New wild Lactuca genetic resources with resistance against Bremia lactucae

Alex Beharav, Dalia Lewinsohn, Aleš Lebeda, Eviatar Nevo

Research output: Contribution to journalArticlepeer-review


A total of 1027 genotypes of wild Lactuca spp. (L. serriola, L. saligna, and L. aculeata), originating from Israel, Jordan, East Turkey, Armenia, Kazakhstan, China, and various other countries in Europe were screened for resistance to the lettuce downy mildew (Bremia lactucae Regel). The genotypes of L. serriola (N = 962); L. saligna (N = 43); and L. aculeata (N = 22) were tested at the seedling stage with two isolates of B. lactucae (race Bl-21 and Isr-74) isolated from cultivated lettuce in Italy and Israel, respectively. Altogether, the isolates possess virulence against 17 out of 20 Dm genes/R-factors composing the established differential set of lettuce lines/varieties. They could therefore be used for preliminary detection of the presence of new resistance factors. A total of 83 and three genotypes of L. serriola and L. saligna, respectively, were resistant to infection by each of the two isolates alone as well as to the infection by a mix of the two isolates. These genotypes probably carry previously unknown resistance, and therefore could be suitable for exploitation by breeders and further detailed research. The wild progenitor of lettuce, L. serriola, and related species harbor significant untapped genetic resources for lettuce improvement.

Original languageEnglish
Pages (from-to)467-474
Number of pages8
JournalGenetic Resources and Crop Evolution
Issue number3
StatePublished - May 2006

Bibliographical note

Funding Information:
The Israel Ministry of Science, grant no. 2132, the financial support of the Israel Discount Bank Chair of Evolutionary Biology, and the Ancell Teicher Foundation for Molecular Genetics and Evolution supported this research. The authors wish to thank Dr. David Netzer for his advice, Ms. Souad Khalifa, Ms. Naela Meladi, and Ms. Lora Mhawesh for their technical assistance.


  • Bremia lactucae
  • Genetic diversity
  • Lettuce downy mildew
  • Lettuce improvement
  • Plant genetic resources
  • Race-specificity
  • Sources of resistance
  • Wild lettuce
  • lactucea spp.

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Agronomy and Crop Science
  • Genetics
  • Plant Science


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