RELATIONSHIPS OF TAXA IN THE GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. VIL M. TORNATA COMPLEX

1973 ◽  
Vol 15 (2) ◽  
pp. 321-325
Author(s):  
K. Lesins ◽  
S. M. Singh
Keyword(s):  
Segregation Ratio ◽  
Coiling Direction ◽  
Incompatibility Barrier

Different taxa of Medicago tornata Mill, were investigated on their relationships using hybridization and inheritance studies. It was found that taxa with lenticular pods, spiny and spineless, could be intercrossed and the inheritance of spininess in F2 was 3 spiny and intermediate to 1 spineless (35:1s). Hybrids between lenticular and cylindric pods segregated 3:1 spiny: spineless; 3:1 anticlockwise pod coiling: clockwise coiling (3C:1c), and 1:4:6:4:1 for number of coils per pod (1-2:2-3:3-4:4-5:5-6) indicating that two genes acted additively. Spininess and pod coiling direction segregated independently. M. striata was recognized as a variety of M. tornata because no serious impairment in vitality of hybrid progenies was observed and the inheritance of pod coiling direction in F2 followed closely the normal 3:1 segregation ratio. M. tornata var. shepardii has a complete incompatibility barrier with the M. tornata tested and should not be considered as belonging to M. tornata.

Laboratory Exercise on the Segregation of Flower Color and Related Genes Using Salpiglossis sinuata

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 555b-555
Author(s):  
Chiwon W. Lee
Keyword(s):  
Phenotypic Expression ◽  
Pollen Grains ◽  
Flower Color ◽  
Segregation Ratio ◽  
Crop Breeding ◽  
Flower Opening ◽  
Pigmentation Pattern ◽  
Laboratory Exercise ◽  
Demonstration Plant ◽  
Corolla Color

Velvet flower (Salpiglossis sinuata, Solanaceae) can be used as an excellent demonstration plant for horticultural crop breeding classes. Salpiglossis produces large trumpet-like flowers exhibiting an assortment of corolla color and pigmentation pattern. The pistil is large (3 to 4 cm long) with a sticky stigmatal tip and anthers can be easily emasculated prior to anthesis. The large pollen grains are shed in tetrads, which can be separated and individually placed on the stigma. It takes 8 to 9 weeks from seeding to blooming, with a prolific flowering cycle repeated in flushes. Numerous seeds (about 750/capsule) are obtained in 3 weeks after self- or cross-pollination. The influences of three genes that control flower color and pigmentation pattern can be conveniently demonstrated with their dominant and recessive alleles. The R gene controls flower color with red (RR or Rr) being dominant over yellow (rr) flower color. The D gene controls the density of pigmentation with solid (DD or Dd) color being dominant over dilute (dd) color. Corolla color striping is controlled by the St gene with striped (stst) being recessive to non-striped (StSt or Stst) pattern. For example, by using diploid lines of genotypes RRDD (red, solid), RRdd (red, dilute), or rrdd (yellow, dilute) and their crosses, students can easily learn a dominant phenotypic expression in the F1 hybrid and the digenic 9:3:3:1 segregation ratio in the F2 progeny. Another gene (C) that controls flower opening can also be used to show its influence on cleistogamous (closed, self-pollinated, CC or Cc) versus normal chasmogamous (open-pollinated, cc) corolla development. In addition, the induction and use of polyploid (4X, 3X) plants in plant breeding can be effectively demonstrated using this species.

Effects of an intercultivaral chromosome substitution on winterhardiness and vernalization in wheat.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 453-456
Author(s):  
R S Zemetra ◽  
R Morris
Keyword(s):  
Winter Wheat ◽  
Growth Habit ◽  
Wheat Cultivar ◽  
Triticum Aestivum L ◽  
Segregation Ratio ◽  
Substitution Line ◽  
Winter Survival ◽  
Winter Wheat Cultivar ◽  
Vernalization Gene ◽  
Chromosome 3B

