Cytogenetic relationships of certain artificial and natural species of Avena

1. The desirability of employing the genetic variation present in diploid and tetraploid wild species for the improvement of the cultivated hexaploid species stimulated an investigation into the synthesis of various amphiploid forms in Avena.2. Five amphiploids at the hexaploid level have been produced, but the present investigation is limited to the amphiploids developed from the cross A. barbata (2n = 28)×.A. strigosa subsp. hirtula (2n= 14), their hybrids with the natural hexaploid species and with other amphiploid types.3. These amphiploids, like their parents, possessed black paleae, with hairs and a fairly strong geniculate awn on both the lower and upper grains. The bases of both the lower and upper grains possessed the articulation surfaces characteristic of A. fatua. Their hybrids with A. fatua were similar in spikelet morphology, but the A. sterilis type of spikelet was dominant in both the amphiploid 6x × A. sterilis and amphiploid 6x × A. byzantina. Partial dominance of the cultivated type base over the shedding type was evident in crosses with A. sativa and A. nuda but the naked caryopsis and multiflorous spikelet were recessive in the latter cross. In crosses between the A. barbata/A. hirtula 6x amphiploid and the A. abyssinica/A. strigosa 6x amphiploid (Cc 4387) the hybrid exhibited a reversal of dominance relationships, with the cultivated base type of Cc4387 being completely recessive to the shedding base.

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Specific genetic markers for wheat, spelt, and four wild relatives: comparison of isozymes, RAPDs, and wheat microsatellites

Genome ◽

10.1139/g01-050 ◽

2001 ◽

Vol 44 (4) ◽

pp. 610-621 ◽

Cited By ~ 22

Author(s):

Roberto Guadagnuolo ◽

Dessislava Savova Bianchi ◽

François Felber

Keyword(s):

Genetic Variation ◽

Wild Species ◽

Wild Relatives ◽

Species Differentiation ◽

Large Set ◽

Strongly Correlated ◽

Aegilops Cylindrica ◽

Elymus Caninus ◽

Set Up ◽

Mantel’S Test

Three types of markersisozymes, RAPDs (random amplified polymorphic DNAs), and wheat microsatelliteswere tested on wheat, spelt, and four wild wheat relatives (Aegilops cylindrica, Elymus caninus, Hordeum marinum, and Agropyron junceum). The aim was to evaluate their capability to provide specific markers for differentiation of the cultivated and wild species. The markers were set up for subsequent detection of hybrids and introgression of wheat DNA into wild relatives. All markers allowed differentiation of the cultivated from the wild species. Wheat microsatellites were not amplified in all the wild relatives, whereas RAPDs and isozymes exhibited polymorphism for all species. The dendrograms obtained with RAPD and isozyme data separated Swiss wheat cultivars from those collected in Austria and England, while no difference was found between Swiss spelt and wheat. RAPD data provided a weak discrimination between English and Austrian E. caninus. The microsatellite-based dendrogram discriminated populations of Ae. cylindrica, but no clear separation of H. marinum from E. caninus was revealed. The similarity matrices based on the three different sets of data were strongly correlated. The highest value was recorded between the matrices based on RAPDs and isozymes (Mantel's test, r = 0.93). Correlations between the similarity matrix based on microsatellites and matrices based on RAPDs and isozymes were lower: 0.74 and 0.68, respectively. While microsatellites are very useful for comparisons of closely related accessions, they are less suitable for studies involving less-related taxa. Isozymes provide interesting markers for species differentiation, but their use seems less appropriate for studies of within-species genetic variation. RAPDs can produce a large set of markers, which can be used for the evaluation of both between- and within-species genetic variation, more rapidly and easily than isozymes and microsatellites.Key words: Triticeae, isozymes, RAPDs, microsatellites, polymorphism.

