Original Paper

Theoretical and Applied Genetics

, Volume 113, Issue 4, pp 661-671

First online:

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

  • Bruno StuderAffiliated withAgroscope Reckenholz-Tänikon Research Station ART
  • , Beat BollerAffiliated withAgroscope Reckenholz-Tänikon Research Station ART
  • , Doris HerrmannAffiliated withAgroscope Reckenholz-Tänikon Research Station ART
  • , Eva BauerAffiliated withState Plant Breeding Institute, University of Hohenheim
  • , Ulrich K. PosseltAffiliated withState Plant Breeding Institute, University of Hohenheim
  • , Franco WidmerAffiliated withAgroscope Reckenholz-Tänikon Research Station ART
  • , Roland KöllikerAffiliated withAgroscope Reckenholz-Tänikon Research Station ART Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


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.


Disease resistance Linkage mapping Lolium multiflorum Quantitative trait loci (QTL) Xanthomonas translucens pv. graminis