bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of barley genome segments introgressed into wheat using PCR markers
Authors: Sherman J D , Smith L Y , Blake T K , Talbert L E
Published: October 2017

Barley has several important traits that might be used in the genetic improvement of wheat. For this report, we have produced wheat-barley recombinants involving barley chromosomes 4 (4H) and 7 (5H). Wheat-barley disomic addition lines were crossed with 'Chinese Spring' wheat carrying the ph1b mutation to promote homoeologous pairing. Selection was performed using polymerase chain reaction (PCR) markers to identify lines with the barley chromosome in the ph1b background. These lines were self pollinated, and recombinants were identified using sequence-tagged-site (STS) primer sets that allowed differentiation between barley and wheat chromosomes. Several recombinant lines were isolated that involved different STS-PCR markers. Recombination was confirmed by allowing the lines to self pollinate and rescreening the progeny via STS-PCR. Progeny testing confirmed 9 recombinants involving barley chromosome 4 (4H) and 11 recombinants involving barley chromosome 7 (5H). Some recombinants were observed cytologically to eliminate the possibility of broken chromosomes. Since transmission of the recombinant chromosomes was lower than expected and since seed set was reduced in recombinant lines, the utility of producing recombinants with this method is uncertain.Key words: introgression, sequence-tagged-site, recombination.
Molecular cytogenetic analysis of DNA sequences with flanking telomeric repeats inTriticum aestivumcv. Begra
Authors: Dobrzanska Marta , Kraszewska Elzbieta , Bucholc Maria , Jenkins Glyn
Published: October 2017

A cloned genomic DNA fragment (pTa241) formerly derived from a DNA fraction obtained from isolated nuclei of embryos of a Polish cultivar of wheat (Triticum aestivum cv. Begra) comprises a tandem repeat of the telomeric array CCCTAAA, and hybridizes in situ exclusively to the telomeres of all chromosome arms of the somatic chromosome complement of wheat. A second cloned fragment (pTa637) derived from the same fraction is 637 bp long, flanked by 28 bp of the same telomeric repeat unit, and hybridizes in situ to the entire lengths of all the chromosomes of the complement. The same pattern of hybridization was observed when the flanking telomeric sequences were removed. A third DNA fragment (pTa1439), derived from unfractionated genomic DNA and flanked with 62 bp of the same telomeric unit, showed the same patterns of distribution. Together with additional evidence from Southern analysis, these observations were interpreted to mean that these sequences are associated with mobile DNA elements and are distributed widely throughout the genome. The chromosomal distribution of the non-telomeric parts of the clones is consistent with the dispersed genomic distribution characteristic of transposons and retroelements.Key words: wheat, Triticum aestivum cv. Begra, mobile elements, telomeric DNA sequence, FISH.
Development of a STS marker assay for detecting loss of heterozygosity in rice hybrids
Authors: Li Xiaomei , Wang Richard R-C , Larson Steve R , Chatterton N Jerry
Published: October 2017

The RAPD (random amplified polymorphic DNA) markers OPE15750 and OPE15300 were affected by loss of heterozygosity (LOH) in rice hybrids AMR × 'M202' and AMR × 'L202'. The markers were mapped to the same locus at or near the centromere of rice chromosome 2. The two RAPD products were cloned, sequenced, and found to have lengths of 734 bp and 297 bp, respectively. The 297-bp sequence shares a 98% homology with one end of the 734-bp sequence, accounting for the cross-hybridization previously observed between the two clones. Based on the DNA sequence of the 734-bp fragment, a pair of STS (sequence-tagged site) primers was designed and tested. Rice plants homozygous for either OPE15734 or OPE15297 all produced PCR fragments of the same length, 482 bp. However, the two PCR products were discernible by digestion with the restriction enzyme XbaI prior to gel electrophoresis. The STS product from plants homozygous for OPE15734 was cut into two fragments of 239 and 240 bp, which appeared as one single band in an agarose gel; whereas the STS product from plants homozygous for OPE15297 was not cut by XbaI and was characterized by a 482-bp band in the agarose gel. These STS primers were tested in rice hybrids and F2 progenies derived from the hybrids of AMR × 'M202' and AMR × 'L202'. Homozygosity for OPE15297 was confirmed for all F2 panicle rows derived from AMR × 'M202'. In contrast, F2 panicle rows of AMR × 'L202' exhibited two different segregation patterns (genotypes), i.e., either uniformly homozygous for the 240-bp marker (OPE15734/OPE15734) or segregating for the 482- and 240-bp markers (OPE15734/OPE15297). This STS-marker system provides a robust assay for detecting the occurrence of LOH in rice hybrid progenies.Key words: DNA sequence, homology, PCR, RAPD.
Organization of 5S ribosomal RNA genes in tea (Camellia sinensis)
Authors: Singh Dharam , Singh Mahipal
Published: October 2017

The 5S rRNA genes in the Camellia sinensis (L.) O. Kuntze (tea) genome are arranged as tandem repeat units of 300 and 325 bps. The 2 classes of tandem repeats were discovered by Southern hybridisation of tea genomic DNA with a 5S rRNA gene PCR product.Key words: Camellia species, 5S rDNA, multigene family, tandem repeats, spacers.
Development of microsatellite markers in potato and their use in phylogenetic and fingerprinting analyses
Authors: Ashkenazi Varda , Chani Eduard , Lavi Uri , Levy David , Hillel Jossi , Veilleux Richard E
Published: October 2017

