Allozyme analysis of the hybrid Phoxinus eos × Phoxinus neogaeus (Pisces: Cyprinidae) in Nebraska

1982 ◽  
Vol 60 (5) ◽  
pp. 968-973 ◽  
Author(s):  
Gerard R. Joswiak ◽  
Richard H. Stasiak ◽  
William S. Moore
Keyword(s):  
F1 Hybrids ◽  
Allozyme Analysis ◽  
Parthenogenetic Species ◽  
Marker Loci

Twenty-three fish from two localities in Nebraska were electrophoresed for three marker loci that distinguish Phoxinus eos and P. neogaeus. Seven had patterns of pure P. eos and 16 were heterozygous at all three markers. Of these, two were morphologically similar to P. eos, while the rest more closely resembled neogaeus. All hybrids were female. Two hypotheses are suggested: (1) The F1 hybrids fall into two morphological groups, dependent on the species of the maternal progenitor and (2) the hybrids are a parthenogenetic species. No introgression was detected in this study and the question of hybrid reproduction remains unresolved.

scholarly journals Linkage Analysis and Map Construction in Genetic Populations of Clonal F1 and Double Cross

2015 ◽  
Vol 5 (3) ◽  
pp. 427-439 ◽  
Author(s):  
Luyan Zhang ◽  
Huihui Li ◽  
Jiankang Wang
Keyword(s):  
Analytic Solution ◽  
Frequency Estimation ◽  
Female Parent ◽  
Marker Locus ◽  
Maximum Likelihood Estimates ◽  
F1 Hybrids ◽  
Map Construction ◽  
Marker Loci ◽  
Raphson Method ◽  
Double Cross

Abstract In this study, we considered four categories of molecular markers based on the number of distinguishable alleles at the marker locus and the number of distinguishable genotypes in clonal F1 progenies. For two marker loci, there are nine scenarios that allow the estimation of female, male, and/or combined recombination frequencies. In a double cross population derived from four inbred lines, five categories of markers are classified and another five scenarios are present for recombination frequency estimation. Theoretical frequencies of identifiable genotypes were given for each scenario, from which the maximum likelihood estimates of one or more of the three recombination frequencies could be estimated. If there was no analytic solution, then Newton-Raphson method was used to acquire a numerical solution. We then proposed to use an algorithm in Traveling Salesman Problem to determine the marker order. Finally, we proposed a procedure to build the two haploids of the female parent and the two haploids of the male parent in clonal F1. Once the four haploids were built, clonal F1 hybrids could be exactly regarded as a double cross population. Efficiency of the proposed methods was demonstrated in simulated clonal F1 populations and one actual maize double cross. Extensive comparisons with software JoinMap4.1, OneMap, and R/qtl show that the methodology proposed in this article can build more accurate linkage maps in less time.

A Genetic Map of Tomato Based on BC1 Lycopersicon esculentum × Solanum lycopersicoides Reveals Overall Synteny but Suppressed Recombination Between These Homeologous Genomes

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 857-867 ◽  
Author(s):  
Roger T Chetelat ◽  
Vladimir Meglic ◽  
Pedro Cisneros
Keyword(s):  
Lycopersicon Esculentum ◽  
Chiasma Formation ◽  
Genetic Maps ◽  
Plant Genome ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Recombination Suppression ◽  
Solanum Lycopersicoides ◽  
Marker Loci ◽  
Homeologous Recombination

Abstract F1 hybrids between the cultivated tomato (Lycopersicon esculentum) and the wild nightshade Solanum lycopersicoides are male sterile and unilaterally incompatible, breeding barriers that impede further crosses to tomato. Meiosis is disrupted in 2× hybrids, with reduced chiasma formation and frequent univalents, but is normal in allotetraploid hybrids, indicating the genomes are homeologous. In this study, a partially male-fertile F1 was backcrossed to tomato, producing the first BC1 population suitable for genetic mapping from this cross. BC1 plants were genotyped at marker loci to study the transmission of wild alleles and to measure rates of homeologous recombination. The pattern of segregation distortion, in favor of homozygotes on chromosomes 2 and 5 and heterozygotes on chromosomes 6 and 9, suggested linkage to a small number of loci under selection on each chromosome. Genome ratios nonetheless fit Mendelian expectations. Resulting genetic maps were essentially colinear with existing tomato maps but showed an overall reduction in recombination of ~27%. Recombination suppression was observed for all chromosomes except 9 and 12, affected both proximal and distal regions, and was most severe on chromosome 10 (70% reduction). Recombination between markers on the long arm of this chromosome was completely eliminated, suggesting a lack of colinearity between S. lycopersicoides and L. esculentum homeologues in this region. Results are discussed with respect to phylogenetic relationships between the species and their potential use for studies of homeologous pairing and recombination in a diploid plant genome.

