Theoretical and Applied Genetics

, Volume 113, Issue 4, pp 661–671

Genetic mapping reveals a single major QTL for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.)

  • Bruno Studer
  • Beat Boller
  • Doris Herrmann
  • Eva Bauer
  • Ulrich K. Posselt
  • Franco Widmer
  • Roland Kölliker
Original Paper

DOI: 10.1007/s00122-006-0330-2

Cite this article as:
Studer, B., Boller, B., Herrmann, D. et al. Theor Appl Genet (2006) 113: 661. doi:10.1007/s00122-006-0330-2

Abstract

Bacterial wilt caused by Xanthomonas translucens pv. graminis (Xtg) is a major disease of economically important forage crops such as ryegrasses and fescues. Targeted breeding based on seedling inoculation has resulted in cultivars with considerable levels of resistance. However, the mechanisms of inheritance of resistance are poorly understood and further breeding progress is difficult to obtain. This study aimed to assess the relevance of the seedling screening in the glasshouse for adult plant resistance in the field and to investigate genetic control of resistance to bacterial wilt in Italian ryegrass (Lolium multiflorum Lam.). A mapping population consisting of 306 F1 individuals was established and resistance to bacterial wilt was assessed in glasshouse and field experiments. Highly correlated data (r = 0.67–0.77, P < 0.01) between trial locations demonstrated the suitability of glasshouse screens for phenotypic selection. Analysis of quantitative trait loci (QTL) based on a high density genetic linkage map consisting of 368 amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers revealed a single major QTL on linkage group (LG) 4 explaining 67% of the total phenotypic variance (Vp). In addition, a minor QTL was observed on LG 5. Field experiments confirmed the major QTL on LG 4 to explain 43% (in 2004) to 84% (in 2005) of Vp and also revealed additional minor QTLs on LG 1, LG 4 and LG 6. The identified QTLs and the closely linked markers represent important targets for marker-assisted selection of Italian ryegrass.

Keywords

Disease resistanceLinkage mappingLolium multiflorumQuantitative trait loci (QTL)Xanthomonas translucens pv. graminis

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Bruno Studer
    • 1
  • Beat Boller
    • 1
  • Doris Herrmann
    • 1
  • Eva Bauer
    • 2
  • Ulrich K. Posselt
    • 2
  • Franco Widmer
    • 1
  • Roland Kölliker
    • 1
  1. 1.Agroscope Reckenholz-Tänikon Research Station ARTZurichSwitzerland
  2. 2.State Plant Breeding InstituteUniversity of HohenheimStuttgartGermany