Three genomic libraries were constructed using a mixture of DNA from Solanum phureja Juz. & Buk., and S. chacoense Bitt. Two of the libraries were enriched for ATT and GT repeats (a 27-fold enrichment was achieved). In total, 3500 clones of the conventional library, 1000 of the library enriched for ATT, and 12 000 of the one enriched for GT were screened with five different repeat motifs, and a total of 18 primer pairs was obtained. Another group of 12 primer pairs was obtained from the SSR-containing sequences in the public databases (18 SSR-containing sequences were utilized). From among 30 newly developed primer pairs, 12 previously published ones, and 12 pairs developed for tomato, 7 were used to identify 12 different potato cultivars and introductions, and 12 were used to study phylogenetic distance among seven wild and cultivated potato species. Two SSR markers were sufficient to discriminate the 12 cultivars. The mean number of alleles per polymorphic locus was 5 for the 12 cultivars and 4.5 for the seven species. The results obtained in this study confirm those achieved in similar studies in other plant species regarding the abundance and use of SSR markers in identifying species and cultivars.Key words: Solanum, simple sequence repeats, SSRs, genomic library.
Towards an expanded and integrated linkage map of cucumber (Cucumis sativusL.)
Authors: Bradeen J M , Staub J E , Wye C , Antonise R , Peleman J
Published: October 2017

Linkage maps in cucumber (Cucumis sativus var. sativus L.) have been constructed using morphological traits, isozymes, restriction fragment length polymorphisms (RFLPs), and random amplified polymorphic DNAs (RAPDs). The lack of polymorphism in cucumber has led to the construction of relatively unsaturated maps (13- to 80-point). We have added amplified fragment length polymorphism (AFLP) markers to existing narrow-based (within C. sativus) and wide-based (C. sativus × C. sativus var. hardwickii) maps. JoinMap v. 2.0 was used to construct maps and to join these with historical maps from several previous studies. Our narrow- and wide-based merged maps contain 255 and 197 markers, respectively, including morphological traits, disease resistance loci, isozymes, RFLPs, RAPDs, and AFLPs. Condensation of total map distance occurred in merged maps compared to historic maps using many of the same markers. This phenomenon is most likely due to differences in map construction algorithms. The merged maps represent the best fit of the data used and are an important first step towards the construction of a comprehensive linkage map for cucumber. Identification of additional anchor markers between the narrow- and wide-based maps presented here may allow their future integration into a unified model.Key words: map merging, JoinMap, cucumber, AFLP.
Centromeric tandem repeat from the chaffinch genome: Isolation and molecular characterization
Authors: Saifitdinova A F , Derjusheva S E , Malykh A G , Zhurov V G , Andreeva T F , Gaginskaya E R
Published: October 2017

A new family of avian centromeric satellites is described. The highly repeated sequence, designated FCP (Fringilla coelebs PstI element), was cloned from the 500-bp PstI digest fraction of the chaffinch (Fringilla coelebs L.) genomic DNA, sequenced, and characterized. The FCP repeat was found to have 505506 bp length of monomer, 57% content of GC, to compose about 0.9% of the chaffinch genome, and to be highly methylated. Results of Southern-blot hybridization of cloned FCP element onto genomic DNA digested with different restriction enzymes, and sequencing directly from total genomic DNA using FCP-specific primers and ThermoFidelase enzyme (Fidelity Systems Inc.) were in agreement with a tandem arrangement of this repeat in the chaffinch genome. Five positions of single-nucleotide polymorphism (SNP) were found in the FCP monomers using direct genomic sequencing. Fluorescence in situ hybridization (FISH) with FCP probe and primed in situ labelling (PRINS) with FCP specific primers showed that the FCP elements occupy pericentric regions of all chaffinch chromosomes. On chromosome spreads, the fluorescent signals were also observed in the intercentromeric connectives between nonhomologous chromosomes. The results suggest that the centromeric FCP repeat is responsible for chromosome ordering during mitosis in chaffinch.Key words: satellite DNA, centromeric heterochromatin, Fringilla coelebs.
Genetic mapping of resistance factors toPhytophthora palmivorain cocoa
Authors: Flament M -H , Kebe I , Clément D , Pieretti I , Risterucci A -M , N'Goran J -A-K , Cilas C , Despréaux D , Lanaud C
Published: October 2017

Phytophthora palmivora causes pod rot, a serious disease on cocoa widespread throughout the producing regions. In order to ascertain the genetic determination of cocoa resistance to P. palmivora, a study was carried out on two progenies derived from crosses between a heterozygous, moderately resistant Forastero clone, T60/887, and two closely related and highly susceptible Forastero clones, one completely homozygous, IFC2, and one partially heterozygous, IFC5. The cumulative size of both progenies was 112 individuals. Plants were subjected to natural and artificial inoculation of P. palmivora in Côte d'Ivoire. The genetic maps of T60/887 and of IFC5 were constructed using amplified fragment length polymorphism (AFLP) markers and microsatellites. The map of T60/887 comprised 198 markers assembled in 11 linkage groups and representing a total length of 793 cM. The map of IFC5 comprised 55 AFLP markers that were assembled into six linkage groups for a total length of 244 cM. Ratio of rotten over total number of fruit under natural infection was measured for each tree over two harvests. Artificial inoculations were performed on leaves and pods. These tests were weakly correlated with the pod rot rate in the field. Five quantitative trait loci (QTLs) of resistance were detected for T60/887 but none were common between the three traits measured. Stability and reliability of the experimental procedures are discussed and revealed the difficult use of these artificial tests on adult trees for a good prediction of field resistance.Key words: Theobroma cacao, Phytophthora palmivora, cocoa black pod disease, genetic map, quantitative trait locus (QTL).
Autoradiographic study of transcription and dosage compensation in the sex and neo-sex chromosome ofDrosophila nasuta nasutaandDrosophila nasuta albomicans
Authors: Mahesh G , Ramachandra N B , Ranganath H A
Published: October 2017

