The identification and characteristics of field resistance to lettuce downy mildew (Bremia lactucae Regel)

Crute, I. R.; Norwood, Judith M.

doi:10.1007/bf00038799

Cited by 36 publications

(19 citation statements)

References 8 publications

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“…Additionally, gene dosage affects the resistance phenotype of some Dm genes, for example Dm17 under high pathogen pressure (Maisonneuve et al 1994). Some lettuce cultivars such as Iceberg and Grand Rapids exhibit resistance at the adult plant stage in the field that cannot be attributed to Dm genes (Milbrath 1923;Verhoeff 1960;Crute and Norwood 1981). This quantitative resistance phenotype (Norwood and Crute 1985;Grube and Ochoa 2005) has so far been shown to be inherited polygenically (Simko et al 2013); transgressive segregation resulting in elevated resistance has been observed in progeny from cvs.…”

Section: Genetics Of Resistance and Nomenclature Of Resistance Genesmentioning

confidence: 99%

Rationalization of genes for resistance to Bremia lactucae in lettuce

Parra¹,

Maisonneuve²,

Lebeda³

et al. 2016

Euphytica

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Lettuce downy mildew caused by Bremia lactucae is the most important disease of lettuce worldwide. Breeding for resistance to this disease is a major priority for most lettuce breeding programs. Many genes and factors for resistance to B. lactucae have been reported by multiple researchers over the past *50 years. Their nomenclature has not been coordinated, resulting in duplications and gaps in nominations. We have reviewed the available information and rationalized it into 51 resistance genes and factors and 15 quantitative trait loci along with supporting documentation as well as genetic and molecular information. This involved multiple rounds of consultation with many of the original authors. This paper provides the foundation for naming additional genes for resistance to B. lactucae in the future as well as for deploying genes to provide more durable resistance. Keywords

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Section: Genetics Of Resistance and Nomenclature Of Resistance Genesmentioning

confidence: 99%

Rationalization of genes for resistance to Bremia lactucae in lettuce

Parra¹,

Maisonneuve²,

Lebeda³

et al. 2016

Euphytica

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“…Quantitative resistance has been documented in several lettuce cultivars202122 that typically become infected with most races of the pathogen but the lesions are small and sporulation is limited. Often this phenotype is more evident in adult plants and hence its designation as adult plant, partial, or field resistance.…”

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confidence: 99%

“…Cv. Iceberg was introduced to the U.S. from Europe in 1894, but its synonyms were mentioned in European catalogues as early as 177120. Resistance to downy mildew in these cultivars appears to be durable as it was reported in Grand Rapids at least 50+ years ago26 and in Iceberg over 90 years ago27, although their lack of recent use has reduced their exposure to sustained selection for virulent races of the pathogen.…”

mentioning

confidence: 99%

Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce

Šimko

Atallah

Ochoa

et al. 2013

Sci Rep

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Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids.

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“…Hence, reduced Bremia-susceptibility in the field may partially be explained by the respective "strong" leaf structure of fully developed plants (Crute and Norwood, 1980). In the present investigation, however, overall leaf structure of both butterhead and batavia-type seedlings in their early stage of development may not be very different; in contrast, photosynthetic responses to Bremia-infection clearly are.…”

Section: Discussionmentioning

confidence: 86%

“…Indeed, it has been shown that batavia-type cultivars in field studies were less susceptible against Bremia infections than those of butterhead lettuce (Crute and Norwood, 1980), where batavia cultivars are described as crisp lettuce types. Hence, reduced Bremia-susceptibility in the field may partially be explained by the respective "strong" leaf structure of fully developed plants (Crute and Norwood, 1980).…”

Section: Discussionmentioning

confidence: 99%