Abstract During a study on the genetic control of winterhardiness in winter wheat (Triticum aestivum L. group aestivum), a gene that affected vernalization was found on chromosome 3B in the winter wheat cultivar ;Wichita.' When chromosome 3B from Wichita was substituted into the winter wheat cultivar ;Cheyenne,' the resultant substitution line exhibited a spring growth habit. This is unusual since a cross between the cultivars Wichita and Cheyenne results in progeny that exhibit the winter growth habit. The F(2) plants from a cross of the 3B substitution line to Cheyenne, the recipient parent, segregated 3:1 for heading/no heading response in the absence of vernalization (chi(2) = 2.44). Earliness of heading appeared to be due to an additive effect of the 3B gene as shown by the segregation ratio 1:2:1 (early heading-later heading-no heading) (chi(2) = 2.74). This vernalization gene differs from previously described vernalization genes because, while dominant in a Cheyenne background, its expression is suppressed in Wichita. The gene may have an effect on winter hardiness in Wichita. In a field test for winter survival the 3B substitution line had only 5% survival, while Wichita and Cheyenne had 50 and 80% survival, respectively. No other substitution line significantly reduced winter survival. The difference between Wichita and Cheyenne in winterhardiness may be due to the vernalization gene carried on the 3B chromosome.

scholarly journals A thermodynamic assessment of precipitation, growth, and control of MnS inclusion in U75V heavy rail steel

2021 ◽  
Vol 40 (1) ◽  
pp. 178-192
Author(s):  
Wen-Qiang Ren ◽  
Lu Wang ◽  
Zheng-Liang Xue ◽  
Cheng-Zhi Li ◽  
Hang-Yu Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Rail Steel ◽  
Solidification Process ◽  
Segregation Ratio ◽  
Two Phase ◽  
Final Particle ◽  
Solid Liquid ◽  
And Control ◽  
Heavy Rail ◽  
Heavy Rail Steel

Abstract Thermodynamic analysis of the precipitation behavior, growth kinetic, and control mechanism of MnS inclusion in U75V heavy rail steel was conducted in this study. The results showed that solute element S had a much higher segregation ratio than that of Mn, and MnS would only precipitate in the solid–liquid (two-phase) regions at the late stage during the solidification process at the solid fraction of 0.9518. Increasing the cooling rate had no obvious influence on the precipitation time of MnS inclusion; however, its particle size would be decreased greatly. The results also suggested that increasing the concentration of Mn would lead to an earlier precipitation time of MnS, while it had little effect on the final particle size; as to S, it was found that increasing its concentration could not only make the precipitation time earlier but also make the particle size larger. Adding a certain amount of Ti additive could improve the mechanical properties of U75V heavy rail steel due to the formation of TiO x –MnS or MnS–TiS complex inclusions. The precipitation sequences of Ti3O5 → Ti2O3 → TiO2 → TiO → MnS → TiS for Ti treatment were determined based on the thermodynamic calculation.

RELATIONSHIP OF TAXA IN THE GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. I. M. STRIATA × M. LITTORALIS

1968 ◽  
Vol 10 (2) ◽  
pp. 263-275 ◽  
Author(s):  
K. Lesins ◽  
A. Erac
Keyword(s):  
High Mortality ◽  
Genetic Factor ◽  
Genetic Factors ◽  
Chromosomal Rearrangements ◽  
Cytoplasmic Factor ◽  
Reciprocal Crosses ◽  
Gross Chromosomal Rearrangements ◽  
Coiling Direction ◽  
Chlorophyll Deficiencies ◽  
Relationship Of

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.