Cellular autoradiography is used to study the transcription patterns of the polytene X chromosomes in Drosophila nasuta nasuta and D. n. albomicans. D. n. nasuta, with 2n = 8, includes a pair of complete heteromorphic sex chromosomes, whereas D. n. albomicans, with 2n = 6, has a pair of metacentric neo-sex chromosomes representing incomplete heteromorphic sex chromosomes. The neo-X chromosome has two euchromatic arms, one representing the ancestral X while the other represents the ancestral autosome 3 chromosomes. The metacentric neo-Y chromosome has one arm with a complete heterochromatic ancestral Y and the other arm with a euchromatic ancestral autosome 3. The transcription study has revealed that the X chromosome in D. n. nasuta is hyperactive, suggesting complete dosage compensation, while in the neo-X chromosome of D. n. albomicans the ancestral X chromosome is hyperactive and the ancestral autosome 3, which is part of the neo-sex chromosome, is similar to any other autosomes. This finding shows dosage compensation on one arm (XLx/) of the neo-X chromosome, while the other arm (XR3/YR3) is not dosage compensated and has yet to acquire the dosage compensatory mechanism.Key words: Drosophila, chromosomal races, neo-sex chromosome, transcription and dosage compensation.
Large-scale mutagenesis directed at specific chromosomes in wheat
Authors: Koebner Robert , Hadfield James
Published: October 2017

A novel approach has been developed to allow for the efficient selection of loss-of-function wheat mutants in the M1generation, following either physical or chemical mutagenesis. This has generated an order of magnitude increase in the efficiency of identification of mutants, and also greatly increases the likelihood that selected individuals reflect mutation events at the target locus, rather than at genes acting elsewhere in the disease resistance pathway. The approach relies only on prior knowledge of the chromosomal location of the target gene, and uses the polyploidy of wheat to construct populations for mutagenesis in which large numbers of individuals are hemizygous for the target gene. The idea is illustrated with the mass identification of mutants at three independent genes for race-specific resistance to yellow rust, and one gene for resistance to powdery mildew.Key words: disease resistance mutant, hemizygotes, loss-of-function mutant.
Production of durum wheat substitution haploids from durum × maize crosses and their cytological characterization
Authors: Dogramac1-Altuntepe M , Jauhar P P
Published: October 2017

The objective of this study was to investigate the effect of individual durum wheat (Triticum turgidum L.) chromosomes on crossability with maize (Zea mays L.) and to cytologically characterize the haploids recovered. Fourteen 'Langdon' (LDN) D-genome disomic substitution lines, a LDN Ph mutant (Ph1b ph1b), and normal 'Langdon' were pollinated with maize pollen. After pollination, hormonal treatment was given daily for up to 14 days. Haploid embryos were obtained from all lines and were aseptically cultured. From a total of 55 358 pollinated florets, 895 embryos were obtained. Only 14 of the embryos germinated and developed into healthy plants. Different substitution lines showed varying degrees of success. The most successful was the substitution 5D(5B) for both embryo formation and haploid plantlet production. These results indicate that the substitution of 5D for 5B confers on durum wheat a greater ability to produce haploids. Fluorescent genomic in situ hybridization (GISH) showed that the substitution haploids consisted of 7 A-genome chromosomes, 6 B-genome chromosomes, and 1 D-genome chromosome. Triticum urartu Tum. genomic DNA was efficient in probing the 7 A-genome chromosomes, although the D-genome chromosome also showed intermediate hybridization. This shows a close affinity between the A genome and D genome. We also elucidated the evolutionary translocation involving the chromosomes 4A and 7B that occurred at the time of evolution of durum wheat. We found that the distal segment translocated from chromosome 7B constitutes about 24% of the long arm of 4A.Key words: cyclic translocation 4A·5A·7B, crossability, disomic substitution, fluorescent genomic in situ hybridization (GISH), Triticum turgidum.
Development of sequence-characterized amplified regions (SCARs) from amplified fragment length polymorphism (AFLP) markers tightly linked to the Vf gene in apple
Authors: Xu Mingliang , Huaracha Ernesto , Korban Schuyler S
Published: October 2017

Amplified fragment length polymorphism (AFLP) markers have become widely used in saturating the region of a gene of interest for the ultimate goal of map-based cloning of the gene or for marker-assisted selection. However, conversion of AFLP markers into restriction fragment length polymorphism (RFLP) or polymerase chain reaction (PCR)-based markers will greatly expand their usefulness in genetic applications. Previously, we have identified 15 AFLP markers tightly linked to the Vf gene conferring scab resistance in apple. In this study, we have successfully converted 11 of these AFLPs into sequence-characterized amplified region (SCAR) markers. Of the remaining four nonconverted AFLP markers, one, ET2MC8-1, has been found to be very short (83 base pairs) and is an A/T rich (90%) marker; a second, EA2MG11-1, has shown identical sequences between Malus floribunda 821 (the original source of the Vf gene) and scab-susceptible apple cultivars; while the other two, EA12MG16-1 and ET8MG1-1, have not been cloned. Using the 11 converted SCAR markers along with 5 previously identified SCAR markers, a high-resolution linkage map around the Vf gene has been constructed, and found to be consistent with its corresponding AFLP map. Three converted SCAR markers (ACS-3, -7, and -9) are inseparable from the Vf gene; whereas one (ACS-6) is located left of, and the remaining seven (ACS-1, -2, -4, -5, -8, -10, and -11) are located right of the Vf gene at genetic distances of 0.4 and 0.2 cM, respectively. A reliable and robust procedure for development of SCAR markers from AFLP markers is presented.Key words: apple, AFLP, SCAR, apple scab disease, Vf gene.
Different chromosomal distribution patterns of radiation-induced interchange breakpoints in barley: First post-treatment mitosis versus viable offspring
Authors: Künzel G , Gecheff K I , Schubert I
Published: October 2017

