Inheritance of resistance to Phytophthora infestans in two diploid Mexican solanum species

Euphytica ◽  
1963 ◽  
Vol 12 (1) ◽  
pp. 35-40 ◽  
Author(s):  
K. M. Graham
2020 ◽  
Vol 148 ◽  
pp. 103475 ◽  
Author(s):  
Ramesh R. Vetukuri ◽  
Laura Masini ◽  
Rebecca McDougal ◽  
Preeti Panda ◽  
Levine de Zinger ◽  
...  

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.


1998 ◽  
Vol 88 (2) ◽  
pp. 137-143 ◽  
Author(s):  
Robert W. Sandrock ◽  
Hans D. VanEtten

α-Tomatine, synthesized by Lycopersicon and some Solanum species, is toxic to a broad range of fungi, presumably because it binds to 3β-hydroxy sterols in fungal membranes. Several fungal pathogens of tomato have previously been shown to be tolerant of this glycoalkaloid and to possess enzymes thought to be involved in its detoxification. In the current study, 23 fungal strains were examined for their ability to degrade α-tomatine and for their sensitivity to this compound and two breakdown products, β2-tomatine and tomatidine. Both saprophytes and all five non-pathogens of tomato tested were sensitive, while all but two tomato pathogens (Stemphylium solani and Verticillium dahliae) were tolerant of α-to-matine (50% effective dose > 300 μM). Except for an isolate of Botrytis cinerea isolated from grape, no degradation products were detected when saprophytes and nonpathogens were grown in the presence of α-tomatine. All tomato pathogens except Phytophthora infestans and Pythium aphani-dermatum degraded α-tomatine. There was a strong correlation between tolerance to α-tomatine, the ability to degrade this compound, and pathogenicity on tomato. However, while β2-tomatine and tomatidine were less toxic to most tomato pathogens, these breakdown products were inhibitory to some of the saprophytes and nonpathogens of tomato, suggesting that tomato pathogens may have multiple tolerance mechanisms to α-tomatine.


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.


Plant Disease ◽  
1997 ◽  
Vol 81 (3) ◽  
pp. 311-311 ◽  
Author(s):  
P. J. Oyarzun ◽  
M. E. Ordoñes ◽  
G. A. Forbes ◽  
W. E. Fry

The tropical highlands of Ecuador are a genetic center for several Solanaceous species, including potato. In 1995 and 1996, severe late blight epidemics occurred in wild Solanum species, e.g., Solanum brevifolium, growing in the transitional area between the highlands and the coastal tropical lowlands near the city of Quito. Sixteen isolates of Phytophthora infestans were collected in 1995 and 36 isolates in 1996. Of these, three from 1995 and four from 1996 were A2 mating type. Extensive and systematic sampling of commercial potato and tomato in Ecuador have failed to reveal the presence of the A2 mating type (G. A. Forbes, X. M. Escobar, C. C. Ayala, J. Revelo, M. E. Ordoñez, B. A. Fry, K. Doucet, and W. E. Fry, Phytopathology, in press.). Apparently the A2 mating type reported for the first time in Ecuador is only associated with wild Solanaceous spp. Further research is required to determine the consequences of this event for management of late blight in both potato and tomato, two important field crops in the Andean highlands.


2007 ◽  
Vol 164 (10) ◽  
pp. 1268-1277 ◽  
Author(s):  
Lidia Polkowska-Kowalczyk ◽  
Bernard Wielgat ◽  
Urszula Maciejewska

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