Inheritance of resistance against Phytophthora infestans in Lycopersicon pimpenellifolium L3707

Euphytica ◽  
2006 ◽  
Vol 149 (3) ◽  
pp. 309-316 ◽  
Author(s):  
Irit Irzhansky ◽  
Yigal Cohen
1944 ◽  
Vol 61 (1) ◽  
pp. 137-147 ◽  
Author(s):  
William Black

The existence in Mexico of blight-resistant species of potato has been known for many years, but they occur in the wild and are quite unsuitable for agricultural purposes. In order to utilise their resistance to disease it is necessary to combine disease resistance with the cropping qualities of cultivated forms while eliminating the undesirable characters which are prominent in the wild forms. Breeding work with this object in view has been in progress at the Scottish Plant Breeding Station for several years, and results obtained in the course of testing progenies for reaction to blight infection are discussed in the following pages.


1951 ◽  
Vol 64 (3) ◽  
pp. 312-352 ◽  
Author(s):  
William Black

SynopsisThe common strain and six specialised strains of Phytophthora infestans have been employed in testing potato varieties and seedling progenies bred from the wild species S. demissum for resistance to the disease. Resistance, due to the hypersensitive condition of the protoplasm, is manifested in the presence of major genes, and four such genes have been identified, viz. R1, R2, R3 and R4. Each gene induces in the plant a hypersensitive response to infection with the common strain and with a particular group of specialised strains of the parasite. The genes are inherited independently in simple Mendelian fashion, but in the segregations three different types of deviations from standard disomic ratios occur due to (a) unpaired chromosomes, (b) incompatibility factors, and (c) partial autosyndesis. A series of minor genes modify the phenotypic expression of the major gene system and so differentiate grades of hypersensitivity or of susceptibility as the case may be.The common strain of P. infestans appears to be a population persisting at an equilibrium determined by host range and environmental conditions. Mutations frequently occur, but new forms survive only when host genotypes, to which they are specially adapted, are available.


2014 ◽  
Vol 66 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Jadwiga Śliwka ◽  
Iga Tomczyńska ◽  
Marcin Chmielarz ◽  
Emil Stefańczyk ◽  
Renata Lebecka ◽  
...  

AbstractSolanum nigrumis a self-pollinating, hexaploid weed and one of a fewSolanaceaespecies native to Europe. It used to be described as a non-host forPhytophthora infestans. However, now it is known that, like its distant relatives: potato (Solanum tuberosumL.) and tomato (Solanum lycopersicumL.),S. nigrumcan suffer from potato late blight caused by this pathogen. Both susceptible and resistantS. nigrumgenotypes have been previously identified and inheritance of resistance originating from one accession has been described based on population of F2plants and 15 F3lines. The goal of this study was to evaluate resistance of three families of F3lines, originating from crosses between a susceptible and three different resistantS. nigrumaccessions followed by two self-pollinations. Parental accessions were tested for the spectrum of late blight resistance against 48P. infestansisolates. The three families consisted of 106, 96 and 115 F3lines, respectively, and from each line 20 plants were tested for resistance toP. infestans. Laboratory detached leaf assays were performed in two dates and two replications of three leaves each. Segregation of the trait within the line allowed us to distinguish hetero- and homozygous lines. In one F3family, the ratio of resistant homozygotes: heterozygotes: susceptible homozygotes was 1:2:1, indicating that a single gene is most likely underlying the late blight resistance in this case. In the other two, observed segregations of the trait significantly deviated from this model suggesting more complex inheritance patterns.


1950 ◽  
Vol 64 (2) ◽  
pp. 216-228 ◽  
Author(s):  
William Black

SynopsisThe common strain A of the blight fungus (Phytophthora infestans) and two new strains, B and C, have been employed in testing potato varieties and seedling progenies, bred from the wild species S. demissum, for resistance to the disease. The reactions of seedlings to infection with strain C are compared with those of strains A and B. The C strain is shown to be more virulent than A, since it attacks some A resistant as well as all A susceptible plants. Likewise the B strain is more virulent than A. The difference between the pathogenicity of strains B and C, however, is not one of degree of virulence; one plant may be B resistant-C susceptible, while another may be B susceptible-C resistant. This difference is essentially of a qualitative nature. Resistance to these strains, which is manifested by the hypersensitive condition of the plant's cells, is produced in the presence of three major independent genes, Re, Rb and Rbc, which confer resistance to strains A and C, A and B, and A, B and C respectively. Segregations in each case are similar in type, and are characterised by an excess of recessive individuals.


1949 ◽  
Vol 63 (3) ◽  
pp. 290-301 ◽  
Author(s):  
William Black

Previous reports (Black, 1943, 1945) on the resistance of potatoes to the blight fungus (Phytophthora infestans) have shown the existence of at least two major genetic factors (Ra and Rb) in the host, and the occurrence of not less than two strains (A and B) of the pathogen.From the studies then reported, it was concluded that the two genes had been brought into the potato from different phyletic sources and that one, Ra, when in the dominant state, conferred resistance to strain A, while similarly Rb conferred resistance to strain B.


Euphytica ◽  
2006 ◽  
Vol 155 (1-2) ◽  
pp. 183-191 ◽  
Author(s):  
Raj Kumar ◽  
G. S. Kang ◽  
S. K. Pandey

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