Translocation breakpoints (TBs) induced by ionizing radiation are nonrandomly distributed along barley chromosomes. When first post-treatment mitoses were evaluated, centromeres and the heterochromatin-containing proximal segments tended to be more than randomly involved, and terminal segments to be less than randomly involved in translocations. Contrary to this, small chromosomal regions in median and distal arm positions, characterized by high recombination rates and high gene density, were identified as preferred sites for the origination of viable translocations, probably due to deviations in chromatin organization. Apparently, the position of a TB has an influence on the rate of viability versus elimination of the carrier cells. Surprisingly, TBs within centromeres and heterochromatin-containing segments seem to be more harmful for survival than those induced in gene-rich regions.Key words: Hordeum vulgare, radiation-induced chromosome breaks, translocation lines, breakpoint distribution.
ISOZYME CHARACTERIZATION OF CORN (Zea mays) INBREDS AND ITS RELATIONSHIP TO SINGLE CROSS HYBRID PERFORMANCE
Authors: Hunter R. Bruce , Kannenberg L. W.
Published: October 2017

The extent of heterosis observed in a single cross hybrid has generally been reported to be a function of the genetic diversity of its inbred components. We used isozyme variability as an indicator of genetic diversity. Fifteen inbred lines of maize (Zea mays L.) were characterized for esterase, amylase, leucine aminopepridasc, catalase, alcohol dehydrogenase and peroxidase isozymes. Differences in these systems were used to calculate a diversity index (DI). The DI for an inbred pair represented the number of isozymes that were dissimilar in the two inbreds. Hybrids produced from inbred pairs with higher DI's outyielded those with low DI's. However, the correlation between grain yield performance of the single cross hybrids and DI was low (r = 0.09) and not significant. Hence, the DI, as used here, is of very limited predictive value.
THE MITOTIC CYCLE IN AN AMPHIPLOID (TRITICALE) AND ITS PARENTAL SPECIES
Authors: Kaltsikes P. J.
Published: October 2017

The durations of the mitotic cycle and its phases were determined by 3H-thymidine labelling of root meristematic cells of a strain of a wheat-rye amphiploid (triticale), and its parents Triticum turgidum L. var durum 'Stewart' and Secale cereale L. 'Prolific'.The duration, in hours, of the various phases of the mitotic cycle were:[Formula: see text]Feulgen microspectrophotometry showed triticale to have 15% less DNA per 4C nucleus than the sum total of its parents Prolific and Stewart whose DNA contents were in the ratio of 2:3, indicating that the duration of the S period is independent of DNA content per nucleus. The rate of DNA synthesis, measured as number of silver grains over interphase nuclei, was correlated with the total area of the nuclear membrane.
MEIOTIC CHROMOSOME BEHAVIOR IN INDUCED AUTOTETRAPLOIDS AND AMPHIDIPLOIDS IN THE LOTUS CORNICULATUS GROUP
Authors: Somaroo B. H. , Grant W. F.
Published: October 2017

A comparative meiotic study was conducted on 12 induced Lotus autotetraploids (2n = 4x = 24; L. alpinus, L. japonicus, L. filicaulis, L. schoelleri, L. krylovii, L. tenuis and L. corniculatus var. minor), and 22 amphidiploids (2n = 4x = 24) obtained by doubling the chromosome number of 12 diploid interspecific hybrids. Meiocytes of the autoretraploids were characterized by a rather high frequency of bivalents (average 8.79 per cell) and a low occurrence of quadrivalents (average 0.77 per cell). In many of the amphidiploids there was a relatively high frequency of bivalents (mean 9.92 per cell) and a low number of multivalents (mean 0.39 per cell) providing evidence for the structural differentiation of the chromosomes and preferential pairing. Homology of the chromosomes of the parental species was indicated by the presence of trivalents and quadrivalents, and the occurrence of inversion bridges with accompanying fragments in the amphidiploids. It appears that the chromosomes of L. japonicus and L. alpinus have considerable homology since the amphidiploid (L. japonicus × L. alpinus)2 exhibited a high frequency of quadrivalents in comparison with the number of quadrivalents observed in L. japonicus (4x) and L. alpinus (4x), A comparison of a) the pollen stainability and b) the frequencies of multivalent configurations in the autoretraploids and the amphidiploids indicated that both multiple gene substitution and cryptic structural changes of the chromosomes are important in differentiating the diploid species.
THE CHRONOLOGY OF DNA SYNTHESIS, MEIOSIS AND SPERMIOGENESIS IN THE MALE MOUSE AND GOLDEN HAMSTER
Authors: Ghosal Sudhangsu K. , Mukherjee Barid B.
Published: October 2017

A method is described for estimating the duration of DNA synthesis in mammalian spermatocytes. This duration is about 29 and 40 hr in the male mouse and golden hamster, respectively. The duration of spermiogenesis and various stages of meiosis was also studied. The spermatocyte DNA was labelled with thymidine-H3 and the kinetics of the labelled cells was followed radioautographically until the formation of mature spermatozoa. In both animals leptotene lasts for less than 3 days, zygotene shorter than 1 day and pachytene as long as 7-8 days. Transition from diplotene to anaphase II is extremely rapid and requires about 1 day or less. Spermiogenesis is completed in approximately 14-16 days. Labelled mature spermatozoa of the mouse and those of the golden hamster appear at 26.5 ± 0.5. and 25.5 ± 0.5 days postlabelling, respectively.
DIALLEL ANALYSIS OF LEAF CHARACTERISTICS IN INDIAN MUSTARD
Authors: Singh Shree Pal , Singh Dharampal
Published: October 2017