Determination of the Surface Segregation Ratio of P in Si

2006 ◽  
Author(s):  
P.E. Thompson ◽  
G.G. Jernigan ◽  
G.G. Jernigan
Keyword(s):  
Surface Segregation ◽  
Segregation Ratio

Evidence for a new form of dominant negative imprinting at the ovine callipyge locus

1996 ◽  
Vol 1996 ◽  
pp. 51-51
Author(s):  
N.E. Cockett ◽  
S.P. Jackson ◽  
T.L. Shay ◽  
F. Farnir ◽  
S. Berghmans ◽  
...  
Keyword(s):  
Strong Evidence ◽  
Distal Part ◽  
Segregation Ratio ◽  
Dominant Negative ◽  
Chromosome 18 ◽  
Dominant Mutation ◽  
Independent Segregation ◽  
Parental Imprinting ◽  
New Form ◽  
Unusual Phenotype

In 1983, the occurrence of a ram exhibiting an exceptional muscular development was reported in a flock of Dorset sheep. This unusual phenotype was transmitted to some of the offspring, and subsequent matings involving hypermuscled male descendents of the founder ram and normal ewes clearly demonstrated a 50%-50%, sex-independent segregation ratio of the trait. It was therefore postulated that a dominant mutation (CLPG versus the normal clpg allele) at the autosomal “callipyge“ locus was responsible for this hypertrophy. Using the same family material, the callipyge locus was unambiguously mapped to the distal part of ovine chromosome 18 (Cockett et al., 1994).In this paper, we present very strong evidence that the callipyge locus is subjected to a previously undescribed form of parental imprinting. It is indeed demonstrated that animals only express the callipyge phenotype if they have inherited the CLPG mutation from their sire, not if it is transmitted by the dam.

scholarly journals Inheritance of glyphosate resistance in rigid ryegrass (Lolium rigidum) from California

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 615-619 ◽  
Author(s):  
Marulak Simarmata ◽  
Suleiman Bughrara ◽  
Donald Penner
Keyword(s):  
First Generation ◽  
Recurrent Selection ◽  
Maternal Inheritance ◽  
Glyphosate Resistance ◽  
Segregation Ratio ◽  
Lolium Rigidum ◽  
Response Curves ◽  
Mendelian Segregation ◽  
Rigid Ryegrass ◽  
Homozygous Resistant

Glyphosate resistance was found in a rigid ryegrass population in northern California. A sample of the resistant plants were collected and grown under greenhouse conditions. The objective of this study was to evaluate glyphosate resistance in the progeny of the collected plants by recurrent selection, obtain the homozygous resistant and sensitive lines to establish dose-response curves, and to determine the inheritance of glyphosate resistance in rigid ryegrass. Diverse levels of resistance were observed in the first generation with survival of 89, 59, 45, and 9% from glyphosate at 1x, 2x, 4x, and 8x respectively, where x = 1.12 kg ha−1isopropylamine salt of glyphosate. Clones of plants that died from 1x were allowed to produce seed and were further subjected to recurrent selection to generate the most sensitive plants (S lines), which died from 0.125x glyphosate. The most resistant plants (R lines) were generated from the survivors receiving 8x glyphosate. The ratio between I50rates for the glyphosate resistant and the glyphosate sensitive plants was > 100-fold. The R and S lines were crossed reciprocally and F1progeny of both (R × S) and (S × R) showed intermediate resistance. These survived up to 2x glyphosate. The F2progeny were generated by intercrossing of F1plants. The ratio of sensitive, intermediate, and resistant plants in the F2population before the treatment of glyphosate at 0.125x followed by 8x was 1 : 16, 14 : 16, and 1 : 16 respectively, which corresponded to the Mendelian segregation ratio of two genes. The results indicated that the inheritance of glyphosate resistance in rigid ryegrass from California appeared to be nuclear, incompletely dominant, multigenic, and pollen-transmitted with no indication of maternal inheritance.

scholarly journals Segregation for Resistance to Eastern Filbert Blight in Progeny of `Zimmerman' Hazelnut

2006 ◽  
Vol 131 (6) ◽  
pp. 731-737 ◽  
Author(s):  
China F. Lunde ◽  
Shawn A. Mehlenbacher ◽  
David C. Smith
Keyword(s):  
Rapd Markers ◽  
Chromosome Region ◽  
Random Amplified Polymorphic Dna ◽  
Rapd Marker ◽  
Segregation Ratio ◽  
Enzyme Linked Immunosorbent Assay ◽  
Resistance Locus ◽  
Resistance Allele ◽  
Reciprocal Translocations ◽  
Eastern Filbert Blight

