Degree of Dominance

2007 ◽  
pp. 169-187
Author(s):  
Irina Georgescu
Keyword(s):  
Degree Of Dominance

COMBINING ABILITY FOR INHERITANCE OF ECONOMIC TRAITS IN OPIUM POPPY (Papaver somniferum L.)

2011 ◽  
Vol 24 (2) ◽  
pp. 01-08
Author(s):  
B. Kumar ◽  
N. K. Patra
Keyword(s):  
Combining Ability ◽  
Diallel Cross ◽  
Papaver Somniferum ◽  
Opium Poppy ◽  
Economic Traits ◽  
Degree Of Dominance ◽  
Parental Material ◽  
The Mean ◽  
Per Se ◽  
Important Medicinal Plant

Opium poppy (Papaver somniferum L.) is an important medicinal plant produces more than 80 alkaloids obtained from the capsules and straw of the plant. The estimate of combining ability gives an indication of the genetic behaviour of the parental material. It is therefore, desirable to select the parents for hybridization on the basis of their per se performance and combining ability effects. The F1, F2 and their reciprocals of an eight parent diallel cross in opium poppy were studied for combining ability of seven economic traits. The mean sum of squares due to GCA, SCA and reciprocals were significant for all the traits. The magnitude of GCA variances were invariably higher than those of SCA and thus indicating the preponderance of non-additive genetic variances, which was further affirmed by the measure of average degree of dominance i.e. ?(?2s/? 2g).  Among the parents VN35I for plant height, Sanchita and VG26 for capsules per plant, VN23, VN35I and Vivek for capsule index, VG26 and Sanchita for seed and straw yield per plant, and VN35I and VG20 for morphine content were found good general combiners. Earliness being a desired trait, parent VG20 having significant negative GCA estimates coupled with per se performance can be considered as good general combiner for early flowering. Inclusion of good general combiners in a multiple crossing program or an inter-mating population involving all possible crosses among them subjected to bi-parental mating may be expected to offer maximum promise in breeding for economic traits.DOI: http://dx.doi.org/10.3329/bjpbg.v24i2.17000

Inheritance of Some Morphological Characteristics of Parental Lines in Mustard-Rape Hybrid

2020 ◽  
pp. 23-30
Keyword(s):  
First Generation ◽  
Agronomic Traits ◽  
Morphological Characteristics ◽  
Morphological Characters ◽  
Hybrid Plant ◽  
Distant Hybridization ◽  
Degree Of Dominance ◽  
Whole Plant ◽  
Row Width ◽  
The Difference

Distant hybridization is known to play an important role in expanding the gene pool of any crop. It is believed that the combination of different genomes in one nucleus, as a rule, is accompanied by the phenomenon of “genomic shock”, resulting in a variety of genetic and epigenetic changes. This provides a wealth of material for the selection of genotypes adapted to different environmental conditions. Interspecific hybrids in different combinations were obtained in the genus Brassica, however, until now, interest in distant hybridization in this genus has not died out, since such important crops as rapeseed and mustard demand an improvement of many important agronomic traits. The aim of this work was to study the degree of manifestation of morphological characters of a leaf, flower, and plant as a whole in the hybrid obtained by crossing of brown mustard of the variety Slavyanka and a collection specimen of spring rape. Seeds were sown in the spring of 2019 in a field with 30 cm row width. During the flowering period a number of morphological characters of a flower, leaf, and the whole plant were analyzed. Each parameter was evaluated with 10 plants. The degree of dominance in first-generation hybrid was calculated by the formula of Beil, Atkins (1965). The dominance coefficients were not determined in the case when the difference between the parental samples was insignificant. Differences between parental samples were determined by Student t-test. The level of heterosis was calculated according to the formula of Rasul et al (2002). In a mustard-rapeseed hybrid, the size of the leaves of the lower row was inherited by the type of rapeseed, which had larger leaves than mustard. The height of the hybrid plant was inherited by the type of mustard (hp = 1.32, Ht = 4.89%), and intermediate inheritance was observed for the length of the internodes (hp = -0.48). The size of the flower petals and sepals was inherited by the type of rapeseed, and significant heterosis was observed for the length of the pistil (Ht = 33.57%). The data obtained are of interest for understanding the interaction of genes of different genomes in the genus Brassica.

scholarly journals Mode of Selection and Experimental Evolution of Antifungal Drug Resistance in Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1287-1298
Author(s):  
James B Anderson ◽  
Caroline Sirjusingh ◽  
Ainslie B Parsons ◽  
Charles Boone ◽  
Claire Wickens ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Pleiotropic Effect ◽  
Antifungal Drug ◽  
Recessive Mutation ◽  
High Concentration ◽  
Gene Encoding ◽  
Antifungal Drug Resistance ◽  
Degree Of Dominance ◽  
A Genome ◽  
Abc Transporter Genes