A complete diallel cross involving four experimental strains and six standard cultivars of Indian mustard. Brassica juncea (L.) Czern. and Coss., was investigated for the inheritance of leaf length and leaf width. Considerable heterosis and heterobeltiosis were found in certain hybrid combinations for both characters. Several crosses exceeded the performance of the best cultivar. Partial dominance for leaf length and overdominance for leaf width were observed. Highly significant additive gene effects were found for both characters bur only about one third of the total variance exhibited by leaf length and about one sixth of that by leaf width may be ascribed to this component. The correlation between the two characters was positive. It was concluded that breeding programs should put more emphasis on leaf length rather than leaf width for effective manipulations of leaf size.
STRUCTURE OF CHROMOSOMES VISUALIZED BY SCANNING ELECTRON MICROSCOPY
Authors: Yu C. K.
Published: October 2017

Isolated metaphase chromosomes of Chinese hamster observed under the scanning electron microscope appear to have a distinct rough surface composed of chromonemata. The chromonema is a fine filament coated with nucleoprotein, which can be easily removed by hypotonic sodium citrate solution. The centromere, a narrowed, tight portion of the chromosome, is also multistranded. No membrane has been seen in metaphase chromosomes.
CHROMOSOME ASSOCIATIONS AT PACHYTENE AND METAPHASE INMEDICAGO SATIVA
Authors: Armstrong K. C.
Published: October 2017

Chromosome associations were analyzed at pachytene and metaphase I from six plants of Medicago sativa L. (2n = 4x = 32). Quadrivalent frequency at pachytene ranged from 0.89 to 2.93. These values are considerably below theoretical expectations for an autotetraploid. The chromosome associations at metaphase I did not entirely reflect differences in quadrivalent frequency at pachytene, although there was a general tendency for plants with higher quadrivalent frequencies at pachytene to have a higher trivalent and univalent frequency at metaphase I. However, there were obvious differences in the amount and kind of pachytene quadrivalent dissociation that occurred, which are probably a result of small differences in chiasma frequency and distribution.
INHERITANCE OF A SOYBEAN FLOWERING RESPONSE TO FLUORESCENT-DAYLENGTH CONDITIONS
Authors: Buzzell R. I.
Published: October 2017

The inheritance of flowering time was studied in the short-day soybean, Glycine max (L.) Merr., under long-day conditions in the greenhouse using natural day length extended to 20 hours with cool-white fluorescent light. A single, major gene with two alleles was found to control the flowering response. The dominant allele which gave a fluorescent-sensitive response of delayed flowering also resulted in later field maturity whereas the recessive allele which gave an insensitive response resulted in earlier maturity. The maturity symbols E3 and e3 are proposed for these alleles. Isolines have been developed.
CHROMOSOMES IN MALES OF FIVE STRAINS OF CALLOSOBRUCHUS MACULATUS (COLEOPTERA: BRUCHIDAE)
Authors: Takenouchi Yasushi
Published: October 2017

The chromosomes of five strains of Callosobruchus maculatus (Fab.) originating from four different countries were compared in male germ-line cells. All had 2n = 20 which paired to form 9 II + Xy at MI. No typical, nucleolus-associated Xyp sex complex was observed in any strain.
PREPARATION OF PROTOPLASTS FROM STATIONARY PHASE CELLS OFSCHIZOSACCHAROMYCES POMBE
Authors: Shahin M. M.
Published: October 2017

A high percentage of protoplasts was obtained from stationary phase cells of Schizosaccharomyces pombe by using the commercial preparation Helicase, obtained from the snail Helix pomatia. This was achieved with five different strains of S. pombe: the wild strains of three different mating types, 975h+and 972h−(heterothalic), and 968h90(homothalic); one adenine auxotroph (adn-3h+); and a radiation-sensitive strain (UVS-1h−). In all five strains the time required for protoplast formation increased greatly as soon as the culture outgrew the logarithmic and entered the stationary phase. Cells from the same logarithmic or stationary phase also showed different susceptibility to attack by Helicase. However, it is interesting to note that no protoplast formation was achieved from stationary phase cells of the three adenine-requiring strains: adn-7, 407h−, adn7-50//la UVS1h−and adn-7, adn-1.
VARIETAL DIFFERENTIATION IN BROWN SARSON
Authors: Rao T. Swamy
Published: October 2017

Chromosomal inversions are partly responsible for differentiation between self-compatible and self-incompatible types of brown sarson.
DESYNAPSIS IN SOME DIPLOID AND POLYPLOID SPECIES OF ALLIUM
Authors: Gohil R. N. , Koul A. K.
Published: October 2017

Desynapsis has been reported in two diploid (Allium sativum and A. consanguineum) and one tecraploid (A. tuberosum) species of Allium. The desynaptic A. sativum is totally male sterile. A. consanguineum is a medium-strong, and A. tuberosum a weak desynaptic. Desynapsis in the latter two species upsets the course of meiosis and results in pollen grains with varying chromosome numbers and considerably reduced fertility.
INHERITANCE OF LEAF VARIEGATION IN BUCKWHEAT
Authors: Ali-Khan S. T.
Published: October 2017

Two chlorophyll mutants occurred spontaneously in a buckwheat cultivar grown at Morden, Manitoba. In variegated plants yellow sectors appeared within green tissue of leaves, the sectors varying in size from a small spot to an entire leaf. Progeny tests indicated that variegation was due to instability of alleles controlling chlorophyll production. Designations for the alleles controlling chlorophyll production have been suggested.
COMPUTER ANALYSIS OF DISEASE DATA TO DERIVE HYPOTHETICAL GENOTYPES FOR REACTION OF HOST VARIETIES TO PATHOGENS
Authors: Loegering W. Q. , McIntosh R. A. , Burton Coleman H.
Published: October 2017