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Molecular diversity in Lactucaspeciesusing Isozymes and RAPD Markers

10.21203/rs.3.rs-221342/v2 ◽

2021 ◽

Author(s):

Reda H. Helmy Sammour ◽

A-Z. A. Mustafa

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Wild Species ◽

Molecular Basis ◽

Rapd Markers ◽

Molecular Diversity ◽

Breeding Programs ◽

Primitive Form ◽

In The Wild ◽

Cultivated Species

Abstract Understanding of the molecular basis of genetic diversity in Lactucaaccessions is substantial for the management, improvementand efficient uses of Lactuca accessions. Therefore, this workaimed to evaluate molecular diversity among twenty-six accessions of Lactuca species usingisozymes and RAPD analyses. The polymorphic percentages were 87.09%and 100% in isozymes and RAPD analyses respectively, indicating a high genetic variation within and among Lactuca species. The number of alleles were higher in the wild species compared to the cultivated species, reflecting a reduction in the richness of alleles in the cultivated species due to domestication that caused a reduction in genetic diversity to meet the demand for high crop productivity.Isozymes and RAPD clustering dendrogrames: (1) separated,L. sativa accessions in more than one cluster confirming their polyphyletic origin; (2)collected the accessions of L. vimineain one cluster revealed its homogeneity; and (3) divided the accessions of L.saligna in two clusters varied in the number of alleles, particularly “A” form. The corresponding analysis associated the accessions of the wild species based on the alleles “B”of the tested isozymes and the cultivated species on alleles “A” and “C”, suggesting that: (1) allele “B” might be the primitive form of these loci that can tolerate the environmental stresses which prevails in the habitats of the wild species, and (2) “A” and “C” could be the derived forms. These results are of great interest for the management of Lactuca germplasm and for future breeding programs of lettuce.

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RAPD and ISSR fingerprints as useful genetic markers for analysis of genetic diversity, varietal identification, and phylogenetic relationships in peanut (Arachis hypogaea) cultivars and wild species

Genome ◽

10.1139/g01-064 ◽

2001 ◽

Vol 44 (5) ◽

pp. 763-772 ◽

Cited By ~ 60

Author(s):

S N Raina ◽

V Rani ◽

T Kojima ◽

Y Ogihara ◽

K P Singh ◽

...

Keyword(s):

Genetic Variation ◽

Genetic Markers ◽

Arachis Hypogaea ◽

Wild Species ◽

Phylogenetic Relationships ◽

Varietal Identification ◽

Ssr Primers ◽

Cultivated Peanut ◽

Wild Progenitors ◽

Botanical Varieties

Twenty-one random and 29 SSR primers were used to assess genetic variation and interrelationships among subspecies and botanical varieties of cultivated peanut, Arachis hypogaea (2n = 4x = 40), and phylogenetic relationships among cultivated peanut and wild species of the genus Arachis. In contrast with the previous generalization that peanut accessions lack genetic variation, both random and SSR primers revealed 42.7 and 54.4% polymorphism, respectively, among 220 and 124 genetic loci amplified from 13 accessions. Moreover, the dendrograms based on RAPD, ISSR, and RAPD + ISSR data precisely organized the five botanical varieties of the two subspecies into five clusters. One SSR primer was identified that could distinguish all the accessions analysed within a variety. Although the polymorphic index content varied from 0.1 to 0.5 for both ISSR and RAPD markers, primer index values were substantially higher for RAPD primers (0.354.65) than for SSR primers (0.351.73). It was possible to identify accessions, particularly those of divergent origins, by RAPD and (or) ISSR fingerprints. Based on these results, marker-based genetic improvement in A. hypogaea appears possible. None of the 486 RAPD and 330 ISSR amplification products were found to be commonly shared among 13 species of section Arachis and one species each of sections Heteranthae, Rhizomatosae, and Procumbentes. Dendrograms constructed from RAPD, ISSR, and RAPD + ISSR data showed overall similar topologies. They could be resolved into four groups corresponding to the species grouped in four taxonomic sections. The present results strongly support the view that Arachis monticola (2n = 4x = 40) and A. hypogaea are very closely related, and indicate that A. villosa and A. ipaensis are the diploid wild progenitors of these tetraploid species.Key words: Arachis hypogaea, genetic markers, varietal identification, DNA polymorphism, Arachis species.

