. redivivus and P. silusiae were found to have the same DNA base composition their ability to interbreed was examined. These two forms were cross-fertile and the offspring were fully fertile.
INHERITANCE OF CLUBROOT RESISTANCE IN CABBAGE (BRASSICA OLERACEA L. VAR. CAPITATA L.)
Authors: Chiang Morgan S. , Crête R.
Published: November 2014

Two clubroot-susceptible cabbage cultivars, Red Acre and Golden Acre, were crossed with the resistant line, 8-41. F1 data showed that susceptibility was dominant over resistance and data from F2 and backcross progenies supported a duplicate gene hypothesis. Genes Pb1 and Pb2 were proposed to designate susceptible loci. All genotypes of these two genes were susceptible except the homozygous recessive pb1, pb1, pb2, ph2, which was resistant.
INHERITANCE OF HYPERSENSITIVITY TO ROSY APPLE APHID DYSAPHIS PLANTAGINEA IN APPLE
Authors: Alston F. H. , Briggs J. B.
Published: November 2014

Hypersensitivity to Dysaphis plantaginea (Pass.) was investigated in progenies of Mains robusta and five other hypersensitive Malus species. MAL 59/9, a M. robusta derivative, was shown to carry a single dominant gene for hypersensitivity, the symbol Smh is suggested.
A CASE OF ABERRANT TRANSMISSION OF GENETIC FACTORS ON THE SHORT ARM OF CHROMOSOME 9 IN MAIZE
Authors: Mouli Chandra , Notani N. K. , Gopal-Ayengar A. R.
Published: November 2014

A locus on the short arm of chromosome 9 completely prevents the transmission of the male gametes carrying it. The female gametes bearing it also have a slightly, but significantly, lower rate of transmission. The locus was mapped at 1.13 units distal to I. The four markers linked to this locus show a polarity of transmission, the transmission of I, Sh, Bz and Wx being 1.13, 2.26, 4.49 and 27.18% respectively. For I it was verified that the transmitted gametes were due to crossing over between I and the 'distorting' locus and the same can be inferred for the other loci from the polarity effect. The basis of the aberrant transmission was considered to be either a mutation of a gametophytic factor or, more likely, a cryptic deletion. Although no aberration was detected cytologically and the stainability of pollen was normal, the transmission data are more compatible with the deletion model since the slightly lower transmission through the female would not be expected from a gametophyte mutation.
THE GENETICS OF PHOTOTAXIS INDROSOPHILA MELANOGASTER
Authors: Walton P. D.
Published: November 2014

Populations of flies were tested for their phototactic response in a maze with 14 choice points. Selections for positive and negative phototaxis established lines with different responses. The phototactic score of the F1and parental populations from a 7 × 7 diallel cross were determined. Calculations from diallel tables indicated that phototaxis is controlled by polygenes, that negative phototaxis was partially dominant and that there were indications of a reciprocal effect.
NON-PERSISTENCE OF MATERNAL EFFECTS IN LOLIUM MULTIFLORUM L
Authors: Emara Y. A.
Published: November 2014

Reciprocal differences known to be maternal effects were reinvestigated by testcrossing the original plants as females with plants of a genetically uniform line as males. The maternal effects on third leaf dimensions, tiller number and plant dry weight were not transmitted to the next generation. It was postulated that these transient maternal effects are due to differences, especially nutritional factors, in the environment of the embryo provided by the seed parent. Such transient effects could interfere in breeding programmes as they will inflate the estimates of one or more of the genetic components of variation and of heritability. It is advisable to perform selection on older plants as transient maternal effects decline as the plants mature.However, rate of tillering was exceptional in that maternal effects were transmitted to the testcrossed generation. This might support the suggested dual control for this character, one attributed to the genome and the other to the plasmon, with the latter becoming the more important in asexual reproduction.
NEW GENE-ENZYME SYSTEM INANOPHELES ATROPARVUS:OCCURRENCEAND FREQUENCIES OF FOUR ALLELES AT THE EST6 LOCUS
Authors: Bianchi Umberto , Rinaldi Antoniettina
Published: November 2014

Four isoallelic molecular variants of a protein having esterase activity (Esterase 6) have been detected in adults belonging to our laboratory strain of Anopheles atroparvus. From the random combination of the four alleles coding for Esterase6 (Est6S, Est6I1, Est6I1, Est6F), 10 different phenotypes (genotypes) can be obtained. The observed gene frequencies, found by screening 134 individuals randomly sampled from the strain, have been found in agreement with the expected ones, assuming Hardy-Weinberg equilibrium. The observed amount of segregation present in a locus of a laboratory strain and the operative value that should be given to this kind of formal genetics in mosquitoes is discussed.
STUDIES ON THE GENOME CONSTITUTION OF TRITICUM TIMOPHEEVI ZHUK: III. SEGREGATION OF MEIOTIC CHROMOSOME BEHAVIOUR IN BACKCROSS GENERATIONS
Authors: Wagenaar E. B.
Published: November 2014

Cytogenetic analysis of three backcross generations of the hybrid Triticum turgidum × T. timopheevi (2n = 28) showed segregation of meiotic behaviour in each successive generation. The segregation was continuous and was possibly under control of polygenes. These results indicate that the meiotic irregularities commonly found in F1 hybrids between T. turgidum and T. timopheevi are primarly genetically induced.
CROSSOVER VALUES BETWEEN DIELDRIN-RESISTANCE AND DDT-RESISTANCE AND LINKAGE-GROUP-2 GENES IN AEDES AEGYPTI
Authors: Lockhart W. L. , Klassen W. , Brown A. W. A.
Published: November 2014

Crosses and backcrosses between five dieldrin-resistant strains and the MYS susceptible strain in Aedes aegypti indicate the order of the genes to be Dl—si — s, the distance si — s being 6-7 units and the total distance Dl — s being 25-31 units.Crosses between the Trinidad DDT-resistant strain and the MYS marker strain indicate the order to be si — s — DDT, the distance si — s being 4 units and the total distance s — DDT being 10 units. Crosses between this strain and the AO and Multiple marker strains indicate the order to be y — s — DDT.These results indicate that the order of the genes in linkage-group 2 of Aedes aegypti is probably Dl — si — y —s — DDT. The total crossover distance of some 45 units thus implied between Dl and DDT is, however, at variance with previous work which found the direct crossover between these two genes to be only 4-7%.