A method is described for deriving genotypes for low reaction in varieties of a host from data resulting from inoculating many host varieties with many cultures of a pathogen. A computer program utilizing Boolean algebra was used to compare and group patterns of low and high infection types produced by host variety: pathogen culture combinations. Visual inspection within each group allows derivation of the genotype. A successful trial of the system was made with data on wheat leaf rust involving 60 varieties of wheat and nine cultures of Puccinia recondita.
A THIN-LAYER CHROMATOGRAPHIC STUDY OF SOME AMPHIPLOIDS IN AVENA
Authors: Rajhathy Tibor , Shearer D. A. , Warner E. M.
Published: October 2017

A thin-layer chromatographic study was carried out using five synthetic Avena amphiploids and their parental genotypes. The Dass-Nybom solvent and an extraction time of 120 hr were found to be optimum for Avena. About 42% of 3 total of 62 spots were common to all, or all but one species, and these were considered characteristic for the genus. The over-all additiveness of the parental spectra was low (32.5%) in the experimental alloploids; therefore, comparisons of total spectra of natural alloploids and their putative progenitors may not be useful in Avena. A number of hybrid spots, due to complementary gene interactions, was detected. Selected spots specific for either the A- or C-genome diploids could be traced in the polyploids. These suggested the presence of the C genome in the new tetraploid species A. magna, and in the hexaploids, and confirmed A. magna as the putative tetraploid ancestor of the hexaploid species. The chromatographic phenotype, due to its large number of well defined traits, may be very useful in studying gene interactions in polyploid Avena and for marking linkage groups in chromosome deficient lines.
CYTOGENETICS OF SOME MONOTELOTRISOMICS IN BARLEY
Authors: Fedak George , Tsuchiya T. , Helgason S. B.
Published: October 2017

Linkage markers and translocation stocks were used to identify four monotelotrisomics in barley as 14 + 1S, 14 + 2L, 14 + 4L, and 14 + 5S. In morphology they displayed the same deviations from disomic plants as the corresponding primary trisomics but to a lesser extent, ranging from an approach to the disomic for 14 + 1S to close resemblance to the trisomic for 14 + 2L. At meiotic metaphase, an average of 61.1% of the cells contained heteromorphic trivalents, with tandem-chain and ring-rod configurations predominating. The extra telocentrics were transmitted to 28.3% of selfed progeny, almost exclusively through the female gamete.
ESTERASE POLYMORPHISM IN A NATURAL POPULATION OFANOPHELES PUNCTIPENNIS. II. ANALYSIS OF THEEST-CSYSTEM
Authors: Narang S. , Kitzmiller J. B.
Published: October 2017

A series of reddish staining bands (acrylamide gel electrophoresis) has been designated the Est-C system in Anopheles punctipennis. These bands, specific for beta substrate and therefore easily recognized, are the phenotypic expressions of three alleles Est-CF, Est-CI, and Est-CSat a single autosomal locus. Analysis of a natural population (140 individuals) indicates that homozygotes have a higher frequency and heterozygotes a lower frequency than expected on a Hardy-Weinberg basis. This locus should be an excellent autosomal marker.
Es-3 ESTERASES IN ERYTHROCYTES OFMUS MUSCULUS
Authors: Martin James E. , Petras Michael L.
Published: October 2017

An esterase found in low frequency in the erythrocytes of wild mice is probably controlled by a fourth allele, tentatively designated Es-3d, at the Es-3 locus. Attempts to characterize this new esterase, using substrate specificity, temperature sensitivity, and interaction with eserine sulphate and iodoacetamide, have shown it to behave like the other esterases controlled by this locus.
QUANTITATIVE GENETICS OF FERTILITY. III. A NEW MODEL FOR INTERSTRAIN LIFETIME EGG PRODUCTION COMPARISONS
Authors: Fitz-Earle Malcolm
Published: October 2017

A new model for use in theoretical and practical studies of egg production is derived: N(t) = (1−e−ξ(t–to))e−α(t–tq), where N(t) is the number of eggs laid on day t; ξ is the rate of increase in egg production; α is the rate of decrease in egg production; tois the day of initiation of egg-laying; tqis the day of cessation of egg-laying. Egg production curves for Drosophila melanogaster strains were fitted using non-linear least squares regression analyses such that all parameters in the model and their errors were generated simultaneously. The goodness-of-fit of the model to the observed data was precise. The experimental evidence showed that parameters α and tqwere basically describing the genetic components of egg production in females whereas parameters ξ and toexhibited additional components, the interactions between males and females. Expressions derived from the model, tmax, the time of maximum production, N(tmax), the maximum production at this time and T(to,tq), the production over lifetime, gave results consistent with the observations.
CHROMOSOMAL POLYMORPHISM IN THE LESSER BUSH BABIES (GALAGO SENEGALENSIS)
Authors: Ying K. L. , Butler H.
Published: October 2017

Chromosome studies were performed on 11 lesser bush babies (Galago senegalensis) which were divided into three subspecies. Among these animals five different karyotypes were identified with the diploid numbers 36, 37 and 38. A fusion type of mechanism might have been involved in the chromosomal evolution of this species.
THEBLOBMUTANT OFTRIBOLIUM CASTANEUM
Authors: Dawson Peter S.
Published: October 2017

