RECOMBINATION AT THE Ml-a LOCUS IN BARLEY CONDITIONING RESISTANCE TO ERYSIPHE GRAMINIS F. SP. HORDEI

1972 ◽  
Vol 14 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J. Helms Jørgensen ◽  
J. G. Moseman
Keyword(s):  
Resistance Genes ◽  
Erysiphe Graminis ◽  
Coupling Phase ◽  
Test Cross ◽  
Recessive Genes ◽  
Recombination Percentage

Attempts were made to recombine the dominant or semidominant resistance genes Ml-a, Ml-a3, Ml-a8 and Ml-a9 from the barley varieties Algerian Ricardo, Heil's Hanna and Monte Cristo, respectively. No recombinants with two resistance genes in the coupling phase were found in a total of 3117 test-cross seedlings from four crosses studied. The true recombination percentages between the genes Ml-a/Ml-a3, Ml-a/Ml-a8, Ml-a/Ml-a9 and Ml-a8/Ml-a9 are between zero and 0.5. One possible recombinant susceptible to Erysiphe graminis f. sp. hordei suggests that the recombination percentage between the recessive genes ml-a/ml-a8 is 0.083.

scholarly journals Improved Selection with Newly Identified RAPD Markers Linked to Resistance Gene to Four Pathotypes of Colletotrichum lindemuthianum in Common Bean

1999 ◽  
Vol 89 (4) ◽  
pp. 281-285 ◽  
Author(s):  
Ana Lilia Alzate-Marin ◽  
Henrique Menarim ◽  
Geraldo Assis de Carvalho ◽  
Trazilbo José de Paula ◽  
Everaldo Gonçalves de Barros ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Resistance Genes ◽  
Rapd Markers ◽  
Single Gene ◽  
Colletotrichum Lindemuthianum ◽  
Susceptible Cultivar ◽  
Coupling Phase ◽  
Repulsion Phase ◽  
Complex Locus ◽  
Two Populations

Three F2 populations derived from crosses between the resistant cultivar AB 136 and the susceptible cultivar Michelite (MiA), and one F2 population derived from a cross between AB 136 and Mexico 222 (MeA), were used to identify markers linked to anthracnose resistance genes present in cultivar AB 136. Primer OPZ04 produced a DNA band (OPZ04560) linked in coupling phase to the resistance gene for pathotype 89 (8.5 ± 0.025 cM) in one population derived from the cross MiA. In the same population, primer OPZ09 produced one band (OPZ09950) linked in repulsion phase (20.4 ± 0.014 cM) to the same resistance gene. The simultaneous use of markers in coupling and in repulsion phases allowed the identification of the three genotypic classes. In the other two populations from cross MiA, OPZ04560 was linked in coupling phase to resistance genes for pathotypes 73 (2.9 ± 0.012 cM) and 81 (2.8 ± 0.017 cM). In population MeA, OPZ04560 was linked in coupling phase (7.5 ± 0.033 cM) to resistance to pathotype 64. These data suggest that a single gene or complex locus of linked resistance genes present in cultivar AB 136 confers resistance to all four pathotypes of C. lindemuthianum.

Linkage analysis of open bud (ob2) and yellow petal (Y1) in cotton

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 461-463 ◽  
Author(s):  
J. E. Endrizzi ◽  
D. T. Ray
Keyword(s):  
Linkage Group ◽  
Recombination Frequency ◽  
The Other ◽  
Linkage Groups ◽  
Chromosome 18 ◽  
Gossypium Hirsutum L ◽  
Recessive Genes ◽  
Yellow Petal ◽  
Dominant Genes ◽  
Recombination Percentage

In allotetraploid Gossypium species yellow petal is controlled by duplicate dominant genes Y1 (Ah genome) and Y2 (Dh genome), and open bud is controlled by duplicate recessive genes designated ob1 (Dh genome) and ob2 (Ah genome). Y2 and ob1 have been shown previously to be linked on chromosome 18 and 11.5 map units (MU) apart. In this study ob2 and Y1 were transferred from Gossypium darwinii (Watt) accession CB3099 into Gossypium hirsutum L. and found to have a mean recombination percentage of 3.14 for backcross and 3.40 for self-pollinated families from 2n parental heterozygotes and 10.73 in families from mono-18 parental heterozygotes. The lower recombination frequency in the homoeologous linkage group was perhaps due to this chromosome segment being transferred from G. darwinii. The higher frequency of recombination in the monosomic progeny families suggests that the absence of recombination in one homoeologue (chromosome 18) is compensated for by an increase in recombination in the other homoeologue.Key words: cotton, G. hirsutum L., homoeologous linkage groups, genetic markers.

