Theoretical and Applied Genetics

, Volume 94, Issue 1, pp 75–82

Mapping of two genes for resistance to clubroot (Plasmodiophora brassicae) in a population of doubled haploid lines of Brassica oleracea by means of RFLP and AFLP markers

  • R. E. Voorrips
  • M. C. Jongerius
  • H. J. Kanne
Article

DOI: 10.1007/s001220050384

Cite this article as:
Voorrips, R.E., Jongerius, M.C. & Kanne, H.J. Theoret. Appl. Genetics (1997) 94: 75. doi:10.1007/s001220050384

Abstract

A genetic map covering 615 cM in 12 linkage groups was assembled based on 92 RFLP and AFLP markers segregating in a population of 107 doubled haploid lines (DH lines) of Brassica oleracea. The DH-line population was obtained through microspore culture from the F1 of two homozygous parents: DH-line Bi derived from the cabbage landrace Bindsachsener, and DH-line Gr from broccoli cv ‘Greenia’. Sixty-five percent of the loci, and in some cases complete linkage groups, displayed distorted segregation ratios, a frequency much higher than that observed in F2 populations of the same species. DH-line Bi was resistant to clubroot, which is caused by a Dutch field isolate of Plasmodiophora brassicae. Resistance in the DH-line population was determined in two ways: by assigning symptom grades to each plant, and by measuring the fresh weights of the healthy and affected parts of the root system of each plant. Using a multiple QTL mapping approach to analyze the fresh weight data, we found two loci for clubroot resistance; these were designated pb-3 and pb-4. The additive effects of these loci were responsible for 68% of the difference between the parents and for 60% of the genetic variance among DH-line means. Also, indications for the presence of two additional, minor QTLs were found. Analysis of symptom grades revealed the two QTLs pb-3 and pb-4, as well as one of the two minor QTLs indicated by analysis of the fresh weight data.

Key words

Microspore cultureQuantitative trait locus (QTL)Multiple QTL models (MQM)

Abbreviations

AFLP

Amplified fragment length polymorphism

DH line

doubled haploid line

MQM

multiple QTL model

RFLP

restriction fragment length polymorphism

QTL

quantitative trait locus

Copyright information

© Springer-Verlag 1997

Authors and Affiliations

  • R. E. Voorrips
    • 1
  • M. C. Jongerius
    • 1
  • H. J. Kanne
    • 1
  1. 1.Department of Vegetable and Fruit CropsDLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO)WageningenThe Netherlands