A new sex-linked mutation in the flour beetle Tribolium castaneum is described and illustrated. Blob (bb), an antennal mutant, is located near the far right end of the known linkage map of the X chromosome. It is recessive, with incomplete penetrance and variable expressivity, and fails to exhibit dosage compensation. The expression of bb is discussed in relationship to models of antennal development in this species. Apparent rediscovery of the pegleg mutation has confirmed a previous report on the linkage relationships of pearl and pegleg in linkage group II.
FLUORESCENT STAINING OF EUCHROMATIN AND HETEROCHROMATIN IN MAIZE (Zea mays)
Authors: Horn J. D. , Walden D. B.
Published: October 2017

Somatic metaphase chromosomes of maize (Zea mays L.), including the largely heterochromatic supernumerary "B" and an abnormal No. 10, were stained with the fluorometric agent quinacrine mustard (QM).When the fluorescent regions of the chromosomes were compared to the known cytological positions of heterochromatin in maize, both euchromatic and heterochromatic regions showed fluorescence. Not all heterochromatin was fluorescent after staining with QM. We concluded that fluorescence with QM is not an exclusive property of heterochromatin. We also postulate that in maize there are at least two different types of heterochromatin, one which takes up the fluorometric agent QM readily and a second which does not.
PERFORMANCE OF HYBRID POPULATIONS DERIVED FROM CROSSES OF SUBSTITUTION LINES OF COMMON WHEAT
Authors: Ahmed Sadeque U.
Published: October 2017

The recipient variety 'Chinese Spring', chromosome substitution lines 1B of Timstein' and 4A of 'Thatcher', and donor varieties Timstein and Thatcher were studied with respect to six quantitative characters, viz. earliness, plant height, tiller number per plant, kernel number per spike, 1000-kernel weight and total grain yield per plant. Heterosis was observed for all characters; however, the degree and direction of heterosis varied for different characters and for different hybrid populations. Evidence for significant improvement in kernel weight and total grain yield per plant combined with early heading and short plant height were obtained. Evidence was obtained indicating that substitution lines may be effective breeding materials in common wheat (Triticum aestivum L.) breeding programs.
THE GENETIC BASIS OF A SPECIFIC PHENOCOPY RESPONSE
Authors: Rapport Ellen , Sing Charles F.
Published: October 2017

Utilizing glucosamine susceptibility as an indicator of developmental homeostasis of the aminosugar pathway in Drosophila melanogaster, experiments were performed to explore the genetic nature of this buffering.Chromosomes derived from four laboratory strains were tested for additive, dominant and epistatic gene action. Dominant alleles were shown to confer homeostatic properties on the organism and the data arc consistent with the view that different genotypes use nonallelic genes to achieve homeostasis. Epistasis was found to play some part in the genetic control of phenocopy susceptibility. For example, while heterozygosity was generally associated with phenocopy tolerance, single chromosome heterozygotes were found in some cases to be more tolerant than double heterozygotes. A model accounting for these findings was formulated.The study indicates that the utilization of excess endogenous metabolites to test for the existence of genes controlling developmental buffering may provide a useful method of approaching problems of developmental homeostasis.
EVOLUTION OF FERTILITY IN ADVANCED GENERATIONS OF AN ALFALFA SINGLE CROSS HYBRID
Authors: Dessureaux L. , Gallais A.
Published: October 2017

Cross-fertility of a single cross hybrid was found to decrease gradually in advanced generations. When the same parents were selfed without selection for two or three generations, seed setting increased from Syn1to Syn2, then decreased in Syn3and Syn4. Interpretation of these data according to various genetic models, assuming no epistasis, indicates that fertility is influenced more by the mother plant than by the zygote, especially in the F1. Even with the best model, deviations from regression remain significant, except when the Syn1generation is removed from the analysis.
CHROMOSOME NUMBER, VOLUME AND NUCLEAR VOLUME RELATIONSHIPS IN A POLYPLOID SERIES (2X-20X) OF THE GENUSRUMEX
Authors: Ichikawa S. , Sparrow A. H. , Frankton C. , Nauman Anne F. , Smith E. B. , Pond Virginia
Published: October 2017

Ninety-one acquisitions of the genus Rumex obtained from various sources were examined taxonomically and cytologically. These acquisitions included 36 species plus 2 unidentified species. The chromosome numbers counted were 2n = 14 (or 15), 16, 18, 20, 40, 42, 60, 80, 100, 120, 140, 160, ca. 170, 180 and ca. 200. The count of 2n = 180 made on one of the R. orbiculatus acquisitions is a new count for this genus, but other acquisitions had 160 and ca. 170. First counts were obtained for four species, R. frutescens (2n = 160), R. crystallinus (2n = 60), R. cristatus (2n = 80) and R. tenax (2n = 80). The count of 2n = 160 for R. frutescens is the highest chromosome number ever reported in the section Axillares. The chromosome numbers determined in R. palustris (2n = 60), R. confertus (2n = 100), R. arcticus (2n = 120) and R. aquaticus (2n = 140) differ from previously published counts. Our counts for eight other species support one of the previous counts where two or more counts are reported. It is shown that the species of the subgenus Acetosa sections Acetosa and Vesicarii and of the subgenus Platypodium have relatively large chromosomes, those of the subgenus Acetosa section Scutati and of the subgenus Acetosella have medium-sized chromosomes, and the members of the subgenus Rumex sections Axillares and Rumex have smaller chromosomes. The chromosomes of the diploid species of the section Rumex were larger than those of the polyploids (4x to 20x) of the same section. Within the section Rumex the log of nuclear volume increased with increasing ploidy, with an abrupt change (decrease) in slope between the 12x and 14x levels.
ADDITIVE AND NONADDITIVE GENETIC VARIANCES AND GENOTYPIC CORRELATIONS FOR YIELD AND OTHER TRAITS IN OATS
Authors: Sampson D. R.
Published: October 2017

