Ronald G. van den Berg

Publications (3)4.85 Total impact

• Article: Role of Solanum dulcamara L. in Potato Late Blight Epidemiology

  Tomek M. Golas, Gerard M. van der Weerden, Ronald G. van den Berg, Celestina Mariani, J. J. H. M. Allefs
  [show abstract] [hide abstract]
  ABSTRACT: Four sites with naturally growing Solanum dulcamara were surveyed during 2006 and 2007 for the presence of late blight. Despite 2years of observations, no late blight was detected among natural populations of bittersweet. Nevertheless, repeated infections occurred on few S. dulcamara plants from a collection growing in a botanical garden in the same years. These plants were used to investigate the possibility of survival of the inoculum between seasons. In the respective years, a set of 21 and 52 S. dulcamara accessions inoculated with Phytophthora infestans under field conditions resulted in a wide range of responses to the disease. More susceptible reactions were found among genotypes collected at greater distance from commercial potato fields indicating the possibility of genetic selection caused by P. infestans. However, both scarceness of natural infections and no overwintering, suggest that bittersweet may not play a role in late blight epidemiology. Keywords Phytophthora infestans -Potato epidemiology- Solanum dulcamara (bittersweet)
  Potato Research 04/2012; 53(1):69-81.
• Article: Genetic diversity of the African hexaploid species Solanum scabrum Mill. and Solanum nigrum L. (Solanaceae)

  Mkabwa L. K. Manoko, Ronald G. van den Berg, Richard M. C. Feron, Gerard M. van der Weerden, Celestina Mariani
  [show abstract] [hide abstract]
  ABSTRACT: Two hexaploid species of Solanum sect. Solanum are present in Africa: Solanum scabrum and S. nigrum. Solanum scabrum is a widely cultivated species and is used as a leafy vegetable, as a source of medicine and as a source of ink dye. In previous studies a wide range of morphological diversity has been reported in this species and in some studies subspecies have been proposed. Subspecies are also recognized in S. nigrum. However, it has not been established whether or not the morphological differences are reflected at the genomic level. The present study applies AFLPs to study the genetic diversity in S. scabrum and its relationship to geographical provenance, morphological differences and the possible existence of subspecies within S. scabrum and S. nigrum. The data obtained were analyzed with cluster analysis (using UPGMA and NJ). The results indicate that the genetic variation within S. scabrum was higher within accessions than between accessions. Accessions did not cluster according to their geographical provenance, indicating that accessions from different geographical areas were not significantly different genetically. The clustering reflected neither morphological differences nor domestication status (cultivated or wild). The morphological differences exhibited by S. scabrum could be due to selection by farmers for different plant types. The AFLP derived clustering pattern did not segregate the subspecies recognized in S. scabrum and S. nigrum into separate subclusters.
  Genetic Resources and Crop Evolution 04/2012; 55(3):409-418. · 1.55 Impact Factor
• Source

  Available from: PubMed Central

  Article: Identification of a resistance gene Rpi-dlc1 to Phytophthora infestans in European accessions of Solanum dulcamara.

  Tomasz Michal Golas, Anne Sikkema, Jack Gros, Richard M C Feron, Ronald G van den Berg, Gerard M van der Weerden, Celestina Mariani, J J H M Allefs
  [show abstract] [hide abstract]
  ABSTRACT: Initial screening of 14 Solanum dulcamara accessions enabled the identification of individuals resistant and susceptible to Phytophthora infestans. Crosses between contrasting genotypes resulted in three F(2)-BC(1) populations segregating for resistance to late blight in a laboratory assay and under field conditions. Genetic profiling of one of these populations using 128 AFLP primers generated three markers linked to the resistant phenotype. Blast analysis of the sequenced markers resulted in a plausible gene position on the distal end of the long arm of chromosome 9 that could be confirmed by CAPS markers. Thus, we describe a first resistant gene, named Rpi-dlc1, from S. dulcamara, a Solanum species native to Europe. In addition, one population was tested for broadness of resistance responses using a set of seven additional P. infestans isolates, varying in virulence. This indicated the possible presence of additional Rpi genes.
  Theoretical and Applied Genetics 11/2009; 120(4):797-808. · 3.30 Impact Factor