Abstract We show that mode of selection, degree of dominance of mutations, and ploidy are determining factors in the evolution of resistance to the antifungal drug fluconazole in yeast. In experiment 1, yeast populations were subjected to a stepwise increase in fluconazole concentration over 400 generations. Under this regimen, two mutations in the same two chromosomal regions rose to high frequency in parallel in three replicate populations. These mutations were semidominant and additive in their effect on resistance. The first of these mutations mapped to PDR1 and resulted in the overexpression of the ABC transporter genes PDR5 and SNQ2. These mutations had an unexpected pleiotropic effect of reducing the residual ability of the wild type to reproduce at the highest concentrations of fluconazole. In experiment 2, yeast populations were subjected to a single high concentration of fluconazole. Under this regimen, a single recessive mutation appeared in each of three replicate populations. In a genome-wide screen of ∼4700 viable deletion strains, 13 were classified as resistant to fluconazole (ERG3, ERG6, YMR102C, YMR099C, YPL056C, ERG28, OSH1, SCS2, CKA2, SML1, YBR147W, YGR283C, and YLR407W). The mutations in experiment 2 all mapped to ERG3 and resulted in the overexpression of the gene encoding the drug target ERG11, but not PDR5 and SNQ2. Diploid hybrids from experiments 1 and 2 were less fit than the parents in the presence of fluconazole. In a variation of experiment 2, haploids showed a higher frequency of resistance than diploids, suggesting that degree of dominance and ploidy are important factors in the evolution of antifungal drug resistance.

scholarly journals The Rate of Mutation and the Homozygous and Heterozygous Mutational Effects for Competitive Viability: A Long-Term Experiment With Drosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 681-693 ◽  
Author(s):  
David Chavarrías ◽  
Carlos López-Fanjul ◽  
Aurora García-Dorado
Keyword(s):  
Drosophila Melanogaster ◽  
Minimum Distance ◽  
Deleterious Mutations ◽  
Regression Estimate ◽  
Term Experiment ◽  
Degree Of Dominance ◽  
Long Term Experiment ◽  
Rate Of Decline ◽  
Good Agreement

Abstract The effect of 250 generations of mutation accumulation (MA) on the second chromosome competitive viability of Drosophila melanogaster was analyzed both in homozygous and heterozygous conditions. We used full-sib MA lines, where selection hampers the accumulation of severely deleterious mutations but is ineffective against mildly deleterious ones. A large control population was simultaneously evaluated. Competitive viability scores, unaffected by the expression of mutations in heterozygosis, were obtained relative to a Cy/L2 genotype. The rate of decline in mean ΔM ≈ 0.1% was small. However, that of increase in variance ΔV ≈ 0.08 × 10-3 was similar to the values obtained in previous experiments when severely deleterious mutations were excluded. The corresponding estimates of the mutation rate λ ≥ 0.01 and the average effect of mutations E(s) ≤ 0.08 are in good agreement with Bateman-Mukai and minimum distance estimates for noncompetitive viability obtained from the same MA lines after 105 generations. Thus, competitive and noncompetitive viability show similar mutational properties. The regression estimate of the degree of dominance for mild-to-moderate deleterious mutations was ∼0.3, suggesting that the pertinent value for new unselected mutations should be somewhat smaller.

scholarly journals Diversity and Community Structure of Oribatid Mites (Acari, Oribatei) at Memorial Complexes of a Megapolis

2013 ◽  
Vol 47 (4) ◽  
pp. 291-297
Author(s):  
L. A. Kolodochka ◽  
O. S. Shevchenko
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Species Complex ◽  
Common Species ◽  
Oribatid Mites ◽  
Direct Relation ◽  
City Center ◽  
Degree Of Dominance ◽  
Different Types ◽  
The City

Abstract In different types of substrate (soil, litter, lichens and mosses) collected at three memorial complexes (cemeteries) of Kyiv (Ukraine), 70 species from 57 genera, 34 families of oribatid mites were found. A few eurytopic species capable of tolerance to different types of pollution make up an essential part in each species complex. The species diversity and complexity of oribatid community structure at researched areas increased with distance from the city center. There was no direct relation between the degree of dominance of most common species and the cemetery’s relative remoteness from the center of the city.

scholarly journals PHYTOSOCIOLOGICAL ANALYSIS OF THE MEDICINAL PLANT SPECIES, THALICTRUM JAVANICUM BLUME IN THOTTABETTA, NILGIRIS, THE WESTERN GHATS

2015 ◽  
Vol 2 (1) ◽  
pp. 56-62
Author(s):  
Abinaya G ◽  
Paulsamy S
Keyword(s):  
Western Ghats ◽  
Tamil Nadu ◽  
Degree Of Dominance ◽  
The Family ◽  
Qualitative Characters ◽  
The Nilgiris ◽  
The Western Ghats ◽  
Study Species ◽  
Phytosociological Study