The oat cultivate 'Dorval', 'Kelsey', 'Stormont', 'Orbit', 'Goodfield', 'Tyler' and 'Egdolon' and two numbered lines were crossed in a 3 × 6 factorial design. F1's, F2's and bullied F2 progenies were grown in successive years at seeding rates of 2.7, 9.5 and at the commercial rare of 76 Kg/ha, respectively; the F1's in irrigated cages, the F2's and F3's in nonirrigated fields. Additive genetic variance was the most important component of the phenotypic variances among progenies. Major differences occurred between the F1's and F2's, but the F2's and F3's agreed closely. The percentages of additive variance (narrow sense heritability) for the joint F2, F3 analyses were: height (91); heading date (87); seed weight (74); yield per panicle (71); seeds per panicle (63); panicle number (58); stem diameter (55); plot yield (52). Important nonadditive variance was present in the F2, F3 data for plot yield (17%), stem diameter (15%) and seed weight (12%). All traits were positively correlated with each other in the F1's. Correlations were weaker in the F2 and F3 and reversed for panicle number. Seed weight showed the least correlation with other traits. These results are discussed from the practical viewpoint of combining strong straw with high grain yield. The usefulness of selecting for seed weight and panicle yield to improve plot yield is underlined.
THE MITOTIC SPINDLE APPARATUS OFNEUROSPORA CRASSA
Authors: Winkle W. Barry Van , Biesele John J. , Wagner R. P.
Published: October 2017

Electron microscopic studies of the sl-327 mutant of Neurospora crassa reveal that somatic nuclear division in hyphlet somatic cells involves a definite spindle apparatus consisting of spindle microtubules terminating at specific loci on the external surface of the nuclear envelope. These loci, termed spindle plaques, have been observed in a variety of other fungal species and seem to play a role in the initiation of spindle microtubule growth during mitosis. The development of the various spindle components and their possible functions in nuclear division in this strain of Neurospora are discussed.
MORPHOLOGIE POLLINIQUE ET NOMBRE CHROMOSOMIQUE DANS LA SOUS-SECTION HETEROPHYLLA DU GENRE CAMPANULA
Authors: Geslot Alain , Medus Jacques
Published: October 2017

A comparative study of the palynological morphology and the chromosome numbers of 14 populations representing six species from the s.s. Heterophylla (Wit.) Fed. of the genus Campanula L. has been made. It has shown that the frequency distribution based upon the number of pores in each grain is related to the ploidy level of the species. Correspondences analysis shows the prevailing action of two factors in this phenomenon.The most important factor regarding the increased pore number is an increase of the chromosome number. Another factor still escapes interpretation. It sometimes appears without being directly dependent on the number of apertures, but it must be taken into account in the explanation of the phenomenon.The diameter of the grains seems partly to be related to polyploidy but it is independent of the number of apertures in each grain. The linear relationship between diameter and aperture number is not significant.
FURTHER EVIDENCE ON THE DERIVATION OF UNIVALENTS IN HEXAPLOID TRITICALE
Authors: Larter E. N. , Shigenaga S.
Published: October 2017

Approximately 70% of the PMC's of the triticale cultivar 'Rosner' have 21 bivalents at MI; the remaining cells exhibit varying numbers of univalents. By careful measurement and classification of univalents, the range of univalent size corresponds to that obtained from measurement of the complete compliment of univalents of a haploid of Rosner. This verified earlier findings that the varying degrees of meiotic instability observed in triticale involved chromosomes of both the wheat and rye genomes, not only those of rye as earlier believed.
RELATIONSHIPS BETWEEN GERMINAL VESICLE VOLUME AND CYTOPLASMIC VOLUME IN AMPHIBIAN OOCYTES
Authors: Peterson Arlan W.
Published: October 2017

Germinal vesicle growth dots not keep pace with amphibian oöcyte enlargement. However, specific size relationships between nuclear volume and oöcyte volume hold for several different species. The nuclear volumes of oöcytes of similar size from Taricha granulosa and Ascaphus truei are nearly equal even though A. truei oöcytes are multinucleate. Nucleoplasmic volume relationships are maintained in A. truei by a reduction in germinal vesicle size.
HIGH LEVELS OF NONDISJUNCTION INDROSOPHILA MELANOGASTER♀ ♀ WITHbw/bwandst/+
Authors: Douglas Lee T. , Posma Resi M.
Published: October 2017

Pronounced elevation of primary X,YBnondisjunction occurs in Drosophila melanogaster ♀ ♀ homozygous for brown (2,104.5) and heterozygous for scarlet (3,44). In control stocks without marked autosomes, 5 nondisjunction flies in a total of 696 were counted, whereas 352 in 4020 were produced by 29 experimental ♀ ♀. A histogram of nondisjunction fractions against number of males test crossed to bw/bw; st/st ♂ ♂ as single pairs suggests dividing the 29 pairs examined into two subgroups. One of these, with a mean % [Formula: see text] nondisjunction of 30%, appears to be homogeneous, whereas the other one (mean = 3%) is not.
Chromosome studies in 2n = 14 and 2n = 16 types of Medicago murex
Authors: Mariani A. , Falistocco E.
Published: October 2017

Karyological and morphological studies of Medicago murex with 2n = 16 and 2n = 14 chromosomes were undertaken. Analysis of the somatic chromosomes, using both conventional staining techniques and C-banding, showed that the 2n = 14 karyotype derived from the 2n = 16 karyotype. Plant morphology of the two types differs in relation to the characters of the leaves, florets, and pods. Attempts to obtain hybrids between the two types were completely unsuccessful. From these results it appears that the two M. murex types are not as closely related as has been usually considered and that they should be regarded as two different species.Key words: Medicago murex, chromosome number, C-banding.