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Molecular tagging of genes for brown planthopper resistance and earliness introgressed from Oryza australiensis into cultivated rice, O. sativa

Genome ◽

10.1139/g94-030 ◽

1994 ◽

Vol 37 (2) ◽

pp. 217-221 ◽

Cited By ~ 118

Author(s):

T. Ishii ◽

D. S. Brar ◽

D. S. Multani ◽

G. S. Khush

Keyword(s):

Wild Species ◽

Brown Planthopper ◽

Introgression Line ◽

Recurrent Parent ◽

Cultivated Rice ◽

Molecular Tagging ◽

Alien Gene ◽

Brown Planthopper Resistance ◽

The Cross ◽

Oryza Australiensis

Restriction fragment length polymorphism analysis was carried out to tag the alien genes for brown planthopper (BPH) resistance and earliness introgressed from wild species Oryza australiensis into cultivated rice, O. sativa L. One introgression line (IR65482-4-136-2-2), resistant to biotypes 1, 2, and 3 of BPH and early in flowering, was selected from BC2F4 of the cross between O. sativa (IR31917-45-3-2) and O. australiensis (accession 100882). Recurrent parent, O. australiensis, and introgression line were surveyed for RFLP using probes of chromosomes 10 and 12. Two probes, RG457 and CDO98, detected introgression from O. australiensis. Cosegregation between introgressed characters and molecular markers was studied in F2 derived from the cross between the introgression line and recurrent parent. The gene for BPH resistance is linked with RG457 of chromosome 12 at a distance of 3.68 ± 1.29 cM, and the gene for earliness is linked with CDO98 of chromosome 10 at a distance of 9.96 ± 3.28 cM. Such close linkage is useful in marker-based selection while transferring BPH resistance from introgression line into other elite breeding lines. Introgression at the molecular level indicates that the mechanism of alien gene transfer is probably genetic recombination through crossing over rather than substitution of whole or large segment of chromosomes of wild species.Key words: molecular tagging, alien gene introgression, rice, wild species, brown planthopper resistance.

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Characteristics of Progeny Obtained from the Cross between Geraniums (Pelargonium^|^times;hortorum) and Wild Species in Section Ciconium, Including Heat Tolerance and Odor of Leaves

Environment Control in Biology ◽

10.2525/ecb.52.37 ◽

2014 ◽

Vol 52 (1) ◽

pp. 37-43

Author(s):

Kana HONDO ◽

Chikage IWASAKA ◽

Fumika KAKIHARA

Keyword(s):

Heat Tolerance ◽

Wild Species ◽

The Cross

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INHERITANCE STUDIES OF SEVERAL QUALITATIVE AND QUANTITATIVE CHARACTERS IN SPRING WHEAT CROSSES BETWEEN VARIETIES RELATIVELY SUSCEPTIBLE AND RESISTANT TO DROUGHT

Canadian Journal of Research ◽

10.1139/cjr36c-028 ◽

1936 ◽

Vol 14c (10) ◽

pp. 368-385 ◽

Cited By ~ 5

Author(s):

J. H. Torrie

Keyword(s):

Grain Yield ◽

Plant Height ◽

Transgressive Segregation ◽

Strong Positive Correlation ◽

Genetic Studies ◽

Partial Dominance ◽

Significant Relationships ◽

Quantitative Characters ◽

The Cross ◽

Made In

Genetic studies were made in the F2 and F3 generations of the crosses, Selection I-28-60 × Milturum, Reward × Caesium, and Caesium × Marquis. It was found that the character glume color was controlled by either one or two factor pairs in the cross Selection I-28-60 × Milturum, and by two factor pairs in the crosses Reward × Caesium and Caesium × Marquis. The characters, awning, straw color, glume pubescence and spike regularity were each governed by one factor pair, while three factor pairs were operative in the inheritance of seed color.Polymeric factors apparently control the inheritance of the quantitative characters straw strength, plant height, earliness and grain yield. A partial dominance of strong straw and earliness was found in the crosses Reward × Caesium and Caesium × Marquis. Tallness and low grain yield were partially dominant in the cross Reward × Caesium. Evidence for transgressive segregation of earliness was obtained in the cross between Caesium and Marquis.The characters glume color, awning, straw color, glume pubescence and spike regularity were inherited independently. White straw color and earliness were definitely associated in the crosses Reward × Caesium and Caesium × Marquis. The characters straw color and plant height were loosely linked in the Caesium × Marquis cross. Grain yield was not significantly correlated with straw strength, plant height or earliness in the cross between Reward and Caesium. Small but significant relationships were found among the characters straw strength, plant height and earliness in the crosses Reward × Caesium and Caesium × Marquis. The relation between heading and maturity was studied only in the F4 of Reward × Caesium, in which case a strong positive correlation was obtained.