The scale insect Coccus pseudomagnoliarum (Kuwana) (Hemiptera: Coccomorpha: Coccidae) on citrus in Greece

2020 ◽  
Vol 13 (2) ◽  
pp. 93-97
Author(s):  
G.J. Stathas ◽  
Ch.F. Karipidis
Keyword(s):  
Citrus Sinensis ◽  
Maximum Rate ◽  
Scale Insect ◽  
Instar Nymph ◽  
Summer Period ◽  
Parasitoid Species ◽  
Parthenogenetic Species

SummaryPhenology and parasitism of the scale insect, Coccus pseudomagnoliarum (Kuwana) (Hemiptera: Coccomorpha: Coccidae), infesting Citrus sinensis (Rutaceae), were studied in Papagou area, in northeastern Athens, from June 2015 to June 2017. Coccus pseudomagnoliarum is a univoltine, viviparous, parthenogenetic species. It overwintered as settled 1st instar nymph on the shoots of the trees. The 2nd instar nymphs appeared between the beginning of April and the end of May, and the mature females were recorded from the beginning of May until the middle of June. The crawlers appeared between the middle of May and the middle of June and the 1st instar nymphs settled on the shoots at the end of May, where they remained during the whole summer period, winter, until the beginning of April next year. Parasitism of the scale was recorded between the beginning of May and the middle of May and reached a maximum rate of 35%. The recorded parasitoid species were Coccophagus shillongensis Hayat and Singh (Hymenoptera: Aphelinidae), Coccophagus spp. and Metaphycus dispar (Mercet) (Hymenoptera: Encyrtidae).

FEATURES OF THE WINTER WHITE CABBAGE VARIETIES GENERATIVE DEVELOPMENT

1970 ◽  
pp. 38-40
Author(s):  
R. E. Kazakhmedov ◽  
М. А Magomedova
Keyword(s):  
Hormonal Regulation ◽  
F1 Hybrids ◽  
Vegetable Crops ◽  
Stem Extension ◽  
Market Competitiveness ◽  
White Cabbage ◽  
Environmentally Safe ◽  
Selection Tasks ◽  
High Yielding Varieties ◽  
High Yields

One of the modern selection tasks in vegetable growing is quality products improving, obtaining high yields of environmentally safe wide assortment vegetables. To the new varieties of vegetable crops including winter white cabbage are specified new requirements such as market competitiveness, resistance to unfavorable environmental conditions, heat resistance of the varieties and F1 hybrids. The article is shown investigation results about studies of exogenous treatment by solutions on the base of physiologically active compounds of hormonal nature on the started process of stem extension stage activation and flowering of winter white cabbage plants. For the first time in the Dagestan conditions has been studied the possibility of hormonal regulation of the premature stem extension stage and flowering prevention of winter white cabbage after the initiation of natural induction. In our studies with an early planting there are not more than 20% of blooming plants, most varieties showed a high propensity to premature stem extension stage and flowering. The possibility of the hormonal exogenous regulation of the unfavorable winter white cabbage flowering has been revealed. The most pronounced effect on the transition to stem extension stage and flowering were provided by auxin nature preparations. In particular, treatment with NAS at a dose of 5 mg / l significantly reduced the number of blossom plants, krezatsin (50 mg / l) had a similar effect, but it was less pronounced. The use of cabbage in winter crops makes it possible to obtain two or three yields per year from the same area. Creation and introduction into production of promising and high-yielding varieties and hybrids will allow increasing production and reducing its cost.

EVALUATION OF HYBRID SPRING WHEAT POPULATIONS

2018 ◽  
pp. 37-39
Author(s):  
O. V. Gladysheva ◽  
Т. А. Barkovskaya
Keyword(s):  
Correlation Coefficient ◽  
Spring Wheat ◽  
Dominant Role ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Selection Of

This article presents the results of a study of hybrid spring wheat populations. Revealed different patterns of inheritance of important traits in F1 hybrids, which is caused by hereditary features of the original forms and circumstances. Analysis of hybrid populations showed that the dominant role in the formation of 1000 grains mass belongs to productivity and weight of grain with an ear, correlation coefficient r = 0.90 and amounted to r = 0.73, respectively. Found that the hybrid population in F4-5, created on the basis of grades Moscow 35, Esther, Agatha, Rome, Saratovskaya 29 (Russia), Ostinka (Ukraine) are a valuable material for selection of highly productive genotypes for future use breeding process. 