Phytosociological study is the most essential in any community to know its structure and organization. The various qualitative characters obtained are used to determine the level of distribution, numerical strength and degree of dominance exhibited by the constituent species in the community. Thalictrum javanicum belongs to the family Ranunculaceae family, it is medium sized erect herb, found in the temperate Himalayas from Kasmir to Sikkim in Khasi hills, and Kodaikanal and Nilgiri hills of Western Ghats in Tamil Nadu, India. At global level, it is generally distributed in the hilly tracts of India, Srilanka, China and Java at the altitude of around 2400 m above msl. The present study was undertaken in Thottabetta , the Nilgiris by sampling using belt transects of 10x1000m size which further divided into 100 segments each which 10x10m size. The total number of species encountered in the study area is 45 which includes 5 grasses and 40 forbs. The quantitative ecological characters of the study species, T. javanicum is a detailed below: frequency 11%, abundance 3.82 individuals/m2, density 0.42 individuals/m2, basal cover 172.20/mm2/ m2, relative frequency 0.55% and relative density 0.08%, relative dominance 0.16%. Based on the ecological attributes it is determined that the species, T. javanicum is less perpetuated in the community studied. Hence, further studies on the determination of propagation strategies for population enhancement and conservationof wilds are suggested.

scholarly journals THE ALCOHOL DEHYDROGENASE POLYMORPHISM IN POPULATIONS OF DROSOPHILA MELANOGASTER. I. SELECTION IN DIFFERENT ENVIRONMENTS

Genetics ◽  
1978 ◽  
Vol 90 (1) ◽  
pp. 161-191
Author(s):  
W van Delden ◽  
A C Boerema ◽  
A Kamping
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Experimental Evidence ◽  
Balancing Selection ◽  
Adult Survival ◽  
High Survival ◽  
High Humidity ◽  
Allozyme Polymorphism ◽  
Degree Of Dominance ◽  
Frequency Changes

ABSTRACT The allozyme polymorphism at the alcohol dehydrogenase locus in Drosophila melanogaster was studied in order to obtain experimental evidence about the maintenance of this polymorphism. Populations started with different initial allele frequencies from homozygous F and S lines showed a convergence of frequencies on regular food at 25°, leading to values equal to those in the base populations. These results were interpreted as due to some kind of balancing selection. In populations kept at 29.8°, a lower equilibrium F frequency was attained. Addition of ethanol and some other alcohols to the food gave a rapid increase in F frequency, and high humidity decreased the F frequency slightly. Combination or alternation of ethanol and high humidity had variable effects in the populations tested. For a further analysis of the allele-frequency changes, estimates were obtained for egg-to-adult survival under different conditions and for adult survival on ethanol-supplemented food. On ethanol food (both at regular and high humidity), egg-to-adult survival of SS homozygotes was considerably lower than that of the FF and FS genotypes. Under regular conditions of food, temperature and humidity, a tendency to heterozygote superiority was observed, while at high humidity a relative high survival of SS was noticed in some tests. Adult survival of SS was lower than that of FF, but FS was generally intermediate, though the degree of dominance differed between populations. The results are consistent with the hypothesis of the occurrence of selection at the Adh locus.

Fuel characteristics and fire behaviour in mature Mediterranean gorse shrublands

2004 ◽  
Vol 13 (1) ◽  
pp. 79 ◽  
Author(s):  
Martín De Luis ◽  
Manuel J. Baeza ◽  
José Raventós ◽  
José C. González-Hidalgo
Keyword(s):  
Forest Fires ◽  
Plant Density ◽  
Structural Characteristics ◽  
Fire Severity ◽  
Fire Behaviour ◽  
Fuel Distribution ◽  
Degree Of Dominance ◽  
Mediterranean Regions ◽  
The Relationship

Since the early 1990s, Mediterranean gorse shrublands have expanded significantly in the Mediterranean regions of Spain mainly as a result of the increase in the frequency and extension of forest fires. Mediterranean gorse (Ulex parviflorus), which has been described as a degradation stage of forest communities after fire, has also been described as a fire-prone community. Thus, its presence increases the risk that new fires might occur. In spite of this evidence, there is little information on both the composition and structural characteristics of these communities or the relationship that might exist between these vegetation characteristics and fire behaviour. In this paper we present the results of a characterization of the vegetative structure (plant density, specific composition, biomass fractions, and horizontal and vertical fuel distribution) in Mediterranean gorse. We also analyse fire behaviour using indicators obtained at different scales. Our results show mature Mediterranean gorse shrublands to be communities with high biomass values (3000–4000 g m−2) and high horizontal and vertical vegetation continuity, in which the proportion of fine dead fuel fractions with low moisture content is around 50% of the total phytomass present. Ulex parviflorus is the dominant species and its degree of dominance is a key element in the behaviour of fire. Both the fire-line intensity values and the fire severity values observed can be considered high with respect to those observed in other Mediterranean communities, thus confirming Mediterranean gorse as a high-risk community.

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