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Nonlinear Developmental Processes as Sources of Dominance

Genetics ◽

10.1093/genetics/159.1.423 ◽

2001 ◽

Vol 159 (1) ◽

pp. 423-432

Author(s):

Michael A Gilchrist ◽

H Fredrik Nijhout

Keyword(s):

Genetic Variation ◽

Metabolic Pathways ◽

Developmental Process ◽

Nonlinear Process ◽

Nonlinear Relationship ◽

Developmental Processes ◽

Developmental Mechanism ◽

Dominance Relationships ◽

Threshold Mechanism ◽

New Mutations

Abstract Phenotypes are the products of developmental processes whose dynamics are controlled by genes. In many developmental processes there is a nonlinear relationship between genetic variation and phenotypic variation. These nonlinear relationships can result in the emergence of dominance among alleles that control the developmental process. We explore the properties of dominance relationships in a simple developmental system consisting of a diffusion-gradient-threshold mechanism commonly deployed in pattern formation. We show that a single nonlinear process (diffusion) within this integrated mechanism leads to the emergence of dominance in all components of the mechanism. Unlike the situation in metabolic pathways, where new mutations are most likely to be recessive, the structure of the nonlinearities in this developmental mechanism is such that in certain circumstances new mutations are equally likely to be dominant or recessive. Although the dominance we observe in this system is the result of a physiological process, we also find that dominance can evolve by microevolutionary mechanisms and thus are able to reconcile the opposing views of Fisher and Wright on dominance.

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MARGINAL OVERDOMINANCE IN DROSOPHILA

Genetics ◽

10.1093/genetics/81.1.177 ◽

1975 ◽

Vol 81 (1) ◽

pp. 177-189 ◽

Cited By ~ 1

Author(s):

Christopher Wills

Keyword(s):

Genetic Variation ◽

General Model ◽

Partial Dominance

ABSTRACT A reanalysis of Drosophila viability data was undertaken to determine the role of genotype-environment interactions in the maintenance of polymorphism. Between-replicate variances of viabilities in chromosomal homozygotes and heterozygotes with the same mean fitnesses were compared, with the expectation that if the heterozygote variance were on the average greater, conditional overdominance would be prevalent; if it were less, partial dominance would be prevalent; and if it were the same, marginal overdominance of the type considered by Wallace (1968) would be the prevalent type of variation. In fact, heterozygote variance was slightly less. The work of Dempster (1955) and of Gillespie and Langley (1974) is cited to show that this situation can still lead to balanced polymorphisms. Their general model for genetic variation in populations, consistent with the viability data, is reinforced.

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Inheritance of Abaxial Leaf Pubescence in Beans

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.115.1.158 ◽

1990 ◽

Vol 115 (1) ◽

pp. 158-160 ◽

Cited By ~ 10

Author(s):

Haytham Z. Zaiter ◽

Dermot P. Coyne ◽

James R. Steadman ◽

James S. Beaver

Keyword(s):

Genetic Variation ◽

Phaseolus Vulgaris ◽

Dominican Republic ◽

Quantitative Trait ◽

Major Gene ◽

Trichome Density ◽

Leaf Pubescence ◽

Dry Bean ◽

The Cross

Genetic variation for abaxial leaf pubescence was detected among dry bean (Phaseolus vulgaris L.) cultivars/lines. Inheritance of pubescence (long, straight hairs) was studied in the dry bean crosses of pubescent `Pompadour Checa-50' (Dominican Republic) × eight glabrous cultivars/lines. Segregation for pubescence vs. glabrousness indicated that pubescence was determined by a single major gene or by duplicate recessive epistatic genes, depending on the cross involved. Trichome density (number trichomes per mm) was a quantitative trait. Thus, pubescence was a discrete trait, but trichome density ranged from low to high.

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