Heterosis in F1 Hybrids of Sorghum vulgare × S. sudanense and S. vulgare × S. arundinaceum 1

1958 ◽  
Vol 50 (11) ◽  
pp. 714-715 ◽  
Author(s):  
J. P. Craigmiles ◽  
H. B. Harris ◽  
J. P. Newton ◽  
J. W. Dobson
Keyword(s):  
F1 Hybrids ◽  
Sorghum Vulgare

Genetic Evaluation and Bi-plot Analysis in Okra Hybrids for Yield, Quality Components and YVMV Resistance

2018 ◽  
Vol 5 (04) ◽  
Author(s):  
SS SOLANKEY ◽  
ANIL K SINGH
Keyword(s):  
Genetic Divergence ◽  
Principal Component ◽  
F1 Hybrids ◽  
Genetic Advance ◽  
Economic Traits ◽  
Cross Combination ◽  
Plot Analysis ◽  
Eigen Value ◽  
Coefficient Of Variability ◽  
Yield Quality

Fifty one okra F1 hybrids (using 17 lines as female and 3 testers as male parent) were evaluated in RCBD design during two different consecutive seasons (summer and rainy). Phenotypic coefficient of variability (PCV) was higher than genotypic coefficient of variability (GCV) for all studied character exhibiting environmental effects on the expression of characters. Heritability (h2b) along with genetic advance per cent of mean was found highest for character YVMV (86.95% and 150.61%). All the 51 okra hybrids were grouped into 4 distinct clusters in which Cluster II was the largest cluster having 28 F1s (54.90% of total F1s) followed by Cluster I with 14 F1s (27.45% of total F1s). Out of the major 6 PCs, 4 principal components (PC1, PC2, PC3 and PC4) accounted with proportionate values of 22.61, 17.22, 11.87 and 10.63%, respectively and contributed 62.33 % of the cumulative variation having Eigen value more than one. Moreover, based on PCs and genetic divergence in Cluster I and Cluster IV for plant height, YVMV and number of fruit per plant is important to identify the best cross combination (Arka Abhay × Arka Anamika) in okra. Therefore, the best cross combinations for improvement in various economic traits can be recommended on the basis of genetic divergence and principal component analysis in okra.

scholarly journals Coupled complementation of immune response genes controlling responsiveness to the H-2.2 alloantigen.

1977 ◽  
Vol 146 (2) ◽  
pp. 571-578 ◽  
Author(s):  
M E Dorf ◽  
J H Stimpfling
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Humoral Response ◽  
Mixed Lymphocyte Culture ◽  
Lymphocyte Culture ◽  
F1 Hybrids ◽  
Gene Control ◽  
Low Responder ◽  
Resistant Strains ◽  
High Level

The ability of various B10 congenic resistant strains to respond to the alloantigen H-2.2 was tested. High and low antibody-producing strains were distinguished by their anti-H-2.2 hemagglutinating respones. However, these strains do not differ in their ability to respond to these antigenic differences in the mixed lymphocyte culture. The humoral response to the H-2.2 alloantigen was shown to be controlled by two interacting genes localized within the H-2 complex. Thus, F1 hybrids prepared between parental low responder strains could yield high level immune responses. In addition, strains bearing recombinant H-2 haplotypes were used to map the two distinct genes controlling the immune response. The alleles at each locus were shown to be highly polymorphic as evidenced by the asymmetric complementation patterns observed. The restricted interactions of specific alleles was termed coupled complementation. The significance of the results in the terms of mechanisms of Ir gene control are discussed.

scholarly journals Epistatic Control of Non-Mendelian Inheritance in Mouse Interspecific Crosses

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1739-1752 ◽  
Author(s):  
Xavier Montagutelli ◽  
Rowena Turner ◽  
Joseph H Nadeau
Keyword(s):  
X Chromosome ◽  
Genetic Basis ◽  
Mendelian Inheritance ◽  
The Other ◽  
Interspecific Crosses ◽  
Chromosome 2 ◽  
Mus Spretus ◽  
F1 Hybrid ◽  
Strong Deviation ◽  
Marker Loci

Abstract Strong deviation of allele frequencies from Mendelian inheritance favoring Mus spretus-derived alleles has been described previously for X-linked loci in four mouse interspecific crosses. We reanalyzed data for three of these crosses focusing on the location of the gene(s) controlling deviation on the X chromosome and the genetic basis for incomplete deviation. At least two loci control deviation on the X chromosome, one near Xist (the candidate gene controlling X inactivation) and the other more centromerically located. In all three crosses, strong epistasis was found between loci near Xist and marker loci on the central portion of chromosome 2. The mechanism for this deviation from Mendelian expectations is not yet known but it is probably based on lethality of embryos carrying particular combinations of alleles rather than true segregation distortion during oogenesis in F1 hybrid females.

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