Eastern filbert blight (EFB), caused by the fungus Anisogramma anomala (Peck) E. Müller, is an important disease of european hazelnut (Corylus avellana L.) in the Pacific northwestern United States. In 1989, a chance seedling free of EFB was discovered adjacent to a severely diseased orchard near Troutdale, Ore. This selection, subsequently named `Zimmerman', was crossed with three susceptible selections. Based on morphological characters and incompatibility alleles, we speculated that `Zimmerman' (S1 S3) was a hybrid between `Barcelona' (S1 S2) and `Gasaway' (S3 S26). The three seedling populations were inoculated with spores of the pathogen in a greenhouse test and assayed by indirect enzyme-linked immunosorbent assay (ELISA) and by observation of canker incidence. The observed segregation fit a 3 resistant : 1 susceptible ratio in all three progenies, in contrast to the 1 : 1 ratio found when the resistant pollinizer `Gasaway' was crossed to susceptible genotypes. Random amplified polymorphic DNA (RAPD) marker UBC 152800 linked to the resistance gene in `Gasaway' co-segregated with the resistant phenotype in all three populations with 2%, 4%, and 6% recombination, respectively. Seed germination and transplanting records did not provide evidence of selection in favor of resistant seedlings. Pollen germination was 71% in `Gasaway', 29% in `Zimmerman', and 18% in `Barcelona', indicating possible selection at the gametophytic level. Subsequently 16 resistant seedlings of `Zimmerman' were crossed with the highly susceptible selection OSU 313.078. Segregation fit a 3 : 1 ratio in 14 of the 16 progenies, and showed a surplus of resistant seedlings in the other two. None showed a 1 : 1 segregation. Resistance co-segregated with two RAPD markers that flank the `Gasaway' resistance allele. To test allelism of resistance from `Gasaway' and `Zimmerman', VR 6-28 with resistance from `Gasaway' was crossed with `Zimmerman'. Eight resistant selections from this progeny were crossed with OSU 313.078. Five of the eight progenies segregated 3 : 1, two progenies segregated 1 : 1, and OSU 313.078 × OSU 720.056 gave only resistant offspring. The ratios indicate that OSU 720.056 is homozygous resistant and that `Zimmerman' and `Gasaway' share a common resistance allele. Reciprocal translocations have been reported in hazelnut cultivars, including `Barcelona', the leading cultivar in Oregon. `Zimmerman' appears to be a hybrid of `Barcelona' and `Gasaway', but because of cytogenetic abnormalities, `Zimmerman' may have inherited two copies of the chromosome region that contain the resistance locus and flanking RAPD markers. If the region containing the resistance were attached to two independent centromeres, a 3 : 1 segregation ratio for disease response and flanking markers would be expected, and we propose this as the most likely explanation. Resistance from `Gasaway' and `Zimmerman' has been called “immunity” or “complete resistance.” However, we noted a few seedlings with small cankers, nearly all of which lacked sporulating stromata. Flanking RAPD markers indicate that the resistance allele is present in these seedlings. Although not “immune” or “completely resistant,” `Gasaway' and `Zimmerman' transmit a very high level of resistance.

scholarly journals Inheritance of different undertones of onion (Allium cepa L.) dry skin color and the relationship between color and adherence

2013 ◽  
Vol 39 (2) ◽  
pp. 341-345
Author(s):  
Roch W. Doruchowski
Keyword(s):  
Statistical Analysis ◽  
Allium Cepa ◽  
Skin Color ◽  
Segregation Ratio ◽  
Dry Skin ◽  
Yellow Color ◽  
Allium Cepa L ◽  
Dark Color ◽  
The Relationship ◽  
Additive Genes

The research was carried out in 1977 and 1978. The inheritance of undertones, dry skin color from light straw to brown was controlled by two additive genes. The segregation ratio obtained was 15:1 and 11:5. The dry skin of a dark color (dark yellow, bronze, brown ochre, orange-brown) was stronger than the skin with a straw yellow or yellow color. Skin adherence was strictly related to its color. This was proved by statistical analysis of the correlation.

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