RFLP mapping of three new loci for resistance genes to powdery mildew (Erysiphe graminis f. sp. hordei) in barley

1996 ◽  
Vol 93-93 (1-2) ◽  
pp. 48-56 ◽  
Author(s):  
M. Schönfeld ◽  
A. Ragni ◽  
G. Fischbeck ◽  
A. Jahoor
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Erysiphe Graminis ◽  
Rflp Mapping

GENETICS OF SEED COLOR IN REED CANARYGRASS, Phalaris arundinacea L.

1987 ◽  
Vol 67 (4) ◽  
pp. 1051-1055 ◽  
Author(s):  
R. P. KNOWLES
Keyword(s):  
Phalaris Arundinacea ◽  
Seed Color ◽  
Reed Canarygrass ◽  
Yellow Seed ◽  
Test Cross ◽  
Disomic Inheritance ◽  
Recessive Genes

A yellow-seeded mutant of reed canarygrass was crossed with normal black-seeded plants and F2 and test-cross populations observed for seed color. Disomic inheritance was postulated with two recessive genes y1 and y2 being responsible for yellow seed color. Black-seeded plants were designated Y1Y1Y2Y2 although in two black-seeded plants one locus appeared heterozygous, i.e. Y1y1Y2Y2, thereby suggesting that the alleles for yellow seed may occur quite frequently in this species.Key words: Reed canarygrass, Phalaris arundinacea L., seed color, disomic inheritance, genetics

A new gene, developed through mutagenesis, for resistance of rice to bacterial leaf blight (Xanthomonas campestris pv. oryzae)

1990 ◽  
Vol 114 (2) ◽  
pp. 219-224 ◽  
Author(s):  
H. Nakai ◽  
K. Nakamura ◽  
S. Kuwahara ◽  
M. Saito
Keyword(s):  
Resistance Genes ◽  
Xanthomonas Campestris ◽  
Recessive Gene ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Thermal Neutrons ◽  
Single Recessive Gene ◽  
Recessive Genes ◽  
New Gene ◽  
Induced Mutant

SUMMARYAn induced mutant of rice, designated M41, resistant to several races of bacterial leaf blight, obtained after irradiation with thermal neutrons, was crossed with the original variety, Harebare. Test crosses revealed that the resistance of M41 to the Japanese races I, II, III and IV is controlled by a single recessive gene, considered to be different from four previously identified dominant resistance genes of japonica-type varieties and from three recessive genes in indica-type varieties for resistance to Philippine races. The gene in M41 was tentatively designated xa-nm(t).

scholarly journals The genetic background of resistance to common bacterial blight in newly identified common bean lines on the basis of inheritance studies

2000 ◽  
Vol 6 (1) ◽  
Author(s):  
E. Mergenthaler ◽  
Bisztray Gy.
Keyword(s):  
Common Bean ◽  
Genetic Background ◽  
Bacterial Blight ◽  
Xanthomonas Campestris ◽  
Resistance Breeding ◽  
Inheritance Of Resistance ◽  
Common Bacterial Blight ◽  
Phaseolus Vulgaris L ◽  
Coupling Phase ◽  
Recessive Genes

Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli (Xcp). is a major disease problem of common bean (Phaseolus vulgaris L.). The inheritance of resistance in Xrl and Xr2 lines to two isolates of Xcp was studied in the F2 and F3 popu­lations from the crosses between these lines and the Masay variety (susceptible to Xcp). Segregation patterns indicated that different single recessive genes presumably in coupling phase linkage determined the resistance to the HUN and EK-1 1 strains of Xcp in both lines. The presence of some minor, modifying genes beside the monogenic genetic background of resistance was also observed. Xrl and Xr2 lines represent valuable new monogenic genetic sources in resistance breeding to CBB.

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