Theoretical and Applied Genetics

, Volume 103, Issue 5, pp 710–717

’Forrest’ resistance to the soybean cyst nematode is bigenic: saturation mapping of the Rhg1and Rhg4 loci

  • K. Meksem
  • P. Pantazopoulos
  • V.N. Njiti
  • L.D. Hyten
  • P. R. Arelli
  • D. A. Lightfoot

Abstract  

Field resistance to cyst nematode (SCN) race 3 (Heterodera glycines I.) in soybean [Glycine max (L.) Merr.] cv ’Forrest’ is conditioned by two QTLs: the underlying genes are presumed to include Rhg1 on linkage group G and Rhg4 on linkage group A2. A population of recombinant inbred lines (RILs) and two populations of near-isogenic lines (NILs) derived from a cross of Forrest×Essex were used to map the loci affecting resistance to SCN. Bulked segregant analysis, with 512 AFLP primer combinations and microsatellite markers, produced a high-density genetic map for the intervals carrying Rhg1 and Rhg4. The two QTLs involved in resistance to SCN were strongly associated with the AFLP marker EATGMCGA87 (P=0.0001, R2=24.5%) on linkage group G, and the AFLP marker ECCGMAAC405 (P=0.0001, R2 =26.2%) on linkage group A2. Two- way analysis of variance showed epistasic interaction (P=0.0001, R2 =16%) between the two loci controlling SCN resistance in Essex×Forrest recombinant inbred lines. Considering the two loci as qualitative genes and the resistance as female index FI <5%, jointly the two loci explained over 98% of the resistance. The locations of the two QTLs were confirmed in the NILs populations. Therefore SCN resistance in Forrest×Essex is bigenic. High-efficiency marker-assisted selection can be performed using the markers to develop cultivars with stable resistance to SCN.

Keywords  Soybean cyst nematode AFLP High-resolution genetic mapping Marker assisted breeding Rhg1 Rhg4 Qualitative mapping 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • K. Meksem
    • 1
  • P. Pantazopoulos
    • 1
  • V.N. Njiti
    • 1
  • L.D. Hyten
    • 1
  • P. R. Arelli
    • 2
  • D. A. Lightfoot
    • 1
  1. 1.Department of Plant Soil and General Agriculture, Center for Excellence in Soybean Research, Teaching and Outreach, Southern Illinois University at Carbondale, Room 176. Carbondale, IL 62901-4415, USA e-mail: meksemk@siu.edu http://www.siu.edu/∼pbgc Fax: 618-453-7457US
  2. 2.Department of Agronomy, 104 Curtis Hall. University of Missouri, Columbia, MO 65211, USAUS

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